added particles

src/de/miaurizius/jgame2d/entity/particle/Particle.java

@@ -0,0 +1,50 @@
+package de.miaurizius.jgame2d.entity.particle;
+
+import de.miaurizius.jgame2d.core.GamePanel;
+import de.miaurizius.jgame2d.entity.Entity;
+
+import java.awt.*;
+
+public class Particle extends Entity {
+
+    GamePanel panel;
+    Entity generator;
+    Color color;
+    int size;
+    int xd, yd;
+
+    public Particle(GamePanel panel, Entity generator, Color color, int size, int speed, int maxLife, int xd, int yd) {
+        super(panel);
+        this.panel = panel;
+        this.generator = generator;
+        this.color = color;
+        this.size = size;
+        this.speed = speed;
+        this.maxLife = maxLife;
+        this.xd = xd;
+        this.yd = yd;
+
+        life = maxLife;
+        int offset = (panel.tileSize/2) - (size/2);
+        worldX = generator.worldX + offset;
+        worldY = generator.worldY + offset;
+    }
+
+    @Override
+    public void update() {
+        life--;
+        if(life < maxLife/3) yd++;
+        worldX += xd*speed;
+        worldY += yd*speed;
+        alive = (life != 0);
+    }
+
+    @Override
+    public void draw(Graphics2D graphics2d) {
+        int screenX = worldX - panel.player.worldX + panel.player.screenX;
+        int screenY = worldY - panel.player.worldY + panel.player.screenY;
+
+        graphics2d.setColor(color);
+        graphics2d.fillRect(screenX, screenY, size, size);
+    }
+}