Specular BDRF

This commit is contained in:
Nigel Barink 2023-06-05 18:40:06 +02:00
parent ae516a8007
commit e4587f7c82
25 changed files with 383 additions and 19 deletions

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Shaders/BRDFIntegration.fs Normal file
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@ -0,0 +1,111 @@
#version 460 core
out vec2 FragColor;
in vec2 TexCoords;
const float PI = 3.14159265359;
// http://holger.dammertz.org/stuff/notes_HammersleyOnHemisphere.html
// efficient VanDerCorpus calculation.
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 Hammersley(uint i, uint N)
{
return vec2(float(i)/float(N), RadicalInverse_VdC(i));
}
float GeometrySchlickGGX(float NdotV, float roughness)
{
float a = roughness;
float k = (a * a) / 2.0;
float nom = NdotV;
float denom = NdotV * (1.0 - k) + k;
return nom / denom;
}
vec3 ImportanceSampleGGX(vec2 Xi, vec3 N, float roughness){
float a = roughness*roughness;
float phi = 2.0 * PI * Xi.x;
float cosTheta = sqrt((1.0 - Xi.y) / (1.0 + (a*a - 1.0) * Xi.y));
float sinTheta = sqrt(1.0 - cosTheta*cosTheta);
// Spherical to cartesian
vec3 H;
H.x = cos(phi) * sinTheta;
H.y = sin(phi) * sinTheta;
H.z = cosTheta;
// tangent space to world sample vector
vec3 up = abs(N.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
vec3 tangent = normalize(cross(up,N));
vec3 bitangent = cross(N, tangent);
vec3 sampleVec = tangent * H.x + bitangent * H.y + N * H.z;
return normalize(sampleVec);
}
float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
{
float NdotV = max(dot(N, V), 0.0);
float NdotL = max(dot(N, L), 0.0);
float ggx2 = GeometrySchlickGGX(NdotV, roughness);
float ggx1 = GeometrySchlickGGX(NdotL, roughness);
return ggx1 * ggx2;
}
vec2 IntegrateBRDF (float NdotV, float roughness){
vec3 V;
V.x = sqrt(1.0 - NdotV * NdotV);
V.y = 0.0;
V.z = NdotV;
float A = 0.0;
float B = 0.0;
vec3 N = vec3(0.0,0.0,1.0);
const uint SAMPLE_COUNT = 1024u;
for(uint i = 0u; i < SAMPLE_COUNT; ++i){
vec2 Xi = Hammersley(i, SAMPLE_COUNT);
vec3 H = ImportanceSampleGGX(Xi, N, roughness);
vec3 L = normalize(2.0 * dot(V, H) * H - V);
float NdotL = max(L.z, 0.0);
float NdotH = max(H.z, 0.0);
float VdotH = max(dot(V, H), 0.0);
if(NdotL > 0.0)
{
float G = GeometrySmith(N, V, L, roughness);
float G_Vis = (G * VdotH) / (NdotH * NdotV);
float Fc = pow(1.0 - VdotH, 5.0);
A += (1.0 - Fc) * G_Vis;
B += Fc * G_Vis;
}
}
A /= float(SAMPLE_COUNT);
B /= float(SAMPLE_COUNT);
return vec2(A, B);
}
void main()
{
vec2 integratedBRDF = IntegrateBRDF(TexCoords.x, TexCoords.y);
FragColor = integratedBRDF;
}

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#version 460 core
layout (location = 0) in vec3 aPos;
layout (location = 1) in vec2 aTexCoords;
out vec2 TexCoords;
void main(){
TexCoords = aTexCoords;
gl_Position = vec4(aPos, 1.0);
}

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@ -7,7 +7,6 @@ uniform samplerCube environmentMap;
void main(){ void main(){
vec3 envColor = texture(environmentMap, localPos).rgb; vec3 envColor = texture(environmentMap, localPos).rgb;
envColor = envColor /(envColor + vec3(1.0)); envColor = envColor /(envColor + vec3(1.0));
envColor = pow(envColor, vec3(1.0/2.2)); envColor = pow(envColor, vec3(1.0/2.2));

