WIP - switch PBR implementations

16 files changed, 510 insertions, 265 deletions

diff --git a/indra/llrender/llshadermgr.cpp b/indra/llrender/llshadermgr.cpp
index 2ea1c0d698..b609a74e32 100644
--- a/indra/llrender/llshadermgr.cpp
+++ b/indra/llrender/llshadermgr.cpp
@@ -1324,6 +1324,7 @@ void LLShaderMgr::initAttribsAndUniforms()
 	mReservedUniforms.push_back("diffuseRect");
 	mReservedUniforms.push_back("specularRect");
     mReservedUniforms.push_back("emissiveRect");
+    mReservedUniforms.push_back("brdfLut");
 	mReservedUniforms.push_back("noiseMap");
 	mReservedUniforms.push_back("lightFunc");
 	mReservedUniforms.push_back("lightMap");
diff --git a/indra/llrender/llshadermgr.h b/indra/llrender/llshadermgr.h
index 249eeace31..aa002014a7 100644
--- a/indra/llrender/llshadermgr.h
+++ b/indra/llrender/llshadermgr.h
@@ -177,6 +177,7 @@ public:
         DEFERRED_DIFFUSE,                   //  "diffuseRect"
         DEFERRED_SPECULAR,                  //  "specularRect"
         DEFERRED_EMISSIVE,                  //  "emissiveRect"
+        DEFERRED_BRDF_LUT,                  //  "brdfLut"
         DEFERRED_NOISE,                     //  "noiseMap"
         DEFERRED_LIGHTFUNC,                 //  "lightFunc"
         DEFERRED_LIGHT,                     //  "lightMap"
diff --git a/indra/newview/app_settings/shaders/class1/deferred/deferredUtil.glsl b/indra/newview/app_settings/shaders/class1/deferred/deferredUtil.glsl
index 652e609718..52345e7e51 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/deferredUtil.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/deferredUtil.glsl
@@ -23,9 +23,38 @@
  * $/LicenseInfo$
  */
 
+
+
+
+
+/*  Parts of this file are taken from Sascha Willem's Vulkan GLTF refernce implementation
+MIT License
+
+Copyright (c) 2018 Sascha Willems
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
 uniform sampler2DRect   normalMap;
 uniform sampler2DRect   depthMap;
 uniform sampler2D projectionMap; // rgba
+uniform sampler2D brdfLut;
 
 // projected lighted params
 uniform mat4 proj_mat; //screen space to light space projector
@@ -482,38 +511,227 @@ vec3 BRDFSpecularGGX( vec3 reflect0, vec3 reflect90, float alphaRough, float spe
     return fresnel * vis * d;
 }
 
+// Based omn http://byteblacksmith.com/improvements-to-the-canonical-one-liner-glsl-rand-for-opengl-es-2-0/
+float random(vec2 co)
+{
+	float a = 12.9898;
+	float b = 78.233;
+	float c = 43758.5453;
+	float dt= dot(co.xy ,vec2(a,b));
+	float sn= mod(dt,3.14);
+	return fract(sin(sn) * c);
+}
+
+vec2 hammersley2d(uint i, uint N) 
+{
+	// Radical inverse based on http://holger.dammertz.org/stuff/notes_HammersleyOnHemisphere.html
+	uint bits = (i << 16u) | (i >> 16u);
+	bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u);
+	bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u);
+	bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u);
+	bits = ((bits & 0x00FF00FFu) << 8u) | ((bits & 0xFF00FF00u) >> 8u);
+	float rdi = float(bits) * 2.3283064365386963e-10;
+	return vec2(float(i) /float(N), rdi);
+}
+
+// Based on http://blog.selfshadow.com/publications/s2013-shading-course/karis/s2013_pbs_epic_slides.pdf
+vec3 importanceSample_GGX(vec2 Xi, float roughness, vec3 normal) 
+{
+	// Maps a 2D point to a hemisphere with spread based on roughness
+	float alpha = roughness * roughness;
+	float phi = 2.0 * M_PI * Xi.x + random(normal.xz) * 0.1;
+	float cosTheta = sqrt((1.0 - Xi.y) / (1.0 + (alpha*alpha - 1.0) * Xi.y));
+	float sinTheta = sqrt(1.0 - cosTheta * cosTheta);
+	vec3 H = vec3(sinTheta * cos(phi), sinTheta * sin(phi), cosTheta);
+
+	// Tangent space
+	vec3 up = abs(normal.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
+	vec3 tangentX = normalize(cross(up, normal));
+	vec3 tangentY = normalize(cross(normal, tangentX));
+
+	// Convert to world Space
+	return normalize(tangentX * H.x + tangentY * H.y + normal * H.z);
+}
+
+// Geometric Shadowing function
+float G_SchlicksmithGGX(float dotNL, float dotNV, float roughness)
+{
+	float k = (roughness * roughness) / 2.0;
+	float GL = dotNL / (dotNL * (1.0 - k) + k);
+	float GV = dotNV / (dotNV * (1.0 - k) + k);
+	return GL * GV;
+}
+
+#define NUM_SAMPLES 16
+
+vec2 BRDF(float NoV, float roughness)
+{
+#if 0
+	// Normal always points along z-axis for the 2D lookup 
+	const vec3 N = vec3(0.0, 0.0, 1.0);
+	vec3 V = vec3(sqrt(1.0 - NoV*NoV), 0.0, NoV);
+
+	vec2 LUT = vec2(0.0);
+	for(uint i = 0u; i < NUM_SAMPLES; i++) {
+		vec2 Xi = hammersley2d(i, NUM_SAMPLES);
+		vec3 H = importanceSample_GGX(Xi, roughness, N);
+		vec3 L = 2.0 * dot(V, H) * H - V;
+
+		float dotNL = max(dot(N, L), 0.0);
+		float dotNV = max(dot(N, V), 0.0);
+		float dotVH = max(dot(V, H), 0.0); 
+		float dotNH = max(dot(H, N), 0.0);
+
+		if (dotNL > 0.0) {
+			float G = G_SchlicksmithGGX(dotNL, dotNV, roughness);
+			float G_Vis = (G * dotVH) / (dotNH * dotNV);
+			float Fc = pow(1.0 - dotVH, 5.0);
+			LUT += vec2((1.0 - Fc) * G_Vis, Fc * G_Vis);
+		}
+	}
+	return LUT / float(NUM_SAMPLES);
+#else
+    return texture(brdfLut, vec2(NoV, roughness)).rg;
+#endif
+}
+
 // set colorDiffuse and colorSpec to the results of GLTF PBR style IBL
-void pbrIbl(out vec3 colorDiffuse, // diffuse color output
-            out vec3 colorSpec, // specular color output,
+vec3 pbrIbl(vec3 diffuseColor,
+            vec3 specularColor,
             vec3 radiance, // radiance map sample
             vec3 irradiance, // irradiance map sample
             float ao,       // ambient occlusion factor
             float nv,       // normal dot view vector
-            float perceptualRough, // roughness factor
-            float gloss,        // 1.0 - roughness factor
-            vec3 reflect0,      // see also: initMaterial
-            vec3 c_diff)
+            float perceptualRough)
 {
-    // Common to RadianceGGX and RadianceLambertian
-    vec2  brdfPoint  = clamp(vec2(nv, perceptualRough), vec2(0,0), vec2(1,1));
-    vec2  vScaleBias = getGGX( brdfPoint); // Environment BRDF: scale and bias applied to reflect0
-    vec3  fresnelR   = max(vec3(gloss), reflect0) - reflect0; // roughness dependent fresnel
-    vec3  kSpec      = reflect0 + fresnelR*pow(1.0 - nv, 5.0);
-
-    vec3 FssEssGGX = kSpec*vScaleBias.x + vScaleBias.y;
-    colorSpec = radiance * FssEssGGX;
+    // retrieve a scale and bias to F0. See [1], Figure 3
+	vec2 brdf = BRDF(clamp(nv, 0, 1), 1.0-perceptualRough);
+	vec3 diffuseLight = irradiance;
+	vec3 specularLight = radiance;
 
