Initial fire example

examples/js/Fire.js

@@ -0,0 +1,1041 @@
+/**
+ * @author Mike Piecuch / https://github.com/mikepiecuch
+ *
+ * Based on research paper "Real-Time Fluid Dynamics for Games" by Jos Stam
+ * http://www.dgp.toronto.edu/people/stam/reality/Research/pdf/GDC03.pdf
+ *
+ */
+
+THREE.Fire = function ( geometry, options ) {
+
+	THREE.Mesh.call( this, geometry );
+
+	this.type = 'Fire';
+
+	var scope = this;
+
+	this.clock = new THREE.Clock();
+
+	options = options || {};
+
+	var textureWidth = options.textureWidth || 512;
+	var textureHeight = options.textureHeight || 512;
+	var oneOverWidth = 1.0 / textureWidth;
+	var oneOverHeight = 1.0 / textureHeight;
+
+	var debug = (options.debug === undefined)? false : options.debug;
+	this.color1 = options.color1 || new THREE.Color( 0xffffff );
+	this.color2 = options.color2 || new THREE.Color( 0xffa000 );
+	this.color3 = options.color3 || new THREE.Color( 0x000000 );
+	this.colorBias = (options.colorBias === undefined)? 0.8 : options.colorBias;
+	this.diffuse = (options.diffuse === undefined)? 1.33 : options.diffuse;
+	this.viscosity = (options.viscosity === undefined)? 0.25 : options.viscosity;
+	this.expansion = (options.expansion === undefined)? -0.25 : options.expansion;
+	this.swirl = (options.swirl === undefined)? 50.0 : options.swirl;
+	this.burnRate = (options.burnRate === undefined)? 0.3 : options.burnRate;
+	this.drag = (options.drag === undefined)? 0.35 : options.drag;
+	this.airSpeed = (options.airSpeed === undefined)? 6.0 : options.airSpeed;
+	this.windVector = options.windVector || new THREE.Vector2( 0.0, 0.75 );
+	this.speed = (options.speed === undefined)? 500.0 : options.speed;
+	this.massConservation = (options.massConservation === undefined)? false : options.massConservation;
+
+	var size = textureWidth * textureHeight;
+	this.sourceData = new Uint8Array( 4 * size );
+
+	this.clearSources = function() {
+
+		for ( var y = 0; y < textureHeight; y++ ) {
+			for ( var x = 0; x < textureWidth; x++ ) {
+
+				i = y * textureWidth + x;
+				var stride = i * 4;
+
+				this.sourceData[ stride     ] = 0;
+				this.sourceData[ stride + 1 ] = 0;
+				this.sourceData[ stride + 2 ] = 0;
+				this.sourceData[ stride + 3 ] = 0;
+			}
+		}
+
+		this.sourceMaterial.uniforms.sourceMap.value = this.internalSource;
+		this.sourceMaterial.needsUpdate = true;
+
+		return this.sourceData;
+	}
+
+	this.addSource = function(u, v, radius, density=null, windX=null, windY=null) {
+
+		var startX = Math.max(Math.floor((u - radius) * textureWidth), 0);
+		var startY = Math.max(Math.floor((v - radius) * textureHeight), 0);
+		var endX = Math.min(Math.floor((u + radius) * textureWidth), textureWidth);
+		var endY = Math.min(Math.floor((v + radius) * textureHeight), textureHeight);
+
+		for (var y = startY; y < endY; y++) {
+			for (var x = startX; x < endX; x++) {
+
+				var diffX = x * oneOverWidth - u;
+				var diffY = y * oneOverHeight - v;
+
+				if (diffX * diffX + diffY * diffY < radius * radius) {
+					i = y * textureWidth + x;
+					var stride = i * 4;
+
+					if (density != null) {
+						this.sourceData[ stride ] = Math.min(Math.max(density, 0.0), 1.0) * 255;
+					}
+					if (windX != null) {
+						var wind = Math.min(Math.max(windX, -1.0), 1.0);
+						wind = (wind < 0.0)? Math.floor(wind * 127) + 255 : Math.floor(wind * 127);
+						this.sourceData[ stride + 1 ] = wind;
+					}
+					if (windY != null) {
+						var wind = Math.min(Math.max(windY, -1.0), 1.0);
+						wind = (wind < 0.0)? Math.floor(wind * 127) + 255 : Math.floor(wind * 127);
+						this.sourceData[ stride + 2 ] = wind;
+					}
+				}
+			}
+		}
+
+		this.internalSource.needsUpdate = true;
+
+		return this.sourceData;
+	}
+
+	// When setting source map, red channel is density. Green and blue channels
+	// encode x and y velocity respectively as signed chars:
+	// (0 -> 127 = 0.0 -> 1.0, 128 -> 255 = -1.0 -> 0.0 )
+	this.setSourceMap = function(texture) {
+		this.sourceMaterial.uniforms.sourceMap.value = texture;
+	}
+
+	var parameters = {
+		minFilter: THREE.NearestFilter,
+		magFilter: THREE.NearestFilter,
+		format: THREE.RGBAFormat,
+		depthBuffer: false,
+		stencilBuffer: false
+	};
+
+
+	this.field0 = new THREE.WebGLRenderTarget( textureWidth,
+											   textureHeight,
+											   parameters );
+
+	this.field0.background = new THREE.Color( 0x000000 );
+
+	this.field1 = new THREE.WebGLRenderTarget( textureWidth,
+											   textureHeight,
+											   parameters );
+
+	this.field0.background = new THREE.Color( 0x000000 );
+
+	this.fieldProj = new THREE.WebGLRenderTarget( textureWidth,
+											      textureHeight,
+											      parameters );
+
+	this.field0.background = new THREE.Color( 0x000000 );
+
+	if ( ! THREE.Math.isPowerOfTwo( textureWidth ) ||
+		 ! THREE.Math.isPowerOfTwo( textureHeight ) ) {
+
+		this.field0.texture.generateMipmaps = false;
+		this.field1.texture.generateMipmaps = false;
