Calc rotation

Performance/PixelPerfectCollision/Project.xml

@@ -16,7 +16,7 @@
 	<!-- ____________________________ Window Settings ___________________________ -->
 
 	<!--These window settings apply to all targets-->
-	<window width="640" height="400" fps="60" background="#000000" hardware="true" vsync="false" />
+	<window width="640" height="400" fps="60" background="#222034" hardware="true" vsync="false" />
 
 	<!--HTML5-specific-->
 	<window if="html5" resizable="false" />

Performance/PixelPerfectCollision/source/Alien.hx

@@ -0,0 +1,59 @@
+import flixel.FlxG;
+import flixel.FlxSprite;
+import flixel.tweens.FlxEase;
+import flixel.tweens.FlxTween;
+
+class Alien extends DemoSprite
+{
+	var collides:Bool = false;
+
+	public function new()
+	{
+		super();
+
+		// set dance dance interstellar animations
+		loadGraphic("assets/alien.png", true);
+		/*
+		 * WebGL has trouble displaying large number of sprites with dynamic coloring,
+		 * so we switch bewteen two similar animations with different colors.
+		 */
+		var fps = FlxG.random.int(6, 10);
+		animation.add("dance_off", [0, 1, 0, 2], fps);
+		animation.add("dance_on", [3, 4, 3, 5], fps);
+		animation.play("dance_off"); // dance!
+	}
+
+	/**
+	 * Randomize position, scrollFactor, velocity and alpha.
+	 */
+	public function randomize()
+	{
+		var ran = FlxG.random;
+		x = ran.int(0, Std.int(FlxG.width - width)) + FlxG.camera.scroll.x;
+		y = ran.int(0, Std.int(FlxG.height - height)) + FlxG.camera.scroll.y;
+		alpha = ran.float(0.1, 1.0);
+		scrollFactor.x = alpha;
+		// negate the x-offset caused from scrollFactor
+		x += FlxG.camera.scroll.x * (scrollFactor.x - 1);
+		velocity.set(-ran.float(5, 25), 0);
+
+		// Neat tweening effect for new aliens appearing
+		var toY = y;
+		y = (y < FlxG.height / 2) ? -20 : FlxG.height + 20;
+		FlxTween.tween(this, {y: toY}, 1.0, { ease: FlxEase.expoOut, startDelay: ran.float() * 0.5 });
+	}
+
+	/**
+	 * Switches the between the red/white color to show whether an overlap is occurring.
+	 * @param value 
+	 */
+	override function setCollides(value:Bool)
+	{
+		if (value != collides)
+		{
+			collides = value;
+			var frame = animation.curAnim.curFrame;
+			animation.play("dance_" + (collides ? "on" : "off"), false, false, frame);
+		}
+	}
+}

Performance/PixelPerfectCollision/source/DemoSprite.hx

@@ -0,0 +1,66 @@
+import flixel.FlxG;
+import flixel.FlxObject;
+import flixel.FlxSprite;
+import flixel.math.FlxRect;
+
+class DemoSprite extends FlxSprite
+{
+	public function new (x = 0.0, y = 0.0)
+	{
+		super(x, y);
+	}
+
+	/**
+	 * Switches the between the red/white color to show whether an overlap is occurring.
+	 */
+	public function setCollides(value:Bool)
+	{
+		color = value ? 0xFFac3232 : 0xFF6abe30;
+	}
+
+	public function resetAngle()
+	{
+		angle = 0;
+		angularVelocity = 0;
+	}
+
+	public function resetScale()
+	{
+		scale.set(1, 1);
+	}
+
+	public function randomAngle()
+	{
+		angle = FlxG.random.float() * 360;
+		angularVelocity = FlxG.random.float(50, 100);
+	}
+
+	public function randomScale()
+	{
+		scale.x = FlxG.random.float(0.5, 2.0);
+		scale.y = scale.x;
+	}
+
+	#if debug
+	override function draw()
+	{
+		// For debugging
+		// drawDebugScreenBounds();
+
+		super.draw();
+	}
+
+	function drawDebugScreenBounds()
+	{
+		for (camera in cameras)
+		{
+			var rect = getScreenBounds(camera);
+			var gfx = beginDrawDebug(camera);
+			// fill static graphics object with square shape
+			gfx.lineStyle(1, 0x0000ff, 0.5);
+			gfx.drawRect(rect.x, rect.y, rect.width, rect.height);
+			endDrawDebug(camera);
+		}
+	}
+	#end
+}