@luma.gl/shadertools/dist/modules-webgl1/lighting/pbr/pbr-fragment-glsl.d.ts

Shader module system for luma.gl

export declare const fs = "precision highp float;\n\nuniform bool pbr_uUnlit;\n\n#ifdef USE_IBL\nuniform samplerCube u_DiffuseEnvSampler;\nuniform samplerCube u_SpecularEnvSampler;\nuniform sampler2D u_brdfLUT;\nuniform vec2 u_ScaleIBLAmbient;\n#endif\n\n#ifdef HAS_BASECOLORMAP\nuniform sampler2D u_BaseColorSampler;\n#endif\n#ifdef HAS_NORMALMAP\nuniform sampler2D u_NormalSampler;\nuniform float u_NormalScale;\n#endif\n#ifdef HAS_EMISSIVEMAP\nuniform sampler2D u_EmissiveSampler;\nuniform vec3 u_EmissiveFactor;\n#endif\n#ifdef HAS_METALROUGHNESSMAP\nuniform sampler2D u_MetallicRoughnessSampler;\n#endif\n#ifdef HAS_OCCLUSIONMAP\nuniform sampler2D u_OcclusionSampler;\nuniform float u_OcclusionStrength;\n#endif\n\n#ifdef ALPHA_CUTOFF\nuniform float u_AlphaCutoff;\n#endif\n\nuniform vec2 u_MetallicRoughnessValues;\nuniform vec4 u_BaseColorFactor;\n\nuniform vec3 u_Camera;\n\n// debugging flags used for shader output of intermediate PBR variables\n#ifdef PBR_DEBUG\nuniform vec4 u_ScaleDiffBaseMR;\nuniform vec4 u_ScaleFGDSpec;\n#endif\n\nin vec3 pbr_vPosition;\n\nin vec2 pbr_vUV;\n\n#ifdef HAS_NORMALS\n#ifdef HAS_TANGENTS\nin mat3 pbr_vTBN;\n#else\nin vec3 pbr_vNormal;\n#endif\n#endif\n\n// Encapsulate the various inputs used by the various functions in the shading equation\n// We store values in this struct to simplify the integration of alternative implementations\n// of the shading terms, outlined in the Readme.MD Appendix.\nstruct PBRInfo\n{\n  float NdotL;                  // cos angle between normal and light direction\n  float NdotV;                  // cos angle between normal and view direction\n  float NdotH;                  // cos angle between normal and half vector\n  float LdotH;                  // cos angle between light direction and half vector\n  float VdotH;                  // cos angle between view direction and half vector\n  float perceptualRoughness;    // roughness value, as authored by the model creator (input to shader)\n  float metalness;              // metallic value at the surface\n  vec3 reflectance0;            // full reflectance color (normal incidence angle)\n  vec3 reflectance90;           // reflectance color at grazing angle\n  float alphaRoughness;         // roughness mapped to a more linear change in the roughness (proposed by [2])\n  vec3 diffuseColor;            // color contribution from diffuse lighting\n  vec3 specularColor;           // color contribution from specular lighting\n  vec3 n;                       // normal at surface point\n  vec3 v;                       // vector from surface point to camera\n};\n\nconst float M_PI = 3.141592653589793;\nconst float c_MinRoughness = 0.04;\n\nvec4 SRGBtoLINEAR(vec4 srgbIn)\n{\n#ifdef MANUAL_SRGB\n#ifdef SRGB_FAST_APPROXIMATION\n  vec3 linOut = pow(srgbIn.xyz,vec3(2.2));\n#else //SRGB_FAST_APPROXIMATION\n  vec3 bLess = step(vec3(0.04045),srgbIn.xyz);\n  vec3 linOut = mix( srgbIn.xyz/vec3(12.92), pow((srgbIn.xyz+vec3(0.055))/vec3(1.055),vec3(2.4)), bLess );\n#endif //SRGB_FAST_APPROXIMATION\n  return vec4(linOut,srgbIn.w);;\n#else //MANUAL_SRGB\n  return srgbIn;\n#endif //MANUAL_SRGB\n}\n\n// Find the normal for this fragment, pulling either from a predefined normal map\n// or from the interpolated mesh normal and tangent attributes.