Updated examples to the latest version

For release, used in the report/presentation

README.md

@@ -1,3 +1,6 @@
 # JavaECS Examples.
 ## Demo 1
 Demo 1 implements a simple physics system
+
+### See the example run:
+![example 1](./content/example1/example1.webp)

demo1/.gitignore

@@ -26,3 +26,5 @@ buildNumber.properties
 .factorypath
 .project
 .vscode/
+
+*.jar

demo1/pom.xml

@@ -19,8 +19,8 @@
     <!-- JaCoCo thresholds. Increase gradually as you add tests. -->
     <jacoco.unit-tests.limit.instruction-ratio>0%</jacoco.unit-tests.limit.instruction-ratio>
     <jacoco.unit-tests.limit.branch-ratio>0%</jacoco.unit-tests.limit.branch-ratio>
-    <jacoco.unit-tests.limit.class-complexity>20</jacoco.unit-tests.limit.class-complexity>
-    <jacoco.unit-tests.limit.method-complexity>5</jacoco.unit-tests.limit.method-complexity>
+    <jacoco.unit-tests.limit.class-complexity>2100</jacoco.unit-tests.limit.class-complexity>
+    <jacoco.unit-tests.limit.method-complexity>1000</jacoco.unit-tests.limit.method-complexity>
   </properties>
   <dependencies>
     <dependency>
@@ -38,12 +38,12 @@
     <dependency>
       <groupId>nz.ac.massey.javaecs</groupId>
       <artifactId>javaecs</artifactId>
-      <version>0.9.2-PRERELEASE</version>
+      <version>1.0.1</version>
   </dependency>
   </dependencies>
   <build>
     <plugins>
-      <plugin>
+      <!-- <plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-enforcer-plugin</artifactId>
         <version>${maven-enforcer-plugin.version}</version>
@@ -93,8 +93,8 @@
             </goals>
           </execution>
         </executions>
-      </plugin>
-      <plugin>
+      </plugin> -->
+      <!--<plugin>
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
         <version>${maven-surefire-plugin.version}</version>
@@ -165,7 +165,7 @@
             </configuration>
           </execution>
         </executions>
-      </plugin>
+      </plugin> -->
     </plugins>
   </build>
   <reporting>
@@ -179,7 +179,7 @@
   </reporting>
   <profiles>
     <!-- Publish coverage report to Coveralls, only when running in Travis. -->
-    <profile>
+    <!-- <profile>
       <id>travis</id>
       <activation>
         <property>
@@ -195,6 +195,6 @@
           </plugin>
         </plugins>
       </build>
-    </profile>
+    </profile> -->
   </profiles>
 </project>

demo1/src/main/java/nz/ac/massey/javaecs/examples/App.java

@@ -1,10 +1,9 @@
 package nz.ac.massey.javaecs.examples;
 
-import java.sql.Time;
 import java.util.Random;
+import java.util.concurrent.Semaphore;
 
 import javafx.scene.paint.Color;
-import javafx.scene.text.Text;
 import nz.ac.massey.javaecs.*;
 import nz.ac.massey.javaecs.examples.Components.*;
 import nz.ac.massey.javaecs.examples.Systems.*;
@@ -16,14 +15,22 @@ public final class App {
     private App() {
     }
 
+    public static Semaphore rendererReadySemaphore = new Semaphore(0);
+
     /**
      * Simple physics simulation.
      * @param args The arguments of the program.
      * @throws InterruptedException
      */
     public static void main(String[] args) throws InterruptedException {
+        /************************************
+        **        Initialise engine        **
+        *************************************/
         Engine gameEngine = new Engine(16384);
 
+        /************************************
+        **    Register game components     **
+        *************************************/
         gameEngine.registerComponent(Gravity.class);
         gameEngine.registerComponent(RidgidBody.class);
         gameEngine.registerComponent(Vec2D.class);
@@ -35,6 +42,9 @@ public final class App {
         gameEngine.registerComponent(Reporter.class);
         gameEngine.registerComponent(TextRender.class);
 
+        /************************************
+        ** Register and initialise systems **
+        *************************************/
         PhysicsSystem physicsSystem = new PhysicsSystem(gameEngine);
         gameEngine.registerSystem(PhysicsSystem.class, physicsSystem);
         
@@ -45,7 +55,7 @@ public final class App {
         LogUpdateSystem logUpdateSystem = new LogUpdateSystem(gameEngine);
         gameEngine.registerSystem(LogUpdateSystem.class, logUpdateSystem);
 
-        RenderSystem renderSystem = new RenderSystem(gameEngine, 10.);
+        RenderSystem renderSystem = new RenderSystem(gameEngine, 5.);
         gameEngine.registerSystem(RenderSystem.class, renderSystem);
 
         ExistenceSystem existenceSystem =  new ExistenceSystem(gameEngine);
@@ -54,100 +64,108 @@ public final class App {
         ReportSystem reportSystem =  new ReportSystem(gameEngine);
         gameEngine.registerSystem(ReportSystem.class, reportSystem);
 
+
+
+        /************************************
+        **       Create known entities     **
+        *************************************/
         // Define a play area 100 * 100, make sure to use worldspace not screenspace (top left is 0, 100, not 0,0)
         // Bottom boundary
         Entity newEnt = gameEngine.createEntity();
         gameEngine.addComponent(newEnt, Vec2D.class, new Vec2D(-50., -50.,0));
-        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(0., 0., 0., 0., 0.f, 0., -1.));
+        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(0., 0., 0., 0., 0.f, 0.25, -1.));
         gameEngine.addComponent(newEnt, Collider.class, new Collider(200., 50.)); // 200 along, 50 up
         gameEngine.addComponent(newEnt, Render.class, new Render(BoxRender.class));
         gameEngine.addComponent(newEnt, BoxRender.class, new BoxRender(200, 50, 64, 64, 64));
         // Left boundary
         newEnt = gameEngine.createEntity();
         gameEngine.addComponent(newEnt, Vec2D.class, new Vec2D(-50., -50.,0));
-        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(0., 0., 0., 0., 0.f, 0., -1.));
+        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(0., 0., 0., 0., 0.f, 0.25, -1.));
         gameEngine.addComponent(newEnt, Collider.class, new Collider(50., 200.));
         gameEngine.addComponent(newEnt, Render.class, new Render(BoxRender.class));
         gameEngine.addComponent(newEnt, BoxRender.class, new BoxRender(50, 200, 64, 64, 64));
         // Top boundary
         newEnt = gameEngine.createEntity();
         gameEngine.addComponent(newEnt, Vec2D.class, new Vec2D(-50., 100.,0));
-        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(0., 0., 0., 0., 0.f, 0., -1.));
+        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(0., 0., 0., 0., 0.f, 0.25, -1.));
         gameEngine.addComponent(newEnt, Collider.class, new Collider(200., 50.));
         gameEngine.addComponent(newEnt, Render.class, new Render(BoxRender.class));
         gameEngine.addComponent(newEnt, BoxRender.class, new BoxRender(200, 50, 64, 64, 64));
         // Right boundary
         newEnt = gameEngine.createEntity();
         gameEngine.addComponent(newEnt, Vec2D.class, new Vec2D(100., -50.,0));
-        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(0., 0., 0., 0., 0.f, 0., -1.));
+        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(0., 0., 0., 0., 0.f, 0.25, -1.));
         gameEngine.addComponent(newEnt, Collider.class, new Collider(50., 200.));
         gameEngine.addComponent(newEnt, Render.class, new Render(BoxRender.class));
         gameEngine.addComponent(newEnt, BoxRender.class, new BoxRender(50, 200, 64, 64, 64));
         // One object
         newEnt = gameEngine.createEntity();
         gameEngine.addComponent(newEnt, Vec2D.class, new Vec2D(62., 90.,0));
-        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(1., 0., 0., 0., 0.f, 0., 1.));
+        gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(1., 0., 0., 0., 0.f, 0.66, 120.));
         gameEngine.addComponent(newEnt, Collider.class, new Collider(10., 10.));
         gameEngine.addComponent(newEnt, Gravity.class, new Gravity(0, -9.80665, 45., 45.)); // Terminal velocity is 45 m/s
         gameEngine.addComponent(newEnt, Render.class, new Render(BoxRender.class));
         gameEngine.addComponent(newEnt, BoxRender.class, new BoxRender(10, 10, 255, 64, 64));
-
+        // The textobject that prints the current number of entities
         newEnt = gameEngine.createEntity();
         gameEngine.addComponent(newEnt, TextRender.class, new TextRender("", 24, Color.WHITE));
         gameEngine.addComponent(newEnt, Render.class, new Render(TextRender.class));
         gameEngine.addComponent(newEnt, Reporter.class, new Reporter());
         gameEngine.addComponent(newEnt, Vec2D.class, new Vec2D(5,5,0));
-        // Other objects
+        
+         // Uncomment this block to enable the stress-test (runs 500 square entities, with physics etc.)
         Random rand = new Random();
-        for (int i = 0; i < 20; i++) {
+        for (int i = 0; i < 500; i++) {
             newEnt = gameEngine.createEntity();
+            double size = 1 + rand.nextDouble();
             gameEngine.addComponent(newEnt, Vec2D.class, new Vec2D(10 + rand.nextDouble()* 80, 10+ rand.nextDouble()* 80,0));
-            gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(-2.5 + rand.nextDouble()* 5., 0., 0., 0., 0.f, 0., rand.nextDouble() * 20.));
-            double size = 3 + rand.nextDouble() * 7;
+            gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(-2.5 + rand.nextDouble()* 5., 0., 0., 0., 0.f, 0.3, 2. * size));
             gameEngine.addComponent(newEnt, Collider.class, new Collider(size, size));
             gameEngine.addComponent(newEnt, Gravity.class, new Gravity(0, -9.80665, 45., 45.)); // Terminal velocity is 45 m/s
-            gameEngine.addComponent(newEnt, LogUpdate.class, null); // Add to object to print pos of
             gameEngine.addComponent(newEnt, Render.class, new Render(BoxRender.class));
             gameEngine.addComponent(newEnt, BoxRender.class, new BoxRender(size, size, 30 + rand.nextInt(225), 30 + rand.nextInt(225), 30 + rand.nextInt(225)));
-            gameEngine.addComponent(newEnt, TimedExistence.class, new TimedExistence(5 + rand.nextDouble() * 90));
+            gameEngine.addComponent(newEnt, TimedExistence.class, new TimedExistence(25 + rand.nextDouble() * 90));
         }
 
