Code re-work: Advanced OpenGL

src/4.advanced_opengl/6.1.cubemaps_skybox/6.1.cubemaps.fs

@@ -1,14 +1,11 @@
 #version 330 core
-in vec3 Normal;
-in vec3 Position;
-out vec4 color;
+out vec4 FragColor;
 
-uniform vec3 cameraPos;
-uniform samplerCube skybox;
+in vec2 TexCoords;
+
+uniform sampler2D texture1;
 
 void main()
-{             
-    vec3 I = normalize(Position - cameraPos);
-    vec3 R = reflect(I, normalize(Normal));
-    color = texture(skybox, R);
+{    
+    FragColor = texture(texture1, TexCoords);
 }

src/4.advanced_opengl/6.1.cubemaps_skybox/6.1.cubemaps.vs

@@ -1,9 +1,8 @@
 #version 330 core
-layout (location = 0) in vec3 position;
-layout (location = 1) in vec3 normal;
+layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec2 aTexCoords;
 
-out vec3 Normal;
-out vec3 Position;
+out vec2 TexCoords;
 
 uniform mat4 model;
 uniform mat4 view;
@@ -11,7 +10,6 @@ uniform mat4 projection;
 
 void main()
 {
-    gl_Position = projection * view * model * vec4(position, 1.0f);
-    Normal = mat3(transpose(inverse(model))) * normal;
-    Position = vec3(model * vec4(position, 1.0f));
-}  
+    TexCoords = aTexCoords;    
+    gl_Position = projection * view * model * vec4(aPos, 1.0f);
+}

src/4.advanced_opengl/6.1.cubemaps_skybox/6.1.skybox.fs

@@ -1,10 +1,11 @@
 #version 330 core
+out vec4 FragColor;
+
 in vec3 TexCoords;
-out vec4 color;
 
 uniform samplerCube skybox;
 
 void main()
 {    
-    color = texture(skybox, TexCoords);
+    FragColor = texture(skybox, TexCoords);
 }

src/4.advanced_opengl/6.1.cubemaps_skybox/6.1.skybox.vs

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

src/4.advanced_opengl/6.1.cubemaps_skybox/cubemaps_skybox.cpp

@@ -1,356 +1,312 @@
-// Std. Includes
-#include <string>
-#include <algorithm>
-using namespace std;
-
-// GLEW
-#define GLEW_STATIC
-#include <GL/glew.h>
-
-// GLFW
+#include <glad/glad.h>
 #include <GLFW/glfw3.h>
+#include <stb_image.h>
 
-// GL includes
-#include <learnopengl/shader.h>
-#include <learnopengl/camera.h>
-
-// GLM Mathemtics
 #include <glm/glm.hpp>
 #include <glm/gtc/matrix_transform.hpp>
 #include <glm/gtc/type_ptr.hpp>
 
-// Other Libs
-#include <SOIL.h>
 #include <learnopengl/filesystem.h>
+#include <learnopengl/shader_m.h>
+#include <learnopengl/camera.h>
+#include <learnopengl/model.h>
 
-// Properties
-GLuint screenWidth = 800, screenHeight = 600;
+#include <iostream>
 
-// Function prototypes
-void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
-void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
+void framebuffer_size_callback(GLFWwindow* window, int width, int height);
 void mouse_callback(GLFWwindow* window, double xpos, double ypos);
-void Do_Movement();
-GLuint loadTexture(GLchar const * path);
-GLuint loadCubemap(std::vector<std::string> faces);
+void scroll_callback(GLFWwindow* window, double xoffset, double yoffset);
+void processInput(GLFWwindow *window);
+unsigned int loadTexture(const char *path);
+unsigned int loadCubemap(vector<std::string> faces);
 
