From d228fb0c4a6541739888abb693411cfba0bd6bcb Mon Sep 17 00:00:00 2001 From: alteredq Date: Thu, 8 Sep 2011 02:18:50 +0200 Subject: [PATCH] Added physically based specular term to skin shader. --- examples/js/ShaderSkin.js | 153 ++++++++++++++++++----- examples/js/postprocessing/ShaderPass.js | 6 +- examples/webgl_materials_skin.html | 22 +++- 3 files changed, 148 insertions(+), 33 deletions(-) diff --git a/examples/js/ShaderSkin.js b/examples/js/ShaderSkin.js index d981d381..b7f905fa 100644 --- a/examples/js/ShaderSkin.js +++ b/examples/js/ShaderSkin.js @@ -8,13 +8,17 @@ THREE.ShaderSkin = { /* ------------------------------------------------------------------------------------------ // Skin shader - // - Blinn-Phong - // - normal + diffuse maps - // - four blur layers + // - Blinn-Phong diffuse term (using normal + diffuse maps) + // - subsurface scattering approximation by four blur layers + // - physically based specular term (Kelemen/Szirmay-Kalos specular reflectance) + // // - point and directional lights (use with "lights: true" material option) // // - based on Nvidia Advanced Skin Rendering GDC 2007 presentation + // and GPU Gems 3 Chapter 14. Advanced Techniques for Realistic Real-Time Skin Rendering + // // http://developer.download.nvidia.com/presentations/2007/gdc/Advanced_Skin.pdf + // http://http.developer.nvidia.com/GPUGems3/gpugems3_ch14.html // ------------------------------------------------------------------------------------------ */ 'skin' : { @@ -36,13 +40,17 @@ THREE.ShaderSkin = { "tBlur3" : { type: "t", value: 4, texture: null }, "tBlur4" : { type: "t", value: 5, texture: null }, + "tBeckmann" : { type: "t", value: 6, texture: null }, + "uNormalScale": { type: "f", value: 1.0 }, "uDiffuseColor": { type: "c", value: new THREE.Color( 0xeeeeee ) }, "uSpecularColor": { type: "c", value: new THREE.Color( 0x111111 ) }, "uAmbientColor": { type: "c", value: new THREE.Color( 0x050505 ) }, - "uShininess": { type: "f", value: 30 }, - "uOpacity": { type: "f", value: 1 } + "uOpacity": { type: "f", value: 1 }, + + "uRoughness": { type: "f", value: 0.15 }, + "uSpecularBrightness": { type: "f", value: 0.75 } } @@ -53,9 +61,11 @@ THREE.ShaderSkin = { "uniform vec3 uAmbientColor;", "uniform vec3 uDiffuseColor;", "uniform vec3 uSpecularColor;", - "uniform float uShininess;", "uniform float uOpacity;", + "uniform float uRoughness;", + "uniform float uSpecularBrightness;", + "uniform int passID;", "uniform sampler2D tDiffuse;", @@ -66,6 +76,8 @@ THREE.ShaderSkin = { "uniform sampler2D tBlur3;", "uniform sampler2D tBlur4;", + "uniform sampler2D tBeckmann;", + "uniform float uNormalScale;", "varying vec3 vTangent;", @@ -89,6 +101,46 @@ THREE.ShaderSkin = { THREE.ShaderChunk[ "fog_pars_fragment" ], + "float fresnelReflectance( vec3 H, vec3 V, float F0 ) {", + + "float base = 1.0 - dot( V, H );", + "float exponential = pow( base, 5.0 );", + + "return exponential + F0 * ( 1.0 - exponential );", + + "}", + + // Kelemen/Szirmay-Kalos specular BRDF + + "float KS_Skin_Specular( vec3 N,", // Bumped surface normal + "vec3 L,", // Points to light + "vec3 V,", // Points to eye + "float m,", // Roughness + "float rho_s", // Specular brightness + ") {", + + "float result = 0.0;", + "float ndotl = dot( N, L );", + + "if( ndotl > 0.0 ) {", + + "vec3 h = L + V;", // Unnormalized half-way vector + "vec3 H = normalize( h );", + + "float ndoth = dot( N, H );", + + "float PH = pow( 2.0 * texture2D( tBeckmann, vec2( ndoth, m ) ).x, 10.0 );", + "float F = fresnelReflectance( H, V, 