+		this.fieldProj.texture.generateMipmaps = false;
+	}
+
+
+	this.fieldScene = new THREE.Scene();
+	this.fieldScene.background = new THREE.Color( 0x000000 );
+
+	this.orthoCamera = new THREE.OrthographicCamera( textureWidth / -2,
+											         textureWidth / 2,
+											         textureHeight / 2,
+											         textureHeight / -2,
+											         1, 2 );
+    this.orthoCamera.position.z = 1;
+
+	this.fieldGeometry = new THREE.PlaneGeometry(textureWidth, textureHeight);
+
+	this.internalSource = new THREE.DataTexture( this.sourceData,
+										       textureWidth,
+										       textureHeight,
+										       THREE.RGBAFormat );
+
+	// Source Shader
+
+	var shader = THREE.Fire.SourceShader;
+	this.sourceMaterial = new THREE.ShaderMaterial( {
+		uniforms: shader.uniforms,
+		vertexShader: shader.vertexShader,
+		fragmentShader: shader.fragmentShader,
+		transparent: false
+	} );
+
+	this.clearSources();
+
+	this.sourceMesh = new THREE.Mesh( this.fieldGeometry, this.sourceMaterial );
+	this.fieldScene.add(this.sourceMesh);
+
+	// Diffuse Shader
+
+	var shader = THREE.Fire.DiffuseShader;
+	this.diffuseMaterial = new THREE.ShaderMaterial( {
+		uniforms: shader.uniforms,
+		vertexShader: shader.vertexShader,
+		fragmentShader: shader.fragmentShader,
+		transparent: false
+	} );
+
+	this.diffuseMaterial.uniforms.oneOverWidth.value = oneOverWidth;
+	this.diffuseMaterial.uniforms.oneOverHeight.value = oneOverHeight;
+
+	this.diffuseMesh = new THREE.Mesh( this.fieldGeometry, this.diffuseMaterial );
+	this.fieldScene.add(this.diffuseMesh);
+
+	// Drift Shader
+
+	shader = THREE.Fire.DriftShader;
+	this.driftMaterial = new THREE.ShaderMaterial( {
+		uniforms: shader.uniforms,
+		vertexShader: shader.vertexShader,
+		fragmentShader: shader.fragmentShader,
+		transparent: false
+	} );
+
+	this.driftMaterial.uniforms.oneOverWidth.value = oneOverWidth;
+	this.driftMaterial.uniforms.oneOverHeight.value = oneOverHeight;
+
+	this.driftMesh = new THREE.Mesh( this.fieldGeometry, this.driftMaterial );
+	this.fieldScene.add(this.driftMesh);
+
+	// Projection Shader 1
+
+	shader = THREE.Fire.ProjectionShader1;
+	this.projMaterial1 = new THREE.ShaderMaterial( {
+		uniforms: shader.uniforms,
+		vertexShader: shader.vertexShader,
+		fragmentShader: shader.fragmentShader,
+		transparent: false
+	} );
+
+	this.projMaterial1.uniforms.oneOverWidth.value = oneOverWidth ;
+	this.projMaterial1.uniforms.oneOverHeight.value = oneOverHeight;
+
+	this.projMesh1 = new THREE.Mesh( this.fieldGeometry, this.projMaterial1 );
+	this.fieldScene.add(this.projMesh1);
+
+	// Projection Shader 2
+
+	shader = THREE.Fire.ProjectionShader2;
+	this.projMaterial2 = new THREE.ShaderMaterial( {
+		uniforms: shader.uniforms,
+		vertexShader: shader.vertexShader,
+		fragmentShader: shader.fragmentShader,
+		transparent: false
+	} );
+
+
+	this.projMaterial2.uniforms.oneOverWidth.value = oneOverWidth ;
+	this.projMaterial2.uniforms.oneOverHeight.value = oneOverHeight;
+
+	this.projMesh2 = new THREE.Mesh( this.fieldGeometry, this.projMaterial2 );
+	this.fieldScene.add(this.projMesh2);
+
+	// Projection Shader 3
+
+	shader = THREE.Fire.ProjectionShader3;
+	this.projMaterial3 = new THREE.ShaderMaterial( {
+		uniforms: shader.uniforms,
+		vertexShader: shader.vertexShader,
+		fragmentShader: shader.fragmentShader,
+		transparent: false
+	} );
+
+
+	this.projMaterial3.uniforms.oneOverWidth.value = oneOverWidth ;
+	this.projMaterial3.uniforms.oneOverHeight.value = oneOverHeight;
+
+	this.projMesh3 = new THREE.Mesh( this.fieldGeometry, this.projMaterial3 );
+	this.fieldScene.add(this.projMesh3);
+
+	// Color Shader
+
+	if (debug) {
+		shader = THREE.Fire.DebugShader;
+	} else {
+		shader = THREE.Fire.ColorShader;
+	}
+	this.material = new THREE.ShaderMaterial( {
+		uniforms: shader.uniforms,
+		vertexShader: shader.vertexShader,
+		fragmentShader: shader.fragmentShader,
+		transparent: true
+	} );
+
+	this.material.uniforms.densityMap.value = this.field1.texture;
+
+	this.configShaders = function(dt) {
+		this.diffuseMaterial.uniforms.diffuse.value = dt * 0.05 * this.diffuse;
+		this.diffuseMaterial.uniforms.viscosity.value = dt * 0.05 * this.viscosity;
+		this.diffuseMaterial.uniforms.expansion.value = Math.exp(this.expansion * -1.0 );
+		this.diffuseMaterial.uniforms.swirl.value = Math.exp(this.swirl * -0.1 );
+		this.diffuseMaterial.uniforms.drag.value = Math.exp(this.drag * -0.1);
+		this.diffuseMaterial.uniforms.burnRate.value = this.burnRate * dt * 0.01;
+		this.driftMaterial.uniforms.windVector.value = this.windVector;
+		this.driftMaterial.uniforms.airSpeed.value = dt * this.airSpeed * 0.001 * textureHeight;
+		this.material.uniforms.color1.value = this.color1;
+		this.material.uniforms.color2.value = this.color2;
+		this.material.uniforms.color3.value = this.color3;
+		this.material.uniforms.colorBias.value = this.colorBias;
+	}
+
+	this.clearDiffuse = function() {
