Keep a global ShapeRenderer instance rather than an instance per entity

core/src/com/me/brickbuster/BrickBuster.java

@@ -2,16 +2,15 @@ package com.me.brickbuster;
 
 import com.badlogic.gdx.ApplicationAdapter;
 import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.graphics.Color;
 import com.badlogic.gdx.graphics.GL20;
 import com.badlogic.gdx.graphics.g2d.BitmapFont;
 import com.badlogic.gdx.graphics.g2d.SpriteBatch;
+import com.badlogic.gdx.graphics.glutils.ShapeRenderer;
 import com.badlogic.gdx.math.MathUtils;
 import com.badlogic.gdx.math.Vector2;
 import com.me.brickbuster.entity.*;
-import com.me.brickbuster.entity.powerup.GluePowerUp;
-import com.me.brickbuster.entity.powerup.LongerPaddlePowerUp;
-import com.me.brickbuster.entity.powerup.MultiBallPowerUp;
-import com.me.brickbuster.entity.powerup.PowerUp;
+import com.me.brickbuster.entity.powerup.*;
 
 import java.util.*;
 
@@ -21,6 +20,8 @@ public class BrickBuster extends ApplicationAdapter {
 	public static final int HEIGHT = 600;
 	public static final String TITLE = "Brick Buster";
 
+	public static final int SHIELD_HEIGHT = 5;
+
 	public static final Vector2 HORIZONTAL_EDGE = new Vector2(1, 0);
 	public static final Vector2 VERTICAL_EDGE = new Vector2(0, 1);
 
@@ -29,16 +30,20 @@ public class BrickBuster extends ApplicationAdapter {
 
 	private BitmapFont font;
 	private SpriteBatch batch;
+	private ShapeRenderer sr;
 
 	private Paddle paddle;
 	private ArrayList<Ball> balls;
 	private ArrayList<Brick> bricks;
 	private ArrayList<PowerUp> powerUps;
 
+	private boolean shieldActive = false;
+
 	@Override
 	public void create () {
 		font = new BitmapFont();
 		batch = new SpriteBatch();
+		sr = new ShapeRenderer();
 
 		paddle = new Paddle(this);
 
@@ -66,21 +71,30 @@ public class BrickBuster extends ApplicationAdapter {
 		Gdx.gl.glClearColor(0.5f,1,1,1);
 		Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
 
+
 		long start_update = System.nanoTime();
 		update(Gdx.graphics.getDeltaTime());
 		long finish_update = System.nanoTime() - start_update;
 
 		long start_render = System.nanoTime();
 		for (Brick block : bricks) {
-			block.render();
+			block.render(sr);
 		}
 		for (PowerUp powerUp : powerUps) {
-			powerUp.render();
+			powerUp.render(sr);
 		}
 		for (Ball ball : balls) {
-			ball.render();
+			ball.render(sr);
 		}
-		paddle.render();
+		paddle.render(sr);
+
+		if (shieldActive) {
+			sr.begin(ShapeRenderer.ShapeType.Filled);
+			sr.setColor(Color.SALMON);
+			sr.rect(0, 0, WIDTH, SHIELD_HEIGHT);
+			sr.end();
+		}
+
 		long finish_render = System.nanoTime() - start_render;
 
 		batch.begin();
@@ -143,6 +157,14 @@ public class BrickBuster extends ApplicationAdapter {
 		return null;
 	}
 
+	public void setShieldActive(boolean shieldActive) {
+		this.shieldActive = shieldActive;
+	}
+
+	public boolean isShieldActive() {
+		return shieldActive;
+	}
+
 	public ArrayList<Ball> getBalls() {
 		return balls;
 	}
@@ -166,6 +188,7 @@ public class BrickBuster extends ApplicationAdapter {
 		tmp.put(GluePowerUp.class, 30);
 		tmp.put(LongerPaddlePowerUp.class, 40);
 		tmp.put(MultiBallPowerUp.class, 20);
+		tmp.put(ShieldPowerUp.class, 40);
 		powerUpWeights = Collections.unmodifiableMap(tmp);
 
 		int sum = 0;

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

@@ -2,6 +2,7 @@ package com.me.brickbuster.entity;
 
 import com.badlogic.gdx.Gdx;
 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.MathUtils;
 import com.badlogic.gdx.math.Vector2;
@@ -30,11 +31,11 @@ public class Ball extends Entity {
 	}
 
 	@Override
-	public void render() {
-		getShapeRenderer().begin(ShapeType.Filled);
-		getShapeRenderer().setColor(BALL_COLOR);
-		getShapeRenderer().circle(getPos().x, getPos().y, RADIUS);
-		getShapeRenderer().end();
+	public void render(ShapeRenderer sr) {
+		sr.begin(ShapeType.Filled);
+		sr.setColor(BALL_COLOR);
+		sr.circle(getPos().x, getPos().y, RADIUS);
+		sr.end();
 	}
 