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@ -12,9 +12,12 @@ uniform sampler2D metallicMap;
uniform sampler2D normalMap; uniform sampler2D normalMap;
uniform sampler2D roughnessMap; uniform sampler2D roughnessMap;
uniform sampler2D aoMap; uniform sampler2D aoMap;
uniform samplerCube irradianceMap;
uniform samplerCube irradianceMap;
uniform samplerCube prefilterMap;
uniform sampler2D brdfLUT;
uniform vec3 lightPositions[4]; uniform vec3 lightPositions[4];
uniform vec3 lightColors[4]; uniform vec3 lightColors[4];
@ -78,6 +81,8 @@ vec3 getNormalFromNormalMap(){
return normalize(TBN * tangentNormal); return normalize(TBN * tangentNormal);
} }
void main(){ void main(){
vec3 albedo = pow(texture(albedoMap, TexCoords).rgb, vec3(2.2)); vec3 albedo = pow(texture(albedoMap, TexCoords).rgb, vec3(2.2));
@ -88,6 +93,8 @@ void main(){
vec3 N = getNormalFromNormalMap(); vec3 N = getNormalFromNormalMap();
vec3 V = normalize(camPos - WorldPos); vec3 V = normalize(camPos - WorldPos);
vec3 R = reflect(-V, N);
vec3 F0 = vec3(0.04); vec3 F0 = vec3(0.04);
F0 = mix(F0, albedo, metallic); F0 = mix(F0, albedo, metallic);
@ -128,7 +135,15 @@ void main(){
kD *= 1.0 - metallic; kD *= 1.0 - metallic;
vec3 irradiance = texture(irradianceMap, N).rgb; vec3 irradiance = texture(irradianceMap, N).rgb;
vec3 diffuse = irradiance* albedo; vec3 diffuse = irradiance* albedo;
vec3 ambient = (kD * diffuse) * ao;
const float MAX_REFLECTION_LOD = 4.0;
vec3 prefilterColor = textureLod(prefilterMap, R, roughness * MAX_REFLECTION_LOD).rgb;
vec2 envBRDF = texture(brdfLUT, vec2(max(dot(N,V), 0.0), roughness)).rg;
vec3 specular = prefilterColor * (kS * envBRDF.x + envBRDF.y);
vec3 ambient = (kD * diffuse + specular) * ao;
vec3 color = ambient + Lo; vec3 color = ambient + Lo;
// HDR tonemapping // HDR tonemapping

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#version 460 core
out vec4 FragColor;
in vec3 localPos;
uniform samplerCube environmentMap;
uniform float roughness;
const float PI = 3.14159265359;
vec3 ImportanceSampleGGX(vec2 Xi, vec3 N, float roughness){
float a = roughness*roughness;
float phi = 2.0 * PI * Xi.x;
float cosTheta = sqrt((1.0 - Xi.y) / (1.0 + (a*a - 1.0) * Xi.y));
float sinTheta = sqrt(1.0 - cosTheta*cosTheta);
// Spherical to cartesian
vec3 H;
H.x = cos(phi) * sinTheta;
H.y = sin(phi) * sinTheta;
H.z = cosTheta;
// tangent space to world sample vector
vec3 up = abs(N.z) < 0.999 ? vec3(0.0, 0.0, 1.0) : vec3(1.0, 0.0, 0.0);
vec3 tangent = normalize(cross(up,N));
vec3 bitangent = cross(N, tangent);
vec3 sampleVec = tangent * H.x + bitangent * H.y + N * H.z;
return normalize(sampleVec);
}
// Generate Van Der Corput sequence
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 Hammersley(uint i, uint N){
return vec2(float(i)/float(N), RadicalInverse_VdC(i));
}
void main(){
vec3 N = normalize(localPos);
vec3 R = N;
vec3 V = R;
const uint SAMPLE_COUNT = 1024u;
float totalWeight = 0.0;
vec3 prefilteredColor = vec3(0.0);
for(uint i = 0u; i < SAMPLE_COUNT; ++i)
{
vec2 Xi = Hammersley(i, SAMPLE_COUNT);
vec3 H = ImportanceSampleGGX(Xi, N, roughness);
vec3 L = normalize(2.0 * dot(V,H) * H - V );
float NdotL = max(dot(N, L), 0.0);
if(NdotL > 0.0){
prefilteredColor += texture(environmentMap, L).rgb * NdotL;
totalWeight += NdotL;
}
}
prefilteredColor = prefilteredColor / totalWeight;
FragColor = vec4(prefilteredColor, 1.0);
}

