0031096: Visualization, TKOpenGl - support metallic-roughness texture mapping

[occt.git] / src / Shaders / Shaders_PathtraceBase_fs.pxx

diff --git a/src/Shaders/Shaders_PathtraceBase_fs.pxx b/src/Shaders/Shaders_PathtraceBase_fs.pxx
index 138abbb..6d33da8 100644 (file)
--- a/src/Shaders/Shaders_PathtraceBase_fs.pxx
+++ b/src/Shaders/Shaders_PathtraceBase_fs.pxx
@@ -37,14 +37,14 @@ static const char Shaders_PathtraceBase_fs[] =
   "  //! Weight of coat specular/glossy BRDF.\n"
   "  vec4 Kc;\n"
   "\n"
-  "  //! Weight of base diffuse BRDF.\n"
+  "  //! Weight of base diffuse BRDF + base color texture index in W.\n"
   "  vec4 Kd;\n"
   "\n"
   "  //! Weight of base specular/glossy BRDF.\n"
   "  vec4 Ks;\n"
   "\n"
-  "  //! Weight of base specular/glossy BTDF.\n"
-  "  vec3 Kt;\n"
+  "  //! Weight of base specular/glossy BTDF + metallic-roughness texture index in W.\n"
+  "  vec4 Kt;\n"
   "\n"
   "  //! Fresnel coefficients of coat layer.\n"
   "  vec3 FresnelCoat;\n"
@@ -819,11 +819,16 @@ static const char Shaders_PathtraceBase_fs[] =
   "    aBSDF.Kc = texelFetch (uRaytraceMaterialTexture, MATERIAL_KC (aTriIndex.w));\n"
   "    aBSDF.Kd = texelFetch (uRaytraceMaterialTexture, MATERIAL_KD (aTriIndex.w));\n"
   "    aBSDF.Ks = texelFetch (uRaytraceMaterialTexture, MATERIAL_KS (aTriIndex.w));\n"
-  "    aBSDF.Kt = texelFetch (uRaytraceMaterialTexture, MATERIAL_KT (aTriIndex.w)).rgb;\n"
+  "    aBSDF.Kt = texelFetch (uRaytraceMaterialTexture, MATERIAL_KT (aTriIndex.w));\n"
+  "\n"
+  "    // fetch Fresnel reflectance for both layers\n"
+  "    aBSDF.FresnelCoat = texelFetch (uRaytraceMaterialTexture, MATERIAL_FRESNEL_COAT (aTriIndex.w)).xyz;\n"
+  "    aBSDF.FresnelBase = texelFetch (uRaytraceMaterialTexture, MATERIAL_FRESNEL_BASE (aTriIndex.w)).xyz;\n"
+  "\n"
+  "    vec4 anLE = texelFetch (uRaytraceMaterialTexture, MATERIAL_LE (aTriIndex.w));\n"
   "\n"
   "    // compute smooth normal (in parallel with fetch)\n"
   "    vec3 aNormal = SmoothNormal (aHit.UV, aTriIndex);\n"
-  "\n"
   "    aNormal = normalize (vec3 (dot (aInvTransf0, aNormal),\n"
   "                               dot (aInvTransf1, aNormal),\n"
   "                               dot (aInvTransf2, aNormal)));\n"
@@ -831,7 +836,7 @@ static const char Shaders_PathtraceBase_fs[] =
   "    SLocalSpace aSpace = buildLocalSpace (aNormal);\n"
   "\n"
   "#ifdef USE_TEXTURES\n"
-  "    if (aBSDF.Kd.w >= 0.f)\n"
+  "    if (aBSDF.Kd.w >= 0.0 || aBSDF.Kt.w >= 0.0 || anLE.w >= 0.0)\n"
   "    {\n"
   "      vec4 aTexCoord = vec4 (SmoothUV (aHit.UV, aTriIndex), 0.f, 1.f);\n"
   "      vec4 aTrsfRow1 = texelFetch (uRaytraceMaterialTexture, MATERIAL_TRS1 (aTriIndex.w));\n"