-    // Reference: getIBLRadianceLambertian fs
-    vec3  FssEssLambert = kSpec * vScaleBias.x + vScaleBias.y; // NOTE: Very similar to FssEssRadiance but with extra specWeight term
-    float Ems           = 1.0 - (vScaleBias.x + vScaleBias.y);
-    vec3  avg           = (reflect0 + (1.0 - reflect0) / 21.0);
-    vec3  AvgEms        = avg * Ems;
-    vec3  FmsEms        = AvgEms * FssEssLambert / (1.0 - AvgEms);
-    vec3  kDiffuse      = c_diff * (1.0 - FssEssLambert + FmsEms);
-    colorDiffuse        = (FmsEms + kDiffuse) * irradiance;
+	vec3 diffuse = diffuseLight * diffuseColor;
+	vec3 specular = specularLight * (specularColor * brdf.x + brdf.y);
+
+	
+	return (diffuse + specular) * ao;
+}
+
+// Encapsulate the various inputs used by the various functions in the shading equation
+// We store values in this struct to simplify the integration of alternative implementations
+// of the shading terms, outlined in the Readme.MD Appendix.
+struct PBRInfo
+{
+	float NdotL;                  // cos angle between normal and light direction
+	float NdotV;                  // cos angle between normal and view direction
+	float NdotH;                  // cos angle between normal and half vector
+	float LdotH;                  // cos angle between light direction and half vector
+	float VdotH;                  // cos angle between view direction and half vector
+	float perceptualRoughness;    // roughness value, as authored by the model creator (input to shader)
+	float metalness;              // metallic value at the surface
+	vec3 reflectance0;            // full reflectance color (normal incidence angle)
+	vec3 reflectance90;           // reflectance color at grazing angle
+	float alphaRoughness;         // roughness mapped to a more linear change in the roughness (proposed by [2])
+	vec3 diffuseColor;            // color contribution from diffuse lighting
+	vec3 specularColor;           // color contribution from specular lighting
+};
+
+// Basic Lambertian diffuse
+// Implementation from Lambert's Photometria https://archive.org/details/lambertsphotome00lambgoog
+// See also [1], Equation 1
+vec3 diffuse(PBRInfo pbrInputs)
+{
+	return pbrInputs.diffuseColor / M_PI;
+}
+
+// The following equation models the Fresnel reflectance term of the spec equation (aka F())
+// Implementation of fresnel from [4], Equation 15
+vec3 specularReflection(PBRInfo pbrInputs)
+{
+	return pbrInputs.reflectance0 + (pbrInputs.reflectance90 - pbrInputs.reflectance0) * pow(clamp(1.0 - pbrInputs.VdotH, 0.0, 1.0), 5.0);
+}
+
+// This calculates the specular geometric attenuation (aka G()),
+// where rougher material will reflect less light back to the viewer.
+// This implementation is based on [1] Equation 4, and we adopt their modifications to
+// alphaRoughness as input as originally proposed in [2].
+float geometricOcclusion(PBRInfo pbrInputs)
+{
+	float NdotL = pbrInputs.NdotL;
+	float NdotV = pbrInputs.NdotV;
+	float r = pbrInputs.alphaRoughness;
+
+	float attenuationL = 2.0 * NdotL / (NdotL + sqrt(r * r + (1.0 - r * r) * (NdotL * NdotL)));
+	float attenuationV = 2.0 * NdotV / (NdotV + sqrt(r * r + (1.0 - r * r) * (NdotV * NdotV)));
+	return attenuationL * attenuationV;
+}
+
+// The following equation(s) model the distribution of microfacet normals across the area being drawn (aka D())
+// Implementation from "Average Irregularity Representation of a Roughened Surface for Ray Reflection" by T. S. Trowbridge, and K. P. Reitz
+// Follows the distribution function recommended in the SIGGRAPH 2013 course notes from EPIC Games [1], Equation 3.
+float microfacetDistribution(PBRInfo pbrInputs)
+{
+	float roughnessSq = pbrInputs.alphaRoughness * pbrInputs.alphaRoughness;
+	float f = (pbrInputs.NdotH * roughnessSq - pbrInputs.NdotH) * pbrInputs.NdotH + 1.0;
+	return roughnessSq / (M_PI * f * f);
+}
+
+vec3 pbrPunctual(vec3 diffuseColor, vec3 specularColor, 
+                    float perceptualRoughness, 
+                    float metallic,
+                    vec3 n, // normal
+                    vec3 v, // surface point to camera
+                    vec3 l) //surface point to light
+{
+	float alphaRoughness = perceptualRoughness * perceptualRoughness;
+
+	// Compute reflectance.
+	float reflectance = max(max(specularColor.r, specularColor.g), specularColor.b);
+
+	// For typical incident reflectance range (between 4% to 100%) set the grazing reflectance to 100% for typical fresnel effect.
+	// For very low reflectance range on highly diffuse objects (below 4%), incrementally reduce grazing reflecance to 0%.
+	float reflectance90 = clamp(reflectance * 25.0, 0.0, 1.0);
+	vec3 specularEnvironmentR0 = specularColor.rgb;
+	vec3 specularEnvironmentR90 = vec3(1.0, 1.0, 1.0) * reflectance90;
+
+	vec3 h = normalize(l+v);                        // Half vector between both l and v
+	vec3 reflection = -normalize(reflect(v, n));
+	reflection.y *= -1.0f;
+
+	float NdotL = clamp(dot(n, l), 0.001, 1.0);
+	float NdotV = clamp(abs(dot(n, v)), 0.001, 1.0);
+	float NdotH = clamp(dot(n, h), 0.0, 1.0);
+	float LdotH = clamp(dot(l, h), 0.0, 1.0);
+	float VdotH = clamp(dot(v, h), 0.0, 1.0);
+
+	PBRInfo pbrInputs = PBRInfo(
+		NdotL,
+		NdotV,
+		NdotH,
+		LdotH,
+		VdotH,
+		perceptualRoughness,
+		metallic,
+		specularEnvironmentR0,
+		specularEnvironmentR90,
+		alphaRoughness,
+		diffuseColor,
+		specularColor
+	);
+
+	// Calculate the shading terms for the microfacet specular shading model
+	vec3 F = specularReflection(pbrInputs);
+	float G = geometricOcclusion(pbrInputs);
+	float D = microfacetDistribution(pbrInputs);
+
+	const vec3 u_LightColor = vec3(1.0);
+
+	// Calculation of analytical lighting contribution
+	vec3 diffuseContrib = (1.0 - F) * diffuse(pbrInputs);
+	vec3 specContrib = F * G * D / (4.0 * NdotL * NdotV);
+	// Obtain final intensity as reflectance (BRDF) scaled by the energy of the light (cosine law)
+	vec3 color = NdotL * u_LightColor * (diffuseContrib + specContrib);
 