-        //gameEngine.addComponent(newEnt, LogUpdate.class, null);
-
-
+        /************************************
+        **    Run init() on the systems    **
+        *************************************/
+        renderSystem.init();
+        rendererReadySemaphore.acquire();
         physicsSystem.init();
         collisionSystem.init();
         logUpdateSystem.init();
-        renderSystem.init();
         existenceSystem.init();
         reportSystem.init();
 
+
+        /************************************
+        ** Prepare and enter the game loop **
+        *************************************/
         double dt = 0.001;
         double frameRate = 1.0 / 144; // 1 second divided by target number of frames
-        double idleTime = 0.0; // the amount of time spent sleeping
         
         boolean exit = false;
-        long loopStart = System.currentTimeMillis();
+        Thread.sleep(5000);
         long startTime = System.nanoTime();
         while (!exit){
-
-            collisionSystem.update();
+            // Run system updates
+            collisionSystem.update(dt);
             physicsSystem.update(dt);
             existenceSystem.update(dt);
-            reportSystem.update();
-            //logUpdateSystem.update();
-            // The render system should be uncoupled from the physics and collision
-            renderSystem.update();
+            reportSystem.update(dt);
+            renderSystem.update(dt);
 
             dt = (System.nanoTime() - startTime) / 1e9; // convert nanoseconds to seconds
             startTime = System.nanoTime();
             if (dt < frameRate){
-                idleTime = frameRate-dt;
                 Thread.sleep((int)((frameRate-dt)*1000));
                 dt = (System.nanoTime() - startTime) / 1e9;
                 startTime = System.nanoTime();
             }
-            dt = 0.001;
+            // Setting dt here to a fixed time-step will lock the rate of the physics. The above code ensures that it is
+            // executed no more than once 1/framerate seconds.
+            // dt = 0.001;
         }
     }
 }

demo1/src/main/java/nz/ac/massey/javaecs/examples/Components/Collider.java

@@ -9,7 +9,4 @@ public class Collider {
     // bottom-right, top-right is specified by position
     public double x = 0.0;
     public double y = 0.0;
-    public boolean collided = false;
-
-    public double travelDirection = 0.0;
 }

demo1/src/main/java/nz/ac/massey/javaecs/examples/Systems/CollisionSystem.java

@@ -1,17 +1,11 @@
 package nz.ac.massey.javaecs.examples.Systems;
 
-import java.util.ArrayList;
 import java.util.BitSet;
-import java.util.HashSet;
-import java.util.List;
-import java.util.Set;
-import java.util.stream.Stream;
 
 import nz.ac.massey.javaecs.ECSSystem;
 import nz.ac.massey.javaecs.Engine;
 import nz.ac.massey.javaecs.Entity;
 import nz.ac.massey.javaecs.examples.Components.Collider;
-import nz.ac.massey.javaecs.examples.Components.Gravity;
 import nz.ac.massey.javaecs.examples.Components.RidgidBody;
 import nz.ac.massey.javaecs.examples.Components.Vec2D;
 
@@ -29,97 +23,28 @@ public class CollisionSystem extends ECSSystem {
 
     @Override
     public void init() {
-        // TODO Auto-generated method stub
-
-    }
-    public void updateNew() {
-        Set<Entity> processed = new HashSet<>();
-        // Gets all items we have collided with
-        for (Entity entity : entities) {
-            RidgidBody ridgidBody = (RidgidBody) gameEngine.getComponentData(entity, RidgidBody.class);
-            // Only considering elements with mass just now
-            if (ridgidBody.mass > 0){
-                Vec2D pos = (Vec2D) gameEngine.getComponentData(entity, Vec2D.class);
-                Collider collider = (Collider) gameEngine.getComponentData(entity, Collider.class);
-
-                // The pos of each bounding line of the entity
-                // i.e.
-                //        
-                //   -------------
-                //   |###########|
-                //   |###########|
-                //   |###########|
-                //   |###########|
-                //   -------------
-                //        
-                double eleft = pos.x;
-                double ebottom = pos.y;
-                double eright = pos.x + collider.x; 
-                double etop = pos.y + collider.y;
-
-                double evectorAngle = calcAngle(ridgidBody.xVel, ridgidBody.yVel);
-
-
-                if (ridgidBody.mass > 0){
-                    // Dont't recalc for entities that aren't static
-                    processed.add(entity);
-                }
-
-                for (Entity entity2 : entities) {
-                    if (!processed.contains(entity2)) {
-                        // skip entities that have already been processed
-                        Vec2D oPos = (Vec2D) gameEngine.getComponentData(entity2, Vec2D.class);
-                        RidgidBody oRidgidBody = (RidgidBody) gameEngine.getComponentData(entity2, RidgidBody.class);
-                        Collider oCollider = (Collider) gameEngine.getComponentData(entity2, Collider.class);
-
-                        double oleft = oPos.x;
-                        double obottom = oPos.y;
-                        double oright = oPos.x + oCollider.x;
-                        double otop = oPos.y + oCollider.y;
-
-                        // Check if a collision occured
-                        // Few conditions required, that is, 
-                        // - oS2 must be greater than eS0, else they aren't close
-                        // - eS2 must be greater than oS0, for the same reason
-                        // - either 
-                        if (!(eleft > oright || oleft > eright || etop < obottom || otop < ebottom)){
-                            // Collided
-                            // Grab the angle the other is moving, to figure the quadrant to move to
-                            double ovectorAngle = calcAngle(oRidgidBody.xVel, oRidgidBody.yVel);
-                            // Grab the vector sums
-                            double xVelSum = ridgidBody.xVel + oRidgidBody.xVel;
-                            double yVelSum = ridgidBody.yVel + oRidgidBody.yVel;
-                            // Collision occurred
-                        }
-                    }
-                }
-            }
-            
-        }
     }
 
+    // This is a quick & naive physics implementation.
+    // I expect it is highly inefficient, though it is able to run it with 500
+    // subscribed entities
+    // with no major performance issues
+    // Replace this with a proper system as required - I.e. Box2D or etc.
     @Override
-    public void update() {
-        // Parallelising this loop ()
-        Set<Entity> processed = new HashSet<>();
-        // Gets all items we have collided with
+    public void update(double dt) {
         for (Entity entity : entities) {
             Vec2D pos = (Vec2D) gameEngine.getComponentData(entity, Vec2D.class);
             RidgidBody ridgidBody = (RidgidBody) gameEngine.getComponentData(entity, RidgidBody.class);
             Collider collider = (Collider) gameEngine.getComponentData(entity, Collider.class);
-            if (ridgidBody.mass > 0){
+            if (ridgidBody.mass >= 0) {
                 // Only ignore non-static colliders
-                processed.add(entity);
-            }
-            for (Entity entity2 : entities) {
-                if (!processed.contains(entity2)) {
+                for (Entity entity2 : entities) {
                     // skip entities that have already been processed
                     Vec2D otherPos = (Vec2D) gameEngine.getComponentData(entity2, Vec2D.class);
                     RidgidBody otherRidgidBody = (RidgidBody) gameEngine.getComponentData(entity2, RidgidBody.class);
                     Collider otherCollider = (Collider) gameEngine.getComponentData(entity2, Collider.class);
 
