3 #include <glm/gtc/type_ptr.hpp>
5 template <std::size_t N>
6 GLuint setupVertices(GLuint progId, std::array<glm::vec3, N> vertices, bool reverse = false);
8 // matrices used when capturing various environment maps
9 glm::mat4 captureProj = glm::perspective(glm::radians(90.f), 1.f, 0.1f, 10.f);
10 glm::mat4 captureViews[] = {
11 glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 1, 0, 0), glm::vec3(0, -1, 0)),
12 glm::lookAt(glm::vec3(0, 0, 0), glm::vec3(-1, 0, 0), glm::vec3(0, -1, 0)),
13 glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, 1, 0), glm::vec3(0, 0, 1)),
14 glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, -1, 0), glm::vec3(0, 0, -1)),
15 glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, 0, 1), glm::vec3(0, -1, 0)),
16 glm::lookAt(glm::vec3(0, 0, 0), glm::vec3( 0, 0, -1), glm::vec3(0, -1, 0))
19 void Skybox::generatePrefilterMap() const {
20 glBindTexture(GL_TEXTURE_CUBE_MAP, prefilterTexId);
21 for (GLuint i = 0; i < 6; i++)
22 glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0 , GL_RGB16F, 128, 128, 0, GL_RGB, GL_FLOAT, nullptr);
23 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
24 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
25 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
26 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
27 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
29 glGenerateMipmap(GL_TEXTURE_CUBE_MAP);
31 Program prefilterProg("skyboxvert.glsl", "prefilterfrag.glsl");
32 glUseProgram(prefilterProg.progId);
33 glUniform1i(glGetUniformLocation(prefilterProg.progId, "environmentMap"), 0);
34 glUniformMatrix4fv(glGetUniformLocation(prefilterProg.progId, "projection"), 1, GL_FALSE, glm::value_ptr(captureProj));
35 glActiveTexture(GL_TEXTURE0);
36 glBindTexture(GL_TEXTURE_CUBE_MAP, cubemapTexId);
38 setupVertices(prefilterProg.progId, cube());
40 glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
41 constexpr GLuint MAX_MIP_LEVELS = 5;
42 for (GLuint mip = 0; mip < MAX_MIP_LEVELS; mip++) {
43 GLuint mipWidth = 128 * std::pow(0.5, mip);
44 GLuint mipHeight = 128 * std::pow(0.5, mip);
45 glBindRenderbuffer(GL_RENDERBUFFER, captureRBO);
46 glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, mipWidth, mipHeight);
47 glViewport(0, 0, mipWidth, mipHeight);
49 float roughness = (float)mip / (MAX_MIP_LEVELS - 1.f);
50 glUniform1f(glGetUniformLocation(prefilterProg.progId, "roughness"), roughness);
52 for (GLuint i = 0; i < 6; i++) {
53 glUniformMatrix4fv(glGetUniformLocation(prefilterProg.progId, "view"), 1, GL_FALSE, glm::value_ptr(captureViews[i]));
54 glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, prefilterTexId, mip);
55 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
56 glDrawArrays(GL_TRIANGLES, 0, 36);
61 void Skybox::generateBRDFMap() const {
62 glBindTexture(GL_TEXTURE_2D, brdfMapTexId);
64 glTexImage2D(GL_TEXTURE_2D, 0, GL_RG16F, 512, 512, 0, GL_RG, GL_FLOAT, 0);
65 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
66 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
67 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
68 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
70 glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
71 glBindRenderbuffer(GL_RENDERBUFFER, captureRBO);
72 glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, 512, 512);
73 glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, brdfMapTexId, 0);
75 glViewport(0, 0, 512, 512);
76 Program prog("brdfvert.glsl", "brdffrag.glsl");
77 glUseProgram(prog.progId);
78 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
80 setupVertices(prog.progId, plane());
81 glDrawArrays(GL_TRIANGLES, 0, 6);
84 Skybox::Skybox(const Image img): program("skyboxvert.glsl", "skyboxfrag.glsl") {
85 Program equiProg("skyboxvert.glsl", "equirectangularfrag.glsl");
86 glUseProgram(equiProg.progId);
89 glGenTextures(5, allTexIds);
90 hdrTexId = allTexIds[0];
91 cubemapTexId = allTexIds[1];
92 irradianceTexId = allTexIds[2];
93 prefilterTexId = allTexIds[3];
94 brdfMapTexId = allTexIds[4];
96 glBindTexture(GL_TEXTURE_2D, hdrTexId);
98 glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB16, img.width(), img.height(), 0, GL_RGB, GL_UNSIGNED_SHORT, (unsigned short*)img.data());
100 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
101 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
102 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
103 glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
105 // generate framebuffers to store cubemap in
106 glGenFramebuffers(1, &captureFBO);
107 glGenRenderbuffers(1, &captureRBO);