-    colorDiffuse *= ao;
-    colorSpec    *= ao;
+    return color;
 }
 
 void pbrDirectionalLight(inout vec3 colorDiffuse,
@@ -529,7 +747,7 @@ void pbrDirectionalLight(inout vec3 colorDiffuse,
     float nv,
     float nh)
 {
-    float scale = 16.0;
+    float scale = 32.0;
     vec3 sunColor = sunlit * scale;
 
     // scol = sun shadow
diff --git a/indra/newview/app_settings/shaders/class1/deferred/genbrdflutF.glsl b/indra/newview/app_settings/shaders/class1/deferred/genbrdflutF.glsl
new file mode 100644
index 0000000000..f3896191fa
--- /dev/null
+++ b/indra/newview/app_settings/shaders/class1/deferred/genbrdflutF.glsl
@@ -0,0 +1,141 @@
+/** 
+ * @file class1/deferred/genbrdflut.glsl
+ *
+ * $LicenseInfo:firstyear=2022&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2022, Linden Research, Inc.
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * 
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+/*  Taken from Sascha Willem's Vulkan GLTF refernce implementation
+MIT License
+
+Copyright (c) 2018 Sascha Willems
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+*/
+
+/*[EXTRA_CODE_HERE]*/
+
+VARYING vec2 vary_uv;
+
+out vec4 outColor;
+
+#define NUM_SAMPLES 1024
+
+const float PI = 3.1415926536;
+
+// Based omn http://byteblacksmith.com/improvements-to-the-canonical-one-liner-glsl-rand-for-opengl-es-2-0/
+float random(vec2 co)
+{
+	float a = 12.9898;
+	float b = 78.233;
+	float c = 43758.5453;
+	float dt= dot(co.xy ,vec2(a,b));
+	float sn= mod(dt,3.14);
+	return fract(sin(sn) * c);
+}
+
+vec2 hammersley2d(uint i, uint N) 
+{
+	// Radical inverse based on http://holger.dammertz.org/stuff/notes_HammersleyOnHemisphere.html
+	uint bits = (i << 16u) | (i >> 16u);
+	bits = ((bits & 0x55555555u) << 1u) | ((bits & 0xAAAAAAAAu) >> 1u);
+	bits = ((bits & 0x33333333u) << 2u) | ((bits & 0xCCCCCCCCu) >> 2u);
+	bits = ((bits & 0x0F0F0F0Fu) << 4u) | ((bits & 0xF0F0F0F0u) >> 4u);
+	bits = ((bits & 0x00FF00FFu) << 8u) | ((bits & 0xFF00FF00u) >> 8u);
+	float rdi = float(bits) * 2.3283064365386963e-10;
+	return vec2(float(i) /float(N), rdi);
+}
+
+// Based on http://blog.selfshadow.com/publications/s2013-shading-course/karis/s2013_pbs_epic_slides.pdf
+vec3 importanceSample_GGX(vec2 Xi, float roughness, vec3 normal) 
+{
+	// Maps a 2D point to a hemisphere with spread based on roughness
+	float alpha = roughness * roughness;
+	float phi = 2.0 * PI * Xi.x + random(normal.xz) * 0.1;
+	float cosTheta = sqrt((1.0 - Xi.y) / (1.0 + (alpha*alpha - 1.0) * Xi.y));
+	float sinTheta = sqrt(1.0 - cosTheta * cosTheta);
+	vec3 H = vec3(sinTheta * cos(phi), sinTheta * sin(phi), cosTheta);
+
+	// Tangent space
+	vec3 up = abs(normal.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
+	vec3 tangentX = normalize(cross(up, normal));
+	vec3 tangentY = normalize(cross(normal, tangentX));
+
+	// Convert to world Space
+	return normalize(tangentX * H.x + tangentY * H.y + normal * H.z);
+}
+
+// Geometric Shadowing function
+float G_SchlicksmithGGX(float dotNL, float dotNV, float roughness)
+{
+	float k = (roughness * roughness) / 2.0;
+	float GL = dotNL / (dotNL * (1.0 - k) + k);
+	float GV = dotNV / (dotNV * (1.0 - k) + k);
+	return GL * GV;
+}
+
+vec2 BRDF(float NoV, float roughness)
+{
+	// Normal always points along z-axis for the 2D lookup 
+	const vec3 N = vec3(0.0, 0.0, 1.0);
+	vec3 V = vec3(sqrt(1.0 - NoV*NoV), 0.0, NoV);
+
+	vec2 LUT = vec2(0.0);
+	for(uint i = 0u; i < NUM_SAMPLES; i++) {
+		vec2 Xi = hammersley2d(i, NUM_SAMPLES);
+		vec3 H = importanceSample_GGX(Xi, roughness, N);
+		vec3 L = 2.0 * dot(V, H) * H - V;
+
+		float dotNL = max(dot(N, L), 0.0);
+		float dotNV = max(dot(N, V), 0.0);
+		float dotVH = max(dot(V, H), 0.0); 
+		float dotNH = max(dot(H, N), 0.0);
+
+		if (dotNL > 0.0) {
+			float G = G_SchlicksmithGGX(dotNL, dotNV, roughness);
+			float G_Vis = (G * dotVH) / (dotNH * dotNV);
+			float Fc = pow(1.0 - dotVH, 5.0);
+			LUT += vec2((1.0 - Fc) * G_Vis, Fc * G_Vis);
+		}
+	}
+	return LUT / float(NUM_SAMPLES);
+}
+
+void main() 
+{
+	outColor = vec4(BRDF(vary_uv.s, 1.0-vary_uv.t), 0.0, 1.0);
+}
\ No newline at end of file
diff --git a/indra/newview/app_settings/shaders/class1/deferred/genbrdflutV.glsl b/indra/newview/app_settings/shaders/class1/deferred/genbrdflutV.glsl
new file mode 100644
index 0000000000..682244478b
--- /dev/null
+++ b/indra/newview/app_settings/shaders/class1/deferred/genbrdflutV.glsl
@@ -0,0 +1,39 @@
+/** 
+ * @file class3\deferred\genbrdflutV.glsl
+ *
+ * $LicenseInfo:firstyear=2022&license=viewerlgpl$
+ * Second Life Viewer Source Code
+ * Copyright (C) 2022, Linden Research, Inc.
+ * 
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation;
+ * version 2.1 of the License only.
+ * 
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ * 
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
+ * 
+ * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
+ * $/LicenseInfo$
+ */
+
+uniform mat4 modelview_projection_matrix;
+
+ATTRIBUTE vec3 position;
+
+VARYING vec2 vary_uv;
+
+void main()
+{
+	//transform vertex
+	vec4 pos = modelview_projection_matrix * vec4(position.xyz, 1.0);
+	vary_uv = position.xy*0.5+0.5;
+
+	gl_Position = vec4(position.xyz, 1.0);
+}
diff --git a/indra/newview/app_settings/shaders/class1/deferred/pbralphaF.glsl b/indra/newview/app_settings/shaders/class1/deferred/pbralphaF.glsl
index 9d3339f607..ae542f5a1d 100644
--- a/indra/newview/app_settings/shaders/class1/deferred/pbralphaF.glsl
+++ b/indra/newview/app_settings/shaders/class1/deferred/pbralphaF.glsl
@@ -120,7 +120,7 @@ void pbrDirectionalLight(inout vec3 colorDiffuse,
     float nv,
     float nh);
 