-// Camera
+// settings
+const unsigned int SCR_WIDTH = 1280;
+const unsigned int SCR_HEIGHT = 720;
+
+// camera
 Camera camera(glm::vec3(0.0f, 0.0f, 3.0f));
-bool keys[1024];
-GLfloat lastX = 400, lastY = 300;
+float lastX = (float)SCR_WIDTH / 2.0;
+float lastY = (float)SCR_HEIGHT / 2.0;
 bool firstMouse = true;
 
-GLfloat deltaTime = 0.0f;
-GLfloat lastFrame = 0.0f;
+// timing
+float deltaTime = 0.0f;
+float lastFrame = 0.0f;
 
-
-
-// The MAIN function, from here we start our application and run our Game loop
 int main()
 {
-    // Init GLFW
+    // glfw: initialize and configure
+    // ------------------------------
     glfwInit();
     glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
     glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
     glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
-    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);
 
-    GLFWwindow* window = glfwCreateWindow(screenWidth, screenHeight, "LearnOpenGL", nullptr, nullptr); // Windowed
+    // glfw window creation
+    // --------------------
+    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);
     glfwMakeContextCurrent(window);
-
-    // Set the required callback functions
-    glfwSetKeyCallback(window, key_callback);
+    if (window == NULL)
+    {
+        std::cout << "Failed to create GLFW window" << std::endl;
+        glfwTerminate();
+        return -1;
+    }
+    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
     glfwSetCursorPosCallback(window, mouse_callback);
     glfwSetScrollCallback(window, scroll_callback);
 
-    // Options
+    // tell GLFW to capture our mouse
     glfwSetInputMode(window, GLFW_CURSOR, GLFW_CURSOR_DISABLED);
 
-    // Initialize GLEW to setup the OpenGL Function pointers
-    glewExperimental = GL_TRUE;
-    glewInit();
+    // glad: load all OpenGL function pointers
+    // ---------------------------------------
+    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
+    {
+        std::cout << "Failed to initialize GLAD" << std::endl;
+        return -1;
+    }
 
-    // Define the viewport dimensions
-    glViewport(0, 0, screenWidth, screenHeight);
-
-    // Setup some OpenGL options
+    // configure global opengl state
+    // -----------------------------
     glEnable(GL_DEPTH_TEST);
-    glDepthFunc(GL_LESS);
 
-    // Setup and compile our shaders
-    Shader shader("cubemaps.vs", "cubemaps.frag");
-    Shader skyboxShader("skybox.vs", "skybox.frag");
+    // build and compile shaders
+    // -------------------------
+    Shader shader("6.1.cubemaps.vs", "6.1.cubemaps.fs");
+    Shader skyboxShader("6.1.skybox.vs", "6.1.skybox.fs");
 
-#pragma region "object_initialization"
-    // Set the object data (buffers, vertex attributes)
-    GLfloat cubeVertices[] = {
-        // Positions          // Normals
-        -0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-        0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-        0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-        0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-        -0.5f, 0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
-        -0.5f, -0.5f, -0.5f, 0.0f, 0.0f, -1.0f,
+    // set up vertex data (and buffer(s)) and configure vertex attributes
+    // ------------------------------------------------------------------
+    float cubeVertices[] = {
+        // positions          // texture Coords
+        -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
+         0.5f, -0.5f, -0.5f,  1.0f, 0.0f,
+         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
+         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
+        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
+        -0.5f, -0.5f, -0.5f,  0.0f, 0.0f,
 
-        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-        0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-        0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-        0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-        -0.5f, 0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
-        -0.5f, -0.5f, 0.5f, 0.0f, 0.0f, 1.0f,
+        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
+         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
+         0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
+         0.5f,  0.5f,  0.5f,  1.0f, 1.0f,
+        -0.5f,  0.5f,  0.5f,  0.0f, 1.0f,
+        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
 
-        -0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
-        -0.5f, 0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-        -0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-        -0.5f, -0.5f, -0.5f, -1.0f, 0.0f, 0.0f,
-        -0.5f, -0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
-        -0.5f, 0.5f, 0.5f, -1.0f, 0.0f, 0.0f,
+        -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
+        -0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
+        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
+        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
+        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
+        -0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
 
