/**
* @author Prashant Sharma / spidersharma03
* @author Ben Houston / bhouston, https://clara.io
*
* To avoid cube map seams, I create an extra pixel around each face. This way when the cube map is
* sampled by an application later(with a little care by sampling the centre of the texel), the extra 1 border
* of pixels makes sure that there is no seams artifacts present. This works perfectly for cubeUV format as
* well where the 6 faces can be arranged in any manner whatsoever.
* Code in the beginning of fragment shader's main function does this job for a given resolution.
* Run Scene_PMREM_Test.html in the examples directory to see the sampling from the cube lods generated
* by this class.
*/
THREE.PMREMGenerator = ( function () {
var shader = getShader();
var camera = new THREE.OrthographicCamera( - 1, 1, 1, - 1, 0.0, 1000 );
var scene = new THREE.Scene();
var planeMesh = new THREE.Mesh( new THREE.PlaneBufferGeometry( 2, 2, 0 ), shader );
planeMesh.material.side = THREE.DoubleSide;
scene.add( planeMesh );
scene.add( camera );
var PMREMGenerator = function ( sourceTexture, samplesPerLevel, resolution ) {
this.sourceTexture = sourceTexture;
this.resolution = ( resolution !== undefined ) ? resolution : 256; // NODE: 256 is currently hard coded in the glsl code for performance reasons
this.samplesPerLevel = ( samplesPerLevel !== undefined ) ? samplesPerLevel : 32;
var monotonicEncoding = ( this.sourceTexture.encoding === THREE.LinearEncoding ) ||
( this.sourceTexture.encoding === THREE.GammaEncoding ) || ( this.sourceTexture.encoding === THREE.sRGBEncoding );
this.sourceTexture.minFilter = ( monotonicEncoding ) ? THREE.LinearFilter : THREE.NearestFilter;
this.sourceTexture.magFilter = ( monotonicEncoding ) ? THREE.LinearFilter : THREE.NearestFilter;
this.sourceTexture.generateMipmaps = this.sourceTexture.generateMipmaps && monotonicEncoding;
this.cubeLods = [];
var size = this.resolution;
var params = {
format: this.sourceTexture.format,
magFilter: this.sourceTexture.magFilter,
minFilter: this.sourceTexture.minFilter,
type: this.sourceTexture.type,
generateMipmaps: this.sourceTexture.generateMipmaps,
anisotropy: this.sourceTexture.anisotropy,
encoding: this.sourceTexture.encoding
};
// how many LODs fit in the given CubeUV Texture.
this.numLods = Math.log( size ) / Math.log( 2 ) - 2; // IE11 doesn't support Math.log2
for ( var i = 0; i < this.numLods; i ++ ) {
var renderTarget = new THREE.WebGLRenderTargetCube( size, size, params );
renderTarget.texture.name = "PMREMGenerator.cube" + i;
this.cubeLods.push( renderTarget );
size = Math.max( 16, size / 2 );
}
};
PMREMGenerator.prototype = {
constructor: PMREMGenerator,
/*
* Prashant Sharma / spidersharma03: More thought and work is needed here.
* Right now it's a kind of a hack to use the previously convolved map to convolve the current one.
* I tried to use the original map to convolve all the lods, but for many textures(specially the high frequency)
* even a high number of samples(1024) dosen't lead to satisfactory results.
* By using the previous convolved maps, a lower number of samples are generally sufficient(right now 32, which
* gives okay results unless we see the reflection very carefully, or zoom in too much), however the math
* goes wrong as the distribution function tries to sample a larger area than what it should be. So I simply scaled
* the roughness by 0.9(totally empirical) to try to visually match the original result.
* The condition "if(i <5)" is also an attemt to make the result match the original result.