+		this.diffuseMaterial.uniforms.expansion.value = 1.0;
+		this.diffuseMaterial.uniforms.swirl.value = 1.0;
+		this.diffuseMaterial.uniforms.drag.value = 1.0;
+		this.diffuseMaterial.uniforms.burnRate.value = 0.0;
+	}
+
+	this.swapTextures = function() {
+        var swap = this.field0;
+        this.field0 = this.field1;
+        this.field1 = swap;
+	}
+
+	this.saveRenderState = function(renderer) {
+		this.savedRenderTarget = renderer.getRenderTarget();
+		this.savedVrEnabled = renderer.vr.enabled;
+		this.savedShadowAutoUpdate = renderer.shadowMap.autoUpdate;
+		this.savedAntialias = renderer.antialias;
+		this.savedToneMapping = renderer.toneMapping;
+
+	}
+
+	this.restoreRenderState = function(renderer) {
+		renderer.vr.enabled = this.savedVrEnabled;
+		renderer.shadowMap.autoUpdate = this.savedShadowAutoUpdate;
+		renderer.setRenderTarget(this.savedRenderTarget);
+		renderer.antialias = this.savedAntialias;
+		renderer.toneMapping = this.savedToneMapping;
+	}
+
+	this.renderSource = function(renderer) {
+
+		this.sourceMesh.visible = true;
+
+		this.sourceMaterial.uniforms.densityMap.value = this.field0.texture;
+
+		renderer.render( this.fieldScene, this.orthoCamera, this.field1);
+
+		this.sourceMesh.visible = false;
+
+        this.swapTextures();
+	}
+
+	this.renderDiffuse = function(renderer) {
+
+		this.diffuseMesh.visible = true;
+
+		this.diffuseMaterial.uniforms.densityMap.value = this.field0.texture;
+
+		renderer.render( this.fieldScene, this.orthoCamera, this.field1);
+
+		this.diffuseMesh.visible = false;
+
+        this.swapTextures();
+	}
+
+	this.renderDrift = function(renderer) {
+
+		this.driftMesh.visible = true;
+
+		this.driftMaterial.uniforms.densityMap.value = this.field0.texture;
+
+		renderer.render( this.fieldScene, this.orthoCamera, this.field1);
+
+		this.driftMesh.visible = false;
+
+        this.swapTextures();
+	}
+
+	this.renderProject = function(renderer) {
+
+		// Projection pass 1
+
+		this.projMesh1.visible = true;
+
+		this.projMaterial1.uniforms.densityMap.value = this.field0.texture;
+
+		renderer.render( this.fieldScene, this.orthoCamera, this.fieldProj);
+
+		this.projMesh1.visible = false;
+
+		this.projMaterial2.uniforms.densityMap.value = this.fieldProj.texture;
+
+		// Projection pass 2
+
+		this.projMesh2.visible = true;
+
+		for (var i = 0; i < 20; i++) {
+
+			renderer.render( this.fieldScene, this.orthoCamera, this.field1);
+
+			var temp = this.field1;
+			this.field1 = this.fieldProj;
+			this.fieldProj = temp;
+
+			this.projMaterial2.uniforms.densityMap.value = this.fieldProj.texture;
+
+		}
+
+		this.projMesh2.visible = false;
+
+		this.projMaterial3.uniforms.densityMap.value = this.field0.texture;
+		this.projMaterial3.uniforms.projMap.value = this.fieldProj.texture;
+
+		// Projection pass 3
+
+		this.projMesh3.visible = true;
+
+		renderer.render( this.fieldScene, this.orthoCamera, this.field1);
+
+		this.projMesh3.visible = false;
+
+        this.swapTextures();
+	}
+
+	this.onBeforeRender = function ( renderer, scene, camera ) {
+
+		var delta = this.clock.getDelta();
+		if (delta > 0.1) {
+			delta = 0.1;
+		}
+		var dt = delta * (this.speed * 0.1);
+
+		this.configShaders(dt);
+
+		this.saveRenderState(renderer);
+
+		renderer.vr.enabled = false; // Avoid camera modification and recursion
+		renderer.shadowMap.autoUpdate = false; // Avoid re-computing shadows
+		renderer.antialias = false;
+		renderer.toneMapping = THREE.NoToneMapping;
+
+		this.sourceMesh.visible = false;
+		this.diffuseMesh.visible = false;
+		this.driftMesh.visible = false;
+		this.projMesh1.visible = false;
+		this.projMesh2.visible = false;
+		this.projMesh3.visible = false;
+
+		this.renderSource(renderer);
+
+		this.clearDiffuse();
+		for (var i = 0; i < 21; i++) {
+			this.renderDiffuse(renderer);
+		}
+		this.configShaders(dt);
+		this.renderDiffuse(renderer);
+
+		this.renderDrift(renderer);
+
+		if (this.massConservation) {
+			this.renderProject(renderer);
+			this.renderProject(renderer);
+		}
+
+		// Final result out for coloring
+
+		this.material.map = this.field1.texture;
+		this.material.transparent = true;
+		this.material.minFilter = THREE.LinearFilter,
+		this.material.magFilter = THREE.LinearFilter,
+
+		this.restoreRenderState(renderer);
+    }
+}
+
+
+THREE.Fire.prototype = Object.create( THREE.Mesh.prototype );
+THREE.Fire.prototype.constructor = THREE.Fire;
+
+THREE.Fire.SourceShader = {
+
+	uniforms: {
+		'sourceMap': {
+			type: 't',
+			value: null
+		},
+		'densityMap': {
+			type: 't',
+			value: null
+		}
+	},
+
+	vertexShader: [
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		' 	  vUv = uv;',
+
+		'     vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
+		'     gl_Position = projectionMatrix * mvPosition;',
+
+		'}'
+
+	].join("\n"),
+
+	fragmentShader: [
+		'uniform sampler2D sourceMap;',
+		'uniform sampler2D densityMap;',
