onebyonedesign » The Old Snow Trick – In the Third Dimension

While working on a little Valentine’s Day ecard for the most wonderful wife in the world, I suddenly had an idea…

Snow effects have been done in Flash since at least Flash 5 (maybe even Flash 4 if I think back hard enough), but I have yet to see a Flash snow storm in “true 3d”. Well, at least not until now. Seemed the new Particle API in Papervision3d was just the way to go for such a thing. Probably one of the oldest and nicest looking examples of snow in Flash, is the one presented on Kirupa.com. I really like the motion of that version, so borrowed a bit of the math for my own updated version. Also, I like the idea of using depth of field with papervision, so whilst borrowing, I boosted a bit of mrdoob’s “brute force” approach for depth of field. I didn’t go crazy with 200 textures though. I figured 4 were enough. No blur, a light blur, a medium blur, and a heavy blur. To be honest, you can’t really even notice the DOF anyway, but it’s there, and that’s all that matters. Add a little panorama and suddenly it’s snowing everywhere you look. Now, if I could just figure out how to keep the flakes from “sticking” to the camera, I’d have it made in the shade. I’m not sure if this is a clipping problem or what. If anyone knows why that happens, post a comment here and let me know.

The code for some snow:

/** 
* Snow in the Third Dimension (with some math from Kirupa.com) 
* @author Devon O. 
* @version 0.1 
*/  

package {  

	import flash.display.BitmapData; 
	import flash.display.GradientType; 
	import flash.display.Sprite; 
	import flash.filters.BlurFilter; 
	import flash.geom.Matrix; 
	import flash.geom.Point; 
	import org.papervision3d.cameras.FreeCamera3D; 
	import org.papervision3d.materials.special.BitmapParticleMaterial; 
	import org.papervision3d.view.BasicView;  

	import flash.events.Event;  

	import org.papervision3d.objects.DisplayObject3D; 
	import org.papervision3d.core.geom.Particles; 
	import org.papervision3d.core.geom.renderables.Particle;  

	public class Snow3d extends BasicView  {  

		private var snowHolder:DisplayObject3D; 
		private var flakes:Array; 
		private const NUM_FLAKES:int = 300; 
		private var cam:FreeCamera3D;  

		private var noBlurFlake:BitmapData; 
		private var ltBlurFlake:BitmapData; 
		private var medBlurFlake:BitmapData; 
		private var heavyBlurFlake:BitmapData;  

		public function Snow3d() { 
			super(stage.stageWidth, stage.stageHeight, true, false, FreeCamera3D.TYPE); 
			init(); 
		}  

		private function init():void { 
			cam = cameraAsFreeCamera3D; 
			cam.zoom = 1; 
			cam.focus = 400; 
			cam.z = 10;  

			createBitmaps();  

			snowHolder = new DisplayObject3D("snow_holder"); 
			flakes = new Array();  

			for(var i:int = 0; i &lt; NUM_FLAKES; i++) {  

				var mat:BitmapParticleMaterial = new BitmapParticleMaterial(noBlurFlake); 
				mat.smooth = true;  

				var flakeHolder:Particles = new Particles("flake" + i); 
				var flake:Particle = new Particle(mat, 10, 0, 0, 0);  

				flakeHolder.addParticle(flake);   

				flakeHolder.x = randRange(-2000, 2000); 
				flakeHolder.y = randRange(-2000, 2000); 
				flakeHolder.z = randRange( -2000, 2000);  

				flakeHolder.extra = { radians: 0, I:randRange(2, 8), K: (-Math.PI + Math.random() * Math.PI), noblur: new BitmapParticleMaterial(noBlurFlake), blur1: new BitmapParticleMaterial(ltBlurFlake),  blur2: new BitmapParticleMaterial(medBlurFlake), blur3: new BitmapParticleMaterial(heavyBlurFlake) };  

				snowHolder.addChild(flakeHolder); 
				flakes.push(flakeHolder); 
			}  

			scene.addChild(snowHolder);  

			singleRender();   

			addEventListener(Event.ENTER_FRAME, enterFrame); 
		}  

		private function createBitmaps():void { 
			var lightBlur:BlurFilter = new BlurFilter(4, 4, 1); 
			var medBlur:BlurFilter = new BlurFilter (8, 8, 1); 
			var heavyBlur:BlurFilter = new BlurFilter(16, 16, 1);  

			var type:String = GradientType.RADIAL; 
			var colors:Array = [0xFFFFFF, 0xFFFFFF, 0xFFFFFF]; 
			var alphas:Array = [1, .1, 0]; 
			var ratios:Array = [0, 200, 255]; 
			var mat:Matrix = new Matrix(); 
			mat.createGradientBox(10, 10);  

