Babylon.js/Babylon/Particles/babylon.particleSystem.js

var BABYLON = BABYLON || {};

(function () {
    var randomNumber = function (min, max) {
        if (min == max) {
            return (min);
        }

        var random = Math.random();

        return ((random * (max - min)) + min);
    };

    BABYLON.ParticleSystem = function (name, capacity, scene) {
        this.name = name;
        this.id = name;
        this._capacity = capacity;

        this._scene = scene;

        scene.particleSystems.push(this);

        // Vectors and colors
        this.gravity = BABYLON.Vector3.Zero();
        this.direction1 = new BABYLON.Vector3(0, 1.0, 0);
        this.direction2 = new BABYLON.Vector3(0, 1.0, 0);
        this.minEmitBox = new BABYLON.Vector3(-0.5, -0.5, -0.5);
        this.maxEmitBox = new BABYLON.Vector3(0.5, 0.5, 0.5);
        this.color1 = new BABYLON.Color4(1.0, 1.0, 1.0, 1.0);
        this.color2 = new BABYLON.Color4(1.0, 1.0, 1.0, 1.0);
        this.colorDead = new BABYLON.Color4(0, 0, 0, 1.0);
        this.textureMask = new BABYLON.Color4(1.0, 1.0, 1.0, 1.0);

        // Particles
        this.particles = [];
        this._stockParticles = [];
        this._newPartsExcess = 0;

        // VBO
        this._vertexDeclaration = [3, 4, 4];
        this._vertexStrideSize = 11 * 4; // 11 floats per particle (x, y, z, r, g, b, a, angle, size, offsetX, offsetY)
        this._vertexBuffer = scene.getEngine().createDynamicVertexBuffer(capacity * this._vertexStrideSize * 4);

        var indices = [];
        var index = 0;
        for (var count = 0; count < capacity; count++) {
            indices.push(index);
            indices.push(index + 1);
            indices.push(index + 2);
            indices.push(index);
            indices.push(index + 2);
            indices.push(index + 3);
            index += 4;
        }

        this._indexBuffer = scene.getEngine().createIndexBuffer(indices);

        this._vertices = new Float32Array(capacity * this._vertexStrideSize);
        
        // Internals
        this._scaledColorStep = new BABYLON.Color4(0, 0, 0, 0);
        this._colorDiff = new BABYLON.Color4(0, 0, 0, 0);
        this._scaledDirection = BABYLON.Vector3.Zero();
        this._scaledGravity = BABYLON.Vector3.Zero();
        this._currentRenderId = -1;
    };

    // Members
    BABYLON.ParticleSystem.prototype.renderingGroupId = 0;
    BABYLON.ParticleSystem.prototype.emitter = null;
    BABYLON.ParticleSystem.prototype.emitRate = 10;
    BABYLON.ParticleSystem.prototype.manualEmitCount = -1;
    BABYLON.ParticleSystem.prototype.updateSpeed = 0.01;
    BABYLON.ParticleSystem.prototype.targetStopDuration = 0;
    BABYLON.ParticleSystem.prototype.disposeOnStop = false;

    BABYLON.ParticleSystem.prototype.minEmitPower = 1;
    BABYLON.ParticleSystem.prototype.maxEmitPower = 1;

    BABYLON.ParticleSystem.prototype.minLifeTime = 1;
    BABYLON.ParticleSystem.prototype.maxLifeTime = 1;

    BABYLON.ParticleSystem.prototype.minSize = 1;
    BABYLON.ParticleSystem.prototype.maxSize = 1;
    BABYLON.ParticleSystem.prototype.minAngularSpeed = 0;
    BABYLON.ParticleSystem.prototype.maxAngularSpeed = 0;

    BABYLON.ParticleSystem.prototype.particleTexture = null;
    
    BABYLON.ParticleSystem.prototype.onDispose = null;

    BABYLON.ParticleSystem.prototype.blendMode = BABYLON.ParticleSystem.BLENDMODE_ONEONE;

    // Methods   
    BABYLON.ParticleSystem.prototype.isAlive = function () {
        return this._alive;
    };

    BABYLON.ParticleSystem.prototype.start = function () {
        this._started = true;
        this._stopped = false;
        this._actualFrame = 0;
    };

    BABYLON.ParticleSystem.prototype.stop = function () {
        this._stopped = true;
    };
    
    BABYLON.ParticleSystem.prototype._appendParticleVertex = function (index, particle, offsetX, offsetY) {
        var offset = index * 11;
        this._vertices[offset] = particle.position.x;
        this._vertices[offset + 1] = particle.position.y;
        this._vertices[offset + 2] = particle.position.z;
        this._vertices[offset + 3] = particle.color.r;
        this._vertices[offset + 4] = particle.color.g;
        this._vertices[offset + 5] = particle.color.b;
        this._vertices[offset + 6] = particle.color.a;
        this._vertices[offset + 7] = particle.angle;
        this._vertices[offset + 8] = particle.size;
        this._vertices[offset + 9] = offsetX;
        this._vertices[offset + 10] = offsetY;
    };
    