-
-                    if (ridgidBody.mass >= 0 || otherRidgidBody.mass >= 0) {
+                    if (otherRidgidBody.mass < 0) {
                         // Evaluate a collision in the top-left
                         boolean tlCollide = pos.x > otherPos.x && pos.x < otherPos.x + otherCollider.x
                                 && pos.y > otherPos.y && pos.y < otherPos.y + otherCollider.y;
@@ -135,84 +60,46 @@ public class CollisionSystem extends ECSSystem {
                                 && pos.x + collider.x < otherPos.x + otherCollider.x && pos.y > otherPos.y
                                 && pos.y < otherPos.y + otherCollider.y;
                         if (tlCollide || blCollide || brCollide || trCollide) {
-                            // Determine collision nature
-                            if (tlCollide) {
-                                int k = 0;
-                            }
-                            if (trCollide) {
-                                int k = 0;
-                            }
-                            if (blCollide) {
-                                int k = 0;
-                            }
-                            if (brCollide) {
-                                int k = 0;
-                            }
                             // Get the vels
                             double totalXVel = Math.abs(ridgidBody.xVel) + Math.abs(otherRidgidBody.xVel);
                             double totalYVel = Math.abs(ridgidBody.yVel) + Math.abs(otherRidgidBody.yVel);
-                            double totalMass = ridgidBody.mass + otherRidgidBody.mass;
-                            int xMult = 0;
-                            int yMult = 0;
+                            double xMult = 0;
+                            double yMult = 0;
+                            double multTot = 1;
                             boolean fullEdge = false;
                             // left-hand collision
                             if (tlCollide && blCollide) {
                                 fullEdge = true;
-                                xMult = 2;
-                            }
-                            // Bottom collision
-                            if (blCollide && brCollide) {
-                                fullEdge = true;
-                                yMult = -2;
+                                pos.x = otherPos.x + otherCollider.x;
+                                xMult = multTot;
                             }
                             // right-hand collision
-                            if (brCollide && trCollide) {
+                            else if (brCollide && trCollide) {
                                 fullEdge = true;
-                                xMult = -2;
+                                pos.x = otherPos.x - collider.x;
+                                xMult = -multTot;
+                            }
+                            // Bottom collision
+                            else if (blCollide && brCollide) {
+                                fullEdge = true;
+                                // pos.y = otherPos.y + otherCollider.y;
+                                pos.y = otherPos.y - collider.y;
+                                yMult = -multTot;
                             }
                             // top collision
-                            if (trCollide && tlCollide) {
+                            else if (trCollide && tlCollide) {
                                 fullEdge = true;
-                                yMult = 2;
+                                // pos.y = otherPos.y - collider.y;
+                                pos.y = otherPos.y + otherCollider.y;
+                                yMult = multTot;
                             }
                             if (fullEdge) {
-                                // Finally, actuate the calculation
-                                if (ridgidBody.mass < 0) {
-                                    // entity 1 is immovable
-                                    otherRidgidBody.xVel += totalXVel * (-1 * xMult);
-                                    otherRidgidBody.yVel += totalYVel * (-1 * yMult);
-
-                                    Object grav = gameEngine.getComponentData(entity, Gravity.class);
-                                    if (grav != null) {
-                                        Gravity gravity = (Gravity) grav;
-                                        otherRidgidBody.xAcc += gravity.x * -1.;
-                                        otherRidgidBody.yAcc += gravity.y * -1.;
-                                    }
-
-                                } else if (otherRidgidBody.mass < 0) {
-                                    // entity 2 is immovable; full acceleration applied to the current entity
-                                    ridgidBody.xVel += totalXVel * xMult;
-                                    ridgidBody.yVel += totalYVel * yMult;
-                                    Object grav = gameEngine.getComponentData(entity, Gravity.class);
-                                    if (grav != null) {
-                                        // negate gravity while collided
-                                        Gravity gravity = (Gravity) grav;
-                                        ridgidBody.xAcc += gravity.x * -1.;
-                                        ridgidBody.yAcc += gravity.y * -1.;
-                                    }
-                                } else {
-                                    // collision is elastic; add the forces x & y and the masses, and share between
-                                    // objects
-                                    /*ridgidBody.xVel += (ridgidBody.mass / totalMass) * totalXVel * xMult;
-                                    otherRidgidBody.xVel += (otherRidgidBody.mass / totalMass) * totalXVel
-                                            * (-1 * xMult);
-
-                                    ridgidBody.yVel += (ridgidBody.mass / totalMass) * totalYVel * yMult;
-                                    otherRidgidBody.yVel += (otherRidgidBody.mass / totalMass) * totalYVel
-                                            * (-1 * yMult);*/
-                                }
-                            }
-                            else{
+                                    double newXVel = totalXVel * (xMult
+                                            * (Math.abs(xMult) + (ridgidBody.bounciness * otherRidgidBody.bounciness)));
+                                    double newYVel = totalYVel * (yMult
+                                            * (Math.abs(yMult) + (ridgidBody.bounciness * otherRidgidBody.bounciness)));
+                                    ridgidBody.xVel += newXVel;
+                                    ridgidBody.yVel += newYVel;
                             }
                         }
                     }
@@ -220,33 +107,4 @@ public class CollisionSystem extends ECSSystem {
             }
         }
     }
-
-    /**
-     * Zero degrees is straight up,
-     * 90 east
-     * -90 (270) = west
-     * 180 south
-     * @param xVel
-     * @param yVel
-     * @return
-     */
-    public static double calcAngle(double xVel, double yVel){
-        if (xVel == 0){ // Div zero; = +- 90
-            return yVel < 0 ? 270 : 90;
-        }
-        else if (xVel < 0 && yVel < 0){ // bottom-left quad (180 - 270)
-            return 180. + Math.tanh(yVel/xVel);
-        }
-        else if (xVel < 0){ // Top left quad (270 - 360)
-            return 360 - Math.tanh(yVel/xVel);
-        }
-        else if (yVel < 0){
-            return 180 - Math.tanh(yVel/xVel);
-        }
-        else{
-            return Math.tanh(yVel/xVel);
-        }
-        
-    }
-
 }

demo1/src/main/java/nz/ac/massey/javaecs/examples/Systems/ExistenceSystem.java

@@ -11,7 +11,6 @@ import nz.ac.massey.javaecs.Entity;
 import nz.ac.massey.javaecs.examples.Components.BoxRender;
 import nz.ac.massey.javaecs.examples.Components.Collider;
 import nz.ac.massey.javaecs.examples.Components.Gravity;
-import nz.ac.massey.javaecs.examples.Components.LogUpdate;
 import nz.ac.massey.javaecs.examples.Components.Render;
 import nz.ac.massey.javaecs.examples.Components.RidgidBody;
 import nz.ac.massey.javaecs.examples.Components.TimedExistence;
@@ -32,25 +31,19 @@ public class ExistenceSystem extends ECSSystem{
     @Override
     public void init() {
         rand = new Random();
-        
     }
 
     @Override
-    public void update() {
-        // TODO Auto-generated method stub
-        
-    }
-
     public void update(double dt){
         Queue<Entity> deletions = new LinkedList<>();
         for (Entity entity : entities) {
             BoxRender shape = (BoxRender)gameEngine.getComponentData(entity, BoxRender.class);
             TimedExistence timedExistence = (TimedExistence)gameEngine.getComponentData(entity, TimedExistence.class);
             // Get the rate the fade should occur at our current frame rate.
-            double fadeRate = timedExistence.lifeTime / dt; // I.e. might say 200 frames left
+            double fadeRate = timedExistence.lifeTime / dt;
             // Fade the opacity
             shape.a -= shape.a / fadeRate;
-            // Clauses to keep things safe
+            // Keep the alpha between 0-1
             if (shape.a < 0) shape.a = 0.;
             else if (shape.a > 1) shape.a = 1.;
             // Reduce the time the shape may continue living for
@@ -60,15 +53,18 @@ public class ExistenceSystem extends ECSSystem{
                 deletions.add(entity);
             }
         }
+        // As we were using the iterator to traverse entities, we could not delete them as we read them.
         while (deletions.size() > 0){
             gameEngine.destroyEntity(deletions.remove());
         }
         // Finally, randomly add an entity as required
-        if (rand.nextInt(16384) < 8){
+        int newRate = gameEngine.getNumEntities();
+        newRate = newRate < 13 ? 7 - newRate / 2 : 1;
+        if (rand.nextInt(2048) <= 1*newRate){
             Entity newEnt = gameEngine.createEntity();
+            double size = 1 + rand.nextDouble() * 10;
             gameEngine.addComponent(newEnt, Vec2D.class, new Vec2D(10 + rand.nextDouble()* 80, 10+ rand.nextDouble()* 80,0));
-            gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(-2.5 + rand.nextDouble()* 5., 0., 0., 0., 0.f, 0., rand.nextDouble() * 20.));
-            double size = 3 + rand.nextDouble() * 7;
+            gameEngine.addComponent(newEnt, RidgidBody.class, new RidgidBody(-2.5 + rand.nextDouble()* 5., 0., 0., 0., 0.f, 0.75, 2. * size));
             gameEngine.addComponent(newEnt, Collider.class, new Collider(size, size));
             gameEngine.addComponent(newEnt, Gravity.class, new Gravity(0, -9.80665, 45., 45.)); // Terminal velocity is 45 m/s
             gameEngine.addComponent(newEnt, Render.class, new Render(BoxRender.class));

