Complete code re-work 'Getting Started' tutorials.

src/1.getting_started/3.2.shaders_interpolation/shaders_interpolation.cpp

@@ -0,0 +1,180 @@
+#include <glad/glad.h>
+#include <GLFW/glfw3.h>
+
+#include <iostream>
+
+void framebuffer_size_callback(GLFWwindow* window, int width, int height);
+void processInput(GLFWwindow *window);
+
+const char *vertexShaderSource ="#version 330 core\n"
+    "layout (location = 0) in vec3 aPos;\n"
+    "layout (location = 1) in vec3 aColor;\n"
+    "out vec3 ourColor;\n"
+    "void main()\n"
+    "{\n"
+    "   gl_Position = vec4(aPos, 1.0);\n"
+    "   ourColor = aColor;\n"
+    "}\0";
+
+const char *fragmentShaderSource = "#version 330 core\n"
+    "out vec4 fragColor;\n"
+    "in vec3 ourColor;\n"
+    "void main()\n"
+    "{\n"
+    "   fragColor = vec4(ourColor, 1.0f);\n"
+    "}\n\0";
+
+int main()
+{
+    // 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_OPENGL_FORWARD_COMPAT, GL_TRUE); // uncomment this statement to fix compilation on OS X
+
+    // glfw window creation
+    // --------------------
+    GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
+    glfwMakeContextCurrent(window);
+    if (window == NULL)
+    {
+        std::cout << "Failed to create GLFW window" << std::endl;
+        glfwTerminate();
+        return -1;
+    }
+    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+
+    // glad: load all OpenGL function pointers
+    // ---------------------------------------
+    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
+    {
+        std::cout << "Failed to initialize GLAD" << std::endl;
+        return -1;
+    }
+
+
+    // build and compile our shader program
+    // ------------------------------------
+    // vertex shader
+    int vertexShader = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
+    glCompileShader(vertexShader);
+    // check for shader compile errors
+    int success;
+    char infoLog[512];
+    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
+    if (!success)
+    {
+        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
+        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
+    }
+    // fragment shader
+    int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
+    glCompileShader(fragmentShader);
+    // check for shader compile errors
+    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
+    if (!success)
+    {
+        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
+        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
+    }
+    // link shaders
+    int shaderProgram = glCreateProgram();
+    glAttachShader(shaderProgram, vertexShader);
+    glAttachShader(shaderProgram, fragmentShader);
+    glLinkProgram(shaderProgram);
+    // check for linking errors
+    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
+    if (!success) {
+        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
+        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
+    }
+    glDeleteShader(vertexShader);
+    glDeleteShader(fragmentShader);
+
+    // set up vertex data (and buffer(s)) and configure vertex attributes
+    // ------------------------------------------------------------------
+    float vertices[] = {
+        // positions         // colors
+         0.5f, -0.5f, 0.0f,  1.0f, 0.0f, 0.0f,  // bottom right
+        -0.5f, -0.5f, 0.0f,  0.0f, 1.0f, 0.0f,  // bottom left
+         0.0f,  0.5f, 0.0f,  0.0f, 0.0f, 1.0f   // top 
+
+    };
+
+    unsigned int VBO, VAO;
+    glGenVertexArrays(1, &VAO);
+    glGenBuffers(1, &VBO);
+    // bind the Vertex Array Object first, then bind and set vertex buffer(s), and then configure vertex attributes(s).
+    glBindVertexArray(VAO);
+
+    glBindBuffer(GL_ARRAY_BUFFER, VBO);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+    // position attribute
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)0);
+    glEnableVertexAttribArray(0);
+    // color attribute
+    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 6 * sizeof(float), (void*)(3 * sizeof(float)));
+    glEnableVertexAttribArray(1);
+
+    // You can unbind the VAO afterwards so other VAO calls won't accidentally modify this VAO, but this rarely happens. Modifying other
+    // VAOs requires a call to glBindVertexArray anyways so we generally don't unbind VAOs (nor VBOs) when it's not directly necessary.
+    // glBindVertexArray(0);
+
+    // as we only have a single shader, we could also just activate our shader once beforehand if we want to 
+    glUseProgram(shaderProgram);
+
+    // render loop
+    // -----------
+    while (!glfwWindowShouldClose(window))
+    {
+        // input
+        // -----
+        processInput(window);
+
+        // render
+        // ------
+        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        // render the triangle
+        glBindVertexArray(VAO);
+        glDrawArrays(GL_TRIANGLES, 0, 3);
+
+        // 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, &VAO);
+    glDeleteBuffers(1, &VBO);
+
+    // glfw: terminate, clearing all previously allocated GLFW resources.
+    // ------------------------------------------------------------------
+    glfwTerminate();
+    return 0;
+}
+
+// process all input: query GLFW whether relevant keys are pressed/released this frame and react accordingly
+// ---------------------------------------------------------------------------------------------------------
+void processInput(GLFWwindow *window)
+{
+    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+        glfwSetWindowShouldClose(window, true);
+}
+
+// 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)
+{
+    // 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);
+}