-        0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
-        0.5f, 0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
-        0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
-        0.5f, -0.5f, -0.5f, 1.0f, 0.0f, 0.0f,
-        0.5f, -0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
-        0.5f, 0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
+         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
+         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
+         0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
+         0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
+         0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
+         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
 
-        -0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
-        0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
-        0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
-        0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
-        -0.5f, -0.5f, 0.5f, 0.0f, -1.0f, 0.0f,
-        -0.5f, -0.5f, -0.5f, 0.0f, -1.0f, 0.0f,
+        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
+         0.5f, -0.5f, -0.5f,  1.0f, 1.0f,
+         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
+         0.5f, -0.5f,  0.5f,  1.0f, 0.0f,
+        -0.5f, -0.5f,  0.5f,  0.0f, 0.0f,
+        -0.5f, -0.5f, -0.5f,  0.0f, 1.0f,
 
-        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
-        0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f,
-        0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-        0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-        -0.5f, 0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
-        -0.5f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f
+        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f,
+         0.5f,  0.5f, -0.5f,  1.0f, 1.0f,
+         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
+         0.5f,  0.5f,  0.5f,  1.0f, 0.0f,
+        -0.5f,  0.5f,  0.5f,  0.0f, 0.0f,
+        -0.5f,  0.5f, -0.5f,  0.0f, 1.0f
     };
-    GLfloat skyboxVertices[] = {
-        // Positions          
-        -1.0f, 1.0f, -1.0f,
+    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,
-        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
     };
 
-    // Setup cube VAO
-    GLuint cubeVAO, cubeVBO;
+    // cube VAO
+    unsigned int cubeVAO, cubeVBO;
     glGenVertexArrays(1, &cubeVAO);
     glGenBuffers(1, &cubeVBO);
     glBindVertexArray(cubeVAO);
     glBindBuffer(GL_ARRAY_BUFFER, cubeVBO);
     glBufferData(GL_ARRAY_BUFFER, sizeof(cubeVertices), &cubeVertices, GL_STATIC_DRAW);
     glEnableVertexAttribArray(0);
-    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)0);
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
     glEnableVertexAttribArray(1);
-    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(GLfloat), (GLvoid*)(3 * sizeof(GLfloat)));
-    glBindVertexArray(0);
-    // Setup skybox VAO
-    GLuint skyboxVAO, skyboxVBO;
+    glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(3 * sizeof(float)));
+    // skybox VAO
+    unsigned int skyboxVAO, skyboxVBO;
     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(GLfloat), (GLvoid*)0);
-    glBindVertexArray(0);
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
 
-#pragma endregion
+    // load textures
+    // -------------
+    unsigned int cubeTexture = loadTexture(FileSystem::getPath("resources/textures/marble.jpg").c_str());
 
-    // Cubemap (Skybox)
-    std::vector<std::string> faces;
-    faces.push_back(FileSystem::getPath("resources/textures/skybox/right.jpg"));
-    faces.push_back(FileSystem::getPath("resources/textures/skybox/left.jpg"));
-    faces.push_back(FileSystem::getPath("resources/textures/skybox/top.jpg"));
-    faces.push_back(FileSystem::getPath("resources/textures/skybox/bottom.jpg"));
-    faces.push_back(FileSystem::getPath("resources/textures/skybox/back.jpg"));
-    faces.push_back(FileSystem::getPath("resources/textures/skybox/front.jpg"));
-    GLuint skyboxTexture = loadCubemap(faces);
+    vector<std::string> faces
+    {
+        FileSystem::getPath("resources/textures/skybox/right.jpg"),
+        FileSystem::getPath("resources/textures/skybox/left.jpg"),
+        FileSystem::getPath("resources/textures/skybox/top.jpg"),
+        FileSystem::getPath("resources/textures/skybox/bottom.jpg"),
+        FileSystem::getPath("resources/textures/skybox/back.jpg"),
+        FileSystem::getPath("resources/textures/skybox/front.jpg")
+    };
+    unsigned int cubemapTexture = loadCubemap(faces);
 