-void pbrIbl(out vec3 colorDiffuse, // diffuse color output
+/*void pbrIbl(out vec3 colorDiffuse, // diffuse color output
             out vec3 colorSpec, // specular color output,
             vec3 radiance, // radiance map sample
             vec3 irradiance, // irradiance map sample
@@ -129,7 +129,7 @@ void pbrIbl(out vec3 colorDiffuse, // diffuse color output
             float perceptualRough, // roughness factor
             float gloss,        // 1.0 - roughness factor
             vec3 reflect0,
-            vec3 c_diff);
+            vec3 c_diff);*/
 
 // lp = light position
 // la = linear attenuation, light radius
@@ -255,7 +255,7 @@ void main()
     sampleReflectionProbes(irradiance, radiance, legacyenv, pos.xyz, norm.xyz, gloss, 0.0);
     irradiance       = max(amblit,irradiance) * ambocc;
 
-    pbrIbl(colorDiffuse, colorSpec, radiance, irradiance, ao, nv, perceptualRough, gloss, reflect0, c_diff);
+    //pbrIbl(colorDiffuse, colorSpec, radiance, irradiance, ao, nv, perceptualRough, gloss, reflect0, c_diff);
     
     // Sun/Moon Lighting
     if (nl > 0.0 || nv > 0.0)
diff --git a/indra/newview/app_settings/shaders/class3/deferred/multiPointLightF.glsl b/indra/newview/app_settings/shaders/class3/deferred/multiPointLightF.glsl
index d8175aa260..3b57821758 100644
--- a/indra/newview/app_settings/shaders/class3/deferred/multiPointLightF.glsl
+++ b/indra/newview/app_settings/shaders/class3/deferred/multiPointLightF.glsl
@@ -112,7 +112,7 @@ void main()
             if (dist <= 1.0 && nl > 0.0)
             {
                 float dist_atten = calcLegacyDistanceAttenuation(dist, falloff);
-                vec3 intensity = dist_atten * nl * lightColor;
+                vec3 intensity = dist_atten * nl * lightColor * 2.0;
                 colorDiffuse += intensity * BRDFLambertian (reflect0, reflect90, c_diff    , specWeight, vh);
                 colorSpec    += intensity * BRDFSpecularGGX(reflect0, reflect90, alphaRough, specWeight, vh, nl, nv, nh);
             }
diff --git a/indra/newview/app_settings/shaders/class3/deferred/multiSpotLightF.glsl b/indra/newview/app_settings/shaders/class3/deferred/multiSpotLightF.glsl
index bc4b4eb7e1..cabc175da9 100644
--- a/indra/newview/app_settings/shaders/class3/deferred/multiSpotLightF.glsl
+++ b/indra/newview/app_settings/shaders/class3/deferred/multiSpotLightF.glsl
@@ -28,40 +28,6 @@
 