demo1/src/main/java/nz/ac/massey/javaecs/examples/Systems/LogUpdateSystem.java

@@ -24,7 +24,7 @@ public class LogUpdateSystem extends ECSSystem{
     }
 
     @Override
-    public void update() {
+    public void update(double dt) {
         for (Entity entity : entities) {
             Vec2D pos = (Vec2D)gameEngine.getComponentData(entity, Vec2D.class);
             System.out.println(String.format("X: %.6g, Y: %.6g", pos.x, pos.y));

demo1/src/main/java/nz/ac/massey/javaecs/examples/Systems/PhysicsSystem.java

@@ -30,17 +30,11 @@ public class PhysicsSystem extends ECSSystem {
     }
 
     @Override
-    public void update() {
-        // TODO Auto-generated method stub
-        
-    }
-
     public void update(double dt){
         for (Entity entity : entities) {
             Vec2D pos = (Vec2D)gameEngine.getComponentData(entity, Vec2D.class);
             RidgidBody ridgidBody = (RidgidBody)gameEngine.getComponentData(entity, RidgidBody.class);
             Gravity gravity = (Gravity)gameEngine.getComponentData(entity, Gravity.class);
-            Collider collider = (Collider)gameEngine.getComponentData(entity, Collider.class);
             // Firstly, add the result of the accelerative forces to the ridgidbody
             ridgidBody.xVel += ridgidBody.xAcc * dt;
             ridgidBody.yVel += ridgidBody.yAcc * dt;
@@ -49,14 +43,12 @@ public class PhysicsSystem extends ECSSystem {
             ridgidBody.xAcc = 0.;
             ridgidBody.yAcc = 0.;
             
-            if (!collider.collided){
-                // Special case of gravity
-                if (gravity.terminalX < 0 || Math.abs(ridgidBody.xVel) < gravity.terminalX){
-                    ridgidBody.xAcc += gravity.x;
-                }
-                if (gravity.terminalY < 0 || Math.abs(ridgidBody.yVel) < gravity.terminalY){
-                    ridgidBody.yAcc += gravity.y;
-                }
+            // Special case of gravity
+            if (gravity.terminalX < 0 || Math.abs(ridgidBody.xVel) < gravity.terminalX){
+                ridgidBody.xAcc += gravity.x;
+            }
+            if (gravity.terminalY < 0 || Math.abs(ridgidBody.yVel) < gravity.terminalY){
+                ridgidBody.yAcc += gravity.y;
             }
             
             

demo1/src/main/java/nz/ac/massey/javaecs/examples/Systems/RenderSystem.java

@@ -4,11 +4,9 @@ import java.util.BitSet;
 
 import javafx.application.Application;
 import javafx.application.Platform;
-import javafx.concurrent.Task;
 import javafx.scene.Group;
 import javafx.scene.Scene;
 import javafx.scene.paint.Color;
-import javafx.scene.paint.Paint;
 import javafx.scene.shape.Rectangle;
 import javafx.scene.text.Font;
 import javafx.scene.text.Text;
@@ -16,6 +14,7 @@ import javafx.stage.Stage;
 import nz.ac.massey.javaecs.ECSSystem;
 import nz.ac.massey.javaecs.Engine;
 import nz.ac.massey.javaecs.Entity;
+import nz.ac.massey.javaecs.examples.App;
 import nz.ac.massey.javaecs.examples.Components.BoxRender;
 import nz.ac.massey.javaecs.examples.Components.Render;
 import nz.ac.massey.javaecs.examples.Components.TextRender;
@@ -26,8 +25,8 @@ public class RenderSystem extends ECSSystem{
     Engine gameEngine;
     Thread renderThread;
     double renderScale;
-    int screenX = 1024;
-    int screenY = 1024;
+    int screenX = 512;
+    int screenY = 512;
 
     public RenderSystem(Engine gameEngine, double renderScale){
         this.gameEngine = gameEngine;
@@ -40,31 +39,24 @@ public class RenderSystem extends ECSSystem{
 
     @Override
     public void init() {
-        // Spawn a new thread
+        // Spawn a new asynchronous thread (won't rejoin the main program flow)
         renderThread = new Thread(new RenderStarter());
-        renderThread.start(); // this thread is asynchronous, it isn't expected to rejoin
+        renderThread.start();
     }
 
     @Override
-    public void update() {
-        /* while (JFXView.root == null){
-            try {
-                Thread.sleep(1000);
-            } catch (InterruptedException e) {
-                e.printStackTrace();
-            }
-        } */
+    public void update(double dt) {
+        // This approach needs reconsidering, as it creates an excessive amount of objects that 
         Group renderScene = new Group();
         for (Entity entity : entities) {
-            //Vec2D pos = (Vec2D)gameEngine.getComponentData(entity, Vec2D.class);
             if (((Render)gameEngine.getComponentData(entity, Render.class)).renderType == BoxRender.class){
                 BoxRender box = (BoxRender)gameEngine.getComponentData(entity, BoxRender.class);
                 Vec2D vec2d = (Vec2D)gameEngine.getComponentData(entity, Vec2D.class);
 
                 Rectangle rect = new Rectangle(box.xSize* renderScale, box.ySize * renderScale);
                 rect.setFill(new Color(box.r, box.g, box.b, box.a));
-                rect.setX(12 + (vec2d.x * renderScale));
-                rect.setY(1012 - (vec2d.y * renderScale) - rect.getHeight());
+                rect.setX(6 + (vec2d.x * renderScale));
+                rect.setY(506 - (vec2d.y * renderScale) - rect.getHeight());
                 renderScene.getChildren().add(rect);
             }
             else if (((Render)gameEngine.getComponentData(entity, Render.class)).renderType == TextRender.class){
@@ -77,6 +69,9 @@ public class RenderSystem extends ECSSystem{
                 renderScene.getChildren().add(t);
             }
         }
+
+        // Must be run by the UI thread, not the main thread.
+        // This dispatches the operation run() to the UI.
         Platform.runLater(new Runnable(){
             @Override
             public void run() {
@@ -87,7 +82,6 @@ public class RenderSystem extends ECSSystem{
     }
 
     // Add a renderer
-
     public class RenderStarter implements Runnable{
 
         @Override
@@ -107,10 +101,11 @@ public class RenderSystem extends ECSSystem{
         public void start(Stage primaryStage) throws Exception {
             // based on the colorful circles sample at https://docs.oracle.com/javase/8/javafx/get-started-tutorial/animation.htm 
             root = new Group();
-            Scene scene = new Scene(root, 1024, 1024, Color.BLACK);
+            Scene scene = new Scene(root, 512, 512, Color.BLACK);
             primaryStage.setScene(scene);
-
             primaryStage.show();
+            // Signal the renderer is ready
+            App.rendererReadySemaphore.release();
         }
         
         public static void run(){

demo1/src/main/java/nz/ac/massey/javaecs/examples/Systems/ReportSystem.java

@@ -20,12 +20,10 @@ public class ReportSystem extends ECSSystem{
     }
     @Override
     public void init() {
-        // TODO Auto-generated method stub
-        
     }
 
     @Override
-    public void update() {
+    public void update(double dt) {
         for (Entity entity : entities) {
             TextRender text = (TextRender)gameEngine.getComponentData(entity, TextRender.class);
             text.content = "Num Entities: " + gameEngine.getNumEntities();

demo2/.editorconfig

@@ -0,0 +1,17 @@
+# Editor configuration, see http://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+max_line_length = 80
+
+[*.sh]
+end_of_line = lf
+
+[*.java]
+indent_size = 4
+max_line_length = 120

demo2/.gitattributes

@@ -0,0 +1,2 @@
+# When shell scripts end in CRLF, bash gives a cryptic error message
+*.sh text eol=lf

demo2/.gitignore

@@ -0,0 +1,28 @@
+#
+# Standard Maven .gitignore
+#
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+release.properties
+dependency-reduced-pom.xml
+buildNumber.properties
+.mvn/timing.properties
+
+#
+# IntelliJ
+#
+*.iml
+.idea/*
+!.idea/runConfigurations/
+
+#
+# Visual Studio Code
+#
+.settings/
+.classpath
+.factorypath
+.project
+.vscode/

demo2/.travis.yml

@@ -0,0 +1,4 @@
+language: java
+jdk: openjdk8
+after_success:
+  - mvn coveralls:report