-    // Draw as wireframe
-    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+    // shader configuration
+    // --------------------
+    shader.use();
+    shader.setInt("texture1", 0);
 
-    // Game loop
+    skyboxShader.use();
+    skyboxShader.setInt("skybox", 0);
+
+    // render loop
+    // -----------
     while (!glfwWindowShouldClose(window))
     {
-        // Set frame time
-        GLfloat currentFrame = glfwGetTime();
+        // per-frame time logic
+        // --------------------
+        float currentFrame = glfwGetTime();
         deltaTime = currentFrame - lastFrame;
         lastFrame = currentFrame;
 
-        // Check and call events
-        glfwPollEvents();
-        Do_Movement();
+        // input
+        // -----
+        processInput(window);
 
-        // Clear buffers
+        // render
+        // ------
         glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
         glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
 
-
-        // Draw scene as normal
-        shader.Use();
+        // draw scene as normal
+        shader.use();
         glm::mat4 model;
         glm::mat4 view = camera.GetViewMatrix();
-        glm::mat4 projection = glm::perspective(camera.Zoom, (float)screenWidth / (float)screenHeight, 0.1f, 100.0f);
-        glUniformMatrix4fv(glGetUniformLocation(shader.Program, "model"), 1, GL_FALSE, glm::value_ptr(model));
-        glUniformMatrix4fv(glGetUniformLocation(shader.Program, "view"), 1, GL_FALSE, glm::value_ptr(view));
-        glUniformMatrix4fv(glGetUniformLocation(shader.Program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
-        glUniform3f(glGetUniformLocation(shader.Program, "cameraPos"), camera.Position.x, camera.Position.y, camera.Position.z);
-        // Cubes
+        glm::mat4 projection = glm::perspective(camera.Zoom, (float)SCR_WIDTH / (float)SCR_HEIGHT, 0.1f, 100.0f);
+        shader.setMat4("model", model);
+        shader.setMat4("view", view);
+        shader.setMat4("projection", projection);
+        // cubes
         glBindVertexArray(cubeVAO);
-        glBindTexture(GL_TEXTURE_CUBE_MAP, skyboxTexture);
+        glActiveTexture(GL_TEXTURE0);
+        glBindTexture(GL_TEXTURE_2D, cubeTexture);
         glDrawArrays(GL_TRIANGLES, 0, 36);
         glBindVertexArray(0);
 
-        // Draw skybox as last
-        glDepthFunc(GL_LEQUAL);  // Change depth function so depth test passes when values are equal to depth buffer's content
-        skyboxShader.Use();
-        view = glm::mat4(glm::mat3(camera.GetViewMatrix()));	// Remove any translation component of the view matrix
-        glUniformMatrix4fv(glGetUniformLocation(skyboxShader.Program, "view"), 1, GL_FALSE, glm::value_ptr(view));
-        glUniformMatrix4fv(glGetUniformLocation(skyboxShader.Program, "projection"), 1, GL_FALSE, glm::value_ptr(projection));
+        // draw skybox as last
+        glDepthFunc(GL_LEQUAL);  // change depth function so depth test passes when values are equal to depth buffer's content
+        skyboxShader.use();
+        view = glm::mat4(glm::mat3(camera.GetViewMatrix())); // remove translation from the view matrix
+        skyboxShader.setMat4("view", view);
+        skyboxShader.setMat4("projection", projection);
         // skybox cube
         glBindVertexArray(skyboxVAO);
-        glBindTexture(GL_TEXTURE_CUBE_MAP, skyboxTexture);
+        glActiveTexture(GL_TEXTURE0);
+        glBindTexture(GL_TEXTURE_CUBE_MAP, cubemapTexture);
         glDrawArrays(GL_TRIANGLES, 0, 36);
         glBindVertexArray(0);
-        glDepthFunc(GL_LESS); // Set depth function back to default
+        glDepthFunc(GL_LESS); // set depth function back to default
 
