Have a working skybox now.

24-cubemaps/config.json

@@ -8,6 +8,18 @@
       "vertex_path": "shaders/21-screen.vert.glsl",
       "frag_path": "shaders/21-screen.frag.glsl"
     },
+    "skybox_shader": {
+      "vertex_path": "shaders/24-skybox.vert.glsl",
+      "frag_path": "shaders/24-skybox.frag.glsl"
+    },
+    "skybox_faces": [
+      "../assets/skybox/right.jpg",
+      "../assets/skybox/left.jpg",
+      "../assets/skybox/top.jpg",
+      "../assets/skybox/bottom.jpg",
+      "../assets/skybox/front.jpg",
+      "../assets/skybox/back.jpg"
+    ],
     "materials": {
       "default": {
         "ambient": [0.5, 0.5, 0.5],

24-cubemaps/shaders/24-skybox.frag.glsl

@@ -0,0 +1,11 @@
+#version 330 core
+out vec4 FragColor;
+
+in vec3 TexCoords;
+
+uniform samplerCube skybox;
+
+void main()
+{
+    FragColor = texture(skybox, TexCoords);
+}

24-cubemaps/shaders/24-skybox.vert.glsl

@@ -0,0 +1,14 @@
+#version 330 core
+layout (location = 0) in vec3 aPos;
+
+out vec3 TexCoords;
+
+uniform mat4 projection;
+uniform mat4 view;
+
+void main()
+{
+    TexCoords = aPos;
+    vec4 pos = projection * view * vec4(aPos, 1.0);
+    gl_Position = pos.xyww;
+}

24-cubemaps/src/components.hpp

@@ -103,6 +103,8 @@ namespace components {
   struct Scene {
     components::Shader shader;
     components::Shader screen_shader;
+    components::Shader skybox_shader;
+    std::vector<std::string> skybox_faces;
     std::unordered_map<std::string, Material> materials;
     std::unordered_map<std::string, Model> models;
     std::vector<Thing> things;
@@ -110,5 +112,5 @@ namespace components {
     Lighting light;
   };
 
-  ENROLL_COMPONENT(Scene, shader, screen_shader, materials, models, things, camera, light);
+  ENROLL_COMPONENT(Scene, shader, screen_shader, skybox_shader, skybox_faces, materials, models, things, camera, light);
 }

24-cubemaps/src/scene.cpp

@@ -1,6 +1,7 @@
 #include "scene.hpp"
 #include "dbc.hpp"
 #include <math.h>
+#include "skybox.hpp"
 
 void Scene::update() {
   float currentFrame = glfwGetTime();
@@ -51,6 +52,8 @@ void Scene::render(GLFWwindow* window) {
     draw_thing(shader, thing);
   }
 
+  render_skybox(projection);
+
   framebuffer.commit();
 
   framebuffer.draw(screen);
@@ -73,3 +76,58 @@ void Scene::spawn(const std::string& name, components::Position& position, compo
     dbc::log($F("No model named: {}", name));
   }
 }
+
+void Scene::init_skybox() {
+  glGenVertexArrays(1, &skyboxVAO);
+  glGenBuffers(1, &skyboxVBO);
+  glBindVertexArray(skyboxVAO);
+  glBindBuffer(GL_ARRAY_BUFFER, skyboxVBO);
+  glBufferData(GL_ARRAY_BUFFER, sizeof(skyboxVertices), &skyboxVertices, GL_STATIC_DRAW);
+  glEnableVertexAttribArray(0);
+  glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
+
+  load_skybox_textures();
+}
+
+
+void Scene::load_skybox_textures() {
+  int width = 0;
+  int height = 0;
+  int nrChannels = 0;
+  size_t face_i = 0;
+
+  glGenTextures(1, &skybox_texture_id);
+  glBindTexture(GL_TEXTURE_CUBE_MAP, skybox_texture_id);
+
+  for(const auto& face : skybox_faces) {
+    unsigned char *data = stbi_load(face.c_str(), &width, &height, &nrChannels, 0);
+    dbc::check(data != nullptr, $F("Failed to load skybox face {}", face));
+    dbc::check(nrChannels == 3, $F("Skybox face {} must be RGB but you have {} channels", face, nrChannels));
+
+    glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + face_i, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
+    face_i++;
+
+    stbi_image_free(data);
+  }
+
+  glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+  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);
+}
+
+void Scene::render_skybox(const glm::mat4& projection) {
+  glDepthFunc(GL_LEQUAL);
+  skybox_shader.use();
+  glm::mat4 view = glm::mat4(glm::mat3(camera.look_at()));
+  skybox_shader.setMat4("view", view);
+  skybox_shader.setMat4("projection", projection);
+
+  glBindVertexArray(skyboxVAO);
+  glActiveTexture(GL_TEXTURE0);
+  glBindTexture(GL_TEXTURE_CUBE_MAP, skybox_texture_id);
+  glDrawArrays(GL_TRIANGLES, 0, 36);
+  glBindVertexArray(0);
+  glDepthFunc(GL_LESS);
+}