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+		'    vec4 source = texture2D( sourceMap, vUv );',
+		'    vec4 current = texture2D( densityMap, vUv );',
+
+		'    vec2 v0 = (current.gb - step(0.5, current.gb)) * 2.0;',
+		'    vec2 v1 = (source.gb - step(0.5, source.gb)) * 2.0;',
+
+		'    vec2 newVel = v0 + v1;',
+
+		'    newVel = clamp(newVel, -0.99, 0.99);',
+		'    newVel = newVel * 0.5 + step(0.0, -newVel);',
+
+		'    float newDensity = source.r + current.a;',
+		'    float newTemp = source.r + current.r;',
+
+		'    newDensity = clamp(newDensity, 0.0, 1.0);',
+		'    newTemp = clamp(newTemp, 0.0, 1.0);',
+
+		'    gl_FragColor = vec4(newTemp, newVel.xy, newDensity);',
+
+		'}'
+
+	].join("\n")
+}
+
+
+THREE.Fire.DiffuseShader = {
+
+	uniforms: {
+		'oneOverWidth': {
+			type: 'f',
+			value: null
+		},
+		'oneOverHeight': {
+			type: 'f',
+			value: null
+		},
+		'diffuse': {
+			type: 'f',
+			value: null
+		},
+		'viscosity': {
+			type: 'f',
+			value: null
+		},
+		'expansion': {
+			type: 'f',
+			value: null
+		},
+		'swirl': {
+			type: 'f',
+			value: null
+		},
+		'drag': {
+			type: 'f',
+			value: null
+		},
+		'burnRate': {
+			type: 'f',
+			value: null
+		},
+		'densityMap': {
+			type: 't',
+			value: null
+		}
+	},
+
+	vertexShader: [
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		' 	  vUv = uv;',
+
+		'     vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
+		'     gl_Position = projectionMatrix * mvPosition;',
+
+		'}'
+
+	].join("\n"),
+
+	fragmentShader: [
+		'uniform float oneOverWidth;',
+		'uniform float oneOverHeight;',
+		'uniform float diffuse;',
+		'uniform float viscosity;',
+		'uniform float expansion;',
+		'uniform float swirl;',
+		'uniform float burnRate;',
+		'uniform float drag;',
+		'uniform sampler2D densityMap;',
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		'    vec4 dC = texture2D( densityMap, vUv );',
+		'    vec4 dL = texture2D( densityMap, vec2(vUv.x - oneOverWidth, vUv.y) );',
+		'    vec4 dR = texture2D( densityMap, vec2(vUv.x + oneOverWidth, vUv.y) );',
+		'    vec4 dU = texture2D( densityMap, vec2(vUv.x, vUv.y - oneOverHeight) );',
+		'    vec4 dD = texture2D( densityMap, vec2(vUv.x, vUv.y + oneOverHeight) );',
+		'    vec4 dUL = texture2D( densityMap, vec2(vUv.x - oneOverWidth, vUv.y - oneOverHeight) );',
+		'    vec4 dUR = texture2D( densityMap, vec2(vUv.x + oneOverWidth, vUv.y - oneOverHeight) );',
+		'    vec4 dDL = texture2D( densityMap, vec2(vUv.x - oneOverWidth, vUv.y + oneOverHeight) );',
+		'    vec4 dDR = texture2D( densityMap, vec2(vUv.x + oneOverWidth, vUv.y + oneOverHeight) );',
+
+		'    dC.yz = (dC.yz - step(0.5, dC.yz)) * 2.0;',
+		'    dL.yz = (dL.yz - step(0.5, dL.yz)) * 2.0;',
+		'    dR.yz = (dR.yz - step(0.5, dR.yz)) * 2.0;',
+		'    dU.yz = (dU.yz - step(0.5, dU.yz)) * 2.0;',
+		'    dD.yz = (dD.yz - step(0.5, dD.yz)) * 2.0;',
+		'    dUL.yz = (dUL.yz - step(0.5, dUL.yz)) * 2.0;',
+		'    dUR.yz = (dUR.yz - step(0.5, dUR.yz)) * 2.0;',
+		'    dDL.yz = (dDL.yz - step(0.5, dDL.yz)) * 2.0;',
+		'    dDR.yz = (dDR.yz - step(0.5, dDR.yz)) * 2.0;',
+
+		'    vec4 result = (dC + vec4(diffuse, viscosity, viscosity, diffuse) * ( dL + dR + dU + dD + dUL + dUR + dDL + dDR )) / (1.0 + 8.0 * vec4(diffuse, viscosity, viscosity, diffuse)) - vec4(0.0, 0.0, 0.0, 0.001);',
+
+		'    float temperature = result.r;',
+		'    temperature = clamp(temperature - burnRate, 0.0, 1.0);',
+
+		'    vec2 velocity = result.yz;',
+
+		'    vec2 expansionVec = vec2(dL.w - dR.w, dU.w - dD.w);',
+
+		'    vec2 swirlVec = vec2((dL.z - dR.z) * 0.5, (dU.y - dD.y) * 0.5);',
+
+		'    velocity = velocity + (1.0 - expansion) * expansionVec + (1.0 - swirl) * swirlVec;',
+
+		'    velocity = velocity - (1.0 - drag) * velocity;',
+
+		'    gl_FragColor = vec4(temperature, velocity * 0.5 + step(0.0, -velocity), result.w);',
+
+		'    gl_FragColor = gl_FragColor * step(oneOverWidth, vUv.x);',
+		'    gl_FragColor = gl_FragColor * step(oneOverHeight, vUv.y);',
+		'    gl_FragColor = gl_FragColor * step(vUv.x, 1.0 - oneOverWidth);',
+		'    gl_FragColor = gl_FragColor * step(vUv.y, 1.0 - oneOverHeight);',
+
+		'}'
+
+	].join("\n")
+}
+
+THREE.Fire.DriftShader = {
+
+	uniforms: {
+		'oneOverWidth': {
+			type: 'f',
+			value: null
+		},
+		'oneOverHeight': {
+			type: 'f',
+			value: null
+		},
+		'windVector': {
+			type: 'v2',
+			value: new THREE.Vector2(0.0, 0.0)
+		},
+		'airSpeed': {
+			type: 'f',
+			value: null
+		},
+		'densityMap': {
+			type: 't',
+			value: null
+		}
+	},
+
+	vertexShader: [
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		' 	  vUv = uv;',
+
+		'     vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
+		'     gl_Position = projectionMatrix * mvPosition;',
+
+		'}'
+
+	].join("\n"),
+
+	fragmentShader: [
+		'uniform float oneOverWidth;',
+		'uniform float oneOverHeight;',
+		'uniform vec2 windVector;',
+		'uniform float airSpeed;',
+		'uniform sampler2D densityMap;',
