Begin box2d physics implementation.

Created box2d bodies for all game entities (except shield)
Scale units down to box2d friendly units (40:1 <-> pixels:box2d)
Use floats in places integers were used for position and sizing

build.gradle

@@ -46,6 +46,7 @@ project(":desktop") {
         compile project(":core")
         compile "com.badlogicgames.gdx:gdx-backend-lwjgl:$gdxVersion"
         compile "com.badlogicgames.gdx:gdx-platform:$gdxVersion:natives-desktop"
+        compile "com.badlogicgames.gdx:gdx-box2d-platform:$gdxVersion:natives-desktop"
         
     }
 }
@@ -56,7 +57,9 @@ project(":core") {
 
     dependencies {
         compile "com.badlogicgames.gdx:gdx:$gdxVersion"
+        compile "com.badlogicgames.gdx:gdx-box2d:$gdxVersion"
         compile "net.dermetfan.libgdx-utils:libgdx-utils:0.13.4"
+        compile "net.dermetfan.libgdx-utils:libgdx-utils-box2d:0.13.4"
         
     }
 }

core/src/com/me/brickbuster/entity/Ball.java

@@ -6,19 +6,18 @@ import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
 import com.badlogic.gdx.math.MathUtils;
 import com.badlogic.gdx.math.Vector2;
-import com.me.brickbuster.BrickBuster;
+import com.badlogic.gdx.physics.box2d.Body;
-import com.me.brickbuster.Utils;
+import com.badlogic.gdx.physics.box2d.BodyDef;
+import com.badlogic.gdx.physics.box2d.CircleShape;
+import com.badlogic.gdx.physics.box2d.FixtureDef;
 import com.me.brickbuster.state.PlayState;
-import net.dermetfan.utils.Pair;
 
-import java.util.Iterator;
+public class Ball extends Entity implements PhysicsBody {
 
-public class Ball extends Entity {
+	public static final float RADIUS = 1.2f;
-
-	public static final int RADIUS = 45;
 	public static final Color BALL_COLOR = Color.CHARTREUSE;
-	public static final float DEFAULT_SPEED = 1800;
+	public static final float DEFAULT_SPEED = 45;
-	public static final float BOOST_SPEED = 2200;
+	public static final float BOOST_SPEED = 55;
 	public static final int BLOCKS_FOR_BOOST = 39;
 
 	public Vector2 direction;
@@ -26,16 +25,38 @@ public class Ball extends Entity {
 	private boolean isStuck = true;
 	private boolean isDead = false;
 
+	private Body body;
+
 	public Ball(PlayState state) {
-		super(state,BrickBuster.BOARD_WIDTH /2, state.paddle.getY() + Paddle.PADDLE_HEIGHT + RADIUS);
+		super(state,PlayState.BOARD_WIDTH/2, state.paddle.getY() + Paddle.PADDLE_HEIGHT + RADIUS);
 		this.speed = state.bricks.size() > BLOCKS_FOR_BOOST? DEFAULT_SPEED : BOOST_SPEED;
+
+		BodyDef ballBody = new BodyDef();
+		ballBody.type = BodyDef.BodyType.DynamicBody;
+		ballBody.position.set(pos);
+
+		CircleShape ballShape = new CircleShape();
+		ballShape.setRadius(RADIUS);
+
+		FixtureDef ballFixture = new FixtureDef();
+		ballFixture.shape = ballShape;
+		ballFixture.restitution = 1f;
+		ballFixture.friction = 0f;
+
+		body = state.world.createBody(ballBody);
+		body.createFixture(ballFixture);
+		body.setUserData(this);
+
+		ballShape.dispose();
 	}
 
 	@Override
 	public void render(ShapeRenderer sr) {
 		sr.begin(ShapeType.Filled);
 		sr.setColor(BALL_COLOR);
-		sr.circle(pos.x, pos.y, RADIUS);
+		sr.circle(pos.x * PlayState.PIXEL_PER_METER,
+				pos.y * PlayState.PIXEL_PER_METER,
+				RADIUS * PlayState.PIXEL_PER_METER);
 		sr.end();
 	}
 