 /*[EXTRA_CODE_HERE]*/
 
-#define DEBUG_ANY_LIGHT_TYPE         0 // Output blue light cone
-#define DEBUG_LEG_LIGHT_TYPE         0 // Show Legacy objects in blue
-#define DEBUG_PBR_LIGHT_TYPE         0 // Ouput gray if PBR multiSpot lights object
-#define DEBUG_PBR_SPOT               0
-#define DEBUG_PBR_SPOT_DIFFUSE       0 // PBR diffuse lit
-#define DEBUG_PBR_SPOT_SPECULAR      0 // PBR spec lit
-
-#define DEBUG_LIGHT_FRUSTUM            0 // If projected light effects a surface
-#define DEBUG_AMBIANCE_COLOR           0 // calculated ambiance color
-#define DEBUG_AMBIANCE_AOE             0 // area of effect using inverse ambiance color
-#define DEBUG_AMBIANCE_FINAL           0 // light color * ambiance color
-#define DEBUG_NOISE                    0 // monochrome noise
-#define DEBUG_SHADOW                   0 // Show inverted shadow
-#define DEBUG_SPOT_DIFFUSE             0 // dot(n,l) * dist_atten
-#define DEBUG_SPOT_NL                  0 // monochome area effected by light
-#define DEBUG_SPOT_SPEC_POS            0
-#define DEBUG_SPOT_REFLECTION          0 // color: pos reflected along n
-#define DEBUG_SPOT_ZERO                0 // Output zero for spotlight
-
-#define DEBUG_PBR_LIGHT_H              0 // Half vector
-#define DEBUG_PBR_LIHGT_L              0 // Light vector
-#define DEBUG_PBR_LIGHT_NH             0 // colorized dot(n,h)
-#define DEBUG_PBR_LIGHT_NL             0 // colorized dot(n,l)
-#define DEBUG_PBR_LIGHT_NV             0 // colorized dot(n,v)
-#define DEBUG_PBR_LIGHT_VH             0 // colorized dot(v,h)
-#define DEBUG_PBR_LIGHT_DIFFUSE_COLOR  0 // non PBR spotlight
-#define DEBUG_PBR_LIGHT_SPECULAR_COLOR 0 // non PBR spotlight
-#define DEBUG_PBR_LIGHT_INTENSITY      0 // Light intensity
-#define DEBUG_PBR_LIGHT_INTENSITY_NL   0 // Light intensity * dot(n,l)
-#define DEBUG_PBR_LIGHT_BRDF_DIFFUSE   0 // like "fullbright" if no "nl" factor
-#define DEBUG_PBR_LIGHT_BRDF_SPECULAR  0
-#define DEBUG_PBR_LIGHT_BRDF_FINAL     0 // BRDF Diffuse + BRDF Specular
-
-
 #ifdef DEFINE_GL_FRAGCOLOR
 out vec4 frag_color;
 #else
@@ -211,93 +177,13 @@ void main()
                 colorSpec    = shadow * lit * slit * BRDFSpecularGGX( reflect0, reflect90, alphaRough, specWeight, vh, nl, nv, nh );
                 colorSpec   += shadow * lit *        BRDFSpecularGGX( reflect0, reflect90, alphaRough, specWeight, vh, nl, nv, nh );
 
-      #if DEBUG_PBR_SPOT_DIFFUSE
-                colorDiffuse = dlit.rgb; colorSpec = vec3(0);
-      #endif
-      #if DEBUG_PBR_SPOT_SPECULAR
-                colorDiffuse = vec3(0); colorSpec = slit.rgb;
-      #endif
-      #if DEBUG_PBR_SPOT
-                colorDiffuse = dlit; colorSpec = vec3(0);
-                colorDiffuse *= nl;
-                colorDiffuse *= shadow;
-      #endif
             }
 
             amb_rgb = getProjectedLightAmbiance( amb_da, dist_atten, lit, nl, 1.0, proj_tc.xy );
             colorDiffuse += diffuse.rgb * amb_rgb;
 
-  #if DEBUG_AMBIANCE_FINAL
-            colorDiffuse = diffuse.rgb * amb_rgb; colorSpec = vec3(0);
-  #endif
-  #if DEBUG_LIGHT_FRUSTUM
-            colorDiffuse = vec3(0,1,0); colorSpec = vec3(0);
-  #endif
-  #if DEBUG_NOISE
-            float noise = texture2D(noiseMap, tc/128.0).b;
-            colorDiffuse = vec3(noise); colorSpec = vec3(0);
-  #endif
         }
 
-  #if DEBUG_PBR_LIGHT_TYPE
-        colorDiffuse = vec3(0.5,0,0); colorSpec = vec3(0);
-  #endif
-
-  #if DEBUG_PBR_LIGHT_H
-        colorDiffuse = h*0.5 + 0.5;  colorSpec = vec3(0);
-  #endif
-  #if DEBUG_PBR_LIHGT_L
-        colorDiffuse = l*0.5 + 0.5;  colorSpec = vec3(0);
-  #endif
-  #if DEBUG_PBR_LIGHT_NH
-        colorDiffuse = colorized_dot(nh); colorSpec = vec3(0);
-  #endif
-  #if DEBUG_PBR_LIGHT_NL
-        colorDiffuse = colorized_dot(nl); colorSpec = vec3(0);
-  #endif
-  #if DEBUG_PBR_LIGHT_NV
-        colorDiffuse = colorized_dot(nv); colorSpec = vec3(0);
-  #endif
-  #if DEBUG_PBR_LIGHT_VH
-        colorDiffuse = colorized_dot(vh); colorSpec = vec3(0);
-  #endif
-  #if DEBUG_PBR_LIGHT_DIFFUSE_COLOR
-        colorDiffuse = dlit;
-  #endif
-  #if DEBUG_PBR_LIGHT_SPECULAR_COLOR
-        colorDiffuse = slit;
-  #endif
-  #if DEBUG_PBR_LIGHT_INTENSITY
-        colorDiffuse = getLightIntensitySpot( color, size, lightDist, v ); colorSpec = vec3(0);
-//        colorDiffuse = nl * dist_atten;
-  #endif
-  #if DEBUG_PBR_LIGHT_INTENSITY_NL
-        colorDiffuse = getLightIntensitySpot( color, size, lightDist, v ) * nl; colorSpec = vec3(0);
-  #endif
-  #if DEBUG_PBR_LIGHT_BRDF_DIFFUSE
-        vec3 c_diff, reflect0, reflect90;
-        float alphaRough, specWeight;
-        initMaterial( diffuse, packedORM, alphaRough, c_diff, reflect0, reflect90, specWeight );
-
-        colorDiffuse = BRDFLambertian ( reflect0, reflect90, c_diff    , specWeight, vh );
-        colorSpec = vec3(0);
-  #endif
-  #if DEBUG_PBR_LIGHT_BRDF_SPECULAR
-        vec3 c_diff, reflect0, reflect90;
-        float alphaRough, specWeight;
-        initMaterial( diffuse, packedORM, alphaRough, c_diff, reflect0, reflect90, specWeight );
-
-        colorDiffuse = vec3(0);
-        colorSpec = BRDFSpecularGGX( reflect0, reflect90, alphaRough, specWeight, vh, nl, nv, nh );
-  #endif
-  #if DEBUG_PBR_LIGHT_BRDF_FINAL
-        vec3 c_diff, reflect0, reflect90;
-        float alphaRough, specWeight;
-        initMaterial( diffuse, packedORM, alphaRough, c_diff, reflect0, reflect90, specWeight );
-        colorDiffuse = nl * BRDFLambertian ( reflect0, reflect90, c_diff    , specWeight, vh );
-        colorSpec    = nl * BRDFSpecularGGX( reflect0, reflect90, alphaRough, specWeight, vh, nl, nv, nh );
-  #endif
-
         final_color = colorDiffuse + colorSpec;
     }
     else
@@ -326,9 +212,6 @@ void main()
         