* This method requires the most amount of thinking I guess. Here is a paper which we could try to implement in future::
* https://developer.nvidia.com/gpugems/GPUGems3/gpugems3_ch20.html
*/
update: function ( renderer ) {
// Texture should only be flipped for CubeTexture, not for
// a Texture created via THREE.WebGLRenderTargetCube.
var tFlip = ( this.sourceTexture.isCubeTexture ) ? - 1 : 1;
shader.defines[ 'SAMPLES_PER_LEVEL' ] = this.samplesPerLevel;
shader.uniforms[ 'faceIndex' ].value = 0;
shader.uniforms[ 'envMap' ].value = this.sourceTexture;
shader.envMap = this.sourceTexture;
shader.needsUpdate = true;
var gammaInput = renderer.gammaInput;
var gammaOutput = renderer.gammaOutput;
var toneMapping = renderer.toneMapping;
var toneMappingExposure = renderer.toneMappingExposure;
var currentRenderTarget = renderer.getRenderTarget();
renderer.toneMapping = THREE.LinearToneMapping;
renderer.toneMappingExposure = 1.0;
renderer.gammaInput = false;
renderer.gammaOutput = false;
for ( var i = 0; i < this.numLods; i ++ ) {
var r = i / ( this.numLods - 1 );
shader.uniforms[ 'roughness' ].value = r * 0.9; // see comment above, pragmatic choice
// Only apply the tFlip for the first LOD
shader.uniforms[ 'tFlip' ].value = ( i == 0 ) ? tFlip : 1;
var size = this.cubeLods[ i ].width;
shader.uniforms[ 'mapSize' ].value = size;
this.renderToCubeMapTarget( renderer, this.cubeLods[ i ] );
if ( i < 5 ) shader.uniforms[ 'envMap' ].value = this.cubeLods[ i ].texture;
}
renderer.setRenderTarget( currentRenderTarget );
renderer.toneMapping = toneMapping;
renderer.toneMappingExposure = toneMappingExposure;
renderer.gammaInput = gammaInput;
renderer.gammaOutput = gammaOutput;
},
renderToCubeMapTarget: function ( renderer, renderTarget ) {
for ( var i = 0; i < 6; i ++ ) {
this.renderToCubeMapTargetFace( renderer, renderTarget, i );
}
},
renderToCubeMapTargetFace: function ( renderer, renderTarget, faceIndex ) {
shader.uniforms[ 'faceIndex' ].value = faceIndex;
renderer.setRenderTarget( renderTarget, faceIndex );
renderer.clear();
renderer.render( scene, camera );
},
dispose: function () {
for ( var i = 0, l = this.cubeLods.length; i < l; i ++ ) {
this.cubeLods[ i ].dispose();
}
shader.dispose();
},
};
function getShader() {
var shaderMaterial = new THREE.ShaderMaterial( {
defines: {
"SAMPLES_PER_LEVEL": 20,
},
uniforms: {
"faceIndex": { value: 0 },
"roughness": { value: 0.5 },
"mapSize": { value: 0.5 },
"envMap": { value: null },
"tFlip": { value: - 1 },
},
vertexShader:
"varying vec2 vUv;\n\
void main() {\n\
vUv = uv;\n\
gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );\n\
}",
fragmentShader:
"#include <common>\n\
varying vec2 vUv;\n\
uniform int faceIndex;\n\
uniform float roughness;\n\
uniform samplerCube envMap;\n\
uniform float mapSize;\n\
uniform float tFlip;\n\
\n\
float GGXRoughnessToBlinnExponent( const in float ggxRoughness ) {\n\
float a = ggxRoughness + 0.0001;\n\
a *= a;\n\
return ( 2.0 / a - 2.0 );\n\
}\n\
vec3 ImportanceSamplePhong(vec2 uv, mat3 vecSpace, float specPow) {\n\