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@ -119,12 +119,45 @@ void renderCube() {
glBindVertexArray(0); glBindVertexArray(0);
} }
unsigned int quadVAO = 0;
unsigned int quadVBO;
void renderQuad()
{
if (quadVAO == 0)
{
float quadVertices[] = {
// positions // texture Coords
-1.0f, 1.0f, 0.0f, 0.0f, 1.0f,
-1.0f, -1.0f, 0.0f, 0.0f, 0.0f,
1.0f, 1.0f, 0.0f, 1.0f, 1.0f,
1.0f, -1.0f, 0.0f, 1.0f, 0.0f,
};
// setup plane VAO
glGenVertexArrays(1, &quadVAO);
glGenBuffers(1, &quadVBO);
glBindVertexArray(quadVAO);
glBindBuffer(GL_ARRAY_BUFFER, quadVBO);
glBufferData(GL_ARRAY_BUFFER, sizeof(quadVertices), &quadVertices, GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
}
glBindVertexArray(quadVAO);
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
glBindVertexArray(0);
}
unsigned int brdfLUTTexture;
unsigned int prefilterMap;
unsigned int irradianceMap; unsigned int irradianceMap;
unsigned int envCubemap; unsigned int envCubemap;
unsigned int envMapVAO; unsigned int envMapVAO;
void Renderer::Setup() void Renderer::Setup()
{ {
glEnable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
// Create ScreenVAO // Create ScreenVAO
glGenVertexArrays(1, &ScreenVAO); glGenVertexArrays(1, &ScreenVAO);
glBindVertexArray(ScreenVAO); glBindVertexArray(ScreenVAO);
@ -158,11 +191,11 @@ void Renderer::Setup()
shaders[static_cast<int>(RenderPass::PBR)].Load("../Shaders/pbr.vs", "../Shaders/pbr.fs"); shaders[static_cast<int>(RenderPass::PBR)].Load("../Shaders/pbr.vs", "../Shaders/pbr.fs");
albedo = TextureFromFile("../Textures/rusted_iron/albedo.png", "."); albedo = TextureFromFile("../Textures/space-cruiser/albedo.png", ".");
normal = TextureFromFile("../Textures/rusted_iron/normal.png", "."); normal = TextureFromFile("../Textures/space-cruiser/normal.png", ".");
metallic = TextureFromFile("../Textures/rusted_iron/metallic.png", "."); metallic = TextureFromFile("../Textures/space-cruiser/metallic.png", ".");
roughness = TextureFromFile("../Textures/rusted_iron/roughness.png", "."); roughness = TextureFromFile("../Textures/space-cruiser/roughness.png", ".");
ao = TextureFromFile("../Textures/rusted_iron/ao.png","."); ao = TextureFromFile("../Textures/space-cruiser/ao.png",".");
// Create the skybox from an HDR equirectangular environment map // Create the skybox from an HDR equirectangular environment map
@ -199,7 +232,7 @@ void Renderer::Setup()
auto eqShader = Shader(); auto eqShader = Shader();
eqShader.Load("../Shaders/HDRMap.vs", "../Shaders/HDRMap.fs"); eqShader.Load("../Shaders/HDRMap.vs", "../Shaders/HDRMap.fs");
auto hdrTexture = LoadIBL("../Textures/photostudio.hdr"); auto hdrTexture = LoadIBL("../Textures/night_2k.hdr");
eqShader.use(); eqShader.use();
eqShader.setInt("equirectangularMap", 0); eqShader.setInt("equirectangularMap", 0);
@ -319,6 +352,71 @@ void Renderer::Setup()
glBindVertexArray(0); glBindVertexArray(0);
glGenTextures(1, &prefilterMap);
glBindTexture(GL_TEXTURE_CUBE_MAP, prefilterMap);
for (unsigned int i = 0; i < 6; ++i) {
glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGB16F, 128, 128, 0, GL_RGB, GL_FLOAT, nullptr);