             amb_rgb = getProjectedLightAmbiance( amb_da, dist_atten, lit, nl, noise, proj_tc.xy );
             final_color += diffuse.rgb * amb_rgb;
-#if DEBUG_LEG_LIGHT_TYPE
-            final_color = vec3(0,0,0.5);
-#endif
         }
     
         if (spec.a > 0.0)
@@ -376,58 +259,8 @@ void main()
                     }
                 }
             }
-  #if DEBUG_SPOT_REFLECTION
-            final_color = ref;
-  #endif
-        }
-
-#if DEBUG_LIGHT_FRUSTUM
-        if (proj_tc.x > 0.0 && proj_tc.x < 1.0
-        &&  proj_tc.y > 0.0 && proj_tc.y < 1.0)
-        {
-            final_color = vec3(0,0,1);
         }
-#endif
-    }
-
-#if DEBUG_AMBIANCE_AOE
-    if (proj_tc.x > 0.0 && proj_tc.x < 1.0
-    &&  proj_tc.y > 0.0 && proj_tc.y < 1.0)
-    {
-        final_color = 1.0 - amb_rgb;
-    }
-#endif
-#if DEBUG_AMBIANCE_COLOR
-    if (proj_tc.x > 0.0 && proj_tc.x < 1.0
-    &&  proj_tc.y > 0.0 && proj_tc.y < 1.0)
-    {
-        final_color = amb_rgb;
     }
-#endif
-#if DEBUG_SHADOW
-    final_color = 1.0 - vec3(shadow);
-#endif
-#if DEBUG_SPOT_DIFFUSE
-    final_color = vec3(nl * dist_atten);
-#endif
-#if DEBUG_SPOT_NL
-    final_color =vec3(nl);
-#endif
-#if DEBUG_SPOT_SPEC_POS
-    vec3 ref = reflect(normalize(pos), n);
-    vec3 pdelta = proj_p-pos;
-    float ds = dot(ref, proj_n);
-    final_color = pos + ref * dot(pdelta, proj_n)/ds;
-#endif
-#if DEBUG_SPOT_REFLECTION
-    final_color = reflect(normalize(pos), n);
-#endif
-#if DEBUG_SPOT_ZERO
-    final_color = vec3(0,0,0);
-#endif
-#if DEBUG_ANY_LIGHT_TYPE
-    final_color = vec3(0,0,0.3333);
-#endif
 
     //not sure why, but this line prevents MATBUG-194
     final_color = max(final_color, vec3(0.0));
diff --git a/indra/newview/app_settings/shaders/class3/deferred/pointLightF.glsl b/indra/newview/app_settings/shaders/class3/deferred/pointLightF.glsl
index 509f9f6dd0..0472f08852 100644
--- a/indra/newview/app_settings/shaders/class3/deferred/pointLightF.glsl
+++ b/indra/newview/app_settings/shaders/class3/deferred/pointLightF.glsl
@@ -109,7 +109,7 @@ void main()
 
         if (nl > 0.0)
         {
-            vec3 intensity = dist_atten * nl * lightColor; // Legacy attenuation
+            vec3 intensity = dist_atten * nl * lightColor * 2.0; // Legacy attenuation
             colorDiffuse += intensity * BRDFLambertian (reflect0, reflect90, c_diff    , specWeight, vh);
             colorSpec    += intensity * BRDFSpecularGGX(reflect0, reflect90, alphaRough, specWeight, vh, nl, nv, nh);
         }
diff --git a/indra/newview/app_settings/shaders/class3/deferred/reflectionProbeF.glsl b/indra/newview/app_settings/shaders/class3/deferred/reflectionProbeF.glsl
index 3ff039261b..37fe5f53a2 100644
--- a/indra/newview/app_settings/shaders/class3/deferred/reflectionProbeF.glsl
+++ b/indra/newview/app_settings/shaders/class3/deferred/reflectionProbeF.glsl
@@ -524,14 +524,14 @@ void sampleReflectionProbes(inout vec3 ambenv, inout vec3 glossenv, inout vec3 l
         vec3 pos, vec3 norm, float glossiness, float envIntensity)
 {
     // TODO - don't hard code lods
-    float reflection_lods = 8;
+    float reflection_lods = 7;
     preProbeSample(pos);
 
     vec3 refnormpersp = reflect(pos.xyz, norm.xyz);
 
     ambenv = sampleProbeAmbient(pos, norm);
 
-    if (glossiness > 0.0)
+    //if (glossiness > 0.0)
     {
         float lod = (1.0-glossiness)*reflection_lods;
         glossenv = sampleProbes(pos, normalize(refnormpersp), lod, 1.f);
diff --git a/indra/newview/app_settings/shaders/class3/deferred/softenLightF.glsl b/indra/newview/app_settings/shaders/class3/deferred/softenLightF.glsl
index 1a7e11a1cd..6dd140bff3 100644
--- a/indra/newview/app_settings/shaders/class3/deferred/softenLightF.glsl
+++ b/indra/newview/app_settings/shaders/class3/deferred/softenLightF.glsl
@@ -89,34 +89,21 @@ vec4 applyWaterFogView(vec3 pos, vec4 color);
 #endif
 
