skybox.cpp

   1 #include "shapes.hpp"
   2 #include "skybox.hpp"
   3 #include "image.hpp"
   4 #include <glm/gtc/type_ptr.hpp>
   5
   6 Skybox::Skybox(const std::vector<std::string> faces): program("skyboxvert.glsl", "skyboxfrag.glsl") {
   7         glGenTextures(1, &texId);
   8         glBindTexture(GL_TEXTURE_CUBE_MAP, texId);
   9         glDepthFunc(GL_LEQUAL);
  10
  11         int width, height, numChans;
  12         for (int i = 0; i < faces.size(); i++) {
  13                 Image img(faces[i]);
  14
  15                 glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGBA, img.width(), img.height(), 0, GL_RGBA, GL_UNSIGNED_BYTE, img.data());
  16         }
  17
  18         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  19         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  20         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  21         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  22         glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_WRAP_R, GL_CLAMP_TO_EDGE);
  23
  24         glGenVertexArrays(1, &vao);
  25         glBindVertexArray(vao);
  26
  27         GLuint vbo;
  28         glGenBuffers(1, &vbo);
  29
  30         auto vertices = cube();
  31
  32         //reverse so facing inside out
  33         std::reverse(vertices.begin(), vertices.end());
  34
  35         glBindBuffer(GL_ARRAY_BUFFER, vbo);
  36         glBufferData(GL_ARRAY_BUFFER, vertices.size() * sizeof(glm::vec3), &vertices[0], GL_STATIC_DRAW);
  37
  38         GLuint posLoc = glGetAttribLocation(program.progId, "pos");
  39         glEnableVertexAttribArray(posLoc);
  40         glVertexAttribPointer(posLoc, 3, GL_FLOAT, GL_FALSE, 0, 0);
  41 }
  42
  43 void Skybox::draw(glm::mat4 proj, glm::mat4 view) const {
  44         glUseProgram(program.progId);
  45
  46         glBindVertexArray(vao);
  47
  48         GLuint projLoc = glGetUniformLocation(program.progId, "projection");
  49         glUniformMatrix4fv(projLoc, 1, GL_FALSE, glm::value_ptr(proj));
  50
  51         GLuint viewLoc = glGetUniformLocation(program.progId, "view");
  52         view = glm::mat4(glm::mat3(view));
  53         glUniformMatrix4fv(viewLoc, 1, GL_FALSE, glm::value_ptr(view));
  54
  55         glActiveTexture(GL_TEXTURE0);
  56         glBindTexture(GL_TEXTURE_CUBE_MAP, texId);
  57         glDrawArrays(GL_TRIANGLES, 0, 36);
  58 }
  59
  60 GLuint Skybox::getTexture() const {
  61         return texId;
  62 }