@@ -49,55 +70,60 @@ public class Ball extends Entity {
 			}
 		}
 
-		Vector2 new_pos = pos.cpy().add(direction.cpy().scl(speed * dt));
+//		Vector2 new_pos = pos.cpy().add(direction.cpy().scl(speed * dt));
+//
+//		boolean brickCollision = false;
+//		Iterator<Brick> brickIterator = state.bricks.iterator();
+//		while (!brickCollision && brickIterator.hasNext()) {
+//			Brick brick = brickIterator.next();
+//			Vector2[] vertices = brick.getVertices();
+//			for(int i = 0; i < vertices.length; i++) {
+//				Vector2 v1 = vertices[i];
+//				Vector2 v2 = vertices[i+1 < vertices.length? i+1 : 0];
+//				Vector2 segment = v2.cpy().sub(v1);
+//				Vector2 nearest = Utils.nearestPoint(v1.cpy(), segment, new_pos.cpy());
+//
+//				if (nearest.dst(new_pos.x, new_pos.y) <= RADIUS) {
+//					if (brick.hit()) {
+//						brickIterator.remove();
+//					}
+//					Utils.reflect(direction, segment.nor());
+//					brickCollision = true;
+//					break;
+//				}
+//			}
+//		}
+//
+//		if (new_pos.x + RADIUS > BrickBuster.BOARD_WIDTH || new_pos.x - RADIUS < 0) {
+//			Utils.reflect(direction, Utils.VERTICAL_EDGE);
+//		} else if (new_pos.y + RADIUS > BrickBuster.BOARD_HEIGHT) {
+//			Utils.reflect(direction, Utils.HORIZONTAL_EDGE);
+//		} else if (state.getShieldCount() > 0
+//					&& new_pos.y - RADIUS < PlayState.SHIELD_HEIGHT * state.getShieldCount()) {
+//			Utils.reflect(direction, Utils.HORIZONTAL_EDGE);
+//			state.removeShield();
+//		} else if (new_pos.y + RADIUS < 0) {
+//			isDead = true;
+//			return;
+//		} else if (direction.y < 0 && new_pos.y <= state.paddle.getY() + Paddle.PADDLE_HEIGHT + RADIUS) {
+//			Pair<Vector2, Vector2> paddle = state.paddle.getTopEdge();
+//			Vector2 lineDir = paddle.getValue().sub(paddle.getKey());
+//			Vector2 nearest = Utils.nearestPoint(paddle.getKey().cpy(), lineDir, new_pos.cpy());
+//
+//			if (nearest.dst(new_pos.x, new_pos.y) <= RADIUS) {
+//				paddleCollision();
+//				if (state.paddle.isSticky()) {
+//					return;
+//				}
+//			}
+//		}
+//
+//		pos.add(direction.cpy().scl(speed * dt));
+	}
 