 // PBR interface
-void calcHalfVectors(vec3 lv, vec3 n, vec3 v, out vec3 h, out vec3 l, out float nh, out float nl, out float nv, out float vh, out float lightDist);
-void initMaterial( vec3 diffuse, vec3 packedORM,
-        out float alphaRough, out vec3 c_diff, out vec3 reflect0, out vec3 reflect90, out float specWeight );
-// perform PBR image based lighting according to GLTF spec
-// all parameters are in linear space
-void pbrIbl(out vec3 colorDiffuse, // diffuse color output
-            out vec3 colorSpec, // specular color output,
+vec3 pbrIbl(vec3 diffuseColor,
+            vec3 specularColor,
             vec3 radiance, // radiance map sample
             vec3 irradiance, // irradiance map sample
             float ao,       // ambient occlusion factor
-            float nv,
-            float perceptualRough, // roughness factor
-            float gloss,        // 1.0 - roughness factor
-            vec3 reflect0,
-            vec3 c_diff);
-
-void pbrDirectionalLight(inout vec3 colorDiffuse,
-    inout vec3 colorSpec,
-    vec3 sunlit,
-    float scol,
-    vec3 reflect0,
-    vec3 reflect90,
-    vec3 c_diff,
-    float alphaRough,
-    float vh,
-    float nl,
-    float nv,
-    float nh);
+            float nv,       // normal dot view vector
+            float perceptualRoughness);
+
+vec3 pbrPunctual(vec3 diffuseColor, vec3 specularColor, 
+                    float perceptualRoughness, 
+                    float metallic,
+                    vec3 n, // normal
+                    vec3 v, // surface point to camera
+                    vec3 l); //surface point to light
+
 
 void main()
 {
@@ -160,51 +147,34 @@ void main()
     bool hasPBR = GET_GBUFFER_FLAG(GBUFFER_FLAG_HAS_PBR);
     if (hasPBR)
     {
-        // 5.22.2. material.pbrMetallicRoughness.baseColorTexture
-        // The first three components (RGB) MUST be encoded with the sRGB transfer function.
-        //
-        // 5.19.7. material.emissiveTexture
-        // This texture contains RGB components encoded with the sRGB transfer function.
-        //
-        // 5.22.5. material.pbrMetallicRoughness.metallicRoughnessTexture
-        // These values MUST be encoded with a linear transfer function.
-
-        vec3 colorDiffuse      = vec3(0);
-        vec3 colorEmissive     = spec.rgb; // PBR sRGB Emissive.  See: pbropaqueF.glsl
-        vec3 colorSpec         = vec3(0);
-
-        vec3 packedORM        = texture2DRect(emissiveRect, tc).rgb; // PBR linear packed Occlusion, Roughness, Metal. See: pbropaqueF.glsl
-        float IOR             = 1.5;         // default Index Of Refraction 1.5 (dielectrics)
-        float ao         = packedORM.r;
-        float metal      = packedORM.b;
-        vec3  v          = -normalize(pos.xyz);
-        vec3  n          = norm.xyz;
-
-        vec3  h, l;
-        float nh, nl, nv, vh, lightDist;
-        calcHalfVectors(light_dir, n, v, h, l, nh, nl, nv, vh, lightDist);
-
-        float perceptualRough = packedORM.g;  // NOTE: do NOT clamp here to be consistent with Blender, Blender is wrong and Substance is right
-        
-        vec3 c_diff, reflect0, reflect90;
-        float alphaRough, specWeight;
-        initMaterial( diffuse.rgb, packedORM, alphaRough, c_diff, reflect0, reflect90, specWeight );
+        vec3 orm = texture2DRect(emissiveRect, tc).rgb; //orm is packed into "emissiveRect" to keep the data in linear color space
+        float perceptualRoughness = orm.g;
+        float metallic = orm.b;
+        float ao = orm.r * ambocc;
 
-        float gloss      = 1.0 - perceptualRough;
+        vec3 colorEmissive = texture2DRect(specularRect, tc).rgb; //specularRect is sRGB sampler, result is in linear space
+
+        // PBR IBL
+        float gloss      = 1.0 - perceptualRoughness;
         vec3  irradiance = vec3(0);
         vec3  radiance  = vec3(0);
         sampleReflectionProbes(irradiance, radiance, legacyenv, pos.xyz, norm.xyz, gloss, 0.0);
-        irradiance       = max(amblit,irradiance) * ambocc;
+        irradiance       = max(srgb_to_linear(amblit),irradiance) * ambocc*4.0;
 
-        pbrIbl(colorDiffuse, colorSpec, radiance, irradiance, ao, nv, perceptualRough, gloss, reflect0, c_diff);
+        vec3 f0 = vec3(0.04);
+        vec3 baseColor = diffuse.rgb;
         
-        // Add in sun/moon punctual light
-        if (nl > 0.0 || nv > 0.0)
-        {
-            pbrDirectionalLight(colorDiffuse, colorSpec, srgb_to_linear(sunlit), scol, reflect0, reflect90, c_diff, alphaRough, vh, nl, nv, nh);
-        }
+        vec3 diffuseColor = baseColor.rgb*(vec3(1.0)-f0);
+        diffuseColor *= 1.0 - metallic;
+
+        vec3 specularColor = mix(f0, baseColor.rgb, metallic);
 
-        color.rgb = colorDiffuse + colorEmissive + colorSpec;
+        vec3 v = -normalize(pos.xyz);
+        float NdotV = clamp(abs(dot(norm.xyz, v)), 0.001, 1.0);
+        
+        color.rgb += pbrIbl(diffuseColor, specularColor, radiance, irradiance, ao, NdotV, perceptualRoughness);
+        color.rgb += pbrPunctual(diffuseColor, specularColor, perceptualRoughness, metallic, norm.xyz, v, normalize(light_dir)) * sunlit*8.0 * scol;
+        color.rgb += colorEmissive;
 
         color  = linear_to_srgb(color);
         color *= atten.r;
@@ -212,6 +182,7 @@ void main()
         color  = scaleSoftClipFrag(color);
         color  = srgb_to_linear(color);
 
+
         frag_color.rgb = color.rgb; //output linear since local lights will be added to this shader's results
     }
     else
diff --git a/indra/newview/llmaterialeditor.cpp b/indra/newview/llmaterialeditor.cpp
index b4e5e14885..bdc66a85fc 100644
--- a/indra/newview/llmaterialeditor.cpp
+++ b/indra/newview/llmaterialeditor.cpp
@@ -204,14 +204,14 @@ void LLMaterialEditor::setAlbedoUploadId(const LLUUID& id)
 
 LLColor4 LLMaterialEditor::getAlbedoColor()
 {
-    LLColor4 ret = LLColor4(childGetValue("albedo color"));
+    LLColor4 ret = linearColor4(LLColor4(childGetValue("albedo color")));
     ret.mV[3] = getTransparency();
     return ret;
 }
 
 void LLMaterialEditor::setAlbedoColor(const LLColor4& color)
 {
-    childSetValue("albedo color", color.getValue());
+    childSetValue("albedo color", srgbColor4(color).getValue());
     setTransparency(color.mV[3]);
 }
 
diff --git a/indra/newview/llviewershadermgr.cpp b/indra/newview/llviewershadermgr.cpp
index 296a383ed0..63d9a03aba 100644
--- a/indra/newview/llviewershadermgr.cpp
+++ b/indra/newview/llviewershadermgr.cpp
@@ -252,6 +252,7 @@ LLGLSLShader            gDeferredSkinnedFullbrightShinyProgram;
 LLGLSLShader			gDeferredSkinnedFullbrightProgram;
 LLGLSLShader            gDeferredSkinnedFullbrightAlphaMaskProgram;
 LLGLSLShader			gNormalMapGenProgram;
+LLGLSLShader            gDeferredGenBrdfLutProgram;
 