    BABYLON.ParticleSystem.prototype._update = function (newParticles) {
        // Update current
        this._alive = this.particles.length > 0;
        for (var index = 0; index < this.particles.length; index++) {
            var particle = this.particles[index];
            particle.age += this._scaledUpdateSpeed;

            if (particle.age >= particle.lifeTime) {
                this._stockParticles.push(this.particles.splice(index, 1)[0]);
                index--;
                continue;
            }
            else {
                particle.colorStep.scaleToRef(this._scaledUpdateSpeed, this._scaledColorStep);
                particle.color.addInPlace(this._scaledColorStep);

                if (particle.color.a < 0)
                    particle.color.a = 0;

                particle.direction.scaleToRef(this._scaledUpdateSpeed, this._scaledDirection);
                particle.position.addInPlace(this._scaledDirection);

                particle.angle += particle.angularSpeed * this._scaledUpdateSpeed;

                this.gravity.scaleToRef(this._scaledUpdateSpeed, this._scaledGravity);
                particle.direction.addInPlace(this._scaledGravity);
            }
        }
        
        // Add new ones
        var worldMatrix;

        if (this.emitter.position) {
            worldMatrix = this.emitter.getWorldMatrix();
        } else {
            worldMatrix = BABYLON.Matrix.Translation(this.emitter.x, this.emitter.y, this.emitter.z);
        }

        for (var index = 0; index < newParticles; index++) {
            if (this.particles.length == this._capacity) {
                break;
            }

            if (this._stockParticles.length !== 0) {
                particle = this._stockParticles.pop();
                particle.age = 0;
            } else {
                particle = new BABYLON.Particle();
            }
            this.particles.push(particle);

            var emitPower = randomNumber(this.minEmitPower, this.maxEmitPower);

            var randX = randomNumber(this.direction1.x, this.direction2.x);
            var randY = randomNumber(this.direction1.y, this.direction2.y);
            var randZ = randomNumber(this.direction1.z, this.direction2.z);

            BABYLON.Vector3.TransformNormalFromFloatsToRef(randX * emitPower, randY * emitPower, randZ * emitPower, worldMatrix, particle.direction);

            particle.lifeTime = randomNumber(this.minLifeTime, this.maxLifeTime);

            particle.size = randomNumber(this.minSize, this.maxSize);
            particle.angularSpeed = randomNumber(this.minAngularSpeed, this.maxAngularSpeed);

            randX = randomNumber(this.minEmitBox.x, this.maxEmitBox.x);
            randY = randomNumber(this.minEmitBox.y, this.maxEmitBox.y);
            randZ = randomNumber(this.minEmitBox.z, this.maxEmitBox.z);

            BABYLON.Vector3.TransformCoordinatesFromFloatsToRef(randX, randY, randZ, worldMatrix, particle.position);

            var step = randomNumber(0, 1.0);

            BABYLON.Color4.LerpToRef(this.color1, this.color2, step, particle.color);

            this.colorDead.subtractToRef(particle.color, this._colorDiff);
            this._colorDiff.scaleToRef(1.0 / particle.lifeTime, particle.colorStep);
        }
    };

    BABYLON.ParticleSystem.prototype._getEffect = function () {
        var defines = [];
        
        if (BABYLON.clipPlane) {
            defines.push("#define CLIPPLANE");
        }
        
        // Effect
        var join = defines.join("\n");
        if (this._cachedDefines != join) {
            this._cachedDefines = join;
            this._effect = this._scene.getEngine().createEffect("particles",
                ["position", "color", "options"],
                ["invView", "view", "projection", "vClipPlane", "textureMask"],
                ["diffuseSampler"], join);
        }

        return this._effect;
    };

    BABYLON.ParticleSystem.prototype.animate = function () {
        if (!this._started)
            return;

        var effect = this._getEffect();

        // Check
        if (!this.emitter || !effect.isReady() || !this.particleTexture || !this.particleTexture.isReady())
            return;
        
        if (this._currentRenderId === this._scene.getRenderId()) {
            return;
        }

        this._currentRenderId = this._scene.getRenderId();

        this._scaledUpdateSpeed = this.updateSpeed * this._scene.getAnimationRatio();