-		boolean brickCollision = false;
+	@Override
-		Iterator<Brick> brickIterator = state.bricks.iterator();
+	public Body getBody() {
-		while (!brickCollision && brickIterator.hasNext()) {
+		return body;
-			Brick brick = brickIterator.next();
-			Vector2[] vertices = brick.getVertices();
-			for(int i = 0; i < vertices.length; i++) {
-				Vector2 v1 = vertices[i];
-				Vector2 v2 = vertices[i+1 < vertices.length? i+1 : 0];
-				Vector2 segment = v2.cpy().sub(v1);
-				Vector2 nearest = Utils.nearestPoint(v1.cpy(), segment, new_pos.cpy());
-
-				if (nearest.dst(new_pos.x, new_pos.y) <= RADIUS) {
-					if (brick.hit()) {
-						brickIterator.remove();
-					}
-					Utils.reflect(direction, segment.nor());
-					brickCollision = true;
-					break;
-				}
-			}
-		}
-
-		if (new_pos.x + RADIUS > BrickBuster.BOARD_WIDTH || new_pos.x - RADIUS < 0) {
-			Utils.reflect(direction, Utils.VERTICAL_EDGE);
-		} else if (new_pos.y + RADIUS > BrickBuster.BOARD_HEIGHT) {
-			Utils.reflect(direction, Utils.HORIZONTAL_EDGE);
-		} else if (state.getShieldCount() > 0
-					&& new_pos.y - RADIUS < PlayState.SHIELD_HEIGHT * state.getShieldCount()) {
-			Utils.reflect(direction, Utils.HORIZONTAL_EDGE);
-			state.removeShield();
-		} else if (new_pos.y + RADIUS < 0) {
-			isDead = true;
-			return;
-		} else if (direction.y < 0 && new_pos.y <= state.paddle.getY() + Paddle.PADDLE_HEIGHT + RADIUS) {
-			Pair<Vector2, Vector2> paddle = state.paddle.getTopEdge();
-			Vector2 lineDir = paddle.getValue().sub(paddle.getKey());
-			Vector2 nearest = Utils.nearestPoint(paddle.getKey().cpy(), lineDir, new_pos.cpy());
-
-			if (nearest.dst(new_pos.x, new_pos.y) <= RADIUS) {
-				paddleCollision();
-				if (state.paddle.isSticky()) {
-					return;
-				}
-			}
-		}
-
-		pos.add(direction.cpy().scl(speed * dt));
 	}
 
 	public Vector2 paddleReflectAngle() {
@@ -115,7 +141,12 @@ public class Ball extends Entity {
 			// launch at random angle between 135 and 45 degrees
 			float angle = MathUtils.random(MathUtils.PI/2) + MathUtils.PI/4;
 			direction = new Vector2(MathUtils.cos(angle), MathUtils.sin(angle));
+
 		}
+		//body.applyForceToCenter(new Vector2(0,Float.MAX_VALUE/2), true);
+		//body.setLinearVelocity(new Vector2(0,10000000));
+		body.setLinearVelocity(direction.cpy().scl(speed));
+		body.setBullet(true);
 		isStuck = false;
 	}
 

core/src/com/me/brickbuster/entity/Brick.java

@@ -4,29 +4,35 @@ import com.badlogic.gdx.graphics.Color;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
 import com.badlogic.gdx.math.Vector2;
+import com.badlogic.gdx.physics.box2d.Body;
+import com.badlogic.gdx.physics.box2d.BodyDef;
+import com.badlogic.gdx.physics.box2d.FixtureDef;
+import com.badlogic.gdx.physics.box2d.PolygonShape;
 import com.me.brickbuster.entity.powerup.PowerUpType;
 import com.me.brickbuster.state.PlayState;
 
-public class Brick extends Entity {
+public class Brick extends Entity implements PhysicsBody {
 
 	public static final Color DEFAULT_COLOR = Color.FOREST;
-	public static final int BRICK_WIDTH = 200;
+	public static final float BRICK_WIDTH = 5f;
-	public static final int BRICK_HEIGHT = 100;
+	public static final float BRICK_HEIGHT = 2.5f;
 
 	private PowerUpType powerUpType;
 	private Color color;
 
 	private Vector2[] vertices;
 
-	public Brick(PlayState state, PowerUpType powerUpType, int x, int y) {
+	private Body body;
+
+	public Brick(PlayState state, PowerUpType powerUpType, float x, float y) {
 		this(state, powerUpType, true, x, y);
 	}
 
-	public Brick(PlayState state, PowerUpType powerUpType, boolean hidePowerup, int x, int y) {
+	public Brick(PlayState state, PowerUpType powerUpType, boolean hidePowerup, float x, float y) {
 		this(state, powerUpType, DEFAULT_COLOR, hidePowerup, x, y);
 	}
 
