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Diffstat (limited to 'res/effectlib/microfacetBSDF.glsllib')
-rw-r--r-- | res/effectlib/microfacetBSDF.glsllib | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/res/effectlib/microfacetBSDF.glsllib b/res/effectlib/microfacetBSDF.glsllib new file mode 100644 index 0000000..8e48910 --- /dev/null +++ b/res/effectlib/microfacetBSDF.glsllib @@ -0,0 +1,259 @@ +/**************************************************************************** +** +** Copyright (C) 2014 NVIDIA Corporation. +** Copyright (C) 2017 The Qt Company Ltd. +** Contact: https://www.qt.io/licensing/ +** +** This file is part of Qt 3D Studio. +** +** $QT_BEGIN_LICENSE:GPL$ +** Commercial License Usage +** Licensees holding valid commercial Qt licenses may use this file in +** accordance with the commercial license agreement provided with the +** Software or, alternatively, in accordance with the terms contained in +** a written agreement between you and The Qt Company. For licensing terms +** and conditions see https://www.qt.io/terms-conditions. For further +** information use the contact form at https://www.qt.io/contact-us. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3 or (at your option) any later version +** approved by the KDE Free Qt Foundation. The licenses are as published by +** the Free Software Foundation and appearing in the file LICENSE.GPL3 +** included in the packaging of this file. Please review the following +** information to ensure the GNU General Public License requirements will +** be met: https://www.gnu.org/licenses/gpl-3.0.html. +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#ifndef MICROFACET_BSDF_GLSLLIB +#define MICROFACET_BSDF_GLSLLIB 1 + + +float GtermSchlick( in mat3 tanFrame, in vec3 l, in vec3 v, in float roughness ) +{ + float NdotV = clamp(dot(tanFrame[2], v), 0.0, 1.0); + float NdotL = clamp(dot(tanFrame[2], l), 0.0, 1.0); + float k = roughness*roughness*0.79788; + + float G_V = NdotV / (NdotV * (1.0 + k) + k); + float G_L = NdotL / (NdotL * (1.0 + k) + k); + + return clamp(( G_V * G_L ), 0.0, 1.0); +} + +float GtermGGX( in mat3 tanFrame, in vec3 l, in vec3 v, in float roughness ) +{ + float NdotV = clamp(dot(tanFrame[2], v), 0.0, 1.0); + float NdotL = clamp(dot(tanFrame[2], l), 0.0, 1.0); + float k = clamp(roughness*roughness, 0.00, 1.0); + + float G_V = NdotV + sqrt( (NdotV - NdotV * k) * NdotV + k ); + float G_L = NdotL + sqrt( (NdotL - NdotL * k) * NdotL + k ); + + return clamp( 2.0 / ( G_V * G_L ), 0.0, 1.0); +} + +float DtermGGX( in mat3 tanFrame, in vec3 L, in vec3 V, in float roughness ) +{ + float m = clamp(roughness, 0.04, 1.0); + float m2 = m*m; + + vec3 H = normalize(L + V); + float NdotH = clamp(dot( tanFrame[2], H ), 0.0001, 1.0); + float NdotH2 = NdotH * NdotH; + + float denom = NdotH2 * (m2 - 1.0) + 1.0; + float D = m2 / (PI * denom * denom); + + return max( 0.0, D); +} + +float DtermGGXAniso( in mat3 tanFrame, in vec3 L, in vec3 V, in float roughnessU, float roughnessV ) +{ + float roughU = clamp(roughnessU, 0.04, 1.0); + float roughV = clamp(roughnessV, 0.04, 1.0); + vec3 H = normalize(L + V); + float NdotH = clamp( dot(tanFrame[2], H), 0.0001, 1.0 ); + float m = PI * roughU * roughV; + float HdotX = clamp( abs(dot(H, tanFrame[0])), 0.0001, 1.0 ); + float HdotY = clamp( abs(dot(H, tanFrame[1])), 0.0001, 1.0 ); + + float x2 = roughU*roughU; + float y2 = roughV*roughV; + + float D = (HdotX*HdotX/x2) + (HdotY*HdotY/y2) + (NdotH*NdotH); + D = 1.0 / ( m * D * D ); + + return max( 0.0, D); +} + +vec4 microfacetBSDF( in mat3 tanFrame, in vec3 L, in vec3 V, in vec3 lightSpecular, float ior, + in float roughnessU, in float roughnessV, int mode ) +{ + vec4 rgba = vec4( 0.0, 0.0, 0.0, 1.0 ); + vec3 H = normalize(L + V); + float HdotL = clamp(dot(H, L), 0.0, 1.0); + float NdotL = dot(tanFrame[2], L); + + if ( NdotL > 0.0 ) + { + if ( ( mode == scatter_reflect ) || ( mode == scatter_reflect_transmit ) ) + { + float roughness = calculateRoughness( tanFrame[2], roughnessU, roughnessV, tanFrame[0] ); + // G term + //float G = GtermSchlick( tanFrame, L, V, roughness ); + float G = GtermGGX( tanFrame, L, V, roughness ); + + //float D = DtermGGX( tanFrame, L, V, roughness ); + float D = DtermGGXAniso( tanFrame, L, V, roughnessU, roughnessV ); + rgba.rgb = G * D * NdotL * lightSpecular; + } + + if ( ( mode == scatter_transmit ) || ( mode == scatter_reflect_transmit ) ) + { + rgba.a = pow(1.0 - clamp(HdotL, 0.0, 1.0), 5.0); + } + } + + return rgba; +} + +vec4 microfacetBSDFEnvironment( in mat3 tanFrame, in vec3 viewDir, in float roughnessU, in float roughnessV, int mode ) +{ + vec3 rgb = vec3( 0.0, 0.0, 0.0 ); +#if !QT3DS_ENABLE_LIGHT_PROBE + if ( uEnvironmentMappingEnabled ) + { + float roughness = calculateRoughness( tanFrame[2], roughnessU, roughnessV, tanFrame[0] ); + vec3 R = reflect( -viewDir, tanFrame[2] ); + rgb = 0.01 * evalEnvironmentMap( R, roughness ); + rgb = microfacetBSDF( tanFrame, R, viewDir, rgb, 1.0, roughnessU, roughnessV, scatter_reflect ).rgb; + } +#endif + return( vec4( rgb, 1.0 ) ); +} + + +// see http://holger.dammertz.org/stuff/notes_HammersleyOnHemisphere.html + +float radicalInverse_VdC( uint bits) +{ + bits = (bits << 16u) | (bits >> 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); + return float(bits) * 2.3283064365386963e-10; // / 0x100000000 + } + +vec2 hammersley2d(uint i, uint N) +{ + return vec2(float(i)/float(N), radicalInverse_VdC(i)); +} + +vec2 hammersly[4] = vec2[4] ( + vec2(0.0, 0.0), + vec2(0.25, 0.5), + vec2(0.5, 0.25), + vec2(0.75, 0.75) + ); + +vec3 ImportanceGGX( in mat3 tanFrame, vec2 Xi, float roughness , vec3 N ) +{ + float a = roughness * roughness; + float Phi = 2.0 * PI * Xi.y; + float CosTheta = (1.0 - Xi.x); + float SinTheta = sqrt( 1.0 - CosTheta * CosTheta ); + + vec3 H; + H.x = SinTheta * cos( Phi ); + H.y = SinTheta * sin( Phi ); + H.z = CosTheta; + + // Tangent to world space + return tanFrame[0] * H.x + tanFrame[1] * H.y + tanFrame[2] * H.z; +} + +float DtermGGXAnisoSampled( in mat3 tanFrame, in vec3 H, in float roughnessU, float roughnessV ) +{ +#if (MATERIAL_IS_NON_DIELECTRIC == 1) + float roughU = clamp(roughnessU*roughnessU, 0.01, 1.0); + float roughV = clamp(roughnessV*roughnessV, 0.01, 1.0); +#else + float roughU = clamp(roughnessU, 0.02, 1.0); + float roughV = clamp(roughnessV, 0.02, 1.0); +#endif + + float NdotH = clamp( dot(tanFrame[2], H), 0.0001, 1.0 ); + float m = PI * roughU * roughV; + float HdotX = clamp( abs(dot(H, tanFrame[0])), 0.0001, 1.0 ); + float HdotY = clamp( abs(dot(H, tanFrame[1])), 0.0001, 1.0 ); + + float x2 = roughU*roughU; + float y2 = roughV*roughV; + + float pdf = (HdotX*HdotX/x2) + (HdotY*HdotY/y2) + (NdotH*NdotH); + float D = 1.0 / ( m * pdf * pdf ); + + return max( 0.0, D); +} + +vec3 sampleEnv(in vec3 L, float pdf, uint sampleCount, float roughness ) +{ + vec2 envMapSize = vec2( textureSize( uEnvironmentTexture, 0 ) ); + float envMapLevels = log2( max( envMapSize.x, envMapSize.y ) ); + + float a = 0.5*log2( float(envMapSize.x*envMapSize.y) / float(sampleCount) ); + float d = 4.0 * (abs(L.z) + 1.0) * (abs(L.z) + 1.0); + float b = 0.5*log2( pdf * d ); + + // convert coord to 2D + vec2 tc = vec2( ( atan( L.x, -L.z ) + PI ) / ( 2.0 * PI ), acos( -L.y ) / PI ); + float weight = step( 0.0001, roughness ); + + float lod = max( 0.0, min( (a - b)*weight, envMapLevels )); + + return( textureLod( uEnvironmentTexture, tc, lod ).rgb ); +} + +vec4 microfacetSampledBSDF( in mat3 tanFrame, in vec3 viewDir, in float roughnessU, in float roughnessV, int mode ) +{ + vec3 rgb = vec3( 0.0, 0.0, 0.0 ); + + float roughness = clamp( calculateRoughness( tanFrame[2], roughnessU, roughnessV, tanFrame[0] ), 0.0, 1.0 ); + + vec3 R = reflect( -viewDir, tanFrame[2] ); + + const uint NumSamples = 4u; + for( uint i = 0u; i < NumSamples; i++ ) + { + vec2 Xi = hammersly[i]; // pre computed values + //vec2 Xi = hammersley2d(i, NumSamples); + vec3 Half = ImportanceGGX( tanFrame, Xi, roughness , tanFrame[2] ); + vec3 H = normalize( Half ); + + vec3 L = 2.0 * dot( viewDir, Half ) * Half - viewDir; + float NdotV = clamp( dot( tanFrame[2], viewDir ), 0.0001, 1.0 ); + float NdotR = clamp( dot( tanFrame[2], R ), 0.0, 1.0 ); + float NdotH = clamp( dot( tanFrame[2], H ), 0.0001, 1.0 ); + + if( NdotV > 0.0001 ) + { + float G = GtermGGX( tanFrame, L, viewDir, roughness ); + float D = DtermGGXAnisoSampled( tanFrame, H, roughnessU, roughnessV); + + vec3 envColor = 0.01 * sampleEnv( L, D, NumSamples, roughness ); + + rgb += (envColor * G * D * NdotR) / ( 4.0 * NdotV * NdotH); + } + } + + rgb /= float(NumSamples); + + return( vec4( rgb, 1.0 ) ); +} + +#endif |