 	@Override
@@ -75,12 +76,13 @@ public class Ball extends Entity {
 			Utils.reflect(direction, BrickBuster.VERTICAL_EDGE);
 		} else if (new_pos.y + RADIUS > BrickBuster.HEIGHT) {
 			Utils.reflect(direction, BrickBuster.HORIZONTAL_EDGE);
+		} else if (new_pos.y - RADIUS < BrickBuster.SHIELD_HEIGHT && getBrickBuster().isShieldActive()) {
+			Utils.reflect(direction, BrickBuster.HORIZONTAL_EDGE);
+			getBrickBuster().setShieldActive(false);
 		} else if (new_pos.y + RADIUS < 0) {
 			isDead = true;
 			return;
-		}
-
-		if (direction.y < 0 && new_pos.y <= Paddle.PADDLE_Y + Paddle.PADDLE_HEIGHT + RADIUS) {
+		} else if (direction.y < 0 && new_pos.y <= Paddle.PADDLE_Y + Paddle.PADDLE_HEIGHT + RADIUS) {
 			Pair<Vector2, Vector2> paddle = getBrickBuster().getPaddle().getTopEdge();
 			Vector2 lineDir = paddle.getValue().sub(paddle.getKey());
 			Vector2 nearest = Utils.nearestPoint(paddle.getKey().cpy(), lineDir, new_pos.cpy());

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

@@ -1,6 +1,7 @@
 package com.me.brickbuster.entity;
 
 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;
@@ -28,11 +29,11 @@ public class Brick extends Entity {
 	}
 
 	@Override
-	public void render() {
-		getShapeRenderer().begin(ShapeType.Filled);
-		getShapeRenderer().setColor(BLOCK_COLOR);
-		getShapeRenderer().rect(getX(), getY(), BLOCK_WIDTH, BLOCK_HEIGHT);
-		getShapeRenderer().end();
+	public void render(ShapeRenderer sr) {
+		sr.begin(ShapeType.Filled);
+		sr.setColor(BLOCK_COLOR);
+		sr.rect(getX(), getY(), BLOCK_WIDTH, BLOCK_HEIGHT);
+		sr.end();
 	}
 
 	@Override

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

@@ -6,17 +6,15 @@ import com.me.brickbuster.BrickBuster;
 
 public abstract class Entity {
 
-	private ShapeRenderer shapeRenderer;
 	private BrickBuster brickBuster;
 	private Vector2 pos;
 
 	public Entity(BrickBuster brickBuster, float x, float y) {
-		this.shapeRenderer = new ShapeRenderer();
 		this.brickBuster = brickBuster;
 		this.pos = new Vector2(x, y);
 	}
 
-	public abstract void render();
+	public abstract void render(ShapeRenderer sr);
 
 	public abstract void update(float dt);
 
@@ -24,10 +22,6 @@ public abstract class Entity {
 		return brickBuster;
 	}
 
-	public ShapeRenderer getShapeRenderer() {
-		return shapeRenderer;
-	}
-
 	public Vector2 getPos() {
 		return pos;
 	}

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

@@ -3,6 +3,7 @@ package com.me.brickbuster.entity;
 import com.badlogic.gdx.Gdx;
 import com.badlogic.gdx.Input;
 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;
@@ -24,11 +25,11 @@ public class Paddle extends Entity {
 	}
 
 	@Override
-	public void render() {
-		getShapeRenderer().begin(ShapeType.Filled);
-		getShapeRenderer().setColor(sticky? Color.GRAY : PADDLE_COLOR);
-		getShapeRenderer().rect(getX() - width/2, getY(), width, PADDLE_HEIGHT);
-		getShapeRenderer().end();
+	public void render(ShapeRenderer sr) {
+		sr.begin(ShapeType.Filled);
+		sr.setColor(sticky? Color.GRAY : PADDLE_COLOR);
+		sr.rect(getX() - width/2, getY(), width, PADDLE_HEIGHT);
+		sr.end();
 	}
 
 	@Override

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

@@ -2,6 +2,7 @@ package com.me.brickbuster.entity.powerup;
 
 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.me.brickbuster.Utils;
@@ -23,11 +24,11 @@ public abstract class PowerUp extends Entity {
 	}
 
 	@Override
-	public void render() {
-		getShapeRenderer().begin(ShapeRenderer.ShapeType.Filled);
-		getShapeRenderer().setColor(color);
-		getShapeRenderer().circle(getX(), getY(), RADIUS);
-		getShapeRenderer().end();
+	public void render(ShapeRenderer sr) {
+		sr.begin(ShapeType.Filled);
+		sr.setColor(color);
+		sr.circle(getX(), getY(), RADIUS);
+		sr.end();
 	}
 
 	@Override

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

@@ -0,0 +1,18 @@
+package com.me.brickbuster.entity.powerup;
+
+import com.badlogic.gdx.graphics.Color;
+import com.me.brickbuster.BrickBuster;
+import com.me.brickbuster.entity.Brick;
+
+public class ShieldPowerUp extends PowerUp {
+
+	public ShieldPowerUp(BrickBuster brickBuster, Brick brick) {
+		super(brickBuster, brick, Color.SALMON);
+	}
+
+	@Override
+	public void activate() {
+		getBrickBuster().setShieldActive(true);
+	}
+
+}