			var baseFlake:Sprite = new Sprite(); 
			baseFlake.graphics.beginGradientFill(type, colors, alphas, ratios, mat); 
			baseFlake.graphics.drawCircle(5, 5, 5); 
			baseFlake.graphics.endFill();  

			noBlurFlake = new BitmapData(10, 10, true, 0x00000000); 
			noBlurFlake.draw(baseFlake);  

			ltBlurFlake = new BitmapData(10, 10, true, 0x00000000); 
			ltBlurFlake.draw(baseFlake); 
			ltBlurFlake.applyFilter(ltBlurFlake, baseFlake.getBounds(baseFlake), new Point(), lightBlur);  

			medBlurFlake = new BitmapData(10, 10, true, 0x00000000); 
			medBlurFlake.draw(baseFlake); 
			medBlurFlake.applyFilter(medBlurFlake, baseFlake.getBounds(baseFlake), new Point(), medBlur);  

			heavyBlurFlake = new BitmapData(10, 10, true, 0x00000000); 
			heavyBlurFlake.draw(baseFlake); 
			heavyBlurFlake.applyFilter(heavyBlurFlake, baseFlake.getBounds(baseFlake), new Point(), heavyBlur); 
		}  

		function enterFrame(e:Event):void {  

			var pan:Number = cam.rotationY - 210 * stage.mouseX / (stage.stageWidth/2); 
			pan = Math.max( -100, Math.min( pan, 100 ) ); 
			cam.rotationY -= pan / 12;  

			var len:int = flakes.length;  

			for(var i:int = 0; i &lt; len; i++) { 
				var p:Particles = flakes[i];  

				if (Math.abs(p.sceneZ) &lt;= 100) { 
						p.particles[0].material = p.extra["noblur"] 
				} 
				if (Math.abs(p.sceneZ) &gt;= 101 &amp;&amp; Math.abs(p.z) &lt;= 200) { 
					p.particles[0].material = p.extra["blur1"] 
				} 
				if (Math.abs(p.sceneZ) &gt;= 201 &amp;&amp; Math.abs(p.z) &lt;= 300) { 
					p.particles[0].material = p.extra["blur2"] 
				} 
				if (Math.abs(p.sceneZ) &gt;= 301) { 
					p.particles[0].material = p.extra["blur3"] 
				}  

				p.extra["radians"] += (p.extra["K"] / 180) * Math.PI; 
				p.x -= 3 * (Math.cos(p.extra["radians"])); 
				p.z -= 3 * (Math.sin(p.extra["radians"])); 
				p.y -= p.extra["I"]; 
				if (p.y &lt; -2000) { 
					p.y = 2000; 
					p.x = randRange(-2000, 2000); 
					p.z = randRange( -2000, 2000);  

					p.extra["I"] = randRange(2, 8); 
				} 
			}  

			singleRender(); 
		}  

		private function randRange(min:Number, max:Number):Number { 
			return Math.floor(Math.random() * (max - min + 1)) + min; 
		} 
	} 
}

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

/**

* Snow in the Third Dimension (with some math from Kirupa.com)

* @author Devon O.

* @version 0.1

package {

import flash.display.BitmapData;

import flash.display.GradientType;

import flash.display.Sprite;

import flash.filters.BlurFilter;

import flash.geom.Matrix;

import flash.geom.Point;

import org.papervision3d.cameras.FreeCamera3D;

import org.papervision3d.materials.special.BitmapParticleMaterial;

import org.papervision3d.view.BasicView;

import flash.events.Event;

import org.papervision3d.objects.DisplayObject3D;

import org.papervision3d.core.geom.Particles;

import org.papervision3d.core.geom.renderables.Particle;

public class Snow3d extends BasicView {

private var snowHolder:DisplayObject3D;

private var flakes:Array;

private const NUM_FLAKES:int = 300;

private var cam:FreeCamera3D;

private var noBlurFlake:BitmapData;

private var ltBlurFlake:BitmapData;

private var medBlurFlake:BitmapData;

private var heavyBlurFlake:BitmapData;

public function Snow3d() {

super(stage.stageWidth, stage.stageHeight, true, false, FreeCamera3D.TYPE);

init();