@@ -839,20 +844,36 @@ static const char Shaders_PathtraceBase_fs[] =
   "      aTexCoord.st = vec2 (dot (aTrsfRow1, aTexCoord),\n"
   "                           dot (aTrsfRow2, aTexCoord));\n"
   "\n"
-  "      vec4 aTexColor = textureLod (sampler2D (uTextureSamplers[int (aBSDF.Kd.w)]), aTexCoord.st, 0.f);\n"
-  "      aBSDF.Kd.rgb *= aTexColor.rgb * aTexColor.w;\n"
-  "      if (aTexColor.w != 1.0f)\n"
+  "      if (anLE.w >= 0.0)\n"
+  "      {\n"
+  "        anLE.rgb *= textureLod (sampler2D (uTextureSamplers[int (anLE.w)]), aTexCoord.st, 0.0).rgb;\n"
+  "      }\n"
+  "      if (aBSDF.Kt.w >= 0.0)\n"
   "      {\n"
-  "        // mix transparency BTDF with texture alpha-channel\n"
-  "        aBSDF.Kt = (UNIT - aTexColor.www) + aTexColor.w * aBSDF.Kt;\n"
+  "        vec2 aTexMetRough = textureLod (sampler2D (uTextureSamplers[int (aBSDF.Kt.w)]), aTexCoord.st, 0.0).bg;\n"
+  "        float aPbrMetal = aTexMetRough.x;\n"
+  "        float aPbrRough2 = aTexMetRough.y * aTexMetRough.y;\n"
+  "        aBSDF.Ks.a *= aPbrRough2;\n"
+  "        // when using metal-roughness texture, global metalness of material (encoded in FresnelBase) is expected to be 1.0 so that Kd will be 0.0\n"
+  "        aBSDF.Kd.rgb = aBSDF.FresnelBase * (1.0 - aPbrMetal);\n"
+  "        aBSDF.FresnelBase *= aPbrMetal;\n"
+  "      }\n"
+  "      if (aBSDF.Kd.w >= 0.0)\n"
+  "      {\n"
+  "        vec4 aTexColor = textureLod (sampler2D (uTextureSamplers[int (aBSDF.Kd.w)]), aTexCoord.st, 0.0);\n"
+  "        vec3 aDiff = aTexColor.rgb * aTexColor.a;\n"
+  "        aBSDF.Kd.rgb *= aDiff;\n"
+  "        aBSDF.FresnelBase *= aDiff;\n"
+  "        if (aTexColor.a != 1.0)\n"
+  "        {\n"
+  "          // mix transparency BTDF with texture alpha-channel\n"
+  "          aBSDF.Ks.rgb *= aTexColor.a;\n"
+  "          aBSDF.Kt.rgb = (UNIT - aTexColor.aaa) + aTexColor.a * aBSDF.Kt.rgb;\n"
+  "        }\n"
   "      }\n"
   "    }\n"
   "#endif\n"
   "\n"
-  "    // fetch Fresnel reflectance for both layers\n"
-  "    aBSDF.FresnelCoat = texelFetch (uRaytraceMaterialTexture, MATERIAL_FRESNEL_COAT (aTriIndex.w)).xyz;\n"
-  "    aBSDF.FresnelBase = texelFetch (uRaytraceMaterialTexture, MATERIAL_FRESNEL_BASE (aTriIndex.w)).xyz;\n"
-  "\n"
   "    if (uLightCount > 0 && IsNotZero (aBSDF, aThroughput))\n"
   "    {\n"
   "      aExpPDF = 1.f / uLightCount;\n"
@@ -896,7 +917,7 @@ static const char Shaders_PathtraceBase_fs[] =
   "    }\n"
   "\n"
   "    // account for self-emission\n"
-  "    aRadiance += aThroughput * texelFetch (uRaytraceMaterialTexture, MATERIAL_LE (aTriIndex.w)).rgb;\n"
+  "    aRadiance += aThroughput * anLE.rgb;\n"
   "\n"
   "    if (aInMedium) // handle attenuation\n"
   "    {\n"