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| // Cubemap prefilter utility
// http://www.unrealengine.com/files/downloads/2013SiggraphPresentationsNotes.pdf
// http://http.developer.nvidia.com/GPUGems3/gpugems3_ch20.html
import Texture2D from '../Texture2D';
import TextureCube from '../TextureCube';
import Texture from '../Texture';
import FrameBuffer from '../FrameBuffer';
import Pass from '../compositor/Pass';
import Material from '../Material';
import Shader from '../Shader';
import Skybox from '../plugin/Skybox';
import Scene from '../Scene';
import EnvironmentMapPass from '../prePass/EnvironmentMap';
import vendor from '../core/vendor';
import textureUtil from './texture';
import integrateBRDFShaderCode from './shader/integrateBRDF.glsl.js';
import prefilterFragCode from './shader/prefilter.glsl.js';
var cubemapUtil = {};
var targets = ['px', 'nx', 'py', 'ny', 'pz', 'nz'];
/**
* @name clay.util.cubemap.prefilterEnvironmentMap
* @param {clay.Renderer} renderer
* @param {clay.Texture} envMap
* @param {Object} [textureOpts]
* @param {number} [textureOpts.width=64]
* @param {number} [textureOpts.height=64]
* @param {number} [textureOpts.type]
* @param {boolean} [textureOpts.encodeRGBM=false]
* @param {boolean} [textureOpts.decodeRGBM=false]
* @param {clay.Texture2D} [normalDistribution]
* @param {clay.Texture2D} [brdfLookup]
*/
cubemapUtil.prefilterEnvironmentMap = function (
renderer, envMap, textureOpts, normalDistribution, brdfLookup
) {
// Not create other renderer, it is easy having issue of cross reference of resources like framebuffer
// PENDING preserveDrawingBuffer?
Iif (!brdfLookup || !normalDistribution) {
normalDistribution = cubemapUtil.generateNormalDistribution();
brdfLookup = cubemapUtil.integrateBRDF(renderer, normalDistribution);
}
textureOpts = textureOpts || {};
var width = textureOpts.width || 64;
var height = textureOpts.height || 64;
var textureType = textureOpts.type || envMap.type;
// Use same type with given envMap
var prefilteredCubeMap = new TextureCube({
width: width,
height: height,
type: textureType,
flipY: false,
mipmaps: []
});
Iif (!prefilteredCubeMap.isPowerOfTwo()) {
console.warn('Width and height must be power of two to enable mipmap.');
}
var size = Math.min(width, height);
var mipmapNum = Math.log(size) / Math.log(2) + 1;
var prefilterMaterial = new Material({
shader: new Shader({
vertex: Shader.source('clay.skybox.vertex'),
fragment: prefilterFragCode
})
});
prefilterMaterial.set('normalDistribution', normalDistribution);
textureOpts.encodeRGBM && prefilterMaterial.define('fragment', 'RGBM_ENCODE');
textureOpts.decodeRGBM && prefilterMaterial.define('fragment', 'RGBM_DECODE');
var dummyScene = new Scene();
var skyEnv;
Eif (envMap.textureType === 'texture2D') {
// Convert panorama to cubemap
var envCubemap = new TextureCube({
width: width,
height: height,
// FIXME FLOAT type will cause GL_FRAMEBUFFER_INCOMPLETE_ATTACHMENT error on iOS
type: textureType === Texture.FLOAT ?
Texture.HALF_FLOAT : textureType
});
textureUtil.panoramaToCubeMap(renderer, envMap, envCubemap, {
// PENDING encodeRGBM so it can be decoded as RGBM
encodeRGBM: textureOpts.decodeRGBM
});
envMap = envCubemap;
}
skyEnv = new Skybox({
scene: dummyScene,
material: prefilterMaterial
});
skyEnv.material.set('environmentMap', envMap);
var envMapPass = new EnvironmentMapPass({
texture: prefilteredCubeMap
});
// Force to be UNSIGNED_BYTE
Eif (textureOpts.encodeRGBM) {
textureType = prefilteredCubeMap.type = Texture.UNSIGNED_BYTE;
}
var renderTargetTmp = new Texture2D({
width: width,
height: height,
type: textureType
});
var frameBuffer = new FrameBuffer({
depthBuffer: false
});
var ArrayCtor = vendor[textureType === Texture.UNSIGNED_BYTE ? 'Uint8Array' : 'Float32Array'];
for (var i = 0; i < mipmapNum; i++) {
prefilteredCubeMap.mipmaps[i] = {
pixels: {}
};
skyEnv.material.set('roughness', i / (targets.length - 1));
// Tweak fov
// http://the-witness.net/news/2012/02/seamless-cube-map-filtering/
var n = renderTargetTmp.width;
var fov = 2 * Math.atan(n / (n - 0.5)) / Math.PI * 180;
for (var j = 0; j < targets.length; j++) {
var pixels = new ArrayCtor(renderTargetTmp.width * renderTargetTmp.height * 4);
frameBuffer.attach(renderTargetTmp);
frameBuffer.bind(renderer);
