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g/grafos/js/GPUParticleSystem.js

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/*
* GPU Particle System
* @author flimshaw - Charlie Hoey - http://charliehoey.com
*
* A simple to use, general purpose GPU system. Particles are spawn-and-forget with
* several options available, and do not require monitoring or cleanup after spawning.
* Because the paths of all particles are completely deterministic once spawned, the scale
* and direction of time is also variable.
*
* Currently uses a static wrapping perlin noise texture for turbulence, and a small png texture for
* particles, but adding support for a particle texture atlas or changing to a different type of turbulence
* would be a fairly light day's work.
*
* Shader and javascript packing code derrived from several Stack Overflow examples.
*
*/
THREE.GPUParticleSystem = function(options) {
var self = this;
var options = options || {};
// parse options and use defaults
self.PARTICLE_COUNT = options.maxParticles || 1000000;
self.PARTICLE_CONTAINERS = options.containerCount || 1;
self.PARTICLES_PER_CONTAINER = Math.ceil(self.PARTICLE_COUNT / self.PARTICLE_CONTAINERS);
self.PARTICLE_CURSOR = 0;
self.time = 0;
// Custom vertex and fragement shader
var GPUParticleShader = {
vertexShader: [
'precision highp float;',
'const vec4 bitSh = vec4(256. * 256. * 256., 256. * 256., 256., 1.);',
'const vec4 bitMsk = vec4(0.,vec3(1./256.0));',
'const vec4 bitShifts = vec4(1.) / bitSh;',
'#define FLOAT_MAX 1.70141184e38',
'#define FLOAT_MIN 1.17549435e-38',
'lowp vec4 encode_float(highp float v) {',
'highp float av = abs(v);',
'//Handle special cases',
'if(av < FLOAT_MIN) {',
'return vec4(0.0, 0.0, 0.0, 0.0);',
'} else if(v > FLOAT_MAX) {',
'return vec4(127.0, 128.0, 0.0, 0.0) / 255.0;',
'} else if(v < -FLOAT_MAX) {',
'return vec4(255.0, 128.0, 0.0, 0.0) / 255.0;',
'}',
'highp vec4 c = vec4(0,0,0,0);',
'//Compute exponent and mantissa',
'highp float e = floor(log2(av));',
'highp float m = av * pow(2.0, -e) - 1.0;',
//Unpack mantissa
'c[1] = floor(128.0 * m);',
'm -= c[1] / 128.0;',
'c[2] = floor(32768.0 * m);',
'm -= c[2] / 32768.0;',
'c[3] = floor(8388608.0 * m);',
'//Unpack exponent',
'highp float ebias = e + 127.0;',
'c[0] = floor(ebias / 2.0);',
'ebias -= c[0] * 2.0;',
'c[1] += floor(ebias) * 128.0;',
'//Unpack sign bit',
'c[0] += 128.0 * step(0.0, -v);',
'//Scale back to range',
'return c / 255.0;',
'}',
'vec4 pack(const in float depth)',
'{',
'const vec4 bit_shift = vec4(256.0*256.0*256.0, 256.0*256.0, 256.0, 1.0);',
'const vec4 bit_mask = vec4(0.0, 1.0/256.0, 1.0/256.0, 1.0/256.0);',
'vec4 res = fract(depth * bit_shift);',
'res -= res.xxyz * bit_mask;',
'return res;',
'}',
'float unpack(const in vec4 rgba_depth)',
'{',
'const vec4 bit_shift = vec4(1.0/(256.0*256.0*256.0), 1.0/(256.0*256.0), 1.0/256.0, 1.0);',
'float depth = dot(rgba_depth, bit_shift);',
'return depth;',
'}',
'uniform float uTime;',
'uniform float uScale;',
'uniform sampler2D tNoise;',
'attribute vec4 particlePositionsStartTime;',
'attribute vec4 particleVelColSizeLife;',
'varying vec4 vColor;',
'varying float lifeLeft;',
'void main() {',
'// unpack things from our attributes',
'vColor = encode_float( particleVelColSizeLife.y );',
'// convert our velocity back into a value we can use',
'vec4 velTurb = encode_float( particleVelColSizeLife.x );',
'vec3 velocity = vec3( velTurb.xyz );',
'float turbulence = velTurb.w;',
'vec3 newPosition;',
'float timeElapsed = uTime - particlePositionsStartTime.a;',
'lifeLeft = 1. - (timeElapsed / particleVelColSizeLife.w);',
'gl_PointSize = ( uScale * particleVelColSizeLife.z ) * lifeLeft;',
'velocity.x = ( velocity.x - .5 ) * 3.;',
'velocity.y = ( velocity.y - .5 ) * 3.;',