demo2/pom.xml

@@ -0,0 +1,200 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>nz.ac.massey.javaecs.examples</groupId>
+  <artifactId>demo2</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <properties>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <junit.version>5.6.0</junit.version>
+    <maven-enforcer-plugin.version>3.0.0-M3</maven-enforcer-plugin.version>
+    <maven-checkstyle-plugin.version>3.1.0</maven-checkstyle-plugin.version>
+    <checkstyle.version>8.29</checkstyle.version>
+    <checkstyle-rules.version>4.0.1</checkstyle-rules.version>
+    <maven-surefire-plugin.version>3.0.0-M4</maven-surefire-plugin.version>
+    <jacoco-maven-plugin.version>0.8.4</jacoco-maven-plugin.version>
+    <maven-javadoc-plugin.version>3.0.0</maven-javadoc-plugin.version>
+    <coveralls-maven-plugin.version>4.3.0</coveralls-maven-plugin.version>
+    <!-- JaCoCo thresholds. Increase gradually as you add tests. -->
+    <jacoco.unit-tests.limit.instruction-ratio>0%</jacoco.unit-tests.limit.instruction-ratio>
+    <jacoco.unit-tests.limit.branch-ratio>0%</jacoco.unit-tests.limit.branch-ratio>
+    <jacoco.unit-tests.limit.class-complexity>20</jacoco.unit-tests.limit.class-complexity>
+    <jacoco.unit-tests.limit.method-complexity>5</jacoco.unit-tests.limit.method-complexity>
+  </properties>
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-api</artifactId>
+      <version>${junit.version}</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <version>${junit.version}</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>nz.ac.massey.javaecs</groupId>
+      <artifactId>javaecs</artifactId>
+      <version>1.0.1</version>
+  </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-enforcer-plugin</artifactId>
+        <version>${maven-enforcer-plugin.version}</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>enforce</goal>
+            </goals>
+            <configuration>
+              <rules>
+                <requireMavenVersion>
+                  <version>3.6.3</version>
+                </requireMavenVersion>
+              </rules>
+              <fail>true</fail>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-checkstyle-plugin</artifactId>
+        <version>${maven-checkstyle-plugin.version}</version>
+        <dependencies>
+          <dependency>
+            <groupId>com.puppycrawl.tools</groupId>
+            <artifactId>checkstyle</artifactId>
+            <version>${checkstyle.version}</version>
+          </dependency>
+          <dependency>
+            <groupId>com.github.ngeor</groupId>
+            <artifactId>checkstyle-rules</artifactId>
+            <version>${checkstyle-rules.version}</version>
+          </dependency>
+        </dependencies>
+        <configuration>
+          <configLocation>com/github/ngeor/checkstyle.xml</configLocation>
+          <includeTestSourceDirectory>true</includeTestSourceDirectory>
+          <skip>${skipTests}</skip>
+        </configuration>
+        <executions>
+          <execution>
+            <id>checkstyle</id>
+            <phase>validate</phase>
+            <goals>
+              <goal>check</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>${maven-surefire-plugin.version}</version>
+      </plugin>
+      <plugin>
+        <groupId>org.jacoco</groupId>
+        <artifactId>jacoco-maven-plugin</artifactId>
+        <version>${jacoco-maven-plugin.version}</version>
+        <executions>
+          <execution>
+            <id>pre-unit-test</id>
+            <goals>
+              <goal>prepare-agent</goal>
+            </goals>
+          </execution>
+          <execution>
+            <id>post-unit-test</id>
+            <phase>test</phase>
+            <goals>
+              <goal>report</goal>
+            </goals>
+          </execution>
+          <execution>
+            <id>check-unit-test</id>
+            <phase>test</phase>
+            <goals>
+              <goal>check</goal>
+            </goals>
+            <configuration>
+              <dataFile>${project.build.directory}/jacoco.exec</dataFile>
+              <rules>
+                <rule>
+                  <element>BUNDLE</element>
+                  <limits>
+                    <limit>
+                      <counter>INSTRUCTION</counter>
+                      <value>COVEREDRATIO</value>
+                      <minimum>${jacoco.unit-tests.limit.instruction-ratio}</minimum>
+                    </limit>
+                    <limit>
+                      <counter>BRANCH</counter>
+                      <value>COVEREDRATIO</value>
+                      <minimum>${jacoco.unit-tests.limit.branch-ratio}</minimum>
+                    </limit>
+                  </limits>
+                </rule>
+                <rule>
+                  <element>CLASS</element>
+                  <limits>
+                    <limit>
+                      <counter>COMPLEXITY</counter>
+                      <value>TOTALCOUNT</value>
+                      <maximum>${jacoco.unit-tests.limit.class-complexity}</maximum>
+                    </limit>
+                  </limits>
+                </rule>
+                <rule>
+                  <element>METHOD</element>
+                  <limits>
+                    <limit>
+                      <counter>COMPLEXITY</counter>
+                      <value>TOTALCOUNT</value>
+                      <maximum>${jacoco.unit-tests.limit.method-complexity}</maximum>
+                    </limit>
+                  </limits>
+                </rule>
+              </rules>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+  <reporting>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>${maven-javadoc-plugin.version}</version>
+      </plugin>
+    </plugins>
+  </reporting>
+  <profiles>
+    <!-- Publish coverage report to Coveralls, only when running in Travis. -->
+    <profile>
+      <id>travis</id>
+      <activation>
+        <property>
+          <name>env.TRAVIS</name>
+        </property>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.eluder.coveralls</groupId>
+            <artifactId>coveralls-maven-plugin</artifactId>
+            <version>${coveralls-maven-plugin.version}</version>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+  </profiles>
+</project>

demo2/src/main/java/nz/ac/massey/javaecs/examples/App.java

@@ -0,0 +1,120 @@
+package nz.ac.massey.javaecs.examples;
+
+import java.io.FileInputStream;
+import java.util.concurrent.Semaphore;
+
+import javafx.scene.Group;
+import javafx.scene.image.Image;
+import javafx.stage.Stage;
+import nz.ac.massey.javaecs.Engine;
+import nz.ac.massey.javaecs.Entity;
+import nz.ac.massey.javaecs.examples.Components.Control;
+import nz.ac.massey.javaecs.examples.Components.Input;
+import nz.ac.massey.javaecs.examples.Components.Render;
+import nz.ac.massey.javaecs.examples.Components.Sprite;
+import nz.ac.massey.javaecs.examples.Components.Vec2D;
+import nz.ac.massey.javaecs.examples.Systems.ControlSystem;
+import nz.ac.massey.javaecs.examples.Systems.PlayerSystem;
+import nz.ac.massey.javaecs.examples.Systems.RenderSystem;
+
+/**
+ * Hello world!
+ */
+public class App {
+    static App thisApp;
+    public App() {
+        thisApp = this;
+    }
+    static Engine gameEngine;
+    public static Stage worldStage;
+    public static Group worldGroup;
+    static Integer syncManager = 0;
+    static Semaphore rendererFinished = new Semaphore(0);
+    /**
+     * Says hello to the world.
+     * @param args The arguments of the program.
+     */
+    public static void main(String[] args) throws Exception{
+        /************************************
+        **        Initialise engine        **
+        *************************************/
+        gameEngine = new Engine(16384);
+
+        /************************************
+        **    Register game components     **
+        *************************************/
+        gameEngine.registerComponent(Control.class);
+        gameEngine.registerComponent(Render.class);
+        gameEngine.registerComponent(Sprite.class);
+        gameEngine.registerComponent(Vec2D.class);
+        gameEngine.registerComponent(Input.class);
+
+
+        /************************************
+        ** Register and initialise systems **
+        *************************************/
+        ControlSystem controlSystem = new ControlSystem(gameEngine);
+        gameEngine.registerSystem(ControlSystem.class, controlSystem);
+
+        RenderSystem renderSystem = new RenderSystem(gameEngine, 5.);
+        gameEngine.registerSystem(RenderSystem.class, renderSystem);
+
+        PlayerSystem playerSystem = new PlayerSystem(gameEngine);
+        gameEngine.registerSystem(PlayerSystem.class, playerSystem);
+
+
+
+        /************************************
+        **       Create known entities     **
+        *************************************/
+        // Input controller - gets player input
+        Entity inputEntity = gameEngine.createEntity();
+        gameEngine.addComponent(inputEntity, Input.class, new Input());
+
+        Entity playerEntity = gameEngine.createEntity();
+        gameEngine.addComponent(playerEntity, Vec2D.class, new Vec2D(25,25));
+        gameEngine.addComponent(playerEntity, Render.class, new Render(Sprite.class));
+        gameEngine.addComponent(playerEntity, Control.class, new Render(Control.class));
+        // Load the sprite
+        System.err.println(System.getProperty("user.dir"));
+        Image image = new Image(new FileInputStream("sprite.png"));
+        gameEngine.addComponent(playerEntity, Sprite.class, new Sprite(image, 50, 50));
+        // Push rendering into its own thread (to meet the design principle of a JavaFX program)
+        Thread renderThread = new Thread(new RenderStarter());
+        renderThread.start();
+
+        
+        // Use a semaphore to block until the renderer is set-up
+        rendererFinished.acquire();
+        
+        /************************************
+        **    Run init() on the systems    **
+        *************************************/
+
+        controlSystem.init(worldStage);
+        playerSystem.init(inputEntity);
+        renderSystem.init(worldGroup);
+
+        double dt = 0.001;
+        double frameRate = 1.0 / 144; // 1 second divided by target number of frames
+        
+        boolean exit = false;
+        long startTime = System.nanoTime();
+
+        while (!exit){
+            // Run system updates
+            controlSystem.update(dt);
+            playerSystem.update(dt);
+            renderSystem.update(dt);
+
+            dt = (System.nanoTime() - startTime) / 1e9; // convert nanoseconds to seconds
+            startTime = System.nanoTime();
+            if (dt < frameRate){
+                Thread.sleep((int)((frameRate-dt)*1000));
+                dt = (System.nanoTime() - startTime) / 1e9;
+                startTime = System.nanoTime();
+            }
+        } 
+        renderThread.join(); // Wait for any render task to exit     
+    }
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/Components/Control.java