-	public Brick(PlayState state, PowerUpType powerUpType, Color color, boolean hidePowerUp, int x, int y) {
+	public Brick(PlayState state, PowerUpType powerUpType, Color color, boolean hidePowerUp, float x, float y) {
 		super(state, x, y);
 		this.powerUpType = powerUpType;
 		this.color = powerUpType != null && !hidePowerUp? powerUpType.getColor() : color;
@@ -36,13 +42,34 @@ public class Brick extends Entity {
 			new Vector2(x + BRICK_WIDTH, y + BRICK_HEIGHT),
 			new Vector2(x, y + BRICK_HEIGHT)
 		};
+
+		BodyDef brickBody = new BodyDef();
+		brickBody.type = BodyDef.BodyType.StaticBody;
+		brickBody.position.set(pos.cpy());
+
+		PolygonShape brickShape = new PolygonShape();
+		brickShape.setAsBox(BRICK_WIDTH/2, BRICK_HEIGHT/2,
+				new Vector2(BRICK_WIDTH/2,BRICK_HEIGHT/2), 0);
+
+		FixtureDef brickFixture = new FixtureDef();
+		brickFixture.shape = brickShape;
+		brickFixture.friction = 0f;
+
+		body = state.world.createBody(brickBody);
+		body.createFixture(brickFixture);
+		body.setUserData(this);
+
+		brickShape.dispose();
 	}
 
 	@Override
 	public void render(ShapeRenderer sr) {
 		sr.begin(ShapeType.Filled);
 		sr.setColor(color);
-		sr.rect(getX(), getY(), BRICK_WIDTH, BRICK_HEIGHT);
+		sr.rect(getX()*PlayState.PIXEL_PER_METER,
+				getY()*PlayState.PIXEL_PER_METER,
+				BRICK_WIDTH*PlayState.PIXEL_PER_METER,
+				BRICK_HEIGHT*PlayState.PIXEL_PER_METER);
 		sr.end();
 	}
 
@@ -50,6 +77,11 @@ public class Brick extends Entity {
 	public void update(float dt) {
 	}
 
+	@Override
+	public Body getBody() {
+		return body;
+	}
+
 	public boolean hit() {
 		if (state.bricks.size()-1 <= Ball.BLOCKS_FOR_BOOST) {
 			for (Ball ball : state.balls) {

core/src/com/me/brickbuster/entity/Paddle.java

@@ -6,31 +6,58 @@ import com.badlogic.gdx.graphics.Color;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
 import com.badlogic.gdx.math.Vector2;
-import com.me.brickbuster.BrickBuster;
+import com.badlogic.gdx.physics.box2d.Body;
+import com.badlogic.gdx.physics.box2d.BodyDef;
+import com.badlogic.gdx.physics.box2d.EdgeShape;
+import com.badlogic.gdx.physics.box2d.FixtureDef;
 import com.me.brickbuster.state.PlayState;
 import net.dermetfan.utils.Pair;
 
-public class Paddle extends Entity {
+public class Paddle extends Entity implements PhysicsBody {
 
 	public static final Color STICKY_COLOR = Color.GRAY;
 	public static final Color PADDLE_COLOR = Color.BLACK;
-	public static final int DEFAULT_WIDTH = 300;
-	public static final int PADDLE_HEIGHT = 30;
-	public static final int PADDLE_Y = 50;
-	public static final int PADDLE_SPEED = 1500;
 
-	private int width = DEFAULT_WIDTH;
+	public static final float DEFAULT_WIDTH = 7.5f;
+	public static final float PADDLE_HEIGHT = 0.75f;
+	public static final float PADDLE_Y = 1.25f;
+	public static final float PADDLE_SPEED = 40f;
+
+	private float width = DEFAULT_WIDTH;
 	private boolean sticky = false;
 