'velocity.z = ( velocity.z - .5 ) * 3.;',
'newPosition = particlePositionsStartTime.xyz + ( velocity * 10. ) * ( uTime - particlePositionsStartTime.a );',
'vec3 noise = texture2D( tNoise, vec2( newPosition.x * .015 + (uTime * .05), newPosition.y * .02 + (uTime * .015) )).rgb;',
'vec3 noiseVel = ( noise.rgb - .5 ) * 30.;',
'newPosition = mix(newPosition, newPosition + vec3(noiseVel * ( turbulence * 5. ) ), (timeElapsed / particleVelColSizeLife.a) );',
'if( velocity.y > 0. && velocity.y < .05 ) {',
'lifeLeft = 0.;',
'}',
'if( velocity.x < -1.45 ) {',
'lifeLeft = 0.;',
'}',
'if( timeElapsed > 0. ) {',
'gl_Position = projectionMatrix * modelViewMatrix * vec4( newPosition, 1.0 );',
'} else {',
'gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );',
'lifeLeft = 0.;',
'gl_PointSize = 0.;',
'}',
'}'
].join("\n"),
fragmentShader: [
'float scaleLinear(float value, vec2 valueDomain) {',
'return (value - valueDomain.x) / (valueDomain.y - valueDomain.x);',
'}',
'float scaleLinear(float value, vec2 valueDomain, vec2 valueRange) {',
'return mix(valueRange.x, valueRange.y, scaleLinear(value, valueDomain));',
'}',
'varying vec4 vColor;',
'varying float lifeLeft;',
'uniform sampler2D tSprite;',
'void main() {',
'float alpha = 0.;',
'if( lifeLeft > .995 ) {',
'alpha = scaleLinear( lifeLeft, vec2(1., .995), vec2(0., 1.));//mix( 0., 1., ( lifeLeft - .95 ) * 100. ) * .75;',
'} else {',
'alpha = lifeLeft * .75;',
'}',
'vec4 tex = texture2D( tSprite, gl_PointCoord );',
'gl_FragColor = vec4( vColor.rgb * tex.a, alpha * tex.a );',
'}'
].join("\n")
};
// preload a million random numbers
self.rand = [];
for (var i = 1e5; i > 0; i--) {
self.rand.push(Math.random() - .5);
}
self.random = function() {
return ++i >= self.rand.length ? self.rand[i = 1] : self.rand[i];
}
self.particleNoiseTex = THREE.ImageUtils.loadTexture("textures/perlin-512.png");
self.particleNoiseTex.wrapS = self.particleNoiseTex.wrapT = THREE.RepeatWrapping;
self.particleSpriteTex = THREE.ImageUtils.loadTexture("textures/particle2.png");
self.particleSpriteTex.wrapS = self.particleSpriteTex.wrapT = THREE.RepeatWrapping;
self.particleShaderMat = new THREE.ShaderMaterial({
transparent: true,
depthWrite: false,
uniforms: {
"uTime": {
type: "f",
value: 0.0
},
"uScale": {
type: "f",
value: 1.0
},
"tNoise": {
type: "t",
value: self.particleNoiseTex
},
"tSprite": {
type: "t",
value: self.particleSpriteTex
}
},
blending: THREE.AdditiveBlending,
vertexShader: GPUParticleShader.vertexShader,
fragmentShader: GPUParticleShader.fragmentShader
});
// define defaults for all values
self.particleShaderMat.defaultAttributeValues.particlePositionsStartTime = [0, 0, 0, 0];
self.particleShaderMat.defaultAttributeValues.particleVelColSizeLife = [0, 0, 0, 0];
self.particleContainers = [];
// extend Object3D
THREE.Object3D.apply(this, arguments);
this.init = function() {
for (var i = 0; i < self.PARTICLE_CONTAINERS; i++) {
var c = new THREE.GPUParticleContainer(self.PARTICLES_PER_CONTAINER, self);
self.particleContainers.push(c);
self.add(c);
}
}
this.spawnParticle = function(options) {
self.PARTICLE_CURSOR++;
if (self.PARTICLE_CURSOR >= self.PARTICLE_COUNT) {
self.PARTICLE_CURSOR = 1;
}
var currentContainer = self.particleContainers[Math.floor(self.PARTICLE_CURSOR / self.PARTICLES_PER_CONTAINER)];
currentContainer.spawnParticle(options);
}
this.update = function(time) {
for (var i = 0; i < self.PARTICLE_CONTAINERS; i++) {
self.particleContainers[i].update(time);
}
};
this.init();
}
THREE.GPUParticleSystem.prototype = Object.create(THREE.Object3D.prototype);
THREE.GPUParticleSystem.prototype.constructor = THREE.GPUParticleSystem;
// Subclass for particle containers, allows for very large arrays to be spread out
THREE.GPUParticleContainer = function(maxParticles, particleSystem) {