-
-        // Swap the buffers
+        // glfw: swap buffers and poll IO events (keys pressed/released, mouse moved etc.)
+        // -------------------------------------------------------------------------------
         glfwSwapBuffers(window);
+        glfwPollEvents();
     }
 
+    // optional: de-allocate all resources once they've outlived their purpose:
+    // ------------------------------------------------------------------------
+    glDeleteVertexArrays(1, &cubeVAO);
+    glDeleteVertexArrays(1, &skyboxVAO);
+    glDeleteBuffers(1, &cubeVBO);
+    glDeleteBuffers(1, &skyboxVAO);
+
     glfwTerminate();
     return 0;
 }
 
-// Loads a cubemap texture from 6 individual texture faces
-// Order should be:
-// +X (right)
-// -X (left)
-// +Y (top)
-// -Y (bottom)
-// +Z (front)? (CHECK THIS)
-// -Z (back)?
-GLuint loadCubemap(std::vector<std::string> faces)
+// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
+// ---------------------------------------------------------------------------------------------------------
+void processInput(GLFWwindow *window)
 {
-    GLuint textureID;
-    glGenTextures(1, &textureID);
-    glActiveTexture(GL_TEXTURE0);
+    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+        glfwSetWindowShouldClose(window, true);
 
-    int width, height;
-    unsigned char* image;
-
-    glBindTexture(GL_TEXTURE_CUBE_MAP, textureID);
-    for (GLuint i = 0; i < faces.size(); i++)
-    {
-        image = SOIL_load_image(faces[i].c_str(), &width, &height, 0, SOIL_LOAD_RGB);
-        glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
-    }
-    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-    glTexParameteri(GL_TEXTURE_CUBE_MAP, GL_TEXTURE_MIN_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);
-    glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
-
-    return textureID;
-}
-
-
-// This function loads a texture from file. Note: texture loading functions like these are usually 
-// managed by a 'Resource Manager' that manages all resources (like textures, models, audio). 
-// For learning purposes we'll just define it as a utility function.
-GLuint loadTexture(GLchar const * path)
-{
-    //Generate texture ID and load texture data 
-    GLuint textureID;
-    glGenTextures(1, &textureID);
-    int width, height;
-    unsigned char* image = SOIL_load_image(path, &width, &height, 0, SOIL_LOAD_RGB);
-    // Assign texture to ID
-    glBindTexture(GL_TEXTURE_2D, textureID);
-    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, image);
-    glGenerateMipmap(GL_TEXTURE_2D);
-
-    // Parameters
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
-    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-    glBindTexture(GL_TEXTURE_2D, 0);
-    SOIL_free_image_data(image);
-    return textureID;
-}
-
-#pragma region "User input"
-
-// Moves/alters the camera positions based on user input
-void Do_Movement()
-{
-    // Camera controls
-    if (keys[GLFW_KEY_W])
+    float cameraSpeed = 2.5 * deltaTime;
+    if (glfwGetKey(window, GLFW_KEY_W) == GLFW_PRESS)
         camera.ProcessKeyboard(FORWARD, deltaTime);
-    if (keys[GLFW_KEY_S])
+    if (glfwGetKey(window, GLFW_KEY_S) == GLFW_PRESS)
         camera.ProcessKeyboard(BACKWARD, deltaTime);
-    if (keys[GLFW_KEY_A])
+    if (glfwGetKey(window, GLFW_KEY_A) == GLFW_PRESS)
         camera.ProcessKeyboard(LEFT, deltaTime);
-    if (keys[GLFW_KEY_D])
+    if (glfwGetKey(window, GLFW_KEY_D) == GLFW_PRESS)
         camera.ProcessKeyboard(RIGHT, deltaTime);
 }
 