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+		'    vec2 velocity = texture2D( densityMap, vUv ).gb;',
+		'    velocity = (velocity - step(0.5, velocity)) * 2.0;',
+
+		'    velocity = velocity + windVector;',
+
+		'    vec2 sourcePos = vUv - airSpeed * vec2(oneOverWidth, oneOverHeight) * velocity;',
+
+		'    vec2 units = sourcePos / vec2(oneOverWidth, oneOverHeight);',
+
+		'    vec2 intPos = floor(units);',
+		'    vec2 frac = units - intPos;',
+		'    intPos = intPos * vec2(oneOverWidth, oneOverHeight);',
+
+		'    vec4 dX0Y0 = texture2D( densityMap, intPos + vec2(0.0, -oneOverHeight) );',
+		'    vec4 dX1Y0 = texture2D( densityMap, intPos + vec2(oneOverWidth, 0.0) );',
+		'    vec4 dX0Y1 = texture2D( densityMap, intPos + vec2(0.0, oneOverHeight) );',
+		'    vec4 dX1Y1 = texture2D( densityMap, intPos + vec2(oneOverWidth, oneOverHeight) );',
+ 
+
+		'    dX0Y0.gb = (dX0Y0.gb - step(0.5, dX0Y0.gb)) * 2.0;',
+		'    dX1Y0.gb = (dX1Y0.gb - step(0.5, dX1Y0.gb)) * 2.0;',
+		'    dX0Y1.gb = (dX0Y1.gb - step(0.5, dX0Y1.gb)) * 2.0;',
+		'    dX1Y1.gb = (dX1Y1.gb - step(0.5, dX1Y1.gb)) * 2.0;',
+
+		'    vec4 source = mix(mix(dX0Y0, dX1Y0, frac.x), mix(dX0Y1, dX1Y1, frac.x), frac.y);',
+
+		'    source.gb = source.gb * 0.5 + step(0.0, -source.gb);',
+
+		'    gl_FragColor = source;',
+
+		'}'
+
+	].join("\n")
+}
+
+
+THREE.Fire.ProjectionShader1 = {
+
+	uniforms: {
+		'oneOverWidth': {
+			type: 'f',
+			value: null
+		},
+		'oneOverHeight': {
+			type: 'f',
+			value: null
+		},
+		'densityMap': {
+			type: 't',
+			value: null
+		}
+	},
+
+	vertexShader: [
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		' 	  vUv = uv;',
+
+		'     vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
+		'     gl_Position = projectionMatrix * mvPosition;',
+
+		'}'
+
+	].join("\n"),
+
+	fragmentShader: [
+		'uniform float oneOverWidth;',
+		'uniform float oneOverHeight;',
+		'uniform sampler2D densityMap;',
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+		'    float dL = texture2D( densityMap, vec2(vUv.x - oneOverWidth, vUv.y) ).g;',
+		'    float dR = texture2D( densityMap, vec2(vUv.x + oneOverWidth, vUv.y) ).g;',
+		'    float dU = texture2D( densityMap, vec2(vUv.x, vUv.y - oneOverHeight) ).b;',
+		'    float dD = texture2D( densityMap, vec2(vUv.x, vUv.y + oneOverHeight) ).b;',
+
+		'    dL = (dL - step(0.5, dL)) * 2.0;',
+		'    dR = (dR - step(0.5, dR)) * 2.0;',
+		'    dU = (dU - step(0.5, dU)) * 2.0;',
+		'    dD = (dD - step(0.5, dD)) * 2.0;',
+
+		'    float h = (oneOverWidth + oneOverHeight) * 0.5;',
+		'    float div = -0.5 * h * (dR - dL + dD - dU);',
+
+		'    gl_FragColor = vec4( 0.0, 0.0, div * 0.5 + step(0.0, -div), 0.0);',
+
+		'}'
+
+	].join("\n")
+}
+
+
+THREE.Fire.ProjectionShader2 = {
+
+	uniforms: {
+		'oneOverWidth': {
+			type: 'f',
+			value: null
+		},
+		'oneOverHeight': {
+			type: 'f',
+			value: null
+		},
+		'densityMap': {
+			type: 't',
+			value: null
+		}
+	},
+
+	vertexShader: [
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		' 	  vUv = uv;',
+
+		'     vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
+		'     gl_Position = projectionMatrix * mvPosition;',
+
+		'}'
+
+	].join("\n"),
+
+	fragmentShader: [
+		'uniform float oneOverWidth;',
+		'uniform float oneOverHeight;',
+		'uniform sampler2D densityMap;',
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+		'    float div = texture2D( densityMap, vUv ).b;',
+		'    float pL = texture2D( densityMap, vec2(vUv.x - oneOverWidth, vUv.y) ).g;',
+		'    float pR = texture2D( densityMap, vec2(vUv.x + oneOverWidth, vUv.y) ).g;',
+		'    float pU = texture2D( densityMap, vec2(vUv.x, vUv.y - oneOverHeight) ).g;',
+		'    float pD = texture2D( densityMap, vec2(vUv.x, vUv.y + oneOverHeight) ).g;',
+
+		'    float divNorm = (div - step(0.5, div)) * 2.0;',
+		'    pL = (pL - step(0.5, pL)) * 2.0;',
+		'    pR = (pR - step(0.5, pR)) * 2.0;',
+		'    pU = (pU - step(0.5, pU)) * 2.0;',
+		'    pD = (pD - step(0.5, pD)) * 2.0;',
+
+		'    float p = (divNorm + pR + pL + pD + pU) * 0.25;',
+
+		'    gl_FragColor = vec4( 0.0, p * 0.5 + step(0.0, -p), div, 0.0);',
+
+		'}'
+
+	].join("\n")
+}
+
+
+THREE.Fire.ProjectionShader3 = {
+
+	uniforms: {
+		'oneOverWidth': {
+			type: 'f',
+			value: null
+		},
+		'oneOverHeight': {
+			type: 'f',
+			value: null
+		},
+		'densityMap': {
+			type: 't',
+			value: null
+		},
+		'projMap': {
+			type: 't',
+			value: null
+		}
+	},
+
+	vertexShader: [
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		' 	  vUv = uv;',
+
+		'     vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
+		'     gl_Position = projectionMatrix * mvPosition;',
+
+		'}'
+
+	].join("\n"),
+
+	fragmentShader: [
+		'uniform float oneOverWidth;',
+		'uniform float oneOverHeight;',
+		'uniform sampler2D densityMap;',
+		'uniform sampler2D projMap;',
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+		'    vec4 orig = texture2D(densityMap, vUv);',