var self = this;
self.PARTICLE_COUNT = maxParticles || 100000;
self.PARTICLE_CURSOR = 0;
self.time = 0;
self.DPR = window.devicePixelRatio;
self.GPUParticleSystem = particleSystem;
var particlesPerArray = Math.floor(self.PARTICLE_COUNT / self.MAX_ATTRIBUTES);
// extend Object3D
THREE.Object3D.apply(this, arguments);
// construct a couple small arrays used for packing variables into floats etc
var UINT8_VIEW = new Uint8Array(4)
var FLOAT_VIEW = new Float32Array(UINT8_VIEW.buffer)
function decodeFloat(x, y, z, w) {
UINT8_VIEW[0] = Math.floor(w)
UINT8_VIEW[1] = Math.floor(z)
UINT8_VIEW[2] = Math.floor(y)
UINT8_VIEW[3] = Math.floor(x)
return FLOAT_VIEW[0]
}
function componentToHex(c) {
var hex = c.toString(16);
return hex.length == 1 ? "0" + hex : hex;
}
function rgbToHex(r, g, b) {
return "#" + componentToHex(r) + componentToHex(g) + componentToHex(b);
}
function hexToRgb(hex) {
var r = hex >> 16;
var g = (hex & 0x00FF00) >> 8;
var b = hex & 0x0000FF;
if (r > 0) r--;
if (g > 0) g--;
if (b > 0) b--;
return [r, g, b];
};
self.particles = [];
self.deadParticles = [];
self.particlesAvailableSlot = [];
// create a container for particles
self.particleUpdate = false;
// Shader Based Particle System
self.particleShaderGeo = new THREE.BufferGeometry();
// new hyper compressed attributes
self.particleVertices = new Float32Array(self.PARTICLE_COUNT * 3); // position
self.particlePositionsStartTime = new Float32Array(self.PARTICLE_COUNT * 4); // position
self.particleVelColSizeLife = new Float32Array(self.PARTICLE_COUNT * 4);
for (var i = 0; i < self.PARTICLE_COUNT; i++) {
self.particlePositionsStartTime[i * 4 + 0] = 100; //x
self.particlePositionsStartTime[i * 4 + 1] = 0; //y
self.particlePositionsStartTime[i * 4 + 2] = 0.0; //z
self.particlePositionsStartTime[i * 4 + 3] = 0.0; //startTime
self.particleVertices[i * 3 + 0] = 0; //x
self.particleVertices[i * 3 + 1] = 0; //y
self.particleVertices[i * 3 + 2] = 0.0; //z
self.particleVelColSizeLife[i * 4 + 0] = decodeFloat(128, 128, 0, 0); //vel
self.particleVelColSizeLife[i * 4 + 1] = decodeFloat(0, 254, 0, 254); //color
self.particleVelColSizeLife[i * 4 + 2] = 1.0; //size
self.particleVelColSizeLife[i * 4 + 3] = 0.0; //lifespan
}
self.particleShaderGeo.addAttribute('position', new THREE.BufferAttribute(self.particleVertices, 3));
self.particleShaderGeo.addAttribute('particlePositionsStartTime', new THREE.BufferAttribute(self.particlePositionsStartTime, 4).setDynamic(true));
self.particleShaderGeo.addAttribute('particleVelColSizeLife', new THREE.BufferAttribute(self.particleVelColSizeLife, 4).setDynamic(true));
self.posStart = self.particleShaderGeo.getAttribute('particlePositionsStartTime')
self.velCol = self.particleShaderGeo.getAttribute('particleVelColSizeLife');
self.particleShaderMat = self.GPUParticleSystem.particleShaderMat;
this.init = function() {
self.particleSystem = new THREE.Points(self.particleShaderGeo, self.particleShaderMat);
self.particleSystem.frustumCulled = false;
this.add(self.particleSystem);
};
var options = {},
position = new THREE.Vector3(),
velocity = new THREE.Vector3(),
positionRandomness = 0.,
velocityRandomness = 0.,
color = 0xffffff,
colorRandomness = 0.,
turbulence = 0.,
lifetime = 0.,
size = 0.,
sizeRandomness = 0.,
i;
var maxVel = 2;
var maxSource = 250;
this.offset = 0;
this.count = 0;
this.spawnParticle = function(options) {
options = options || {};
// setup reasonable default values for all arguments
position = options.position !== undefined ? position.copy(options.position) : position.set(0., 0., 0.);
velocity = options.velocity !== undefined ? velocity.copy(options.velocity) : velocity.set(0., 0., 0.);
positionRandomness = options.positionRandomness !== undefined ? options.positionRandomness : 0.0;