-// Is called whenever a key is pressed/released via GLFW
-void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
+// glfw: whenever the window size changed (by OS or user resize) this callback function executes
+// ---------------------------------------------------------------------------------------------
+void framebuffer_size_callback(GLFWwindow* window, int width, int height)
 {
-    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
-        glfwSetWindowShouldClose(window, GL_TRUE);
-
-    if (action == GLFW_PRESS)
-        keys[key] = true;
-    else if (action == GLFW_RELEASE)
-        keys[key] = false;
+    // make sure the viewport matches the new window dimensions; note that width and 
+    // height will be significantly larger than specified on retina displays.
+    glViewport(0, 0, width, height);
 }
 
+
+// glfw: whenever the mouse moves, this callback is called
+// -------------------------------------------------------
 void mouse_callback(GLFWwindow* window, double xpos, double ypos)
 {
     if (firstMouse)
@@ -360,8 +316,8 @@ void mouse_callback(GLFWwindow* window, double xpos, double ypos)
         firstMouse = false;
     }
 
-    GLfloat xoffset = xpos - lastX;
-    GLfloat yoffset = lastY - ypos;
+    float xoffset = xpos - lastX;
+    float yoffset = lastY - ypos; // reversed since y-coordinates go from bottom to top
 
     lastX = xpos;
     lastY = ypos;
@@ -369,9 +325,87 @@ void mouse_callback(GLFWwindow* window, double xpos, double ypos)
     camera.ProcessMouseMovement(xoffset, yoffset);
 }
 
+// glfw: whenever the mouse scroll wheel scrolls, this callback is called
+// ----------------------------------------------------------------------
 void scroll_callback(GLFWwindow* window, double xoffset, double yoffset)
 {
     camera.ProcessMouseScroll(yoffset);
 }
 
-#pragma endregion
+// utility function for loading a 2D texture from file
+// ---------------------------------------------------
+unsigned int loadTexture(char const * path)
+{
+    unsigned int textureID;
+    glGenTextures(1, &textureID);
+
+    int width, height, nrComponents;
+    unsigned char *data = stbi_load(path, &width, &height, &nrComponents, 0);
+    if (data)
+    {
+        GLenum format;
+        if (nrComponents == 1)
+            format = GL_RED;
+        else if (nrComponents == 3)
+            format = GL_RGB;
+        else if (nrComponents == 4)
+            format = GL_RGBA;
+
+        glBindTexture(GL_TEXTURE_2D, textureID);
+        glTexImage2D(GL_TEXTURE_2D, 0, format, width, height, 0, format, GL_UNSIGNED_BYTE, data);
+        glGenerateMipmap(GL_TEXTURE_2D);
+
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
+        glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+
+        stbi_image_free(data);
+    }
+    else
+    {
+        std::cout << "Texture failed to load at path: " << path << std::endl;
+        stbi_image_free(data);
+    }
+
+    return textureID;
+}
+
+// loads a cubemap texture from 6 individual texture faces
+// order:
+// +X (right)
+// -X (left)
+// +Y (top)
+// -Y (bottom)
+// +Z (front) 
+// -Z (back)
+// -------------------------------------------------------
+unsigned int loadCubemap(vector<std::string> faces)
+{
+    unsigned int textureID;
+    glGenTextures(1, &textureID);
+    glBindTexture(GL_TEXTURE_CUBE_MAP, textureID);
+
+    int width, height, nrComponents;
+    for (unsigned int i = 0; i < faces.size(); i++)
+    {
+        unsigned char *data = stbi_load(faces[i].c_str(), &width, &height, &nrComponents, 0);
+        if (data)
+        {
+            glTexImage2D(GL_TEXTURE_CUBE_MAP_POSITIVE_X + i, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
+            stbi_image_free(data);
+        }
+        else
+        {
+            std::cout << "Cubemap texture failed to load at path: " << faces[i] << std::endl;
+            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);
+
+    return textureID;
+}