// Copyright (C) 2014 NVIDIA Corporation. // Copyright (C) 2023 The Qt Company Ltd. // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only #ifndef PHYS_GLOSSY_BSDF_GLSLLIB #define PHYS_GLOSSY_BSDF_GLSLLIB 1 float qt_sqr(float v) { return v*v; } float qt_Gterm(float cosTheta, float roughness) { float k = roughness * 0.31830988618; // roughness / pi return clamp((cosTheta / (cosTheta*(1.0-k) + k) + (1.0 - k*k)) * 0.5, 0.0, 1.0); } float qt_SmithGGXMasking(in float NdotL, in float NdotV, in float a2) { float ia2 = 1.0 - a2; float A = NdotV * sqrt(a2 + ia2 * NdotL * NdotL); float B = NdotL * sqrt(a2 + ia2 * NdotV * NdotV); return 2.0 * NdotL * NdotV / (A + B); } // Isotropic GGX + smith vec4 qt_kggxGlossyBSDFMtl(in vec3 N, in vec3 L, in vec3 V, in vec3 lightSpecular, in float roughness) { vec4 rgba = vec4(0.0, 0.0, 0.0, 1.0); float NdotL = dot(N, L); if (NdotL > 0.0) { float NdotV = dot(N, V); vec3 H = normalize(L + V); float NdotH = dot(N, H); float a2 = roughness * roughness; float G2 = qt_SmithGGXMasking(NdotL, NdotV, a2); float D = a2 / (3.1415926535 * qt_sqr(qt_sqr(NdotH) * (a2 - 1.0) + 1.0)); rgba.rgb = lightSpecular * G2 * D / (4.0 * NdotV * NdotH); } return rgba; } vec4 qt_kggxGlossyDefaultMtl(in vec3 normal, in vec3 tangent, in vec3 L, in vec3 V, in vec3 lightSpecular, in vec3 materialSpecular, in float roughness) { return vec4(materialSpecular, 1.0) * qt_kggxGlossyBSDFMtl(normal, L, V, lightSpecular, roughness); } #endif