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PBR attenuation fix with proper Fresnel adjustments.

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This commit is contained in:
Joey de Vries
2017-01-09 19:57:53 +01:00
parent 5042701210
commit 96ced3c198
4 changed files with 32 additions and 42 deletions
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8
src/6.pbr/1.1.lighting/lighting.cpp
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@@ -95,10 +95,10 @@ int main()
glm::vec3( 10.0f, -10.0f, 10.0f),
};
glm::vec3 lightColors[] = {
glm::vec3(2.0f, 2.0f, 2.0f),
glm::vec3(2.0f, 2.0f, 2.0f),
glm::vec3(2.0f, 2.0f, 2.0f),
glm::vec3(2.0f, 2.0f, 2.0f)
glm::vec3(300.0f, 300.0f, 300.0f),
glm::vec3(300.0f, 300.0f, 300.0f),
glm::vec3(300.0f, 300.0f, 300.0f),
glm::vec3(300.0f, 300.0f, 300.0f)
};
int nrRows = 7;
int nrColumns = 7;

31
src/6.pbr/1.1.lighting/pbr.frag
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@@ -60,11 +60,6 @@ vec3 fresnelSchlick(float cosTheta, vec3 F0)
return F0 + (1.0 - F0) * pow(1.0 - cosTheta, 5.0);
}
// ----------------------------------------------------------------------------
vec3 fresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness)
{
return F0 + (max(vec3(1.0 - roughness), F0) - F0) * pow(1.0 - cosTheta, 5.0);
}
// ----------------------------------------------------------------------------
void main()
{
vec3 N = normalize(Normal);
@@ -75,18 +70,6 @@ void main()
// of 0.04 and if it's a metal, use their albedo color as F0 (metallic workflow)
vec3 F0 = vec3(0.04);
F0 = mix(F0, albedo, metallic);
vec3 F = fresnelSchlickRoughness(max(dot(N, V), 0.0), F0, roughness); // use modified Fresnel-Schlick approximation to take roughness into account
// kS is equal to Fresnel
vec3 kS = F;
// for energy conservation, the diffuse and specular light can't
// be above 1.0 (unless the surface emits light); to preserve this
// relationship the diffuse component (kD) should equal 1.0 - kS.
vec3 kD = vec3(1.0) - kS;
// multiply kD by the inverse metalness such that only non-metals
// have diffuse lighting, or a linear blend if partly metal (pure metals
// have no diffuse light).
kD *= 1.0 - metallic;
// reflectance equation
vec3 Lo = vec3(0.0);
@@ -96,17 +79,29 @@ void main()
vec3 L = normalize(lightPositions[i] - WorldPos);
vec3 H = normalize(V + L);
float distance = length(lightPositions[i] - WorldPos);
float attenuation = 1.0 / distance * distance;
float attenuation = 1.0 / (distance * distance);
vec3 radiance = lightColors[i] * attenuation;
// Cook-Torrance BRDF
float NDF = DistributionGGX(N, H, roughness);
float G = GeometrySmith(N, V, L, roughness);
vec3 F = fresnelSchlick(max(dot(H, V), 0.0), F0);
vec3 nominator = NDF * G * F;
float denominator = 4 * max(dot(V, N), 0.0) * max(dot(L, N), 0.0) + 0.001; // 0.001 to prevent divide by zero.
vec3 brdf = nominator / denominator;
// kS is equal to Fresnel
vec3 kS = F;
// for energy conservation, the diffuse and specular light can't
// be above 1.0 (unless the surface emits light); to preserve this
// relationship the diffuse component (kD) should equal 1.0 - kS.
vec3 kD = vec3(1.0) - kS;
// multiply kD by the inverse metalness such that only non-metals
// have diffuse lighting, or a linear blend if partly metal (pure metals
// have no diffuse light).
kD *= 1.0 - metallic;
// scale light by NdotL
float NdotL = max(dot(N, L), 0.0);

2
src/6.pbr/1.2.lighting_textured/lighting_textured.cpp
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@@ -101,7 +101,7 @@ int main()
glm::vec3(0.0, 0.0f, 10.0f),
};
glm::vec3 lightColors[] = {
glm::vec3(2.5f, 2.5f, 2.5f)
glm::vec3(150.0f, 150.0f, 150.0f)
};
int nrRows = 7;
int nrColumns = 7;

31
src/6.pbr/1.2.lighting_textured/pbr.frag
View File

@@ -82,11 +82,6 @@ vec3 fresnelSchlick(float cosTheta, vec3 F0)
return F0 + (1.0 - F0) * pow(1.0 - cosTheta, 5.0);
}
// ----------------------------------------------------------------------------
vec3 fresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness)
{
return F0 + (max(vec3(1.0 - roughness), F0) - F0) * pow(1.0 - cosTheta, 5.0);
}
// ----------------------------------------------------------------------------
void main()
{
vec3 albedo = pow(texture(albedoMap, TexCoords).rgb, vec3(2.2));
@@ -102,18 +97,6 @@ void main()
// of 0.04 and if it's a metal, use their albedo color as F0 (metallic workflow)
vec3 F0 = vec3(0.04);
F0 = mix(F0, albedo, metallic);
vec3 F = fresnelSchlickRoughness(max(dot(N, V), 0.0), F0, roughness); // use modified Fresnel-Schlick approximation to take roughness into account
// kS is equal to Fresnel
vec3 kS = F;
// for energy conservation, the diffuse and specular light can't
// be above 1.0 (unless the surface emits light); to preserve this
// relationship the diffuse component (kD) should equal 1.0 - kS.
vec3 kD = vec3(1.0) - kS;
// multiply kD by the inverse metalness such that only non-metals
// have diffuse lighting, or a linear blend if partly metal (pure metals
// have no diffuse light).
kD *= 1.0 - metallic;
// reflectance equation
vec3 Lo = vec3(0.0);
@@ -123,12 +106,24 @@ void main()
vec3 L = normalize(lightPositions[i] - WorldPos);
vec3 H = normalize(V + L);
float distance = length(lightPositions[i] - WorldPos);
float attenuation = 1.0 / distance * distance;
float attenuation = 1.0 / (distance * distance);
vec3 radiance = lightColors[i] * attenuation;
// Cook-Torrance BRDF
float NDF = DistributionGGX(N, H, roughness);
float G = GeometrySmith(N, V, L, roughness);
vec3 F = fresnelSchlick(max(dot(H, V), 0.0), F0);
// kS is equal to Fresnel
vec3 kS = F;
// for energy conservation, the diffuse and specular light can't
// be above 1.0 (unless the surface emits light); to preserve this
// relationship the diffuse component (kD) should equal 1.0 - kS.
vec3 kD = vec3(1.0) - kS;
// multiply kD by the inverse metalness such that only non-metals
// have diffuse lighting, or a linear blend if partly metal (pure metals
// have no diffuse light).
kD *= 1.0 - metallic;
vec3 nominator = NDF * G * F;
float denominator = 4 * max(dot(V, N), 0.0) * max(dot(L, N), 0.0) + 0.001; // 0.001 to prevent divide by zero.