+
+		'    float pL = texture2D( projMap, vec2(vUv.x - oneOverWidth, vUv.y) ).g;',
+		'    float pR = texture2D( projMap, vec2(vUv.x + oneOverWidth, vUv.y) ).g;',
+		'    float pU = texture2D( projMap, vec2(vUv.x, vUv.y - oneOverHeight) ).g;',
+		'    float pD = texture2D( projMap, vec2(vUv.x, vUv.y + oneOverHeight) ).g;',
+
+		'    float uNorm = (orig.g - step(0.5, orig.g)) * 2.0;',
+		'    float vNorm = (orig.b - step(0.5, orig.b)) * 2.0;',
+
+		'    pL = (pL - step(0.5, pL)) * 2.0;',
+		'    pR = (pR - step(0.5, pR)) * 2.0;',
+		'    pU = (pU - step(0.5, pU)) * 2.0;',
+		'    pD = (pD - step(0.5, pD)) * 2.0;',
+
+		'    float h = (oneOverWidth + oneOverHeight) * 0.5;',
+		'    float u = uNorm - (0.5 * (pR - pL) / h);',
+		'    float v = vNorm - (0.5 * (pD - pU) / h);',
+
+		'    gl_FragColor = vec4( orig.r, u * 0.5 + step(0.0, -u), v * 0.5 + step(0.0, -v), orig.a);',
+
+		'}'
+
+	].join("\n")
+}
+
+THREE.Fire.ColorShader = {
+
+	uniforms: {
+		'color1': {
+			type: 'c',
+			value: null
+		},
+		'color2': {
+			type: 'c',
+			value: null
+		},
+		'color3': {
+			type: 'c',
+			value: null
+		},
+		'colorBias': {
+			type: 'f',
+			value: null
+		},
+		'densityMap': {
+			type: 't',
+			value: null
+		}
+	},
+
+	vertexShader: [
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		' 	  vUv = uv;',
+
+		'     vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
+		'     gl_Position = projectionMatrix * mvPosition;',
+
+		'}'
+
+	].join("\n"),
+
+	fragmentShader: [
+		'uniform vec3 color1;',
+		'uniform vec3 color2;',
+		'uniform vec3 color3;',
+		'uniform float colorBias;',
+		'uniform sampler2D densityMap;',
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+		'    float density = texture2D( densityMap, vUv ).a;',
+		'    float temperature = texture2D( densityMap, vUv ).r;',
+
+		'    float bias = clamp(colorBias, 0.0001, 0.9999);',
+
+		'    vec3 blend1 = mix(color3, color2, temperature / bias) * (1.0 - step(bias, temperature));',
+		'    vec3 blend2 = mix(color2, color1, (temperature - bias) / (1.0 - bias) ) * step(bias, temperature);',
+
+		'    gl_FragColor = vec4(blend1 + blend2, density);',
+		'}'
+
+	].join("\n")
+}
+
+
+THREE.Fire.DebugShader = {
+
+	uniforms: {
+		'color1': {
+			type: 'c',
+			value: null
+		},
+		'color2': {
+			type: 'c',
+			value: null
+		},
+		'color3': {
+			type: 'c',
+			value: null
+		},
+		'colorBias': {
+			type: 'f',
+			value: null
+		},
+		'densityMap': {
+			type: 't',
+			value: null
+		}
+	},
+
+	vertexShader: [
+		'varying vec2 vUv;',
+
+		'void main() {',
+
+		' 	  vUv = uv;',
+
+		'     vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
+		'     gl_Position = projectionMatrix * mvPosition;',
+
+		'}'
+
+	].join("\n"),
+
+	fragmentShader: [
+		'uniform sampler2D densityMap;',
+
+		'varying vec2 vUv;',
+
+		'void main() {',
+		'    float density;',
+		'    density = texture2D( densityMap, vUv ).a;',
+
+		'    vec2 vel = texture2D( densityMap, vUv ).gb;',
+
+		'    vel = (vel - step(0.5, vel)) * 2.0;',
+
+		'    float r = density;',
+		'    float g = max(abs(vel.x), density * 0.5);',
+		'    float b = max(abs(vel.y), density * 0.5);',
+		'    float a = max(density * 0.5, max(abs(vel.x), abs(vel.y)));',
+
+		'    gl_FragColor = vec4(r, g, b, a);',
+
+		'}'
+
+	].join("\n")
+}

examples/webgl_fire.html

@@ -0,0 +1,444 @@
+<!DOCTYPE html>
+<html lang="en">
+	<head>
+		<title>three.js webgl - fire - texture</title>
+		<meta charset="utf-8">
+		<meta name="viewport" content="width=device-width, user-scalable=no, minimum-scale=1.0, maximum-scale=1.0">
+		<style>
+			body {
+				background:#222;
+				padding:0;
+				margin:0;
+				overflow:hidden;
+			}
+
+			#info {
+				position: absolute;
+				top: 0px;
+				width: 100%;
+				color: #ffffff;
+				padding: 5px;
+				font-family:Monospace;
+				font-size:13px;
+				text-align:center;
+			}
+
+			a {
+				color: #ffffff;
+			}
+		</style>
+
+		<script src="../build/three.js"></script>
+		<script src="js/WebGL.js"></script>
+		<script src="js/libs/dat.gui.min.js"></script>
+		<script src="js/libs/stats.min.js"></script>
+		<script src="js/Fire.js"></script>
+
+	</head>
+	<body>
+
+		<div id="info">
+			<a href="https://threejs.org" target="_blank" rel="noopener noreferrer">three.js</a> fire and smoke demo <br/>
+		</div>
+
+		<div id="overlay">
+			<div>
+			</div>
+		</div>
+
+		<script>
+
+			if ( WEBGL.isWebGLAvailable() === false ) {
+
+				document.body.appendChild( WEBGL.getWebGLErrorMessage() );
+
+			}
+
+			var camera, scene, renderer, stats;
+			var mesh, texture, fire;
+
+			var params = {
+				color1: '#ffffff',
+				color2: '#ffa000',
+				color3: '#000000',
+				colorBias: 0.8,
+				burnRate: 0.35,
+				diffuse: 1.33,
+				viscosity: 0.25,
+				expansion: -0.25,
+				swirl: 50.0,
+				drag: 0.35,
+				airSpeed: 12.0,
+				windX: 0.0,
+				windY: 0.75,
+				speed: 500.0,
+				massConservation: false
+			};
+
+			init();