\nvec3 getNormal()\n{\n  // Retrieve the tangent space matrix\n#ifndef HAS_TANGENTS\n  vec3 pos_dx = dFdx(pbr_vPosition);\n  vec3 pos_dy = dFdy(pbr_vPosition);\n  vec3 tex_dx = dFdx(vec3(pbr_vUV, 0.0));\n  vec3 tex_dy = dFdy(vec3(pbr_vUV, 0.0));\n  vec3 t = (tex_dy.t * pos_dx - tex_dx.t * pos_dy) / (tex_dx.s * tex_dy.t - tex_dy.s * tex_dx.t);\n\n#ifdef HAS_NORMALS\n  vec3 ng = normalize(pbr_vNormal);\n#else\n  vec3 ng = cross(pos_dx, pos_dy);\n#endif\n\n  t = normalize(t - ng * dot(ng, t));\n  vec3 b = normalize(cross(ng, t));\n  mat3 tbn = mat3(t, b, ng);\n#else // HAS_TANGENTS\n  mat3 tbn = pbr_vTBN;\n#endif\n\n#ifdef HAS_NORMALMAP\n  vec3 n = texture(u_NormalSampler, pbr_vUV).rgb;\n  n = normalize(tbn * ((2.0 * n - 1.0) * vec3(u_NormalScale, u_NormalScale, 1.0)));\n#else\n  // The tbn matrix is linearly interpolated, so we need to re-normalize\n  vec3 n = normalize(tbn[2].xyz);\n#endif\n\n  return n;\n}\n\n// Calculation of the lighting contribution from an optional Image Based Light source.\n// Precomputed Environment Maps are required uniform inputs and are computed as outlined in [1].\n// See our README.md on Environment Maps [3] for additional discussion.\n#ifdef USE_IBL\nvec3 getIBLContribution(PBRInfo pbrInputs, vec3 n, vec3 reflection)\n{\n  float mipCount = 9.0; // resolution of 512x512\n  float lod = (pbrInputs.perceptualRoughness * mipCount);\n  // retrieve a scale and bias to F0. See [1], Figure 3\n  vec3 brdf = SRGBtoLINEAR(texture(u_brdfLUT,\n    vec2(pbrInputs.NdotV, 1.0 - pbrInputs.perceptualRoughness))).rgb;\n  vec3 diffuseLight = SRGBtoLINEAR(textureCube(u_DiffuseEnvSampler, n)).rgb;\n\n#ifdef USE_TEX_LOD\n  vec3 specularLight = SRGBtoLINEAR(textureCubeLod(u_SpecularEnvSampler, reflection, lod)).rgb;\n#else\n  vec3 specularLight = SRGBtoLINEAR(textureCube(u_SpecularEnvSampler, reflection)).rgb;\n#endif\n\n  vec3 diffuse = diffuseLight * pbrInputs.diffuseColor;\n  vec3 specular = specularLight * (pbrInputs.specularColor * brdf.x + brdf.y);\n\n  // For presentation, this allows us to disable IBL terms\n  diffuse *= u_ScaleIBLAmbient.x;\n  specular *= u_ScaleIBLAmbient.y;\n\n  return diffuse + specular;\n}\n#endif\n\n// Basic Lambertian diffuse\n// Implementation from Lambert's Photometria https://archive.org/details/lambertsphotome00lambgoog\n// See also [1], Equation 1\nvec3 diffuse(PBRInfo pbrInputs)\n{\n  return pbrInputs.diffuseColor / M_PI;\n}\n\n// The following equation models the Fresnel reflectance term of the spec equation (aka F())\n// Implementation of fresnel from [4], Equation 15\nvec3 specularReflection(PBRInfo pbrInputs)\n{\n  return pbrInputs.reflectance0 +\n    (pbrInputs.reflectance90 - pbrInputs.reflectance0) *\n    pow(clamp(1.0 - pbrInputs.VdotH, 0.0, 1.0), 5.0);\n}\n\n// This calculates the specular geometric attenuation (aka G()),\n// where rougher material will reflect less light back to the viewer.\n// This implementation is based on [1] Equation 4, and we adopt their modifications to\n// alphaRoughness as input as originally proposed in [2].\nfloat geometricOcclusion(PBRInfo pbrInputs)\n{\n  float NdotL = pbrInputs.NdotL;\n  float NdotV = pbrInputs.NdotV;\n  float r = pbrInputs.alphaRoughness;\n\n  float attenuationL = 2.0 * NdotL / (NdotL + sqrt(r * r + (1.0 - r * r) * (NdotL * NdotL)));\n  float attenuationV = 2.0 * NdotV / (NdotV + sqrt(r * r + (1.0 - r * r) * (NdotV * NdotV)));\n  return attenuationL * attenuationV;\n}\n\n// The following equation(s) model the distribution of microfacet normals across\n// the area being drawn (aka D())\n// Implementation from \"Average Irregularity Representation of a Roughened Surface\n// for Ray Reflection\" by T. S. Trowbridge, and K. P. Reitz\n// Follows the distribution function recommended in the SIGGRAPH 2013 course notes\n// from EPIC Games [1], Equation 3.