+	private Body body;
+
 	public Paddle(PlayState brickBuster) {
-		super(brickBuster, BrickBuster.BOARD_WIDTH / 2, PADDLE_Y);
+		super(brickBuster, PlayState.BOARD_WIDTH/2, PADDLE_Y);
+
+		BodyDef paddleBody = new BodyDef();
+		paddleBody.type = BodyDef.BodyType.KinematicBody;
+		paddleBody.position.set(pos);
+
+		EdgeShape paddleShape = new EdgeShape();
+		paddleShape.set(new Vector2(-DEFAULT_WIDTH/2,PADDLE_HEIGHT),
+				new Vector2(DEFAULT_WIDTH/2, PADDLE_HEIGHT));
+
+		FixtureDef paddleFixture = new FixtureDef();
+		paddleFixture.shape = paddleShape;
+		paddleFixture.isSensor = true;
+
+		body = state.world.createBody(paddleBody);
+		body.createFixture(paddleFixture);
+		body.setUserData(this);
+
+		paddleShape.dispose();
 	}
 
 	@Override
 	public void render(ShapeRenderer sr) {
 		sr.begin(ShapeType.Filled);
 		sr.setColor(sticky? STICKY_COLOR : PADDLE_COLOR);
-		sr.rect(getX() - width/2, getY(), width, PADDLE_HEIGHT);
+		sr.rect((getX() - width/2) * PlayState.PIXEL_PER_METER,
+				getY() * PlayState.PIXEL_PER_METER,
+				width * PlayState.PIXEL_PER_METER,
+				PADDLE_HEIGHT * PlayState.PIXEL_PER_METER);
 		sr.end();
 	}
 
@@ -50,8 +77,8 @@ public class Paddle extends Entity {
 			}
 		}
 		if (Gdx.input.isKeyPressed(Input.Keys.RIGHT)) {
-			if (pos.x + width/2 + PADDLE_SPEED * dt > BrickBuster.BOARD_WIDTH) {
+			if (pos.x + width/2 + PADDLE_SPEED * dt > PlayState.BOARD_WIDTH) {
-				setX(BrickBuster.BOARD_WIDTH - width/2);
+				setX(PlayState.BOARD_WIDTH - width/2);
 				return;
 			}
 			pos.x = pos.x + PADDLE_SPEED * dt;
@@ -64,6 +91,11 @@ public class Paddle extends Entity {
 		}
 	}
 
+	@Override
+	public Body getBody() {
+		return body;
+	}
+
 	public Pair<Vector2, Vector2> getTopEdge() {
 		return new Pair<Vector2, Vector2>(
 				new Vector2(pos.x - width/2, pos.y + PADDLE_HEIGHT),
@@ -71,11 +103,11 @@ public class Paddle extends Entity {
 		);
 	}
 
-	public int getWidth() {
+	public float getWidth() {
 		return width;
 	}
 
-	public void setWidth(int width) {
+	public void setWidth(float width) {
 		this.width = width;
 	}
 

core/src/com/me/brickbuster/entity/PhysicsBody.java

@@ -0,0 +1,11 @@
+package com.me.brickbuster.entity;
+
+import com.badlogic.gdx.physics.box2d.Body;
+
+public interface PhysicsBody {
+
+	Body getBody();
+
+	//public void handleCollission(Entity other);
+
+}

core/src/com/me/brickbuster/entity/powerup/PowerUp.java

@@ -4,29 +4,55 @@ import com.badlogic.gdx.graphics.Color;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
 import com.badlogic.gdx.math.Vector2;
+import com.badlogic.gdx.physics.box2d.Body;
+import com.badlogic.gdx.physics.box2d.BodyDef;
+import com.badlogic.gdx.physics.box2d.CircleShape;
+import com.badlogic.gdx.physics.box2d.FixtureDef;
 import com.me.brickbuster.Utils;
 import com.me.brickbuster.entity.Entity;
+import com.me.brickbuster.entity.PhysicsBody;
 import com.me.brickbuster.state.PlayState;
 import net.dermetfan.utils.Pair;
 