}
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glGenerateMipmap(GL_TEXTURE_CUBE_MAP);
auto prefilterShader = Shader();
prefilterShader.Load("../Shaders/skybox2.vs", "../Shaders/prefilter.fs");
prefilterShader.setInt("environmentMap", 0);
prefilterShader.setMat4("projection", captureProjection);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_CUBE_MAP, envCubemap);
glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
unsigned int maxMipLevels = 5;
for (unsigned int mip = 0; mip < maxMipLevels; ++mip) {
unsigned int mipWidth = 128 * std::pow(0.5, mip);
unsigned int mipHeight = 128 * std::pow(0.5, mip);
glBindRenderbuffer(GL_RENDERBUFFER, captureRBO);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, mipWidth, mipHeight);
glViewport(0, 0, mipWidth, mipHeight);
float roughness = (float)mip / (float)(maxMipLevels - 1);
prefilterShader.setFloat("roughness", roughness);
for (unsigned int i = 0; i < 6; ++i) {
prefilterShader.setMat4("view", captureViews[i]);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, prefilterMap, mip);
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
renderCube();
}
}
glGenTextures(1, &brdfLUTTexture);
// Pre-allocate enough memory for the LUT texture
glBindTexture(GL_TEXTURE_2D, brdfLUTTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RG16F, 512, 512, 0, GL_RG, GL_FLOAT, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
glBindRenderbuffer(GL_RENDERBUFFER, captureRBO);
glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, 512, 512);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, brdfLUTTexture, 0);
glViewport(0, 0, 512, 512);
auto brdfShader = Shader();
brdfShader.Load("../Shaders/BRDFIntegration.vs", "../Shaders/BRDFIntegration.fs");
brdfShader.use();
glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
renderQuad();
glViewport(0, 0, 800, 600); // reset viewport
glBindFramebuffer(GL_FRAMEBUFFER, 0);
} }
@ -540,6 +638,9 @@ void Renderer::Render(Scene& scene)
shader.setInt("roughnessMap", 3); shader.setInt("roughnessMap", 3);
shader.setInt("aoMap", 4); shader.setInt("aoMap", 4);
shader.setInt("irradianceMap", 5); shader.setInt("irradianceMap", 5);
shader.setInt("prefilterMap", 6);
shader.setInt("brdfLUT", 7);
shader.setMat4("projection", projection); shader.setMat4("projection", projection);
view = scene.MainCamera.GetViewMatrix(); view = scene.MainCamera.GetViewMatrix();
@ -564,6 +665,12 @@ void Renderer::Render(Scene& scene)
glActiveTexture(GL_TEXTURE5); glActiveTexture(GL_TEXTURE5);
glBindTexture(GL_TEXTURE_CUBE_MAP, irradianceMap); glBindTexture(GL_TEXTURE_CUBE_MAP, irradianceMap);
glActiveTexture(GL_TEXTURE6);
glBindTexture(GL_TEXTURE_CUBE_MAP, prefilterMap);
glActiveTexture(GL_TEXTURE7);
glBindTexture(GL_TEXTURE_2D, brdfLUTTexture);
// Render Spheres // Render Spheres
model = glm::mat4(1.0f); model = glm::mat4(1.0f);
@ -632,12 +739,6 @@ void Renderer::Render(Scene& scene)
*/ */
// 4. draw result to screen // 4. draw result to screen
/* /*
glBindFramebuffer(GL_FRAMEBUFFER, 0); glBindFramebuffer(GL_FRAMEBUFFER, 0);