\nfloat microfacetDistribution(PBRInfo pbrInputs)\n{\n  float roughnessSq = pbrInputs.alphaRoughness * pbrInputs.alphaRoughness;\n  float f = (pbrInputs.NdotH * roughnessSq - pbrInputs.NdotH) * pbrInputs.NdotH + 1.0;\n  return roughnessSq / (M_PI * f * f);\n}\n\nvoid PBRInfo_setAmbientLight(inout PBRInfo pbrInputs) {\n  pbrInputs.NdotL = 1.0;\n  pbrInputs.NdotH = 0.0;\n  pbrInputs.LdotH = 0.0;\n  pbrInputs.VdotH = 1.0;\n}\n\nvoid PBRInfo_setDirectionalLight(inout PBRInfo pbrInputs, vec3 lightDirection) {\n  vec3 n = pbrInputs.n;\n  vec3 v = pbrInputs.v;\n  vec3 l = normalize(lightDirection);             // Vector from surface point to light\n  vec3 h = normalize(l+v);                        // Half vector between both l and v\n\n  pbrInputs.NdotL = clamp(dot(n, l), 0.001, 1.0);\n  pbrInputs.NdotH = clamp(dot(n, h), 0.0, 1.0);\n  pbrInputs.LdotH = clamp(dot(l, h), 0.0, 1.0);\n  pbrInputs.VdotH = clamp(dot(v, h), 0.0, 1.0);\n}\n\nvoid PBRInfo_setPointLight(inout PBRInfo pbrInputs, PointLight pointLight) {\n  vec3 light_direction = normalize(pointLight.position - pbr_vPosition);\n  PBRInfo_setDirectionalLight(pbrInputs, light_direction);\n}\n\nvec3 calculateFinalColor(PBRInfo pbrInputs, vec3 lightColor) {\n  // Calculate the shading terms for the microfacet specular shading model\n  vec3 F = specularReflection(pbrInputs);\n  float G = geometricOcclusion(pbrInputs);\n  float D = microfacetDistribution(pbrInputs);\n\n  // Calculation of analytical lighting contribution\n  vec3 diffuseContrib = (1.0 - F) * diffuse(pbrInputs);\n  vec3 specContrib = F * G * D / (4.0 * pbrInputs.NdotL * pbrInputs.NdotV);\n  // Obtain final intensity as reflectance (BRDF) scaled by the energy of the light (cosine law)\n  return pbrInputs.NdotL * lightColor * (diffuseContrib + specContrib);\n}\n\nvec4 pbr_filterColor(vec4 colorUnused)\n{\n  // The albedo may be defined from a base texture or a flat color\n#ifdef HAS_BASECOLORMAP\n  vec4 baseColor = SRGBtoLINEAR(texture(u_BaseColorSampler, pbr_vUV)) * u_BaseColorFactor;\n#else\n  vec4 baseColor = u_BaseColorFactor;\n#endif\n\n#ifdef ALPHA_CUTOFF\n  if (baseColor.a < u_AlphaCutoff) {\n    discard;\n  }\n#endif\n\n  vec3 color = vec3(0, 0, 0);\n\n  if(pbr_uUnlit){\n    color.rgb = baseColor.rgb;\n  }\n  else{\n    // Metallic and Roughness material properties are packed together\n    // In glTF, these factors can be specified by fixed scalar values\n    // or from a metallic-roughness map\n    float perceptualRoughness = u_MetallicRoughnessValues.y;\n    float metallic = u_MetallicRoughnessValues.x;\n#ifdef HAS_METALROUGHNESSMAP\n    // Roughness is stored in the 'g' channel, metallic is stored in the 'b' channel.\n    // This layout intentionally reserves the 'r' channel for (optional) occlusion map data\n    vec4 mrSample = texture(u_MetallicRoughnessSampler, pbr_vUV);\n    perceptualRoughness = mrSample.g * perceptualRoughness;\n    metallic = mrSample.b * metallic;\n#endif\n    perceptualRoughness = clamp(perceptualRoughness, c_MinRoughness, 1.0);\n    metallic = clamp(metallic, 0.0, 1.0);\n    // Roughness is authored as perceptual roughness; as is convention,\n    // convert to material roughness by squaring the perceptual roughness [2].\n    float alphaRoughness = perceptualRoughness * perceptualRoughness;\n\n    vec3 f0 = vec3(0.04);\n    vec3 diffuseColor = baseColor.rgb * (vec3(1.0) - f0);\n    diffuseColor *= 1.0 - metallic;\n    vec3 specularColor = mix(f0, baseColor.rgb, metallic);\n\n    // Compute reflectance.