0.028 );", + "float frSpec = max( PH * F / dot( h, h ), 0.0 );", + + "result = ndotl * rho_s * frSpec;", // BRDF * dot(N,L) * rho_s + + "}", + + "return result;", + + "}", + "void main() {", "gl_FragColor = vec4( 1.0 );", @@ -96,8 +148,6 @@ THREE.ShaderSkin = { "vec4 mColor = vec4( uDiffuseColor, uOpacity );", "vec4 mSpecular = vec4( uSpecularColor, uOpacity );", - "vec3 specularTex = vec3( 1.0 );", - "vec3 normalTex = texture2D( tNormal, vUv ).xyz * 2.0 - 1.0;", "normalTex.xy *= uNormalScale;", "normalTex = normalize( normalTex );", @@ -107,7 +157,6 @@ THREE.ShaderSkin = { "gl_FragColor = gl_FragColor * pow( colDiffuse, vec4( 0.5 ) );", - "mat3 tsb = mat3( vTangent, vBinormal, vNormal );", "vec3 finalNormal = tsb * normalTex;", @@ -116,7 +165,7 @@ THREE.ShaderSkin = { // point lights - "vec4 specularTotal = vec4( vec3( 0.0 ), 1.0 );", + "vec3 specularTotal = vec3( 0.0 );", "#if MAX_POINT_LIGHTS > 0", @@ -125,19 +174,14 @@ THREE.ShaderSkin = { "for ( int i = 0; i < MAX_POINT_LIGHTS; i ++ ) {", "vec3 pointVector = normalize( vPointLight[ i ].xyz );", - "vec3 pointHalfVector = normalize( vPointLight[ i ].xyz + viewPosition );", "float pointDistance = vPointLight[ i ].w;", - "float pointDotNormalHalf = dot( normal, pointHalfVector );", "float pointDiffuseWeight = max( dot( normal, pointVector ), 0.0 );", - "float pointSpecularWeight = 0.0;", - - "if ( passID == 1 && pointDotNormalHalf >= 0.0 )", - "pointSpecularWeight = specularTex.r * pow( pointDotNormalHalf, uShininess );", - "pointTotal += pointDistance * vec4( pointLightColor[ i ], 1.0 ) * ( mColor * pointDiffuseWeight );", - "specularTotal += pointDistance * vec4( pointLightColor[ i ], 1.0 ) * ( mSpecular * pointSpecularWeight * pointDiffuseWeight );", + + "if ( passID == 1 )", + "specularTotal += pointDistance * mSpecular.xyz * pointLightColor[ i ] * KS_Skin_Specular( normal, pointVector, viewPosition, uRoughness, uSpecularBrightness );", "}", @@ -154,17 +198,13 @@ THREE.ShaderSkin = { "vec4 lDirection = viewMatrix * vec4( directionalLightDirection[ i ], 0.0 );", "vec3 dirVector = normalize( lDirection.xyz );", - "vec3 dirHalfVector = normalize( lDirection.xyz + viewPosition );", - "float dirDotNormalHalf = dot( normal, dirHalfVector );", "float dirDiffuseWeight = max( dot( normal, dirVector ), 0.0 );", - "float dirSpecularWeight = 0.0;", - "if ( passID == 1 && dirDotNormalHalf >= 0.0 )", - "dirSpecularWeight = specularTex.r * pow( dirDotNormalHalf, uShininess );", - "dirTotal += vec4( directionalLightColor[ i ], 1.0 ) * ( mColor * dirDiffuseWeight );", - "specularTotal += vec4( directionalLightColor[ i ], 1.0 ) * ( mSpecular * dirSpecularWeight * dirDiffuseWeight );", + + "if ( passID == 1 )", + "specularTotal += mSpecular.xyz * directionalLightColor[ i ] * KS_Skin_Specular( normal, dirVector, viewPosition, uRoughness, uSpecularBrightness );", "}", @@ -224,8 +264,7 @@ THREE.ShaderSkin = { "gl_FragColor.xyz *= pow( colDiffuse.xyz, vec3( 0.5 ) );", - "gl_FragColor += specularTotal;", - "gl_FragColor.xyz += ambientLightColor * uAmbientColor * colDiffuse.xyz;", + "gl_FragColor.xyz += ambientLightColor * uAmbientColor * colDiffuse.xyz + specularTotal;", "#ifndef VERSION1", @@ -406,7 +445,65 @@ THREE.ShaderSkin = { ].join("\n") + }, + + /* ------------------------------------------------------------------------------------------ + // Beckmann distribution function + // - to be used in specular term of skin shader + // - render a screen-aligned quad to precompute a 512 x 512 texture + // + // - from