--- /dev/null
+#version 330
+
+in vec2 texCoords;
+out vec4 fragColor;
+
+const float PI = 3.14159265359;
+
+//TODO: Put this in a separate shader program
+float radicalInverse(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;
+}
+
+vec2 hammersley(uint i, uint N) {
+ return vec2(float(i) / float(N), radicalInverse(i));
+}
+
+float geometrySchlickGGX(float NdotV, float roughness) {
+ float a = roughness * roughness;
+ float k = (a * a) / 2.f;
+
+ return NdotV / (NdotV * (1.f - k) + k);
+}
+
+float geometrySmith(vec3 N, vec3 V, vec3 L, float roughness) {
+ float ggx1 = geometrySchlickGGX(max(dot(N, L), 0.f), roughness);
+ float ggx2 = geometrySchlickGGX(max(dot(N, V), 0.f), roughness);
+ return ggx1 * ggx2;
+}
+
+vec3 importanceSampleGGX(vec2 Xi, vec3 N, float roughness) {
+ float a = roughness * roughness;
+
+ float phi = 2.f * PI * Xi.x;
+ float cosTheta = sqrt((1.f - Xi.y) / (1.f + (a * a - 1.f) * Xi.y));
+ float sinTheta = sqrt(1.f - cosTheta * cosTheta);
+
+ // spherical -> cartesian
+ vec3 H = vec3(cos(phi) * sinTheta, sin(phi) * sinTheta, cosTheta);
+
+ vec3 up = abs(N.z) < 0.999 ? vec3(0, 0, 1) : vec3(1, 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);
+}
+
+vec2 integrateBRDF(float NdotV, float roughness) {
+ vec3 V = vec3(sqrt(1.f - NdotV * NdotV), 0.f, NdotV);
+
+ float A = 0, B = 0;
+
+ vec3 N = vec3(0, 0, 1);
+
+ const uint sampleCount = 1024u;
+ for (uint i = 0u; i < sampleCount; i++) {
+ vec2 Xi = hammersley(i, sampleCount);
+ vec3 H = importanceSampleGGX(Xi, N, roughness);
+ vec3 L = normalize(2.f * dot(V, H) * H - V);
+
+ float NdotL = max(L.z, 0.f);
+ float NdotH = max(H.z, 0.f);
+ float VdotH = max(dot(V, H), 0.f);
+
+ if (NdotL > 0) {
+ float G = geometrySmith(N, V, L, roughness);
+ float Gvis = (G * VdotH) / (NdotH * NdotV);
+ float Fc = pow(1.f - VdotH, 5.f);
+
+ A += (1.f - Fc) * Gvis;
+ B += Fc * Gvis;
+ }
+ }
+
+ A /= float(sampleCount);
+ B /= float(sampleCount);
+
+ return vec2(A, B);
+}
+
+void main() {
+ fragColor = vec4(integrateBRDF(texCoords.x, texCoords.y), 0, 0);
+}
+
+
--- /dev/null
+#version 330
+
+in vec3 localPos, normal;
+out vec4 fragColor;
+
+uniform samplerCube environmentMap;
+uniform float roughness;
+
+const float PI = 3.14159265359;
+
+//TODO: Put this in a separate shader program
+float radicalInverse(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;
+}
+
+vec2 hammersley(uint i, uint N) {
+ return vec2(float(i) / float(N), radicalInverse(i));
+}
+
+vec3 importanceSampleGGX(vec2 Xi, vec3 N, float roughness) {
+ float a = roughness * roughness;
+
+ float phi = 2.f * PI * Xi.x;
+ float cosTheta = sqrt((1.f - Xi.y) / (1.f + (a * a - 1.f) * Xi.y));
+ float sinTheta = sqrt(1.f - cosTheta * cosTheta);
+
+ // spherical -> cartesian
+ vec3 H = vec3(cos(phi) * sinTheta, sin(phi) * sinTheta, cosTheta);
+
+ vec3 up = abs(N.z) < 0.999 ? vec3(0, 0, 1) : vec3(1, 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);
+}
+
+void main() {
+ vec3 N = normalize(localPos);
+
+ // approximate view direction - no grazing specular reflections
+ vec3 R = N;
+ vec3 V = R;
+
+ const uint sampleCount = 1024u;