 // Deferred materials shaders
 LLGLSLShader			gDeferredMaterialProgram[LLMaterial::SHADER_COUNT*2];
@@ -1244,6 +1245,8 @@ BOOL LLViewerShaderMgr::loadShadersDeferred()
         gDeferredHighlightSpecularProgram.unload();
 
 		gNormalMapGenProgram.unload();
+        gDeferredGenBrdfLutProgram.unload();
+
 		for (U32 i = 0; i < LLMaterial::SHADER_COUNT*2; ++i)
 		{
 			gDeferredMaterialProgram[i].unload();
@@ -2855,6 +2858,17 @@ BOOL LLViewerShaderMgr::loadShadersDeferred()
 		success = gNormalMapGenProgram.createShader(NULL, NULL);
 	}
 
+    if (success && gGLManager.mHasCubeMapArray)
+    {
+        gDeferredGenBrdfLutProgram.mName = "Brdf Gen Shader";
+        gDeferredGenBrdfLutProgram.mShaderFiles.clear();
+        gDeferredGenBrdfLutProgram.mShaderFiles.push_back(make_pair("deferred/genbrdflutV.glsl", GL_VERTEX_SHADER));
+        gDeferredGenBrdfLutProgram.mShaderFiles.push_back(make_pair("deferred/genbrdflutF.glsl", GL_FRAGMENT_SHADER));
+        gDeferredGenBrdfLutProgram.mShaderLevel = mShaderLevel[SHADER_DEFERRED];
+        success = gDeferredGenBrdfLutProgram.createShader(NULL, NULL);
+    }
+
+
 	return success;
 }
 
diff --git a/indra/newview/llviewershadermgr.h b/indra/newview/llviewershadermgr.h
index 464efd6e3f..a2ae984caa 100644
--- a/indra/newview/llviewershadermgr.h
+++ b/indra/newview/llviewershadermgr.h
@@ -305,6 +305,7 @@ extern LLGLSLShader			gDeferredWLMoonProgram;
 extern LLGLSLShader			gDeferredStarProgram;
 extern LLGLSLShader			gDeferredFullbrightShinyProgram;
 extern LLGLSLShader			gNormalMapGenProgram;
+extern LLGLSLShader         gDeferredGenBrdfLutProgram;
 
 // Deferred materials shaders
 extern LLGLSLShader			gDeferredMaterialProgram[LLMaterial::SHADER_COUNT*2];
diff --git a/indra/newview/pipeline.cpp b/indra/newview/pipeline.cpp
index 7f42fb71e4..f07d809495 100644
--- a/indra/newview/pipeline.cpp
+++ b/indra/newview/pipeline.cpp
@@ -1182,6 +1182,8 @@ void LLPipeline::releaseLUTBuffers()
 		LLImageGL::deleteTextures(1, &mLightFunc);
 		mLightFunc = 0;
 	}
+
+    mPbrBrdfLut.release();
 }
 
 void LLPipeline::releaseShadowBuffers()
@@ -1363,6 +1365,21 @@ void LLPipeline::createLUTBuffers()
 			
 			delete [] ls;
 		}
+
+        mPbrBrdfLut.allocate(512, 512, GL_RGB16, false, false);
+        mPbrBrdfLut.bindTarget();
+        gDeferredGenBrdfLutProgram.bind();
+
+        gGL.begin(LLRender::TRIANGLE_STRIP);
+        gGL.vertex2f(-1, -1);
+        gGL.vertex2f(-1, 1);
+        gGL.vertex2f(1, -1);
+        gGL.vertex2f(1, 1);
+        gGL.end();
+        gGL.flush();
+
+        gDeferredGenBrdfLutProgram.unbind();
+        mPbrBrdfLut.flush();
 	}
 }
 
@@ -8165,6 +8182,13 @@ void LLPipeline::bindDeferredShader(LLGLSLShader& shader, LLRenderTarget* light_
         deferred_target->bindTexture(3, channel, LLTexUnit::TFO_POINT); // frag_data[3]
     }
 
+    channel = shader.enableTexture(LLShaderMgr::DEFERRED_BRDF_LUT, LLTexUnit::TT_TEXTURE);
+    if (channel > -1)
+    {
+        mPbrBrdfLut.bindTexture(0, channel);
+    }
+
+
     channel = shader.enableTexture(LLShaderMgr::DEFERRED_DEPTH, deferred_depth_target->getUsage());
 	if (channel > -1)
 	{
@@ -8304,7 +8328,7 @@ void LLPipeline::bindDeferredShader(LLGLSLShader& shader, LLRenderTarget* light_
 	}
 
     bindReflectionProbes(shader);
-    
+
     if (gAtmosphere)
     {
         // bind precomputed textures necessary for calculating sun and sky luminance
@@ -9212,6 +9236,7 @@ void LLPipeline::unbindDeferredShader(LLGLSLShader &shader)
     shader.disableTexture(LLShaderMgr::DEFERRED_DIFFUSE, deferred_target->getUsage());
     shader.disableTexture(LLShaderMgr::DEFERRED_SPECULAR, deferred_target->getUsage());
     shader.disableTexture(LLShaderMgr::DEFERRED_EMISSIVE, deferred_target->getUsage());
+    shader.disableTexture(LLShaderMgr::DEFERRED_BRDF_LUT);
     shader.disableTexture(LLShaderMgr::DEFERRED_DEPTH, deferred_depth_target->getUsage());
     shader.disableTexture(LLShaderMgr::DEFERRED_LIGHT, deferred_light_target->getUsage());
 	shader.disableTexture(LLShaderMgr::DIFFUSE_MAP);
diff --git a/indra/newview/pipeline.h b/indra/newview/pipeline.h
index cd7d0b88d8..5665469c1a 100644
--- a/indra/newview/pipeline.h
+++ b/indra/newview/pipeline.h
@@ -682,6 +682,7 @@ public:
 
     LLRenderTarget			mHighlight;
     LLRenderTarget			mPhysicsDisplay;
+    LLRenderTarget          mPbrBrdfLut;
 
     LLCullResult            mSky;
     LLCullResult            mReflectedObjects;