+			animate();
+
+			function init() {
+
+				//
+
+				var width = window.innerWidth;
+				var height = window.innerHeight;
+
+				camera = new THREE.PerspectiveCamera( 70, width / height, 1, 1000 );
+				camera.position.z = 25;
+
+				scene = new THREE.Scene();
+				scene.background = new THREE.Color( 0x000000 );
+
+				var ambientLight = new THREE.AmbientLight( 0xcccccc, 0.4 );
+				scene.add( ambientLight );
+
+				var pointLight = new THREE.PointLight( 0xffffff, 0.8 );
+				camera.add( pointLight );
+				scene.add( camera );
+
+				var plane = new THREE.PlaneGeometry( 20, 20 );
+				fire = new THREE.Fire( plane, {
+					textureWidth: 512,
+					textureHeight: 512,
+					debug: false
+				} );
+				fire.position.z = -2;
+				scene.add( fire );
+
+				renderer = new THREE.WebGLRenderer( { antialias: true, alpha: true } );
+				renderer.setPixelRatio( window.devicePixelRatio );
+				renderer.setSize( window.innerWidth, window.innerHeight );
+				renderer.autoClear = false;
+				renderer.antialias = true;
+				document.body.appendChild( renderer.domElement );
+
+				function updateColor1( value ) {
+					fire.color1.set( value );
+				}
+
+				function updateColor2( value ) {
+					fire.color2.set( value );
+				}
+
+				function updateColor3( value ) {
+					fire.color3.set( value );
+				}
+
+				function updateColorBias( value ) {
+					fire.colorBias = value;
+				}
+
+				function updateBurnRate( value ) {
+					fire.burnRate = value;
+				}
+
+				function updateDiffuse( value ) {
+					fire.diffuse = value;
+				}
+
+				function updateViscosity( value ) {
+					fire.viscosity = value;
+				}
+
+				function updateExpansion( value ) {
+					fire.expansion = value;
+				}
+
+				function updateSwirl( value ) {
+					fire.swirl = value;
+				}
+
+				function updateDrag( value ) {
+					fire.drag = value;
+				}
+
+				function updateAirSpeed( value ) {
+					fire.airSpeed = value;
+				}
+
+				function updateWindX( value ) {
+					fire.windVector.x = value;
+				}
+
+				function updateWindY( value ) {
+					fire.windVector.y = value;
+				}
+
+				function updateSpeed( value ) {
+					fire.speed = value;
+				}
+
+				function updateMassConservation( value ) {
+					fire.massConservation = value;
+				}
+
+				params.Single = function () {
+					fire.clearSources();
+					fire.addSource(0.5, 0.1, 0.1, 1.0, 0.0, 1.0);
+				}
+
+				params.Multiple = function () {
+					fire.clearSources();
+					fire.addSource(0.45, 0.1, 0.1, 0.5, 0.0, 1.0);
+					fire.addSource(0.55, 0.1, 0.1, 0.5, 0.0, 1.0);
+				}
+
+				params.Text = function () {
+					var text = "Three JS";
+					var size = 180;
+					var color = "#FF0040";
+					var canvas = document.createElement("canvas");
+					canvas.width = 1024;
+					canvas.height = 1024;
+					var context = canvas.getContext("2d");
+					context.font = size + "pt Arial";
+
+					var margin = 10;
+					var textWidth = context.measureText(text).width;
+
+					context.strokeStyle = "black";
+					context.strokeRect(0, 0, canvas.width, canvas.height);
+					context.textAlign = "center";
+					context.textBaseline = "middle";
+					context.lineWidth = 5;
+					context.strokeStyle = color;
+					context.fillStyle = "black";
+
+					context.strokeText(text, canvas.width / 2, canvas.height * 0.75);
+					var texture = new THREE.Texture(canvas);
+					texture.needsUpdate = true;
+
+					fire.setSourceMap(texture);
+				}
+
+				// dat.gui
+				var gui = new dat.GUI();
+
+				gui.add(params, "Single");
+				gui.add(params, "Multiple");
+				gui.add(params, "Text");
+
+				gui.addColor( params, 'color1' ).onChange(updateColor1);
+				gui.addColor( params, 'color2' ).onChange(updateColor2);
+				gui.addColor( params, 'color3' ).onChange(updateColor3);
+				gui.add( params, 'colorBias', 0.0, 1.0 ).onChange(updateColorBias);
+				gui.add( params, 'burnRate', 0.0, 10.0 ).onChange(updateBurnRate);
+				gui.add( params, 'diffuse', 0.0, 5.0 ).step( 0.01 ).onChange(updateDiffuse);
+				gui.add( params, 'viscosity', 0.0, 5.0 ).step( 0.01 ).onChange(updateViscosity);
+				gui.add( params, 'expansion', -1.0, 1.0 ).step( 0.01 ).onChange(updateExpansion);
+				gui.add( params, 'swirl', 0.0, 50.0 ).step( 0.01 ).onChange(updateSwirl);
+				gui.add( params, 'drag', 0.0, 1.0).onChange(updateDrag);
+				gui.add( params, 'airSpeed', 0.0, 50.0).onChange(updateAirSpeed);
+				gui.add( params, 'windX', -5, 5 ).step( 0.01 ).onChange(updateWindX);
+				gui.add( params, 'windY', -5, 5 ).step( 0.01 ).onChange(updateWindY);
+				gui.add( params, 'speed', 0, 1000 ).onChange(updateSpeed);
+				gui.add( params, 'massConservation' ).onChange(updateMassConservation);
+
+				function updateAll() {
+					updateColor1( params.color1 );
+					updateColor2( params.color2 );
+					updateColor3( params.color3 );
+					updateColorBias( params.colorBias );
+					updateBurnRate( params.burnRate );
+					updateDiffuse( params.diffuse );