+ float totalWeight = 0;
+ vec3 prefilteredColor = vec3(0);
+ for (uint i = 0u; i < sampleCount; i++) {
+ vec2 Xi = hammersley(i, sampleCount);
+ vec3 H = importanceSampleGGX(Xi, N, roughness);
+ vec3 L = normalize(2.f * dot(V, H) * H - V);
+
+ float NdotL = max(dot(N, L), 0.f);
+ if (NdotL > 0) {
+ prefilteredColor += texture(environmentMap, L).rgb * NdotL;
+ totalWeight += NdotL;
+ }
+ }
+
+ prefilteredColor = prefilteredColor / totalWeight;
+ fragColor = vec4(prefilteredColor, 1.f);
+}
#include "skybox.hpp"
#include <glm/gtc/type_ptr.hpp>
-GLuint setupCubeVertices(GLuint progId, bool reverse = false);
+template <std::size_t N>
+GLuint setupVertices(GLuint progId, std::array<glm::vec3, N> vertices, bool reverse = false);
+
+// matrices used when capturing various environment maps
+glm::mat4 captureProj = glm::perspective(glm::radians(90.f), 1.f, 0.1f, 10.f);
+glm::mat4 captureViews[] = {
+ glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 1, 0, 0), glm::vec3(0, -1, 0)),
+ glm::lookAt(glm::vec3(0, 0, 0), glm::vec3(-1, 0, 0), glm::vec3(0, -1, 0)),
+ glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, 1, 0), glm::vec3(0, 0, 1)),
+ glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, -1, 0), glm::vec3(0, 0, -1)),
+ glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, 0, 1), glm::vec3(0, -1, 0)),
+ glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, 0, -1), glm::vec3(0, -1, 0))
+};
+
+void Skybox::generatePrefilterMap() const {
+ glBindTexture(GL_TEXTURE_CUBE_MAP, prefilterTexId);
+ for (GLuint 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);
+
+ Program prefilterProg("skyboxvert.glsl", "prefilterfrag.glsl");
+ glUseProgram(prefilterProg.progId);
+ glUniform1i(glGetUniformLocation(prefilterProg.progId, "environmentMap"), 0);
+ glUniformMatrix4fv(glGetUniformLocation(prefilterProg.progId, "projection"), 1, GL_FALSE, glm::value_ptr(captureProj));
+ glActiveTexture(GL_TEXTURE0);
+ glBindTexture(GL_TEXTURE_CUBE_MAP, cubemapTexId);
+
+ setupVertices(prefilterProg.progId, cube());
+
+ glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
+ constexpr GLuint MAX_MIP_LEVELS = 5;
+ for (GLuint mip = 0; mip < MAX_MIP_LEVELS; mip++) {
+ GLuint mipWidth = 128 * std::pow(0.5, mip);
+ GLuint 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 / (MAX_MIP_LEVELS - 1.f);
+ glUniform1f(glGetUniformLocation(prefilterProg.progId, "roughness"), roughness);
+
+ for (GLuint i = 0; i < 6; i++) {
+ glUniformMatrix4fv(glGetUniformLocation(prefilterProg.progId, "view"), 1, GL_FALSE, glm::value_ptr(captureViews[i]));
+ glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, prefilterTexId, mip);
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+ glDrawArrays(GL_TRIANGLES, 0, 36);
+ }
+ }
+}
+
+void Skybox::generateBRDFMap() const {
+ glBindTexture(GL_TEXTURE_2D, brdfMapTexId);
+ // allocate memory
+ 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, brdfMapTexId, 0);
+
+ glViewport(0, 0, 512, 512);
+ Program prog("brdfvert.glsl", "brdffrag.glsl");
+ glUseProgram(prog.progId);
+ glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+ setupVertices(prog.progId, plane());