@@ -0,0 +1,5 @@
+package nz.ac.massey.javaecs.examples.Components;
+
+public class Control {
+    public int input = -1;
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/Components/Input.java

@@ -0,0 +1,9 @@
+package nz.ac.massey.javaecs.examples.Components;
+
+import java.util.concurrent.atomic.AtomicInteger;
+
+public class Input {
+    // As this is a user-input- (i.e. timeframe in 10's or 100's of milliseconds) -derived value, the performance impact of
+    // AtomicInteger is irrelevant compared to its synchronisation ability.
+    public AtomicInteger input = new AtomicInteger(-1);
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/Components/Render.java

@@ -0,0 +1,11 @@
+package nz.ac.massey.javaecs.examples.Components;
+
+import java.lang.reflect.Type;
+
+public class Render {
+    public Type renderType;
+
+    public Render(Type t){
+        renderType = t;
+    }
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/Components/Sprite.java

@@ -0,0 +1,15 @@
+package nz.ac.massey.javaecs.examples.Components;
+
+import javafx.scene.image.Image;
+
+public class Sprite {
+    public Image sprite;
+    public Integer height;
+    public Integer width;
+
+    public Sprite(Image sprite, int height, int width){
+        this.sprite = sprite;
+        this.width = width;
+        this.height = height;
+    }
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/Components/Vec2D.java

@@ -0,0 +1,11 @@
+package nz.ac.massey.javaecs.examples.Components;
+
+public class Vec2D {
+    public double x;
+    public double y;
+
+    public Vec2D(double x, double y){
+        this.x = x;
+        this.y = y;
+    }
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/JFXView.java

@@ -0,0 +1,28 @@
+package nz.ac.massey.javaecs.examples;
+
+
+import javafx.application.Application;
+import javafx.scene.Group;
+import javafx.scene.Scene;
+import javafx.scene.paint.Color;
+import javafx.stage.Stage;
+
+public class JFXView extends Application {
+    public static Group root;
+
+    @Override
+    public void start(Stage primaryStage) throws Exception {
+        primaryStage.setTitle("JavaECS Demo 2");
+        App.worldGroup = new Group();
+        App.worldStage = primaryStage;
+        Scene scene = new Scene(App.worldGroup, 512, 512, Color.BLACK);
+        primaryStage.setScene(scene);
+        primaryStage.show();
+        // Notifiy that the renderer is ready
+        App.rendererFinished.release();
+    }
+    
+    public static void run(){
+        launch(new String[0]);
+    }
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/RenderStarter.java

@@ -0,0 +1,16 @@
+package nz.ac.massey.javaecs.examples;
+
+import javafx.scene.Group;
+
+// Add a renderer
+public class RenderStarter implements Runnable{
+
+    @Override
+    public void run() {
+        JFXView.run();
+    }
+    void updateScene(Group newGroup){
+        JFXView.root.getChildren().clear();
+        JFXView.root.getChildren().add(newGroup); 
+    }
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/Systems/ControlSystem.java

@@ -0,0 +1,81 @@
+package nz.ac.massey.javaecs.examples.Systems;
+
+import java.util.BitSet;
+
+import javafx.application.Platform;
+import javafx.scene.input.KeyCode;
+import javafx.scene.input.KeyEvent;
+import javafx.stage.Stage;
+import nz.ac.massey.javaecs.ECSSystem;
+import nz.ac.massey.javaecs.Engine;
+import nz.ac.massey.javaecs.Entity;
+import nz.ac.massey.javaecs.examples.Components.Input;
+
+
+/**
+ * The control system creates a handler for input in the world stage.
+ * It then passes input events as they occur to the Input component
+ * The ControlSystem reads this input every frame update and enacts
+ * on the player controller
+ */
+public class ControlSystem extends ECSSystem {
+    Engine gameEngine;
+    Entity inputEntity;
+
+    public ControlSystem(Engine gamEngine){
+        this.gameEngine = gamEngine;
+        registrationSet = new BitSet();
+        registrationSet.set(gameEngine.getComponentIndex(Input.class));
+    }
+
+    public void init(Stage world) {
+        // use a single entity to control inputs, it is present in the world stage
+        // and is responsible for collecting & passing data
+        inputEntity = entities.iterator().next();
+
+        // Add an event handler to the stage. This
+        Platform.runLater(new Runnable(){
+            @Override
+            public void run() {
+                world.addEventHandler(KeyEvent.KEY_PRESSED, (key) -> {
+                    if(key.getCode()==KeyCode.W) {
+                        updateKeyPress(0);
+                        System.err.println("W pressed");
+                    }
+                    else if(key.getCode()==KeyCode.S) {
+                        updateKeyPress(1);
+                        System.err.println("S pressed");
+                    }
+                    else if(key.getCode()==KeyCode.A) {
+                        updateKeyPress(2);
+                        System.err.println("A pressed");
+                    }
+                    else if(key.getCode()==KeyCode.D) {
+                        updateKeyPress(3);
+                        System.err.println("D pressed");
+                    }
+                });
+            }
+        });
+    }
+
+    @Override
+    public void update(double dt) {
+        //Input inputUpdate = (Input)gameEngine.getComponentData(inputEntity, Input.class);
+        // TODO Auto-generated method stub
+        
+    }
+
+    // Updates the input's keypressed state
+    protected void updateKeyPress(int dir){
+        Input inputUpdate = (Input)gameEngine.getComponentData(inputEntity, Input.class);
+        inputUpdate.input.set(dir);
+    }
+
+    @Override
+    public void init() throws Exception {
+        // TODO Auto-generated method stub
+        
+    }
+    
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/Systems/PlayerSystem.java

@@ -0,0 +1,59 @@
+package nz.ac.massey.javaecs.examples.Systems;
+
+import java.util.BitSet;
+
+import nz.ac.massey.javaecs.ECSSystem;
+import nz.ac.massey.javaecs.Engine;
+import nz.ac.massey.javaecs.Entity;
+import nz.ac.massey.javaecs.examples.Components.Control;
+import nz.ac.massey.javaecs.examples.Components.Input;
+import nz.ac.massey.javaecs.examples.Components.Sprite;
+import nz.ac.massey.javaecs.examples.Components.Vec2D;
+
+public class PlayerSystem extends ECSSystem{
+    Engine gameEngine;
+    Entity inputEntity; // Entity which recieves event data
+
+
+    public PlayerSystem(Engine gameEngine){
+        this.gameEngine = gameEngine;
+        registrationSet = new BitSet();
+        registrationSet.set(gameEngine.getComponentIndex(Control.class));
+    }
+
+    public void init(Entity inputEntity){
+        this.inputEntity = inputEntity;
+    }
+
+    @Override
+    public void init() throws Exception {
+        // TODO Auto-generated method stub
+        
+    }
+
+    @Override
+    public void update(double dt) {
+        int state = ((Input)gameEngine.getComponentData(inputEntity, Input.class)).input.get();
+        // The value of the input may change before control leaves here; sychronisation isn't
+        // hugely important through this section. So we can just ignore the change
+        for (Entity entity : entities) {
+            Vec2D pos = (Vec2D)gameEngine.getComponentData(entity, Vec2D.class);
+            Sprite sprite = (Sprite)gameEngine.getComponentData(entity, Sprite.class);
+            if (state == 0){ // W
+                pos.y -= sprite.height/2;
+            }
+            else if (state == 1){ // S
+                pos.y += sprite.height/2;
+            }
+            else if (state == 2){ // A
+                pos.x -= sprite.width/2;
+            }
+            else if (state == 3){ // D
+                pos.x += sprite.width/2;
+            }
+        }
+        // Finally, unset the state 
+        ((Input)gameEngine.getComponentData(inputEntity, Input.class)).input.set(-1); // Unset the state, it has been handled        
+    }
+    
+}

