Add a new spinning effect

core/src/io/github/lonamiwebs/klooni/Effect.java

@@ -24,6 +24,7 @@ import com.badlogic.gdx.math.Vector2;
 
 import io.github.lonamiwebs.klooni.effects.EvaporateEffect;
 import io.github.lonamiwebs.klooni.effects.IEffect;
+import io.github.lonamiwebs.klooni.effects.SpinEffect;
 import io.github.lonamiwebs.klooni.effects.VanishEffect;
 import io.github.lonamiwebs.klooni.effects.WaterdropEffect;
 import io.github.lonamiwebs.klooni.game.Cell;
@@ -70,7 +71,8 @@ public class Effect {
         return new Effect[] {
                 new Effect("vanish"),
                 new Effect("waterdrop"),
-                new Effect("evaporate")
+                new Effect("evaporate"),
+                new Effect("spin")
         };
     }
 
@@ -92,6 +94,9 @@ public class Effect {
             case 2:
                 effect = new EvaporateEffect();
                 break;
+            case 3:
+                effect = new SpinEffect();
+                break;
         }
         effect.setInfo(deadCell, culprit);
         return effect;
@@ -104,6 +109,7 @@ public class Effect {
         if (name.equals("vanish")) return 0;
         if (name.equals("waterdrop")) return 1;
         if (name.equals("evaporate")) return 2;
+        if (name.equals("spin")) return 3;
         return -1;
     }
 

core/src/io/github/lonamiwebs/klooni/effects/SpinEffect.java

@@ -0,0 +1,60 @@
+package io.github.lonamiwebs.klooni.effects;
+
+import com.badlogic.gdx.Gdx;
+import com.badlogic.gdx.graphics.Color;
+import com.badlogic.gdx.graphics.g2d.Batch;
+import com.badlogic.gdx.math.Interpolation;
+import com.badlogic.gdx.math.Matrix4;
+import com.badlogic.gdx.math.Vector2;
+
+import io.github.lonamiwebs.klooni.game.Cell;
+
+public class SpinEffect implements IEffect {
+    private float age;
+    private Vector2 pos;
+    private float size;
+    private Color color;
+
+    private static final float UP_SPEED = 100.0f;
+    private static final float LIFETIME = 2.0f;
+    private static final float INV_LIFETIME = 1.0f / LIFETIME;
+
+    private static final float TOTAL_ROTATION = 600;
+
+    @Override
+    public void setInfo(Cell deadCell, Vector2 culprit) {
+        age = 0;
+        pos = deadCell.pos.cpy();
+        size = deadCell.size;
+        color = deadCell.getColorCopy();
+    }
+
+    @Override
+    public void draw(Batch batch) {
+        age += Gdx.graphics.getDeltaTime();
+
+        final float progress = age * INV_LIFETIME;
+        final float currentSize = Interpolation.pow2In.apply(size, 0, progress);
+        final float currentRotation = Interpolation.sine.apply(0, TOTAL_ROTATION, progress);
+
+        final Matrix4 original = batch.getTransformMatrix().cpy();
+        final Matrix4 rotated = batch.getTransformMatrix();
+
+        final float disp =
+                + 0.5f * (size - currentSize) // the smaller, the more we need to "push" to center
+                + currentSize * 0.5f; // center the cell for rotation
+
+        rotated.translate(pos.x + disp, pos.y + disp, 0);
+        rotated.rotate(0, 0, 1, currentRotation);
+        rotated.translate(currentSize * -0.5f, currentSize * -0.5f, 0); // revert centering for rotation
+
+        batch.setTransformMatrix(rotated);
+        Cell.draw(color, batch, 0, 0, currentSize);
+        batch.setTransformMatrix(original);
+    }
+
+    @Override
+    public boolean isDone() {
+        return age > LIFETIME;
+    }
+}