+ glDrawArrays(GL_TRIANGLES, 0, 6);
+}
Skybox::Skybox(const Image img): program("skyboxvert.glsl", "skyboxfrag.glsl") {
Program equiProg("skyboxvert.glsl", "equirectangularfrag.glsl");
glUseProgram(equiProg.progId);
- GLuint allTexIds[3];
- glGenTextures(3, allTexIds);
- hdrTexId = allTexIds[0], cubemapTexId = allTexIds[1], irradianceTexId = allTexIds[2];
+ GLuint allTexIds[5];
+ glGenTextures(5, allTexIds);
+ hdrTexId = allTexIds[0];
+ cubemapTexId = allTexIds[1];
+ irradianceTexId = allTexIds[2];
+ prefilterTexId = allTexIds[3];
+ brdfMapTexId = allTexIds[4];
glBindTexture(GL_TEXTURE_2D, hdrTexId);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
// generate framebuffers to store cubemap in
- GLuint captureFBO, captureRBO;
glGenFramebuffers(1, &captureFBO);
glGenRenderbuffers(1, &captureRBO);
glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// generate vertices
- setupCubeVertices(equiProg.progId);
+ setupVertices(equiProg.progId, cube());
// render the cube
- glm::mat4 captureProj = glm::perspective(glm::radians(90.f), 1.f, 0.1f, 10.f);
- glm::mat4 captureViews[] = {
- glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 1, 0, 0), glm::vec3(0, -1, 0)),
- glm::lookAt(glm::vec3(0, 0, 0), glm::vec3(-1, 0, 0), glm::vec3(0, -1, 0)),
- glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, 1, 0), glm::vec3(0, 0, 1)),
- glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, -1, 0), glm::vec3(0, 0, -1)),
- glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, 0, 1), glm::vec3(0, -1, 0)),
- glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, 0, -1), glm::vec3(0, -1, 0))
- };
glUniform1i(glGetUniformLocation(equiProg.progId, "equirectangularMap"), 0);
glUniformMatrix4fv(glGetUniformLocation(equiProg.progId, "projection"), 1, GL_FALSE, glm::value_ptr(captureProj));
glBindTexture(GL_TEXTURE_CUBE_MAP, cubemapTexId);
// generate vertices
- setupCubeVertices(irradianceProg.progId);
+ setupVertices(irradianceProg.progId, cube());
// render irradiance map
glViewport(0, 0, 32, 32);
glDrawArrays(GL_TRIANGLES, 0, 36);
}
+ generatePrefilterMap();
+
+ generateBRDFMap();
+
// switch back to regular skybox shader
glUseProgram(program.progId);
glDepthFunc(GL_LEQUAL);
// reverse so facing inside out
- vao = setupCubeVertices(program.progId, true);
+ vao = setupVertices(program.progId, cube(), true);
// restore default framebuffer
glBindFramebuffer(GL_FRAMEBUFFER, 0);
glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
glActiveTexture(GL_TEXTURE0);
- glBindTexture(GL_TEXTURE_CUBE_MAP, irradianceTexId);
+ glBindTexture(GL_TEXTURE_CUBE_MAP, cubemapTexId);
glDrawArrays(GL_TRIANGLES, 0, 36);
if (glGetError()) exit(1);
}
-GLuint setupCubeVertices(GLuint progId, bool reverse) {
+template <std::size_t N>
+GLuint setupVertices(GLuint progId, std::array<glm::vec3, N> vertices, bool reverse) {
GLuint vao;
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
GLuint vbo;
glGenBuffers(1, &vbo);
- auto vertices = cube();
-
if (reverse)
std::reverse(vertices.begin(), vertices.end());
projects / opengl.git / commitdiff