var camera = envMapPass.getCamera(targets[j]);
camera.fov = fov;
renderer.render(dummyScene, camera);
renderer.gl.readPixels(
0, 0, renderTargetTmp.width, renderTargetTmp.height,
Texture.RGBA, textureType, pixels
);
// var canvas = document.createElement('canvas');
// var ctx = canvas.getContext('2d');
// canvas.width = renderTargetTmp.width;
// canvas.height = renderTargetTmp.height;
// var imageData = ctx.createImageData(renderTargetTmp.width, renderTargetTmp.height);
// for (var k = 0; k < pixels.length; k++) {
// imageData.data[k] = pixels[k];
// }
// ctx.putImageData(imageData, 0, 0);
// document.body.appendChild(canvas);
frameBuffer.unbind(renderer);
prefilteredCubeMap.mipmaps[i].pixels[targets[j]] = pixels;
}
renderTargetTmp.width /= 2;
renderTargetTmp.height /= 2;
renderTargetTmp.dirty();
}
frameBuffer.dispose(renderer);
renderTargetTmp.dispose(renderer);
skyEnv.dispose(renderer);
// Remove gpu resource allucated in renderer
normalDistribution.dispose(renderer);
// renderer.dispose();
return {
environmentMap: prefilteredCubeMap,
brdfLookup: brdfLookup,
normalDistribution: normalDistribution,
maxMipmapLevel: mipmapNum
};
};
cubemapUtil.integrateBRDF = function (renderer, normalDistribution) {
normalDistribution = normalDistribution || cubemapUtil.generateNormalDistribution();
var framebuffer = new FrameBuffer({
depthBuffer: false
});
var pass = new Pass({
fragment: integrateBRDFShaderCode
});
var texture = new Texture2D({
width: 512,
height: 256,
type: Texture.HALF_FLOAT,
minFilter: Texture.NEAREST,
magFilter: Texture.NEAREST,
useMipmap: false
});
pass.setUniform('normalDistribution', normalDistribution);
pass.setUniform('viewportSize', [512, 256]);
pass.attachOutput(texture);
pass.render(renderer, framebuffer);
// FIXME Only chrome and firefox can readPixels with float type.
// framebuffer.bind(renderer);
// var pixels = new Float32Array(512 * 256 * 4);
// renderer.gl.readPixels(
// 0, 0, texture.width, texture.height,
// Texture.RGBA, Texture.FLOAT, pixels
// );
// texture.pixels = pixels;
// texture.flipY = false;
// texture.dirty();
// framebuffer.unbind(renderer);
framebuffer.dispose(renderer);
return texture;
};
cubemapUtil.generateNormalDistribution = function (roughnessLevels, sampleSize) {
// http://holger.dammertz.org/stuff/notes_HammersleyOnHemisphere.html
// GLSL not support bit operation, use lookup instead
// V -> i / N, U -> roughness
var roughnessLevels = roughnessLevels || 256;
var sampleSize = sampleSize || 1024;
var normalDistribution = new Texture2D({
width: roughnessLevels,
height: sampleSize,
type: Texture.FLOAT,
minFilter: Texture.NEAREST,
magFilter: Texture.NEAREST,
wrapS: Texture.CLAMP_TO_EDGE,
wrapT: Texture.CLAMP_TO_EDGE,
useMipmap: false
});
var pixels = new Float32Array(sampleSize * roughnessLevels * 4);
var tmp = [];
function sortFunc(a, b) {
return Math.abs(b) - Math.abs(a);
}
for (var j = 0; j < roughnessLevels; j++) {
var roughness = j / roughnessLevels;
var a = roughness * roughness;
for (var i = 0; i < sampleSize; i++) {
// http://holger.dammertz.org/stuff/notes_HammersleyOnHemisphere.html
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Bitwise_Operators
// http://stackoverflow.com/questions/1908492/unsigned-integer-in-javascript
// http://stackoverflow.com/questions/1822350/what-is-the-javascript-operator-and-how-do-you-use-it
var y = (i << 16 | i >>> 16) >>> 0;
y = ((y & 1431655765) << 1 | (y & 2863311530) >>> 1) >>> 0;
y = ((y & 858993459) << 2 | (y & 3435973836) >>> 2) >>> 0;
y = ((y & 252645135) << 4 | (y & 4042322160) >>> 4) >>> 0;
y = (((y & 16711935) << 8 | (y & 4278255360) >>> 8) >>> 0) / 4294967296;
// CDF
var cosTheta = Math.sqrt((1 - y) / (1 + (a * a - 1.0) * y));
tmp[i] = cosTheta;
}
tmp.sort(sortFunc);
for (var i = 0; i < sampleSize; i++) {
var offset = (i * roughnessLevels + j) * 4;
var cosTheta = tmp[i];
var sinTheta = Math.sqrt(1.0 - cosTheta * cosTheta);
var x = i / sampleSize;
var phi = 2.0 * Math.PI * x;
pixels[offset] = sinTheta * Math.cos(phi);
pixels[offset + 1] = sinTheta * Math.sin(phi);
pixels[offset + 2] = cosTheta;
pixels[offset + 3] = 1.0;
}
}
normalDistribution.pixels = pixels;
return normalDistribution;
};
export default cubemapUtil;
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