}

private function init():void {

cam = cameraAsFreeCamera3D;

cam.zoom = 1;

cam.focus = 400;

cam.z = 10;

createBitmaps();

snowHolder = new DisplayObject3D("snow_holder");

flakes = new Array();

for(var i:int = 0; i < NUM_FLAKES; i++) {

var mat:BitmapParticleMaterial = new BitmapParticleMaterial(noBlurFlake);

mat.smooth = true;

var flakeHolder:Particles = new Particles("flake" + i);

var flake:Particle = new Particle(mat, 10, 0, 0, 0);

flakeHolder.addParticle(flake);

flakeHolder.x = randRange(-2000, 2000);

flakeHolder.y = randRange(-2000, 2000);

flakeHolder.z = randRange( -2000, 2000);

flakeHolder.extra = { radians: 0, I:randRange(2, 8), K: (-Math.PI + Math.random() * Math.PI), noblur: new BitmapParticleMaterial(noBlurFlake), blur1: new BitmapParticleMaterial(ltBlurFlake), blur2: new BitmapParticleMaterial(medBlurFlake), blur3: new BitmapParticleMaterial(heavyBlurFlake) };

snowHolder.addChild(flakeHolder);

flakes.push(flakeHolder);

}

scene.addChild(snowHolder);

singleRender();

addEventListener(Event.ENTER_FRAME, enterFrame);

}

private function createBitmaps():void {

var lightBlur:BlurFilter = new BlurFilter(4, 4, 1);

var medBlur:BlurFilter = new BlurFilter (8, 8, 1);

var heavyBlur:BlurFilter = new BlurFilter(16, 16, 1);

var type:String = GradientType.RADIAL;

var colors:Array = [0xFFFFFF, 0xFFFFFF, 0xFFFFFF];

var alphas:Array = [1, .1, 0];

var ratios:Array = [0, 200, 255];

var mat:Matrix = new Matrix();

mat.createGradientBox(10, 10);

var baseFlake:Sprite = new Sprite();

baseFlake.graphics.beginGradientFill(type, colors, alphas, ratios, mat);

baseFlake.graphics.drawCircle(5, 5, 5);

baseFlake.graphics.endFill();

noBlurFlake = new BitmapData(10, 10, true, 0x00000000);

noBlurFlake.draw(baseFlake);

ltBlurFlake = new BitmapData(10, 10, true, 0x00000000);

ltBlurFlake.draw(baseFlake);

ltBlurFlake.applyFilter(ltBlurFlake, baseFlake.getBounds(baseFlake), new Point(), lightBlur);

medBlurFlake = new BitmapData(10, 10, true, 0x00000000);

medBlurFlake.draw(baseFlake);

medBlurFlake.applyFilter(medBlurFlake, baseFlake.getBounds(baseFlake), new Point(), medBlur);

heavyBlurFlake = new BitmapData(10, 10, true, 0x00000000);

heavyBlurFlake.draw(baseFlake);

heavyBlurFlake.applyFilter(heavyBlurFlake, baseFlake.getBounds(baseFlake), new Point(), heavyBlur);

}

function enterFrame(e:Event):void {

var pan:Number = cam.rotationY - 210 * stage.mouseX / (stage.stageWidth/2);

pan = Math.max( -100, Math.min( pan, 100 ) );

cam.rotationY -= pan / 12;

var len:int = flakes.length;

for(var i:int = 0; i < len; i++) {

var p:Particles = flakes[i];

if (Math.abs(p.sceneZ) <= 100) {

p.particles[0].material = p.extra["noblur"]

}

if (Math.abs(p.sceneZ) >= 101 && Math.abs(p.z) <= 200) {

p.particles[0].material = p.extra["blur1"]

}

if (Math.abs(p.sceneZ) >= 201 && Math.abs(p.z) <= 300) {

p.particles[0].material = p.extra["blur2"]

}

if (Math.abs(p.sceneZ) >= 301) {

p.particles[0].material = p.extra["blur3"]

}

p.extra["radians"] += (p.extra["K"] / 180) * Math.PI;

p.x -= 3 * (Math.cos(p.extra["radians"]));

p.z -= 3 * (Math.sin(p.extra["radians"]));

p.y -= p.extra["I"];

if (p.y < -2000) {

p.y = 2000;

p.x = randRange(-2000, 2000);

p.z = randRange( -2000, 2000);

p.extra["I"] = randRange(2, 8);

}

singleRender();

}

private function randRange(min:Number, max:Number):Number {

return Math.floor(Math.random() * (max - min + 1)) + min;

}

And an example (with panorama):

The Old Snow Trick – In the Third Dimension

Active Window(S) Blur

Update to Website Generation Tool

Digging into the Microphone in Flash Player 10.1

Devon O. Wolfgang

Categories

Recent Comments

Archives