-public abstract class PowerUp extends Entity {
+public abstract class PowerUp extends Entity implements PhysicsBody {
 
-	public static final int RADIUS = 45;
+	public static final float RADIUS = 1.2f;
-	public static final int FALL_SPEED = 600;
+	public static final float FALL_SPEED = 15f;
 
 	private Color color;
 	private boolean isCaught;
 
+	private Body body;
+
 	public PowerUp(PlayState state, Vector2 pos, Color color) {
 		super(state, pos);
 		this.color = color;
+
+		BodyDef ballBody = new BodyDef();
+		ballBody.type = BodyDef.BodyType.DynamicBody;
+		ballBody.position.set(pos);
+
+		CircleShape ballShape = new CircleShape();
+		ballShape.setRadius(RADIUS);
+
+		FixtureDef ballFixture = new FixtureDef();
+		ballFixture.shape = ballShape;
+		ballFixture.isSensor = true;
+
+		body = state.world.createBody(ballBody);
+		body.createFixture(ballFixture);
+		body.setUserData(this);
+
+		ballShape.dispose();
 	}
 
 	@Override
 	public void render(ShapeRenderer sr) {
 		sr.begin(ShapeType.Filled);
 		sr.setColor(color);
-		sr.circle(getX(), getY(), RADIUS);
+		sr.circle(getX() * PlayState.PIXEL_PER_METER,
+				getY() * PlayState.PIXEL_PER_METER,
+				RADIUS * PlayState.PIXEL_PER_METER);
 		sr.end();
 	}
 
@@ -48,6 +74,11 @@ public abstract class PowerUp extends Entity {
 		}
 	}
 
+	@Override
+	public Body getBody() {
+		return body;
+	}
+
 	public abstract void activate();
 
 	public boolean isCaught() {

core/src/com/me/brickbuster/state/PlayState.java

@@ -4,6 +4,8 @@ import com.badlogic.gdx.Gdx;
 import com.badlogic.gdx.graphics.Color;
 import com.badlogic.gdx.graphics.glutils.ShapeRenderer.ShapeType;
 import com.badlogic.gdx.math.MathUtils;
+import com.badlogic.gdx.math.Vector2;
+import com.badlogic.gdx.physics.box2d.*;
 import com.me.brickbuster.BrickBuster;
 import com.me.brickbuster.entity.Ball;
 import com.me.brickbuster.entity.Brick;
@@ -14,12 +16,30 @@ import java.util.*;
 
 public class PlayState extends State {
 
-	public static final int SHIELD_HEIGHT = 30;
+	public static final float PIXEL_PER_METER = 40f;    // Board dimension: 54x96 meters
+	public static final float BOARD_WIDTH = 54f;
+	public static final float BOARD_HEIGHT = 96f;
+	public static final float EDGE_PADDING = .125f;
+
+
+	public static final float SHIELD_HEIGHT = 0.75f;
 	public static final float POWERUP_CHANCE = 0.15f;
 
 	public static final int COLUMNS = 9;
 	public static final int ROWS = 8;
 
+	public static final Vector2 lowerLeftCorner =
+			new Vector2(EDGE_PADDING,EDGE_PADDING);
+	public static final Vector2 lowerRightCorner =
+			new Vector2(BrickBuster.BOARD_WIDTH/PIXEL_PER_METER-EDGE_PADDING,EDGE_PADDING);
+	public static final Vector2 upperRightCorner =
+			new Vector2(BrickBuster.BOARD_WIDTH/PIXEL_PER_METER-EDGE_PADDING, BrickBuster.BOARD_HEIGHT/PIXEL_PER_METER-EDGE_PADDING);
+	public static final Vector2 upperLeftCorner =
+			new Vector2(EDGE_PADDING, BrickBuster.BOARD_HEIGHT/PIXEL_PER_METER-EDGE_PADDING);
+
+	public World world;
+	public Body playArea;
+
 	public List<PowerUp> powerUps;
 	public Paddle paddle;
 	public List<Ball> balls;
@@ -28,28 +48,54 @@ public class PlayState extends State {
 	private int shieldCount = 0;
 	private float updateTime = 0f;
 