float phi = uv.y * 2.0 * PI;\n\
float cosTheta = pow(1.0 - uv.x, 1.0 / (specPow + 1.0));\n\
float sinTheta = sqrt(1.0 - cosTheta * cosTheta);\n\
vec3 sampleDir = vec3(cos(phi) * sinTheta, sin(phi) * sinTheta, cosTheta);\n\
return vecSpace * sampleDir;\n\
}\n\
vec3 ImportanceSampleGGX( vec2 uv, mat3 vecSpace, float Roughness )\n\
{\n\
float a = Roughness * Roughness;\n\
float Phi = 2.0 * PI * uv.x;\n\
float CosTheta = sqrt( (1.0 - uv.y) / ( 1.0 + (a*a - 1.0) * uv.y ) );\n\
float SinTheta = sqrt( 1.0 - CosTheta * CosTheta );\n\
return vecSpace * vec3(SinTheta * cos( Phi ), SinTheta * sin( Phi ), CosTheta);\n\
}\n\
mat3 matrixFromVector(vec3 n) {\n\
float a = 1.0 / (1.0 + n.z);\n\
float b = -n.x * n.y * a;\n\
vec3 b1 = vec3(1.0 - n.x * n.x * a, b, -n.x);\n\
vec3 b2 = vec3(b, 1.0 - n.y * n.y * a, -n.y);\n\
return mat3(b1, b2, n);\n\
}\n\
\n\
vec4 testColorMap(float Roughness) {\n\
vec4 color;\n\
if(faceIndex == 0)\n\
color = vec4(1.0,0.0,0.0,1.0);\n\
else if(faceIndex == 1)\n\
color = vec4(0.0,1.0,0.0,1.0);\n\
else if(faceIndex == 2)\n\
color = vec4(0.0,0.0,1.0,1.0);\n\
else if(faceIndex == 3)\n\
color = vec4(1.0,1.0,0.0,1.0);\n\
else if(faceIndex == 4)\n\
color = vec4(0.0,1.0,1.0,1.0);\n\
else\n\
color = vec4(1.0,0.0,1.0,1.0);\n\
color *= ( 1.0 - Roughness );\n\
return color;\n\
}\n\
void main() {\n\
vec3 sampleDirection;\n\
vec2 uv = vUv*2.0 - 1.0;\n\
float offset = -1.0/mapSize;\n\
const float a = -1.0;\n\
const float b = 1.0;\n\
float c = -1.0 + offset;\n\
float d = 1.0 - offset;\n\
float bminusa = b - a;\n\
uv.x = (uv.x - a)/bminusa * d - (uv.x - b)/bminusa * c;\n\
uv.y = (uv.y - a)/bminusa * d - (uv.y - b)/bminusa * c;\n\
if (faceIndex==0) {\n\
sampleDirection = vec3(1.0, -uv.y, -uv.x);\n\
} else if (faceIndex==1) {\n\
sampleDirection = vec3(-1.0, -uv.y, uv.x);\n\
} else if (faceIndex==2) {\n\
sampleDirection = vec3(uv.x, 1.0, uv.y);\n\
} else if (faceIndex==3) {\n\
sampleDirection = vec3(uv.x, -1.0, -uv.y);\n\
} else if (faceIndex==4) {\n\
sampleDirection = vec3(uv.x, -uv.y, 1.0);\n\
} else {\n\
sampleDirection = vec3(-uv.x, -uv.y, -1.0);\n\
}\n\
vec3 correctedDirection = vec3( tFlip * sampleDirection.x, sampleDirection.yz );\n\
mat3 vecSpace = matrixFromVector( normalize( correctedDirection ) );\n\
vec3 rgbColor = vec3(0.0);\n\
const int NumSamples = SAMPLES_PER_LEVEL;\n\
vec3 vect;\n\
float weight = 0.0;\n\
for( int i = 0; i < NumSamples; i ++ ) {\n\
float sini = sin(float(i));\n\
float cosi = cos(float(i));\n\
float r = rand(vec2(sini, cosi));\n\
vect = ImportanceSampleGGX(vec2(float(i) / float(NumSamples), r), vecSpace, roughness);\n\
float dotProd = dot(vect, normalize(sampleDirection));\n\
weight += dotProd;\n\
vec3 color = envMapTexelToLinear(textureCube(envMap, vect)).rgb;\n\
rgbColor.rgb += color;\n\
}\n\
rgbColor /= float(NumSamples);\n\
//rgbColor = testColorMap( roughness ).rgb;\n\
gl_FragColor = linearToOutputTexel( vec4( rgbColor, 1.0 ) );\n\
}",
blending: THREE.NoBlending
} );
shaderMaterial.type = 'PMREMGenerator';
return shaderMaterial;
}
return PMREMGenerator;
} )();
