init

src/main.cpp

@@ -0,0 +1,157 @@
+#include <glad/glad.h> // Must be included before GLFW
+#include <GLFW/glfw3.h>
+#include <iostream>
+
+// Window dimensions
+const unsigned int SCR_WIDTH = 800;
+const unsigned int SCR_HEIGHT = 600;
+
+// Shaders (in GLSL - OpenGL Shading Language)
+// Vertex Shader: Positions the vertices
+const char *vertexShaderSource = R"glsl(
+    #version 330 core
+    layout (location = 0) in vec3 aPos;
+    void main()
+    {
+        gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
+    }
+)glsl";
+
+// Fragment Shader: Colors the pixels (fragments)
+const char *fragmentShaderSource = R"glsl(
+    #version 330 core
+    out vec4 FragColor;
+    void main()
+    {
+        FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f); // An orange color
+    }
+)glsl";
+
+// Callback function for when the window is resized
+void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
+    glViewport(0, 0, width, height);
+}
+
+int main() {
+    // 1. --- Initialize GLFW ---
+    if (!glfwInit()) {
+        std::cerr << "Failed to initialize GLFW" << std::endl;
+        return -1;
+    }
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
+    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
+    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
+#ifdef __APPLE__
+    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // For macOS
+#endif
+
+    // 2. --- Create a Window ---
+    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "HelloTriangle", NULL, NULL);
+    if (window == NULL) {
+        std::cerr << "Failed to create GLFW window" << std::endl;
+        glfwTerminate();
+        return -1;
+    }
+    glfwMakeContextCurrent(window);
+    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
+
+    // 3. --- Initialize GLAD ---
+    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
+        std::cerr << "Failed to initialize GLAD" << std::endl;
+        return -1;
+    }
+
+    // 4. --- Compile Shaders ---
+
+    // Vertex Shader
+    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
+    glCompileShader(vertexShader);
+    // Check for compilation errors
+    int success;
+    char infoLog[512];
+    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
+    if (!success) {
+        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
+        std::cerr << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
+    }
+
+    // Fragment Shader
+    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
+    glCompileShader(fragmentShader);
+    // Check for compilation errors
+    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
+    if (!success) {
+        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
+        std::cerr << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
+    }
+
+    // Link shaders into a Shader Program
+    unsigned 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::cerr << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
+    }
+    glDeleteShader(vertexShader);   // Shaders are linked, we can delete them
+    glDeleteShader(fragmentShader);
+
+    // 5. --- Set up Vertex Data and Buffers ---
+    // A triangle has 3 vertices, each with 3 coordinates (x, y, z)
+    float vertices[] = {
+        -0.5f, -0.5f, 0.0f, // left
+         0.5f, -0.5f, 0.0f, // right
+         0.0f,  0.5f, 0.0f  // top
+    };
+
+    unsigned int VBO, VAO;
+    glGenVertexArrays(1, &VAO); // 1. Create Vertex Array Object (VAO)
+    glGenBuffers(1, &VBO);      // 2. Create Vertex Buffer Object (VBO)
+
+    glBindVertexArray(VAO);     // 3. Bind the VAO
+
+    glBindBuffer(GL_ARRAY_BUFFER, VBO); // 4. Bind the VBO
+    // 5. Copy vertex data into VBO's memory
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+    // 6. Tell OpenGL how to interpret the vertex data
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
+    glEnableVertexAttribArray(0); // Enable the vertex attribute (location 0)
+
+    // Unbind VBO and VAO (optional, but good practice)
+    glBindBuffer(GL_ARRAY_BUFFER, 0);
+    glBindVertexArray(0);
+
+    // 6. --- The Render Loop ---
+    while (!glfwWindowShouldClose(window)) {
+        // Input (e.g., close window on ESC)
+        if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
+            glfwSetWindowShouldClose(window, true);
+
+        // Rendering
+        glClearColor(0.2f, 0.3f, 0.3f, 1.0f); // Set background color
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        // Draw the triangle
+        glUseProgram(shaderProgram);    // Use our shader program
+        glBindVertexArray(VAO);         // Bind the VAO (our triangle's "recipe")
+        glDrawArrays(GL_TRIANGLES, 0, 3); // Draw it!
+
+        // Swap buffers and poll for events
+        glfwSwapBuffers(window);
+        glfwPollEvents();
+    }
+
+    // 7. --- Cleanup ---
+    glDeleteVertexArrays(1, &VAO);
+    glDeleteBuffers(1, &VBO);
+    glDeleteProgram(shaderProgram);
+
+    glfwTerminate(); // Clean up GLFW
+    return 0;
+}