109 glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
110 glBindRenderbuffer(GL_RENDERBUFFER, captureRBO);
111 glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, 512, 512);
112 glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, captureFBO);
114 // setup cubemap texture
115 glBindTexture(GL_TEXTURE_CUBE_MAP, cubemapTexId);
116 for (GLuint i = 0; i < 6; i++)
117 glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGB16F, 512, 512, 0, GL_RGB, GL_FLOAT, nullptr);
118 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
119 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
120 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
121 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
122 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
125 setupVertices(equiProg.progId, cube());
129 glUniform1i(glGetUniformLocation(equiProg.progId, "equirectangularMap"), 0);
130 glUniformMatrix4fv(glGetUniformLocation(equiProg.progId, "projection"), 1, GL_FALSE, glm::value_ptr(captureProj));
131 glActiveTexture(GL_TEXTURE0);
132 glBindTexture(GL_TEXTURE_2D, hdrTexId);
134 glViewport(0, 0, 512, 512);
135 glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
136 for (GLuint i = 0; i < 6; i++) {
137 glUniformMatrix4fv(glGetUniformLocation(equiProg.progId, "view"), 1, GL_FALSE, glm::value_ptr(captureViews[i]));
138 glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, cubemapTexId, 0);
139 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
140 glDrawArrays(GL_TRIANGLES, 0, 36);
143 // setup irradiance map texture
144 glBindTexture(GL_TEXTURE_CUBE_MAP, irradianceTexId);
145 for (GLuint i = 0; i < 6; i++)
146 glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGB16F, 32, 32, 0, GL_RGB, GL_FLOAT, nullptr);
147 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
148 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
149 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
150 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
151 glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
153 // bind framebuffers for rendering irradiance map into
154 glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
155 glBindRenderbuffer(GL_RENDERBUFFER, captureRBO);
156 glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, 32, 32);
158 Program irradianceProg("skyboxvert.glsl", "irradiancefrag.glsl");
159 glUseProgram(irradianceProg.progId);
160 glUniform1i(glGetUniformLocation(irradianceProg.progId, "environmentMap"), 0);
161 glUniformMatrix4fv(glGetUniformLocation(irradianceProg.progId, "projection"), 1, GL_FALSE, glm::value_ptr(captureProj));
162 glActiveTexture(GL_TEXTURE0);
163 glBindTexture(GL_TEXTURE_CUBE_MAP, cubemapTexId);
166 setupVertices(irradianceProg.progId, cube());
168 // render irradiance map
169 glViewport(0, 0, 32, 32);
170 glBindFramebuffer(GL_FRAMEBUFFER, captureFBO);
171 for (GLuint i = 0; i < 6; i++) {
172 glUniformMatrix4fv(glGetUniformLocation(irradianceProg.progId, "view"), 1, GL_FALSE, glm::value_ptr(captureViews[i]));
173 glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, irradianceTexId, 0);
174 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
175 glDrawArrays(GL_TRIANGLES, 0, 36);
178 generatePrefilterMap();
182 // switch back to regular skybox shader
183 glUseProgram(program.progId);
184 glDepthFunc(GL_LEQUAL);
186 // reverse so facing inside out
187 vao = setupVertices(program.progId, cube(), true);
189 // restore default framebuffer
190 glBindFramebuffer(GL_FRAMEBUFFER, 0);
193 void Skybox::draw(glm::mat4 proj, glm::mat4 view) const {
194 glUseProgram(program.progId);
196 glBindVertexArray(vao);
198 GLuint projLoc = glGetUniformLocation(program.progId, "projection");
199 glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(proj));
201 GLuint viewLoc = glGetUniformLocation(program.progId, "view");
202 view = glm::mat4(glm::mat3(view));
203 glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
205 glActiveTexture(GL_TEXTURE0);
206 glBindTexture(GL_TEXTURE_CUBE_MAP, cubemapTexId);
207 glDrawArrays(GL_TRIANGLES, 0, 36);
209 if (glGetError()) exit(1);
212 template <std::size_t N>
213 GLuint setupVertices(GLuint progId, std::array<glm::vec3, N> vertices, bool reverse) {
215 glGenVertexArrays(1, &vao);
216 glBindVertexArray(vao);
219 glGenBuffers(1, &vbo);
222 std::reverse(vertices.begin(), vertices.end());
224 glBindBuffer(GL_ARRAY_BUFFER, vbo);
225 glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(glm::vec3), &vertices[0], GL_STATIC_DRAW);
227 GLuint posLoc = glGetAttribLocation(progId, "pos");
228 glEnableVertexAttribArray(posLoc);
229 glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, 0, 0);