+					updateViscosity( params.viscosity );
+					updateExpansion( params.expansion );
+					updateSwirl( params.swirl );
+					updateDrag( params.drag );
+					updateAirSpeed( params.airSpeed );
+					updateWindX( params.windX );
+					updateWindY( params.windY );
+					updateSpeed( params.speed );
+					updateMassConservation( params.massConservation );
+
+					for (var i in gui.__controllers) {
+						gui.__controllers[i].updateDisplay();
+					}
+				}
+
+				params.Candle = function() {
+					params.color1 = 0xffffff;
+					params.color2 = 0xffa000;
+					params.color3 = 0x000000;
+					params.windX = 0.0;
+					params.windY = 0.5;
+					params.colorBias = 0.3;
+					params.burnRate = 1.6;
+					params.diffuse = 1.33;
+					params.viscosity = 1.33;
+					params.expansion = 0.0;
+					params.swirl = 0.0;
+					params.drag = 0.0;
+					params.airSpeed = 8.0;
+					params.speed = 500.0;
+					params.massConservation = false;
+
+					updateAll();
+				}
+				gui.add(params, 'Candle');
+
+				params.Torch = function() {
+					params.color1 = 0xffdcaa;
+					params.color2 = 0xffa000;
+					params.color3 = 0x000000;
+					params.windX = 0.0;
+					params.windY = 0.75;
+					params.colorBias = 0.9;
+					params.burnRate = 1.0;
+					params.diffuse = 1.33;
+					params.viscosity = 0.25;
+					params.expansion = 0.0;
+					params.swirl = 50.0;
+					params.drag = 0.35;
+					params.airSpeed = 10.0;
+					params.speed = 500.0;
+					params.massConservation = false;
+
+					updateAll();
+				}
+				gui.add(params, 'Torch');
+
+				params.Campfire = function() {
+					params.color1 = 0xffffff;
+					params.color2 = 0xffa000;
+					params.color3 = 0x000000;
+					params.windX = 0.0;
+					params.windY = 0.75;
+					params.colorBias = 0.8;
+					params.burnRate = 0.3;
+					params.diffuse = 1.33;
+					params.viscosity = 0.25;
+					params.expansion = -0.25;
+					params.swirl = 50.0;
+					params.drag = 0.35;
+					params.airSpeed = 12.0;
+					params.speed = 500.0;
+					params.massConservation = false;
+
+					updateAll();
+				}
+				gui.add(params, 'Campfire');
+
+				params.Fireball = function() {
+					params.color1 = 0xffffff;
+					params.color2 = 0xffa000;
+					params.color3 = 0x000000;
+					params.windX = 0.0;
+					params.windY = 0.75;
+					params.colorBias = 0.8;
+					params.burnRate = 1.2;
+					params.diffuse = 3.0;
+					params.viscosity = 0.0;
+					params.expansion = 0.0;
+					params.swirl = 6.0;
+					params.drag = 0.0;
+					params.airSpeed = 20.0;
+					params.speed = 500.0;
+					params.massConservation = false;
+
+					updateAll();
+				}
+				gui.add(params, 'Fireball');
+
+				params.Iceball = function() {
+					params.color1 = 0x00bdf7;
+					params.color2 = 0x1b3fb6;
+					params.color3 = 0x001869;
+					params.windX = 0.0;
+					params.windY = -0.25;
+					params.colorBias = 0.25;
+					params.burnRate = 2.6;
+					params.diffuse = 5.0;
+					params.viscosity = 0.5;
+					params.expansion = 0.75;
+					params.swirl = 30.0;
+					params.drag = 0.0;
+					params.airSpeed = 40.0;
+					params.speed = 500.0;
+					params.massConservation = false;
+
+					updateAll();
+				}
+				gui.add(params, 'Iceball');
+
+				params.Smoke = function() {
+					params.color1 = 0xd2d2d2;
+					params.color2 = 0xd7d7d7;
+					params.color3 = 0x000000;
+					params.windX = -0.05;
+					params.windY = 0.15;
+					params.colorBias = 0.95;
+					params.burnRate = 0.0;
+					params.diffuse = 1.5;
+					params.viscosity = 0.25;
+					params.expansion = 0.2;
+					params.swirl = 3.75;
+					params.drag = 0.4;
+					params.airSpeed = 18.0;
+					params.speed = 500.0;
+					params.massConservation = false;
+
+					updateAll();
+				}
+				gui.add(params, 'Smoke');
+
+				params.Cigar = function() {
+					params.color1 = 0xc5c5c5;
+					params.color2 = 0x787878;
+					params.color3 = 0x000000;
+					params.windX = 0.0;
+					params.windY = 0.3;
+					params.colorBias = 0.55;
+					params.burnRate = 0.0;
+					params.diffuse = 1.3;
+					params.viscosity = 0.05;
+					params.expansion = -0.05;
+					params.swirl = 3.7;
+					params.drag = 0.6;
+					params.airSpeed = 6.0;
+					params.speed = 500.0;
+					params.massConservation = false;
+
+					updateAll();
+				}
+				gui.add(params, 'Cigar');
+
+				gui.open();
+
+				params.Campfire();
+				params.Single();
+
+				stats = new Stats();
+				document.body.appendChild( stats.dom );
+
+				window.addEventListener( 'resize', onWindowResize, false );
+
+			}
+
+			function onWindowResize() {
+
+				var width = window.innerWidth;
+				var height = window.innerHeight;
+
+				camera.aspect = width / height;
+				camera.updateProjectionMatrix();
+
+				renderer.setSize( window.innerWidth, window.innerHeight );
+
+			}
+
+			function animate() {
+
+				requestAnimationFrame( animate );
+
+				renderer.clear();
+				renderer.render( scene, camera );
+				stats.update();
+			}
+
+		</script>
+
+	</body>
+</html>