\n    float reflectance = max(max(specularColor.r, specularColor.g), specularColor.b);\n\n    // For typical incident reflectance range (between 4% to 100%) set the grazing\n    // reflectance to 100% for typical fresnel effect.\n    // For very low reflectance range on highly diffuse objects (below 4%),\n    // incrementally reduce grazing reflecance to 0%.\n    float reflectance90 = clamp(reflectance * 25.0, 0.0, 1.0);\n    vec3 specularEnvironmentR0 = specularColor.rgb;\n    vec3 specularEnvironmentR90 = vec3(1.0, 1.0, 1.0) * reflectance90;\n\n    vec3 n = getNormal();                          // normal at surface point\n    vec3 v = normalize(u_Camera - pbr_vPosition);  // Vector from surface point to camera\n\n    float NdotV = clamp(abs(dot(n, v)), 0.001, 1.0);\n    vec3 reflection = -normalize(reflect(v, n));\n\n    PBRInfo pbrInputs = PBRInfo(\n      0.0, // NdotL\n      NdotV,\n      0.0, // NdotH\n      0.0, // LdotH\n      0.0, // VdotH\n      perceptualRoughness,\n      metallic,\n      specularEnvironmentR0,\n      specularEnvironmentR90,\n      alphaRoughness,\n      diffuseColor,\n      specularColor,\n      n,\n      v\n    );\n\n#ifdef USE_LIGHTS\n    // Apply ambient light\n    PBRInfo_setAmbientLight(pbrInputs);\n    color += calculateFinalColor(pbrInputs, lighting_uAmbientLight.color);\n\n    // Apply directional light\n    for(int i = 0; i < lighting_uDirectionalLightCount; i++) {\n      if (i < lighting_uDirectionalLightCount) {\n        PBRInfo_setDirectionalLight(pbrInputs, lighting_uDirectionalLight[i].direction);\n        color += calculateFinalColor(pbrInputs, lighting_uDirectionalLight[i].color);\n      }\n    }\n\n    // Apply point light\n    for(int i = 0; i < lighting_uPointLightCount; i++) {\n      if (i < lighting_uPointLightCount) {\n        PBRInfo_setPointLight(pbrInputs, lighting_uPointLight[i]);\n        float attenuation = getPointLightAttenuation(lighting_uPointLight[i], distance(lighting_uPointLight[i].position, pbr_vPosition));\n        color += calculateFinalColor(pbrInputs, lighting_uPointLight[i].color / attenuation);\n      }\n    }\n#endif\n\n    // Calculate lighting contribution from image based lighting source (IBL)\n#ifdef USE_IBL\n    color += getIBLContribution(pbrInputs, n, reflection);\n#endif\n\n    // Apply optional PBR terms for additional (optional) shading\n#ifdef HAS_OCCLUSIONMAP\n    float ao = texture(u_OcclusionSampler, pbr_vUV).r;\n    color = mix(color, color * ao, u_OcclusionStrength);\n#endif\n\n#ifdef HAS_EMISSIVEMAP\n    vec3 emissive = SRGBtoLINEAR(texture(u_EmissiveSampler, pbr_vUV)).rgb * u_EmissiveFactor;\n    color += emissive;\n#endif\n\n    // This section uses mix to override final color for reference app visualization\n    // of various parameters in the lighting equation.\n#ifdef PBR_DEBUG\n    // TODO: Figure out how to debug multiple lights\n\n    // color = mix(color, F, u_ScaleFGDSpec.x);\n    // color = mix(color, vec3(G), u_ScaleFGDSpec.y);\n    // color = mix(color, vec3(D), u_ScaleFGDSpec.z);\n    // color = mix(color, specContrib, u_ScaleFGDSpec.w);\n\n    // color = mix(color, diffuseContrib, u_ScaleDiffBaseMR.x);\n    color = mix(color, baseColor.rgb, u_ScaleDiffBaseMR.y);\n    color = mix(color, vec3(metallic), u_ScaleDiffBaseMR.z);\n    color = mix(color, vec3(perceptualRoughness), u_ScaleDiffBaseMR.w);\n#endif\n\n  }\n\n  return vec4(pow(color,vec3(1.0/2.2)), baseColor.a);\n}\n";
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