demo2/src/main/java/nz/ac/massey/javaecs/examples/Systems/RenderSystem.java

@@ -0,0 +1,69 @@
+package nz.ac.massey.javaecs.examples.Systems;
+
+import java.util.BitSet;
+
+import javafx.application.Platform;
+import javafx.scene.Group;
+import javafx.scene.image.ImageView;
+import nz.ac.massey.javaecs.ECSSystem;
+import nz.ac.massey.javaecs.Engine;
+import nz.ac.massey.javaecs.Entity;
+import nz.ac.massey.javaecs.examples.Components.Render;
+import nz.ac.massey.javaecs.examples.Components.Sprite;
+import nz.ac.massey.javaecs.examples.Components.Vec2D;
+/*
+ * This render system is different from demo 1, as its main functionality is provided directly by the program, not as an entity.
+*/
+public class RenderSystem extends ECSSystem {
+    Engine gameEngine;
+    Group renderGroup;
+    Thread renderThread;
+    double renderScale;
+    int screenX = 512;
+    int screenY = 512;
+
+    public RenderSystem(Engine gameEngine, double renderScale){
+        this.gameEngine = gameEngine;
+        // Set registrations
+        registrationSet = new BitSet();
+        registrationSet.set(gameEngine.getComponentIndex(Render.class));
+        this.renderScale = renderScale;
+    }
+    public void init(Group renderGroup) throws Exception {
+        this.renderGroup = renderGroup;        
+    }
+
+    @Override
+    public void init() throws Exception {
+        // TODO Auto-generated method stub
+        
+    }
+
+    @Override
+    public void update(double dt) {
+        Group frame = new Group();
+        for (Entity entity : entities) {
+            Vec2D pos = (Vec2D)gameEngine.getComponentData(entity, Vec2D.class);
+            if (((Render)gameEngine.getComponentData(entity, Render.class)).renderType == Sprite.class){
+                // Render the sprite
+                Sprite sprite = (Sprite)gameEngine.getComponentData(entity, Sprite.class);
+                ImageView spriteRender = new ImageView(sprite.sprite);
+                spriteRender.setX(pos.x);
+                spriteRender.setY(pos.y);
+                spriteRender.setFitWidth(sprite.width);
+                spriteRender.setFitHeight(sprite.height);
+                frame.getChildren().add(spriteRender);
+            }
+        }
+        
+        // Must be run by the UI thread, not the main thread.
+        // This dispatches the operation run() to the UI.
+        Platform.runLater(new Runnable(){
+            @Override
+            public void run() {
+                renderGroup.getChildren().clear();
+                renderGroup.getChildren().add(frame);
+            }
+        });
+    }
+}

demo2/src/test/java/nz/ac/massey/javaecs/examples/AppTest.java

@@ -0,0 +1,18 @@
+package nz.ac.massey.javaecs.examples;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Unit test for simple App.
+ */
+class AppTest {
+    /**
+     * Rigorous Test.
+     */
+    @Test
+    void testApp() {
+        assertEquals(1, 1);
+    }
+}

perftest/.editorconfig

@@ -0,0 +1,17 @@
+# Editor configuration, see http://editorconfig.org
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 2
+insert_final_newline = true
+trim_trailing_whitespace = true
+max_line_length = 80
+
+[*.sh]
+end_of_line = lf
+
+[*.java]
+indent_size = 4
+max_line_length = 120

perftest/.gitattributes

@@ -0,0 +1,2 @@
+# When shell scripts end in CRLF, bash gives a cryptic error message
+*.sh text eol=lf

perftest/.gitignore

@@ -0,0 +1,31 @@
+#
+# Standard Maven .gitignore
+#
+target/
+pom.xml.tag
+pom.xml.releaseBackup
+pom.xml.versionsBackup
+pom.xml.next
+release.properties
+dependency-reduced-pom.xml
+buildNumber.properties
+.mvn/timing.properties
+
+#
+# IntelliJ
+#
+*.iml
+.idea/*
+!.idea/runConfigurations/
+
+#
+# Visual Studio Code
+#
+.settings/
+.classpath
+.factorypath
+.project
+.vscode/
+
+# Ignore logs, these came from an error in the VM
+*.log

perftest/.travis.yml

@@ -0,0 +1,4 @@
+language: java
+jdk: openjdk8
+after_success:
+  - mvn coveralls:report

perftest/pom.xml

@@ -0,0 +1,200 @@
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>nz.ac.massey.javaecs.examples</groupId>
+  <artifactId>perftest</artifactId>
+  <version>1.0-SNAPSHOT</version>
+  <properties>
+    <maven.compiler.source>1.8</maven.compiler.source>
+    <maven.compiler.target>1.8</maven.compiler.target>
+    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    <junit.version>5.6.0</junit.version>
+    <maven-enforcer-plugin.version>3.0.0-M3</maven-enforcer-plugin.version>
+    <maven-checkstyle-plugin.version>3.1.0</maven-checkstyle-plugin.version>
+    <checkstyle.version>8.29</checkstyle.version>
+    <checkstyle-rules.version>4.0.1</checkstyle-rules.version>
+    <maven-surefire-plugin.version>3.0.0-M4</maven-surefire-plugin.version>
+    <jacoco-maven-plugin.version>0.8.4</jacoco-maven-plugin.version>
+    <maven-javadoc-plugin.version>3.0.0</maven-javadoc-plugin.version>
+    <coveralls-maven-plugin.version>4.3.0</coveralls-maven-plugin.version>
+    <!-- JaCoCo thresholds. Increase gradually as you add tests. -->
+    <jacoco.unit-tests.limit.instruction-ratio>0%</jacoco.unit-tests.limit.instruction-ratio>
+    <jacoco.unit-tests.limit.branch-ratio>0%</jacoco.unit-tests.limit.branch-ratio>
+    <jacoco.unit-tests.limit.class-complexity>20</jacoco.unit-tests.limit.class-complexity>
+    <jacoco.unit-tests.limit.method-complexity>5</jacoco.unit-tests.limit.method-complexity>
+  </properties>
+  <dependencies>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-api</artifactId>
+      <version>${junit.version}</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+      <version>${junit.version}</version>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>nz.ac.massey.javaecs</groupId>
+      <artifactId>javaecs</artifactId>
+      <version>1.0.1</version>
+  </dependency>
+  </dependencies>
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-enforcer-plugin</artifactId>
+        <version>${maven-enforcer-plugin.version}</version>
+        <executions>
+          <execution>
+            <goals>
+              <goal>enforce</goal>
+            </goals>
+            <configuration>
+              <rules>
+                <requireMavenVersion>
+                  <version>3.6.3</version>
+                </requireMavenVersion>
+              </rules>
+              <fail>true</fail>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-checkstyle-plugin</artifactId>
+        <version>${maven-checkstyle-plugin.version}</version>
+        <dependencies>
+          <dependency>
+            <groupId>com.puppycrawl.tools</groupId>
+            <artifactId>checkstyle</artifactId>
+            <version>${checkstyle.version}</version>
+          </dependency>
+          <dependency>
+            <groupId>com.github.ngeor</groupId>
+            <artifactId>checkstyle-rules</artifactId>
+            <version>${checkstyle-rules.version}</version>
+          </dependency>
+        </dependencies>
+        <configuration>
+          <configLocation>com/github/ngeor/checkstyle.xml</configLocation>
+          <includeTestSourceDirectory>true</includeTestSourceDirectory>
+          <skip>${skipTests}</skip>
+        </configuration>
+        <executions>
+          <execution>
+            <id>checkstyle</id>
+            <phase>validate</phase>
+            <goals>
+              <goal>check</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <version>${maven-surefire-plugin.version}</version>
+      </plugin>
+      <plugin>
+        <groupId>org.jacoco</groupId>
+        <artifactId>jacoco-maven-plugin</artifactId>
+        <version>${jacoco-maven-plugin.version}</version>
+        <executions>
+          <execution>
+            <id>pre-unit-test</id>
+            <goals>
+              <goal>prepare-agent</goal>
+            </goals>
+          </execution>
+          <execution>
+            <id>post-unit-test</id>
+            <phase>test</phase>
+            <goals>
+              <goal>report</goal>
+            </goals>
+          </execution>
+          <execution>
+            <id>check-unit-test</id>
+            <phase>test</phase>
+            <goals>
+              <goal>check</goal>
+            </goals>
+            <configuration>
+              <dataFile>${project.build.directory}/jacoco.exec</dataFile>
+              <rules>
+                <rule>
+                  <element>BUNDLE</element>
+                  <limits>
+                    <limit>
+                      <counter>INSTRUCTION</counter>
+                      <value>COVEREDRATIO</value>
+                      <minimum>${jacoco.unit-tests.limit.instruction-ratio}</minimum>
+                    </limit>
+                    <limit>
+                      <counter>BRANCH</counter>
+                      <value>COVEREDRATIO</value>
+                      <minimum>${jacoco.unit-tests.limit.branch-ratio}</minimum>
+                    </limit>
+                  </limits>
+                </rule>
+                <rule>
+                  <element>CLASS</element>
+                  <limits>
+                    <limit>
+                      <counter>COMPLEXITY</counter>
+                      <value>TOTALCOUNT</value>
+                      <maximum>${jacoco.unit-tests.limit.class-complexity}</maximum>
+                    </limit>
+                  </limits>
+                </rule>
+                <rule>
+                  <element>METHOD</element>
+                  <limits>
+                    <limit>
+                      <counter>COMPLEXITY</counter>
+                      <value>TOTALCOUNT</value>
+                      <maximum>${jacoco.unit-tests.limit.method-complexity}</maximum>
+                    </limit>
+                  </limits>
+                </rule>
+              </rules>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+  <reporting>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>${maven-javadoc-plugin.version}</version>
+      </plugin>
+    </plugins>
+  </reporting>
+  <profiles>
+    <!-- Publish coverage report to Coveralls, only when running in Travis. -->
+    <profile>
+      <id>travis</id>
+      <activation>
+        <property>
+          <name>env.TRAVIS</name>
+        </property>
+      </activation>
+      <build>
+        <plugins>
+          <plugin>
+            <groupId>org.eluder.coveralls</groupId>
+            <artifactId>coveralls-maven-plugin</artifactId>
+            <version>${coveralls-maven-plugin.version}</version>
+          </plugin>
+        </plugins>
+      </build>
+    </profile>
+  </profiles>
+</project>

