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source/main.cpp

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+/* #############################################################################
+ *   # openglProject
+ *   This is a test for opengl
+ *
+ *   AUTHER: Preacherdhm
+ *   DATE: 22/06/26
+ * #############################################################################
+ */
+#include <iostream>
+
+// GLEW
+#define GLEW_STATIC
+#include <GL/glew.h>
+
+// GLFW
+#include <GLFW/glfw3.h>
+
+
+// Function prototypes
+void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode);
+
+// Window dimensions
+const GLuint WIDTH = 800, HEIGHT = 600;
+
+// Shaders
+const GLchar* vertexShaderSource = "#version 330 core\n"
+    "layout (location = 0) in vec3 position;\n"
+    "void main()\n"
+    "{\n"
+    "gl_Position = vec4(position.x, position.y, position.z, 1.0);\n"
+    "}\0";
+const GLchar* fragmentShaderSource = "#version 330 core\n"
+    "out vec4 color;\n"
+    "void main()\n"
+    "{\n"
+    "color = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
+    "}\n\0";
+
+// The MAIN function, from here we start the application and run the game loop
+int main()
+{
+    // Init GLFW
+    glfwInit();
+    // Set all the required options for GLFW
+    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);
+
+    // Create a GLFWwindow object that we can use for GLFW's functions
+    GLFWwindow* window = glfwCreateWindow(WIDTH, HEIGHT, "LearnOpenGL", nullptr, nullptr);
+    glfwMakeContextCurrent(window);
+
+    // Set the required callback functions
+    glfwSetKeyCallback(window, key_callback);
+
+    // Set this to true so GLEW knows to use a modern approach to retrieving function pointers and extensions
+    glewExperimental = GL_TRUE;
+    // Initialize GLEW to setup the OpenGL Function pointers
+    glewInit();
+
+    // Define the viewport dimensions
+    int width, height;
+    glfwGetFramebufferSize(window, &width, &height);  
+    glViewport(0, 0, width, height);
+
+
+    // Build and compile our shader program
+    // Vertex shader
+    GLuint vertexShader = glCreateShader(GL_VERTEX_SHADER);
+    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);
+    glCompileShader(vertexShader);
+    // Check for compile time errors
+    GLint success;
+    GLchar 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
+    GLuint fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
+    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);
+    glCompileShader(fragmentShader);
+    // Check for compile time 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
+    GLuint 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 attribute pointers
+    // We add a new set of vertices to form a second triangle (a total of 6 vertices); the vertex attribute configuration remains the same (still one 3-float position vector per vertex)
+    GLfloat vertices[] = {
+        // First triangle
+        0.9f, 0.5f, 0.0f,  // Left 
+        0.0f, 0.5f, 0.0f,  // Right
+        0.9f, -0.5f, 0.0f,  // Top 
+        // Second triangle
+         0.0f, -0.5f, 0.0f,  // Left
+         0.9f, -0.5f, 0.0f,  // Right
+         0.00f, 0.5f, 0.0f   // Top 
+    };
+    GLuint VBO, VAO;
+    glGenVertexArrays(1, &VAO);
+    glGenBuffers(1, &VBO);
+    // Bind the Vertex Array Object first, then bind and set vertex buffer(s) and attribute pointer(s).
+    glBindVertexArray(VAO);
+
+    glBindBuffer(GL_ARRAY_BUFFER, VBO);
+    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
+
+    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(GLfloat), (GLvoid*)0);
+    glEnableVertexAttribArray(0);
+
+    glBindBuffer(GL_ARRAY_BUFFER, 0); // Note that this is allowed, the call to glVertexAttribPointer registered VBO as the currently bound vertex buffer object so afterwards we can safely unbind
+
+    glBindVertexArray(0); // Unbind VAO (it's always a good thing to unbind any buffer/array to prevent strange bugs)
+
+    // Game loop
+    while (!glfwWindowShouldClose(window))
+    {
+        // Check if any events have been activiated (key pressed, mouse moved etc.) and call corresponding response functions
+        glfwPollEvents();
+
+        // Render
+        // Clear the colorbuffer
+        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
+        glClear(GL_COLOR_BUFFER_BIT);
+
+        // Draw our first triangle
+        glUseProgram(shaderProgram);
+        glBindVertexArray(VAO);
+        glDrawArrays(GL_TRIANGLES, 0, 6); // We set the count to 6 since we're drawing 6 vertices now (2 triangles); not 3!
+        glBindVertexArray(0);
+
+        // Swap the screen buffers
+        glfwSwapBuffers(window);
+    }
+    // Properly de-allocate all resources once they've outlived their purpose
+    glDeleteVertexArrays(1, &VAO);
+    glDeleteBuffers(1, &VBO);
+    // Terminate GLFW, clearing any resources allocated by GLFW.
+    glfwTerminate();
+    return 0;
+}
+
+// Is called whenever a key is pressed/released via GLFW
+void key_callback(GLFWwindow* window, int key, int scancode, int action, int mode)
+{
+    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
+        glfwSetWindowShouldClose(window, GL_TRUE);
+}
+