skybox.cpp

   1 #include "shapes.hpp"
   2 #include "skybox.hpp"
   3 #include "image.hpp"
   4 #include <GL/glew.h>
   5 #include <glm/gtc/type_ptr.hpp>
   6
   7 Skybox::Skybox(const std::vector<std::string> faces): program("skyboxvert.glsl", "skyboxfrag.glsl") {
   8         glUseProgram(program.progId);
   9         glGenTextures(1, &texId);
  10         glBindTexture(GL_TEXTURE_CUBE_MAP, texId);
  11
  12         int width, height, numChans;
  13         for (int i = 0; i < faces.size(); i++) {
  14                 Image img(faces[i]);
  15
  16                 glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGBA, img.width(), img.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, img.data());
  17         }
  18
  19         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  20         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  21         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  22         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  23         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
  24
  25         glGenVertexArrays(1, &vao);
  26         glBindVertexArray(vao);
  27
  28         GLuint vbo;
  29         glGenBuffers(1, &vbo);
  30
  31         auto vertices = cube();
  32
  33         glBindBuffer(GL_ARRAY_BUFFER, vbo);
  34         glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(glm::vec3), &vertices[0], GL_STATIC_DRAW);
  35
  36         GLuint posLoc = glGetAttribLocation(program.progId, "pos");
  37         glEnableVertexAttribArray(posLoc);
  38         glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, 0, 0);
  39 }
  40 void validatePrograms(GLuint progId) {
  41         glValidateProgram(progId);
  42
  43         GLint success;
  44         glGetProgramiv(progId, GL_VALIDATE_STATUS, &success);
  45         if (!success) {
  46                 GLchar log[1024];
  47                 glGetProgramInfoLog(progId, sizeof(log), NULL, log);
  48                 fprintf(stderr, "error: %s\n", log);
  49                 exit(1);
  50         }
  51 }
  52
  53 void Skybox::draw(glm::mat4 proj, glm::mat4 view) const {
  54         glUseProgram(program.progId);
  55
  56         glDepthMask(GL_FALSE);
  57         glDisable(GL_CULL_FACE);
  58         glBindVertexArray(vao);
  59         validatePrograms(program.progId);
  60
  61         GLuint projLoc = glGetUniformLocation(program.progId, "projection");
  62         glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(proj));
  63
  64         GLuint viewLoc = glGetUniformLocation(program.progId, "view");
  65         view = glm::mat4(glm::mat3(view));
  66         glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
  67
  68         glBindTexture(GL_TEXTURE_CUBE_MAP, texId);
  69         glDrawArrays(GL_TRIANGLES, 0, 36);
  70         glEnable(GL_CULL_FACE);
  71         glDepthMask(GL_TRUE);
  72 }