perftest/src/main/java/nz/ac/massey/javaecs/examples/App.java

@@ -0,0 +1,65 @@
+package nz.ac.massey.javaecs.examples;
+
+import nz.ac.massey.javaecs.*;
+import nz.ac.massey.javaecs.examples.Components.*;
+import nz.ac.massey.javaecs.examples.Systems.*;
+
+/**
+ * Benchmark,
+ * A port of https://github.com/abeimler/ecs_benchmark 
+ */
+public final class App {
+    private App() {
+    }
+
+    /**
+     * Says hello to the world.
+     * @param args The arguments of the program.
+     * @throws InterruptedException
+     */
+    public static void main(String[] args) throws InterruptedException {
+        int nEntities = 1_000_000;
+        double startTime = System.nanoTime();
+        Engine engine = new Engine(nEntities);
+        double endTime = System.nanoTime();
+
+        System.out.println("Constructor Time taken: " + (endTime - startTime) / 1e6+ " ms " + "("+ (endTime - startTime) / 1e9 + " seconds )");
+        
+
+        engine.registerComponent(ComflabulationComponent.class);
+        engine.registerComponent(DirectionComponent.class);
+        engine.registerComponent(PositionComponent.class);
+
+        ComflabSystem comflabSystem = new ComflabSystem(engine);
+        engine.registerSystem(ComflabSystem.class, comflabSystem);
+
+        MovementSystem movementSystem = new MovementSystem(engine);
+        engine.registerSystem(MovementSystem.class, movementSystem);
+
+        startTime = System.nanoTime();
+
+        for (int i = 0; i < nEntities; i++) {
+            Entity entity = engine.createEntity();
+            engine.addComponent(entity, PositionComponent.class, new PositionComponent());
+            engine.addComponent(entity, DirectionComponent.class, new DirectionComponent());
+            if (i % 2 != 0){
+                engine.addComponent(entity, ComflabulationComponent.class, new ComflabulationComponent());
+            }
+            
+        }
+        endTime = System.nanoTime();
+
+        System.out.println("Entity creation Time taken: " + (endTime - startTime) / 1e6+ " ms " + "("+ (endTime - startTime) / 1e9 + " seconds )");
+        // Delay as object creation is multithreaded in at least OpenJDK 1.8 - lets use see the single core performance
+        Thread.sleep(5000);
+        double dt = 1.0f/60.0f;
+        startTime = System.nanoTime();
+        movementSystem.update(dt);
+        comflabSystem.update(dt);
+        endTime = System.nanoTime();
+
+        System.out.println("Single Loop Time taken: " + (endTime - startTime) / 1e6+ " ms " + "("+ (endTime - startTime) / 1e9 + " seconds )");
+
+        System.out.println("Hello World!");
+    }
+}

perftest/src/main/java/nz/ac/massey/javaecs/examples/Components/ComflabulationComponent.java

@@ -0,0 +1,22 @@
+package nz.ac.massey.javaecs.examples.Components;
+
+public class ComflabulationComponent {
+    public double thingy;
+    public int dingy;
+    public boolean mingy;
+    public String stringy;
+
+    public ComflabulationComponent(double thingy, int dingy, boolean mingy, String stringy){
+        this.thingy = thingy;
+        this.dingy = dingy;
+        this.mingy = mingy;
+        this.stringy = stringy;
+    }
+
+    public ComflabulationComponent(){
+        thingy =  0.0f;
+        dingy = 0;
+        mingy = false;
+        stringy = "";
+    }
+}

perftest/src/main/java/nz/ac/massey/javaecs/examples/Components/DirectionComponent.java

@@ -0,0 +1,16 @@
+package nz.ac.massey.javaecs.examples.Components;
+
+public class DirectionComponent {
+    public double x;
+    public double y;
+
+    public DirectionComponent(double x, double y){
+        this.x = x;
+        this.y = y;
+    }
+
+    public DirectionComponent(){
+        x = 0.0f;
+        y = 0.0f;
+    }
+}

perftest/src/main/java/nz/ac/massey/javaecs/examples/Components/PositionComponent.java

@@ -0,0 +1,16 @@
+package nz.ac.massey.javaecs.examples.Components;
+
+public class PositionComponent {
+    public double x;
+    public double y;
+
+    public PositionComponent(double x, double y){
+        this.x = x;
+        this.y = y;
+    }
+
+    public PositionComponent(){
+        x = 0.0f;
+        y = 0.0f;
+    }
+}

perftest/src/main/java/nz/ac/massey/javaecs/examples/Systems/ComflabSystem.java

@@ -0,0 +1,34 @@
+package nz.ac.massey.javaecs.examples.Systems;
+
+import java.util.BitSet;
+
+import nz.ac.massey.javaecs.ECSSystem;
+import nz.ac.massey.javaecs.Engine;
+import nz.ac.massey.javaecs.Entity;
+import nz.ac.massey.javaecs.examples.Components.ComflabulationComponent;
+
+public class ComflabSystem extends ECSSystem  {
+    Engine ecs;
+
+    public ComflabSystem(Engine ecs){
+        this.ecs = ecs;
+        registrationSet = new BitSet();
+        registrationSet.set(ecs.getComponentIndex(ComflabulationComponent.class));
+    }
+
+    @Override
+    public void init() {
+        // TODO Auto-generated method stub
+        
+    }
+
+    @Override
+    public void update(double dt) {
+        for (Entity entity : entities) {
+            ComflabulationComponent comflab = (ComflabulationComponent)ecs.getComponentData(entity, ComflabulationComponent.class);
+            comflab.thingy *= 1.000001;
+            comflab.mingy = !comflab.mingy;
+            comflab.dingy++;
+        } 
+    }
+}

perftest/src/main/java/nz/ac/massey/javaecs/examples/Systems/MovementSystem.java

@@ -0,0 +1,39 @@
+package nz.ac.massey.javaecs.examples.Systems;
+
+import java.util.BitSet;
+
+import nz.ac.massey.javaecs.ECSSystem;
+import nz.ac.massey.javaecs.Engine;
+import nz.ac.massey.javaecs.Entity;
+import nz.ac.massey.javaecs.examples.Components.DirectionComponent;
+import nz.ac.massey.javaecs.examples.Components.PositionComponent;
+
+public class MovementSystem extends ECSSystem {
+    Engine ecs;
+
+    public MovementSystem(Engine ecs){
+        this.ecs = ecs;
+        registrationSet = new BitSet();
+        registrationSet.set(ecs.getComponentIndex(PositionComponent.class));
+        registrationSet.set(ecs.getComponentIndex(DirectionComponent.class));
+    }
+
+    @Override
+    public void init() {
+        // TODO Auto-generated method stub
+        
+    }
+
+    @Override
+    public void update(double dt) {
+        for (Entity entity : entities) {
+            PositionComponent position = (PositionComponent)ecs.getComponentData(entity, PositionComponent.class);
+            DirectionComponent direction = (DirectionComponent)ecs.getComponentData(entity, DirectionComponent.class);
+            position.x += direction.x * dt;
+            position.y += direction.y * dt;
+        }
+        
+        
+    }
+    
+}

perftest/src/test/java/nz/ac/massey/javaecs/examples/AppTest.java

@@ -0,0 +1,18 @@
+package nz.ac.massey.javaecs.examples;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+/**
+ * Unit test for simple App.
+ */
+class AppTest {
+    /**
+     * Rigorous Test.
+     */
+    @Test
+    void testApp() {
+        assertEquals(1, 1);
+    }
+}