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'disk' emitter, radiusSpread, angles #9

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Merged
squarefeet merged 1 commit into from
Sep 6, 2013
Merged

'disk' emitter, radiusSpread, angles #9

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81 changes: 59 additions & 22 deletions src/ShaderParticleGroup.js
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Original file line number Diff line number Diff line change
Expand Up @@ -40,6 +40,7 @@ function ShaderParticleGroup( options ) {
age: { type: 'f', value: [] },
size: { type: 'f', value: [] },
sizeEnd: { type: 'f', value: [] },
angle: { type: 'f', value: [] },

customColor: { type: 'c', value: [] },
customColorEnd: { type: 'c', value: [] },
Expand Down Expand Up @@ -153,58 +154,79 @@ ShaderParticleGroup.prototype = {

/**
* Create a new THREE.Vector3 instance and project it onto a random point
* on a sphere with radius `radius`.
* on a sphere with randomized radius.
*
* @param {THREE.Vector3} base
* @param {Number} radius
* @param {THREE.Vector3} scale
* @param {THREE.Vector3} radiusSpread
* @param {THREE.Vector3} radiusScale
*
* @private
*
* @return {THREE.Vector3}
*/
_randomVector3OnSphere: function( base, radius, scale ) {
_randomVector3OnSphere: function( base, radius, radiusSpread, radiusScale ) {
var z = 2 * Math.random() - 1;
var t = 6.2832 * Math.random();
var r = Math.sqrt( 1 - z*z );
var vec = new THREE.Vector3( r * Math.cos(t), r * Math.sin(t), z );

vec.multiplyScalar( radius );
vec.multiplyScalar( this._randomFloat( radius, radiusSpread ) );

if( scale ) {
vec.multiply( scale );
if( radiusScale ) {
vec.multiply( radiusScale );
}

vec.add( base );

return vec;
},

/**
* Create a new THREE.Vector3 instance and project it onto a random point
* on a disk (in the XY-plane) centered at `base` and with randomized radius.
*
* @param {THREE.Vector3} base
* @param {Number} radius
* @param {THREE.Vector3} radiusSpread
* @param {THREE.Vector3} radiusScale
*
* @private
*
* @return {THREE.Vector3}
*/
_randomVector3OnDisk: function( base, radius, radiusSpread, radiusScale ) {

var t = 6.2832 * Math.random();
var vec = new THREE.Vector3( Math.cos(t), Math.sin(t), 0 ).multiplyScalar( this._randomFloat( radius, radiusSpread ) );

if ( radiusScale ) {
vec.multiply( radiusScale );
}

vec.add( base );

return vec ;
},

/**
* Create a new THREE.Vector3 instance, and given a base position, and various
* other values, project it onto a random point on a sphere with radius `radius`.
* Create a new THREE.Vector3 instance, and given a sphere with center `base` and
* point `position` on sphere, set direction away from sphere center with random magnitude.
*
* @param {THREE.Vector3} base
* @param {THREE.Vector3} position
* @param {Number} speed
* @param {Number} speedSpread
* @param {THREE.Vector3} scale
* @param {Number} radius
*
* @private
*
* @return {THREE.Vector3}
*/
_randomVelocityVector3OnSphere: function( base, position, speed, speedSpread, scale, radius ) {
_randomVelocityVector3OnSphere: function( base, position, speed, speedSpread ) {
var direction = new THREE.Vector3().subVectors( base, position );

direction.normalize().multiplyScalar( this._randomFloat( speed, speedSpread ) );

if( scale ) {
direction.multiply( scale );
}

return direction;
},

Expand Down Expand Up @@ -245,6 +267,7 @@ ShaderParticleGroup.prototype = {
// ```ParticleSystem.sortParticles = true``` in THREE.r58 at least)
that.attributes.age.needsUpdate = true;
that.attributes.alive.needsUpdate = true;
that.attributes.angle.needsUpdate = true;
that.geometry.verticesNeedUpdate = true;

return that;
Expand Down Expand Up @@ -280,6 +303,7 @@ ShaderParticleGroup.prototype = {
age = a.age.value,
size = a.size.value,
sizeEnd = a.sizeEnd.value,
angle = a.angle.value,
customColor = a.customColor.value,
customColorEnd = a.customColorEnd.value,
opacity = a.opacity.value,
Expand All @@ -292,8 +316,12 @@ ShaderParticleGroup.prototype = {
for( var i = start; i < end; ++i ) {

if( emitter.type === 'sphere' ) {
vertices[i] = that._randomVector3OnSphere( emitter.position, emitter.radius, emitter.radiusScale );
velocity[i] = that._randomVelocityVector3OnSphere( vertices[i], emitter.position, emitter.speed, emitter.speedSpread, emitter.radiusScale, emitter.radius );
vertices[i] = that._randomVector3OnSphere( emitter.position, emitter.radius, emitter.radiusSpread, emitter.radiusScale );
velocity[i] = that._randomVelocityVector3OnSphere( vertices[i], emitter.position, emitter.speed, emitter.speedSpread );
}
else if( emitter.type === 'disk' ) {
vertices[i] = that._randomVector3OnDisk( emitter.position, emitter.radius, emitter.radiusSpread, emitter.radiusScale );
velocity[i] = that._randomVelocityVector3OnSphere( vertices[i], emitter.position, emitter.speed, emitter.speedSpread );
}
else {
vertices[i] = that._randomVector3( emitter.position, emitter.positionSpread );
Expand All @@ -307,10 +335,15 @@ ShaderParticleGroup.prototype = {
// For some stupid reason I was limiting the size value to a minimum of 0.1. Derp.
size[i] = that._randomFloat( emitter.size, emitter.sizeSpread );
sizeEnd[i] = emitter.sizeEnd;
age[i] = 0.0;
if (that.angleAlignVelocity) {
angle[i] = -Math.atan2( velocity[i].y, velocity[i].x );
}
else {
angle[i] = that._randomFloat( emitter.angle, emitter.angleSpread );
}
age[i] = 0.0;
alive[i] = emitter.static ? 1.0 : 0.0;


customColor[i] = that._randomColor( emitter.colorStart, emitter.colorSpread );
customColorEnd[i] = emitter.colorEnd;
opacity[i] = emitter.opacityStart;
Expand Down Expand Up @@ -515,8 +548,10 @@ ShaderParticleGroup.shaders = {
'attribute float age;',
'attribute float size;',
'attribute float sizeEnd;',
'attribute float angle;',

'varying vec4 vColor;',
'varying float vAngle;',

// Linearly lerp a float
'float Lerp( float start, float end, float amount ) {',
Expand Down Expand Up @@ -554,7 +589,8 @@ ShaderParticleGroup.shaders = {

'float positionInTime = (age / duration);',
'float halfDuration = (duration / 2.0);',

'vAngle = angle;',

'if( alive > 0.5 ) {',
// Integrate color "tween"
'vec3 color = vec3( customColor );',
Expand Down Expand Up @@ -610,10 +646,11 @@ ShaderParticleGroup.shaders = {
'uniform int colorize;',

'varying vec4 vColor;',
'varying float vAngle;',

'void main() {',
'float c = cos(0.0);',
'float s = sin(0.0);',
'float c = cos(vAngle);',
'float s = sin(vAngle);',

'vec2 rotatedUV = vec2(c * (gl_PointCoord.x - 0.5) + s * (gl_PointCoord.y - 0.5) + 0.5,',
'c * (gl_PointCoord.y - 0.5) - s * (gl_PointCoord.x - 0.5) + 0.5);',
Expand Down