http://developer.nvidia.com/node/171 + ------------------------------------------------------------------------------------------ */ + + "beckmann" : { + + uniforms: {}, + + vertexShader: [ + + "varying vec2 vUv;", + + "void main() {", + + "vUv = vec2( uv.x, 1.0 - uv.y );", + "gl_Position = projectionMatrix * modelViewMatrix * vec4( position, 1.0 );", + + "}" + + ].join("\n"), + + fragmentShader: [ + + "varying vec2 vUv;", + + "float PHBeckmann( float ndoth, float m ) {", + + "float alpha = acos( ndoth );", + "float ta = tan( alpha );", + + "float val = 1.0 / ( m * m * pow( ndoth, 4.0 ) ) * exp( -( ta * ta ) / ( m * m ) );", + "return val;", + + "}", + + "float KSTextureCompute( vec2 tex ) {", + + // Scale the value to fit within [0,1] – invert upon lookup. + + "return 0.5 * pow( PHBeckmann( tex.x, tex.y ), 0.1 );", + + "}", + + "void main() {", + + "float x = KSTextureCompute( vUv );", + + "gl_FragColor = vec4( x, x, x, 1.0 );", + + "}" + + ].join("\n") + } - }; \ No newline at end of file diff --git a/examples/js/postprocessing/ShaderPass.js b/examples/js/postprocessing/ShaderPass.js index 65c79660..83d2edb6 100644 --- a/examples/js/postprocessing/ShaderPass.js +++ b/examples/js/postprocessing/ShaderPass.js @@ -25,7 +25,11 @@ THREE.ShaderPass.prototype = { render: function ( renderer, writeBuffer, readBuffer, delta ) { - this.uniforms[ this.textureID ].texture = readBuffer; + if ( this.uniforms[ this.textureID ] ) { + + this.uniforms[ this.textureID ].texture = readBuffer; + + } THREE.EffectComposer.quad.materials[ 0 ] = this.material; diff --git a/examples/webgl_materials_skin.html b/examples/webgl_materials_skin.html index 954dfe56..b68959de 100644 --- a/examples/webgl_materials_skin.html +++ b/examples/webgl_materials_skin.html @@ -43,7 +43,6 @@ - @@ -71,7 +70,7 @@ var mesh; - var composer, composerUV1, composerUV2, composerUV3; + var composer, composerUV1, composerUV2, composerUV3, composerBeckmann; var directionalLight, pointLight, ambientLight; @@ -99,6 +98,7 @@ ambientLight = new THREE.AmbientLight( 0x222222 ); scene.add( ambientLight ); + directionalLight = new THREE.DirectionalLight( 0xffeedd, 1 ); directionalLight.position.set( 1, -1, 1 ); directionalLight.position.normalize(); @@ -108,7 +108,7 @@ var ambient = 0x111111, diffuse = 0xbbbbbb, specular = 0x070707, shininess = 50; - specular = 0x090909; + specular = 0x555555; var shader = THREE.ShaderSkin[ "skin" ]; @@ -125,7 +125,8 @@ uniformsUV[ "uSpecularColor" ].value.setHex( specular ); uniformsUV[ "uAmbientColor" ].value.setHex( ambient ); - uniformsUV[ "uShininess" ].value = shininess; + uniformsUV[ "uRoughness" ].value = 0.185; + uniformsUV[ "uSpecularBrightness" ].value = 0.8; var uniforms = THREE.UniformsUtils.clone( uniformsUV ); uniforms[ "tDiffuse" ].texture = uniformsUV[ "tDiffuse" ].texture; @@ -222,6 +223,14 @@ // + var effectBeckmann = new THREE.ShaderPass( THREE.ShaderSkin[ "beckmann" ] ); + + composerBeckmann = new THREE.EffectComposer( renderer, new THREE.WebGLRenderTarget( rtwidth, rtheight, pars ) ); + + composerBeckmann.addPass( effectBeckmann ); + + // + var effectBloom = new THREE.BloomPass( 0.25 ); var effectBleach = new THREE.ShaderPass( THREE.ShaderExtras[ "bleachbypass" ] ); @@ -242,6 +251,8 @@ uniforms[ "tBlur3" ].texture = composerUV2.renderTarget2; uniforms[ "tBlur4" ].texture = composerUV3.renderTarget2; + uniforms[ "tBeckmann" ].texture = composerBeckmann.renderTarget1; + } @@ -292,6 +303,9 @@ renderer.clear(); + composerBeckmann.render(); + + composerScene.render(); composerUV1.render();