Initial commit

.children

@@ -0,0 +1 @@
+Fireworks.dart

.gitignore

@@ -0,0 +1,3 @@
+*~
+*.swp
+

.project

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>Fireworks</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>com.google.dart.tools.core.dartBuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>com.google.dart.tools.core.dartNature</nature>
+	</natures>
+</projectDescription>

Fireworks.dart

@@ -0,0 +1,192 @@
+// a Dart port of http://jsdo.it/zarkswerk/fireworx
+
+// Author: Fuji, Goro (gfx) <gfuji@cpan.org>
+// LICENSE: The MIT License
+
+#import('dart:html');
+
+num random() {
+  final num N = 3;
+  num gen = 0.0;
+  for(int i = 0; i < N; ++i) {
+    gen += Math.random();
+  }
+  return gen / N;
+}
+
+String randomColor() {
+  final List<int> rgb = new List<int>(3);
+  for(int i = 0; i < rgb.length; ++i) {
+    rgb[i] = (random() * 0xFF).toInt();
+  }
+  return "rgb(${rgb[0]},${rgb[1]},${rgb[2]})";
+}
+
+class Spark {
+  static final num rad = Math.PI * 2;
+
+  num posX;
+  num posY;
+  num velX;
+  num velY;
+  num size;
+  bool sw;
+
+  Spark(this.posX, this.posY, this.size) {
+    num angle    = random() * rad;
+    num velocity = random() * 5.0;
+
+    velX = Math.cos(angle) * velocity;
+    velY = Math.sin(angle) * velocity;
+    sw = random() > 0.5;
+  }
+
+  void computeVelocity() {
+    posX += velX;
+    posY += velY;
+  }
+
+  void computeDecay(num d) {
+    velX *= d;
+    velY *= d;
+    size *= d;
+  }
+
+  void computeGravity(num g) {
+    posY += g;
+  }
+
+  void draw(CanvasRenderingContext2D cx, String color) {
+    cx.beginPath();
+    cx.arc(posX, posY, size, 0, rad, true);
+
+    if(sw) {
+      cx.fillStyle = "rgb(255, 255, 255)";
+      sw = false;
+    }
+    else {
+      cx.fillStyle = color;
+      sw = true;
+    }
+
+    cx.fill();
+  }
+}
+
+class Firework {
+  static final num quantity  = 360;
+  static final num size      = 2.0;
+  static final num decay     = 0.98;
+  static final num gravity   = 1.5;
+
+
+  final String color;
+  final List<Spark> sparks;
+
+  Firework(int x, int y) : color = randomColor(), sparks = new List<Spark>() {
+    for(int i = 0; i < quantity; ++i) {
+      sparks.add(new Spark(x, y, size));
+    }
+  }
+
+  void update(CanvasRenderingContext2D cx) {
+    for(int i = 0; i < sparks.length; ++i) {
+      Spark s = sparks[i];
+
+      s.computeVelocity();
+      s.computeDecay(decay);
+      s.computeGravity(gravity);
+
+      s.draw(cx, color);
+
+
+      if(s.size <= 0.1 || s.posX <= 0 || s.posX >= 400 || s.posY >= 400) {
+        sparks.removeRange(i, 1);
+      }
+    }
+  }
+
+  bool isDismissed() => sparks.isEmpty();
+}
+
+class FireworkView {
+  CanvasRenderingContext2D cx;
+  int width;
+  int height;
+  int left;
+  int top;
+
+  List<Firework> fireworks;
+
+  FireworkView(CanvasElement canvas) : fireworks = new List<Firework>() {
+    cx = canvas.getContext("2d");
+
+    width  = canvas.width;
+    height = canvas.height;
+    canvas.rect.then((ElementRect rect) {
+      left = rect.bounding.left;
+      top  = rect.bounding.top;
+
+      canvas.on.mouseDown.add( (MouseEvent e) {
+        explode(e.clientX, e.clientY);
+      });
+      canvas.on.touchStart.add( (TouchEvent e) {
+        explode(e.touches[0].pageX, e.touches[1].pageY);
+      });
+    });
+  }
+
+  void explode(int x, int y) {
+    fireworks.add(new Firework(x - left, y - top));
+  }
+
+  void update() {
+    if(fireworks.isEmpty()) return;
+
+    for(int i = 0; i < fireworks.length; ++i) {
+      Firework fw = fireworks[i];
+
+      fw.update(cx);
+
+      if(fw.isDismissed()) {
+        fireworks.removeRange(i, 1);
+      }
+    }
+
+    cx.fillStyle = "rgba(0, 0, 0, 0.3)";
+    cx.fillRect(0, 0, width, height);
+  }
+}
+
+class FPSWatcher {
+  Stopwatch watch;
+  int fps;
+
+  FPSWatcher() {
+    watch = new Stopwatch.start();
+    fps   = 0;
+  }
+
+  void update() {
+    ++fps;
+
+    if(watch.elapsedInMs() >= 1000) {
+      String message = "FPS: $fps";
+      document.query('#fps').innerHTML = message;
+      watch.reset();
+      fps = 0;
+    }
+  }
+}
+
+void main() {
+  CanvasElement canvas = document.query("#night-sky");
+
+  FireworkView fm   = new FireworkView(canvas);
+  FPSWatcher watcher = new FPSWatcher();
+
+  window.setInterval(() {
+    fm.update();
+    watcher.update();
+  }, 0);
+}