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** Copyright (C) 2019 The Qt Company Ltd.
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// add enum defines
#define scatter_reflect 0
#define scatter_transmit 1
#define scatter_reflect_transmit 2

#define QSSG_ENABLE_UV0 1
#define QSSG_ENABLE_WORLD_POSITION 1
#define QSSG_ENABLE_TEXTAN 1
#define QSSG_ENABLE_BINORMAL 0

#include "vertexFragmentBase.glsllib"

// set shader output
out vec4 fragColor;

// add structure defines
struct layer_result
{
  vec4 base;
  vec4 layer;
  mat3 tanFrame;
};


// temporary declarations
 vec4 tmpShadowTerm;

layer_result layer;

#include "SSAOCustomMaterial.glsllib"
#include "sampleLight.glsllib"
#include "sampleProbe.glsllib"
#include "sampleArea.glsllib"
#include "square.glsllib"
#include "calculateRoughness.glsllib"
#include "evalBakedShadowMap.glsllib"
#include "evalEnvironmentMap.glsllib"
#include "luminance.glsllib"
#include "microfacetBSDF.glsllib"
#include "physGlossyBSDF.glsllib"
#include "simpleGlossyBSDF.glsllib"
#include "fresnelLayer.glsllib"

bool evalTwoSided()
{
  return( false );
}

vec3 computeFrontMaterialEmissive()
{
  return( vec3( 0, 0, 0 ) );
}

void computeFrontLayerColor( in vec3 normal, in vec3 lightDir, in vec3 viewDir, in vec3 lightDiffuse, in vec3 lightSpecular, in float materialIOR, float aoFactor )
{
#if QSSG_ENABLE_CG_LIGHTING
  layer.base += tmpShadowTerm * vec4( 0.0f, 0.0f, 0.0f, 1.0f );
  layer.layer += tmpShadowTerm * microfacetBSDF( layer.tanFrame, lightDir, viewDir, lightSpecular, materialIOR, roughness, roughness, scatter_reflect );
#endif
}

void computeFrontAreaColor( in int lightIdx, in vec4 lightDiffuse, in vec4 lightSpecular )
{
#if QSSG_ENABLE_CG_LIGHTING
  layer.base += tmpShadowTerm * vec4( 0.0f, 0.0f, 0.0f, 1.0f );
  layer.layer += tmpShadowTerm * lightSpecular * sampleAreaGlossy( layer.tanFrame, varWorldPos, lightIdx, viewDir, roughness, roughness );
#endif
}

void computeFrontLayerEnvironment( in vec3 normal, in vec3 viewDir, float aoFactor )
{
#if !QSSG_ENABLE_LIGHT_PROBE
  layer.base += tmpShadowTerm * vec4( 0.0f, 0.0f, 0.0f, 1.0f );
  layer.layer += tmpShadowTerm * microfacetSampledBSDF( layer.tanFrame, viewDir, roughness, roughness, scatter_reflect );
#else
  layer.base += tmpShadowTerm * vec4( 0.0f, 0.0f, 0.0f, 1.0f );
  layer.layer += tmpShadowTerm * sampleGlossy( layer.tanFrame, viewDir, roughness);
#endif
}

vec3 computeBackMaterialEmissive()
{
  return( vec3(0, 0, 0) );
}

void computeBackLayerColor( in vec3 normal, in vec3 lightDir, in vec3 viewDir, in vec3 lightDiffuse, in vec3 lightSpecular, in float materialIOR, float aoFactor )
{
#if QSSG_ENABLE_CG_LIGHTING
  layer.base += vec4( 0.0, 0.0, 0.0, 1.0 );
  layer.layer += vec4( 0.0, 0.0, 0.0, 1.0 );
#endif
}

void computeBackAreaColor( in int lightIdx, in vec4 lightDiffuse, in vec4 lightSpecular )
{
#if QSSG_ENABLE_CG_LIGHTING
  layer.base += vec4( 0.0, 0.0, 0.0, 1.0 );
  layer.layer += vec4( 0.0, 0.0, 0.0, 1.0 );
#endif
}

void computeBackLayerEnvironment( in vec3 normal, in vec3 viewDir, float aoFactor )
{
#if !QSSG_ENABLE_LIGHT_PROBE
  layer.base += vec4( 0.0, 0.0, 0.0, 1.0 );
  layer.layer += vec4( 0.0, 0.0, 0.0, 1.0 );
#else
  layer.base += vec4( 0.0, 0.0, 0.0, 1.0 );
  layer.layer += vec4( 0.0, 0.0, 0.0, 1.0 );
#endif
}

float computeIOR()
{
  return( false ? 1.0f : luminance( vec3( 1, 1, 1 ) ) );
}

float evalCutout()
{
  return( 1.000000 );
}

vec3 computeNormal()
{
  return( normal );
}

void computeTemporaries()
{
     tmpShadowTerm = evalBakedShadowMap( texCoord0 );
}

vec4 computeLayerWeights( in float alpha )
{
  vec4 color;
  color = fresnelLayer( normal, vec3( 25.65, 25.65, 25.65 ), 1.000000, vec4( metal_color, 1.0).rgb, layer.layer, layer.base, alpha );
  return color;
}


void initializeLayerVariables(void)
{
  // clear layers
  layer.base = vec4(0.0, 0.0, 0.0, 1.0);
  layer.layer = vec4(0.0, 0.0, 0.0, 1.0);
  layer.tanFrame = orthoNormalize( mat3( tangent, cross(normal, tangent), normal ) );
}