+	private final Box2DDebugRenderer debugRenderer;
+
 	public PlayState(BrickBuster game) {
 		super(game);
+		debugRenderer = new Box2DDebugRenderer();
 	}
 
 	@Override
 	public void setup() {
+		// Initialize a world with no gravity
+		world = new World(new Vector2(), false);
+
+		// define a playArea body with position set to 0
+		BodyDef playAreaDef = new BodyDef();
+		playAreaDef.position.set(new Vector2());
+		EdgeShape screenEdge = new EdgeShape();
+
+		playArea = world.createBody(playAreaDef);
+		// Right edge
+		screenEdge.set(lowerRightCorner, upperRightCorner);
+		playArea.createFixture(screenEdge, 0f);
+		// Top edge
+		screenEdge.set(upperRightCorner, upperLeftCorner);
+		playArea.createFixture(screenEdge, 0f);
+		// Left edge
+		screenEdge.set(upperLeftCorner, lowerLeftCorner);
+		playArea.createFixture(screenEdge, 0f);
+		// Bottom edge
+		screenEdge.set(lowerLeftCorner, lowerRightCorner);
+		playArea.createFixture(screenEdge, 0f);
+		screenEdge.dispose();
+
 		powerUps = new ArrayList<PowerUp>();
 		paddle = new Paddle(this);
 
-		int brick_padding = (BrickBuster.BOARD_WIDTH - COLUMNS * Brick.BRICK_WIDTH) / (COLUMNS + 1);
+		float brick_padding = ((BrickBuster.BOARD_WIDTH/PIXEL_PER_METER) - COLUMNS * Brick.BRICK_WIDTH) / (COLUMNS + 1);
 		bricks = new ArrayList<Brick>();
 		for (int col = 0; col < COLUMNS; col++) {
 			for (int row = 0; row < ROWS; row++) {
-				int x = brick_padding + (col * (Brick.BRICK_WIDTH + brick_padding));
+				float x = brick_padding + (col * (Brick.BRICK_WIDTH + brick_padding));
-				int y = brick_padding + Brick.BRICK_HEIGHT + (row * (Brick.BRICK_HEIGHT + brick_padding));
+				float y = brick_padding + Brick.BRICK_HEIGHT + (row * (Brick.BRICK_HEIGHT + brick_padding));
 
 				PowerUpType powerUpType = null;
 				if (MathUtils.randomBoolean(POWERUP_CHANCE)) {
 					powerUpType = PowerUpType.getWeightedRandom();
 				}
 
-				bricks.add(new Brick(this, powerUpType, x, BrickBuster.BOARD_HEIGHT - y));
+				bricks.add(new Brick(this, powerUpType, x, BrickBuster.BOARD_HEIGHT/PIXEL_PER_METER - y));
 			}
 		}
 
@@ -84,11 +130,15 @@ public class PlayState extends State {
 		game.font.draw(game.sb, String.format("FPS: %d Update: %.2f ms Render: %.2f ms",
 				Gdx.graphics.getFramesPerSecond(), updateTime/1000000f, renderTime/1000000f), 10, BrickBuster.BOARD_HEIGHT-10);
 		game.sb.end();
+
+		debugRenderer.render(world, game.cam.combined.cpy().scl(PIXEL_PER_METER));
 	}
 
 	@Override
 	public void update(float dt) {
 		long start = System.nanoTime();
+		world.step(dt, 6, 2);
+
 		paddle.update(dt);
 
 		for (Iterator<Ball> it = balls.iterator(); it.hasNext();) {