velocityRandomness = options.velocityRandomness !== undefined ? options.velocityRandomness : 0.0;
color = options.color !== undefined ? options.color : 0xffffff;
colorRandomness = options.colorRandomness !== undefined ? options.colorRandomness : 1.0;
turbulence = options.turbulence !== undefined ? options.turbulence : 1.0;
lifetime = options.lifetime !== undefined ? options.lifetime : 5.0;
size = options.size !== undefined ? options.size : 10;
sizeRandomness = options.sizeRandomness !== undefined ? options.sizeRandomness : 0.0,
smoothPosition = options.smoothPosition !== undefined ? options.smoothPosition : false;
if (self.DPR !== undefined) size *= self.DPR;
i = self.PARTICLE_CURSOR;
self.posStart.array[i * 4 + 0] = position.x + ((particleSystem.random()) * positionRandomness); // - ( velocity.x * particleSystem.random() ); //x
self.posStart.array[i * 4 + 1] = position.y + ((particleSystem.random()) * positionRandomness); // - ( velocity.y * particleSystem.random() ); //y
self.posStart.array[i * 4 + 2] = position.z + ((particleSystem.random()) * positionRandomness); // - ( velocity.z * particleSystem.random() ); //z
self.posStart.array[i * 4 + 3] = self.time + (particleSystem.random() * 2e-2); //startTime
if (smoothPosition === true) {
self.posStart.array[i * 4 + 0] += -(velocity.x * particleSystem.random()); //x
self.posStart.array[i * 4 + 1] += -(velocity.y * particleSystem.random()); //y
self.posStart.array[i * 4 + 2] += -(velocity.z * particleSystem.random()); //z
}
var velX = velocity.x + (particleSystem.random()) * velocityRandomness;
var velY = velocity.y + (particleSystem.random()) * velocityRandomness;
var velZ = velocity.z + (particleSystem.random()) * velocityRandomness;
// convert turbulence rating to something we can pack into a vec4
var turbulence = Math.floor(turbulence * 254);
// clamp our value to between 0. and 1.
velX = Math.floor(maxSource * ((velX - -maxVel) / (maxVel - -maxVel)));
velY = Math.floor(maxSource * ((velY - -maxVel) / (maxVel - -maxVel)));
velZ = Math.floor(maxSource * ((velZ - -maxVel) / (maxVel - -maxVel)));
self.velCol.array[i * 4 + 0] = decodeFloat(velX, velY, velZ, turbulence); //vel
var rgb = hexToRgb(color);
for (var c = 0; c < rgb.length; c++) {
rgb[c] = Math.floor(rgb[c] + ((particleSystem.random()) * colorRandomness) * 254);
if (rgb[c] > 254) rgb[c] = 254;
if (rgb[c] < 0) rgb[c] = 0;
}
self.velCol.array[i * 4 + 1] = decodeFloat(rgb[0], rgb[1], rgb[2], 254); //color
self.velCol.array[i * 4 + 2] = size + (particleSystem.random()) * sizeRandomness; //size
self.velCol.array[i * 4 + 3] = lifetime; //lifespan
if (this.offset == 0) {
this.offset = self.PARTICLE_CURSOR;
}
self.count++;
self.PARTICLE_CURSOR++;
if (self.PARTICLE_CURSOR >= self.PARTICLE_COUNT) {
self.PARTICLE_CURSOR = 0;
}
self.particleUpdate = true;
}
this.update = function(time) {
self.time = time;
self.particleShaderMat.uniforms['uTime'].value = time;
this.geometryUpdate();
};
this.geometryUpdate = function() {
if (self.particleUpdate == true) {
self.particleUpdate = false;
// if we can get away with a partial buffer update, do so
if (self.offset + self.count < self.PARTICLE_COUNT) {
self.posStart.updateRange.offset = self.velCol.updateRange.offset = self.offset * 4;
self.posStart.updateRange.count = self.velCol.updateRange.count = self.count * 4;
} else {
self.posStart.updateRange.offset = 0;
self.posStart.updateRange.count = self.velCol.updateRange.count = (self.PARTICLE_COUNT * 4);
}
self.posStart.needsUpdate = true;
self.velCol.needsUpdate = true;
self.offset = 0;
self.count = 0;
}
}
this.init();
}
THREE.GPUParticleContainer.prototype = Object.create(THREE.Object3D.prototype);
THREE.GPUParticleContainer.prototype.constructor = THREE.GPUParticleContainer;