24-cubemaps/src/scene.hpp

@@ -27,6 +27,8 @@ struct Thing {
 
 struct Scene {
   Shader shader;
+  Shader skybox_shader;
+  std::vector<std::string> skybox_faces;
   Screen screen;
   FrameBuffer framebuffer;
 
@@ -35,12 +37,16 @@ struct Scene {
   components::Lighting light;
   std::unordered_map<std::string, Model> models;
   std::vector<Thing> things;
-
   float deltaTime = 0.0f;
   float lastFrame = 0.0f;
+  unsigned int skyboxVAO = 0;
+  unsigned int skyboxVBO = 0;
+  unsigned int skybox_texture_id = 0;
 
   Scene(components::Scene& config):
     shader{config.shader.vertex_path, config.shader.frag_path},
+    skybox_shader{config.skybox_shader.vertex_path, config.skybox_shader.frag_path},
+    skybox_faces{config.skybox_faces},
     screen{.shader={config.screen_shader.vertex_path, config.screen_shader.frag_path}},
     materials{config.materials},
     camera{
@@ -70,8 +76,12 @@ struct Scene {
     shader.setInt("texture1", 0);
     shader.apply_lighting(light);
 
+    skybox_shader.use();
+    skybox_shader.setInt("skybox", 0);
+
     framebuffer.init();
     screen.init();
+    init_skybox();
   }
 
   void update();
@@ -79,4 +89,7 @@ struct Scene {
   void render(GLFWwindow* window);
   void cleanup();
   void spawn(const std::string& name, components::Position& position, components::Rotation& rotation);
+  void init_skybox();
+  void load_skybox_textures();
+  void render_skybox(const glm::mat4& projection);
 };

24-cubemaps/src/skybox.hpp

@@ -0,0 +1,46 @@
+#pragma once
+
+float skyboxVertices[] = {
+    // positions
+    -1.0f,  1.0f, -1.0f,
+    -1.0f, -1.0f, -1.0f,
+     1.0f, -1.0f, -1.0f,
+     1.0f, -1.0f, -1.0f,
+     1.0f,  1.0f, -1.0f,
+    -1.0f,  1.0f, -1.0f,
+
+    -1.0f, -1.0f,  1.0f,
+    -1.0f, -1.0f, -1.0f,
+    -1.0f,  1.0f, -1.0f,
+    -1.0f,  1.0f, -1.0f,
+    -1.0f,  1.0f,  1.0f,
+    -1.0f, -1.0f,  1.0f,
+
+     1.0f, -1.0f, -1.0f,
+     1.0f, -1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f, -1.0f,
+     1.0f, -1.0f, -1.0f,
+
+    -1.0f, -1.0f,  1.0f,
+    -1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f, -1.0f,  1.0f,
+    -1.0f, -1.0f,  1.0f,
+
+    -1.0f,  1.0f, -1.0f,
+     1.0f,  1.0f, -1.0f,
+     1.0f,  1.0f,  1.0f,
+     1.0f,  1.0f,  1.0f,
+    -1.0f,  1.0f,  1.0f,
+    -1.0f,  1.0f, -1.0f,
+
+    -1.0f, -1.0f, -1.0f,
+    -1.0f, -1.0f,  1.0f,
+     1.0f, -1.0f, -1.0f,
+     1.0f, -1.0f, -1.0f,
+    -1.0f, -1.0f,  1.0f,
+     1.0f, -1.0f,  1.0f
+};