        // determine the number of particles we need to create   
        var emitCout;
        
        if (this.manualEmitCount > -1) {
            emitCout = this.manualEmitCount;
            this.manualEmitCount = 0;
        } else {
            emitCout = this.emitRate;
        }

        var newParticles = ((emitCout * this._scaledUpdateSpeed) >> 0);
        this._newPartsExcess += emitCout * this._scaledUpdateSpeed - newParticles;

        if (this._newPartsExcess > 1.0) {
            newParticles += this._newPartsExcess >> 0;
            this._newPartsExcess -= this._newPartsExcess >> 0;
        }

        this._alive = false;

        if (!this._stopped) {
            this._actualFrame += this._scaledUpdateSpeed;

            if (this.targetStopDuration && this._actualFrame >= this.targetStopDuration)
                this.stop();
        } else {
            newParticles = 0;
        }

        this._update(newParticles);

        // Stopped?
        if (this._stopped) {
            if (!this._alive) {
                this._started = false;
                if (this.disposeOnStop) {
                    this._scene._toBeDisposed.push(this);
                }
            }
        }

        // Update VBO
        var offset = 0;
        for (var index = 0; index < this.particles.length; index++) {
            var particle = this.particles[index];

            this._appendParticleVertex(offset++, particle, 0, 0);
            this._appendParticleVertex(offset++, particle, 1, 0);
            this._appendParticleVertex(offset++, particle, 1, 1);
            this._appendParticleVertex(offset++, particle, 0, 1);
        }
        var engine = this._scene.getEngine();
        engine.updateDynamicVertexBuffer(this._vertexBuffer, this._vertices, this.particles.length * this._vertexStrideSize);
    };

    BABYLON.ParticleSystem.prototype.render = function () {
        var effect = this._getEffect();

        // Check
        if (!this.emitter || !effect.isReady() || !this.particleTexture || !this.particleTexture.isReady() || !this.particles.length)
            return 0;

        var engine = this._scene.getEngine();

        // Render
        engine.enableEffect(effect);

        var viewMatrix = this._scene.getViewMatrix();
        effect.setTexture("diffuseSampler", this.particleTexture);
        effect.setMatrix("view", viewMatrix);
        effect.setMatrix("projection", this._scene.getProjectionMatrix());
        effect.setFloat4("textureMask", this.textureMask.r, this.textureMask.g, this.textureMask.b, this.textureMask.a);

        if (BABYLON.clipPlane) {
            var invView = viewMatrix.clone();
            invView.invert();
            effect.setMatrix("invView", invView);
            effect.setFloat4("vClipPlane", BABYLON.clipPlane.normal.x, BABYLON.clipPlane.normal.y, BABYLON.clipPlane.normal.z, BABYLON.clipPlane.d);
        }        

        // VBOs
        engine.bindBuffers(this._vertexBuffer, this._indexBuffer, this._vertexDeclaration, this._vertexStrideSize, effect);

        // Draw order
        if (this.blendMode === BABYLON.ParticleSystem.BLENDMODE_ONEONE) {
            engine.setAlphaMode(BABYLON.Engine.ALPHA_ADD);
        } else {
            engine.setAlphaMode(BABYLON.Engine.ALPHA_COMBINE);
        }
        engine.draw(true, 0, this.particles.length * 6);
        engine.setAlphaMode(BABYLON.Engine.ALPHA_DISABLE);

        return this.particles.length;
    };

    BABYLON.ParticleSystem.prototype.dispose = function () {
        if (this._vertexBuffer) {
            this._scene.getEngine()._releaseBuffer(this._vertexBuffer);
            this._vertexBuffer = null;
        }

        if (this._indexBuffer) {
            this._scene.getEngine()._releaseBuffer(this._indexBuffer);
            this._indexBuffer = null;
        }

        if (this.particleTexture) {
            this.particleTexture.dispose();
            this.particleTexture = null;
        }

        // Remove from scene
        var index = this._scene.particleSystems.indexOf(this);
        this._scene.particleSystems.splice(index, 1);
        
        // Callback
        if (this.onDispose) {
            this.onDispose();
        }
    };

    // Clone
    BABYLON.ParticleSystem.prototype.clone = function(name, newEmitter) {
        var result = new BABYLON.ParticleSystem(name, this._capacity, this._scene);

        BABYLON.Tools.DeepCopy(this, result, ["particles"], ["_vertexDeclaration", "_vertexStrideSize"]);

        if (newEmitter === undefined) {
            newEmitter = this.emitter;
        }

        result.emitter = newEmitter;
        if (this.particleTexture) {
            result.particleTexture = new BABYLON.Texture(this.particleTexture.name, this._scene);
        }

        result.start();

        return result;
    };
    
    // Statics
    BABYLON.ParticleSystem.BLENDMODE_ONEONE = 0;
    BABYLON.ParticleSystem.BLENDMODE_STANDARD = 1;
})();