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a3a19af3ec
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277
main.c
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277
main.c
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#include <GL/glew.h>
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#include <GLFW/glfw3.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "log.h"
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#include "main.h"
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#define UNUSED(a) (void)a
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#define WINDOW_WIDTH 800
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#define WINDOW_HEIGHT 600
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#define FRAGMENT_SHADER_FILE "main.frag"
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int main() {
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/* Initialize GLFW */
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if (!glfwInit()) {
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log_error("[GLFW] Failed to init");
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return EXIT_FAILURE;
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}
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glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
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glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
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glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
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/* Create window */
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GLFWwindow *window =
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glfwCreateWindow(WINDOW_WIDTH, WINDOW_HEIGHT, "OpenGL Test", NULL, NULL);
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if (window == NULL) {
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log_error("[GLFW] Failed to create window");
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glfwTerminate();
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return EXIT_FAILURE;
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}
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glfwMakeContextCurrent(window);
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log_debug("[GLFW] Created window of size %d, %d", WINDOW_WIDTH,
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WINDOW_HEIGHT);
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glViewport(0, 0, WINDOW_WIDTH, WINDOW_HEIGHT);
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glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
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/* Initialize OpenGL */
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if (glewInit() != GLEW_OK) {
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log_error("[GLEW] Failed to initialize");
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return EXIT_FAILURE;
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}
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log_debug("[GLEW] Initialized successfully");
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/* Define vertices */
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float vertices[] = {
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-1.0, -1.0, 0.0, // bottom left
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-1.0, 1.0, 0.0, // top left
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1.0, -1.0, 0.0, // top right
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1.0, 1.0, 0.0 // bottom right
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};
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unsigned int indices[] = {
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0, 1, 2, // first triangle
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1, 2, 3 // second triangle
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};
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unsigned int VBO = 0;
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glGenBuffers(1, &VBO);
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unsigned int EBO = 0;
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glGenBuffers(1, &EBO);
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unsigned int VAO = 0;
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glGenVertexArrays(1, &VAO);
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glBindVertexArray(VAO);
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glBindBuffer(GL_ARRAY_BUFFER, VBO);
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glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
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glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
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glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices,
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GL_STATIC_DRAW);
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glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void *)0);
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glEnableVertexAttribArray(0);
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log_debug("Vertex data initialized successfully");
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unsigned int shader_program = glCreateProgram();
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int result = compile_shaders(&shader_program, FRAGMENT_SHADER_FILE);
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if (!shader_program || result) {
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log_error("Could not compile shaders");
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return EXIT_FAILURE;
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}
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/* Drawing loop */
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size_t frame = 0;
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while (!glfwWindowShouldClose(window)) {
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process_input(window, &shader_program);
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/* Background */
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glClearColor(0, 0, 0, 1.0f);
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glClear(GL_COLOR_BUFFER_BIT);
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glUseProgram(shader_program);
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float time = glfwGetTime();
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int frag_time_location = glGetUniformLocation(shader_program, "u_time");
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glUniform1f(frag_time_location, time);
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int frag_frame_location = glGetUniformLocation(shader_program, "u_frame");
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glUniform1ui(frag_frame_location, frame);
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int viewport[4] = {0};
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glGetIntegerv(GL_VIEWPORT, viewport);
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int frag_resolution_location =
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glGetUniformLocation(shader_program, "u_resolution");
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glUniform2f(frag_resolution_location, viewport[2], viewport[3]);
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double mouse_x = 0, mouse_y = 0;
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glfwGetCursorPos(window, &mouse_x, &mouse_y);
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int frag_mouse_resolution_location =
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glGetUniformLocation(shader_program, "u_mouse");
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glUniform2f(frag_mouse_resolution_location, mouse_x, mouse_y);
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// glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); /* For wireframe mode */
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glBindVertexArray(VAO);
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glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
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glBindVertexArray(0);
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glfwSwapBuffers(window);
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glfwPollEvents();
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frame++;
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}
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glfwTerminate();
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return EXIT_SUCCESS;
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}
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/**
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* @brief Compile shaders from source files.
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*
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* This function reads the source files of the vertex and fragment
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* shaders, compiles them, and links them together in a shader
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* program.
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*
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* @param shader_program Pointer to the ID of the shader program
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* where the shaders will be stored.
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* @param fragment_shader_file File name of the fragment shader.
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* @return 0 on success, 1 on error.
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*/
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int compile_shaders(unsigned int *shader_program,
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const char *const fragment_shader_file) {
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/* Compile vertex shader */
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const char *const vertex_shader_source =
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"#version 330 core\n"
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"layout (location = 0) in vec3 aPos;\n"
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"void main()\n"
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"{\n"
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" gl_Position = vec4(aPos, 1.0);\n"
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"}\n";
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unsigned int vertex_shader = glCreateShader(GL_VERTEX_SHADER);
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glShaderSource(vertex_shader, 1, &vertex_shader_source, NULL);
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glCompileShader(vertex_shader);
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int success = 0;
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char info_log[512];
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glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &success);
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if (!success) {
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glGetShaderInfoLog(vertex_shader, 512, NULL, info_log);
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log_error("Vertex shader compilation failed: %s", info_log);
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}
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/* Compile fragment shader */
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const char *const fragment_shader_source = read_file(fragment_shader_file);
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if (fragment_shader_source == NULL) {
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log_error("Could not load fragment shader from file %s",
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fragment_shader_file);
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return 1;
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}
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unsigned int fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
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glShaderSource(fragment_shader, 1, &fragment_shader_source, NULL);
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glCompileShader(fragment_shader);
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glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &success);
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if (!success) {
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glGetShaderInfoLog(fragment_shader, 512, NULL, info_log);
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log_error("Fragment shader compilation failed: %s", info_log);
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return 1;
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}
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/* Link shaders */
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unsigned int new_shader_program = glCreateProgram();
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glAttachShader(new_shader_program, vertex_shader);
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glAttachShader(new_shader_program, fragment_shader);
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glLinkProgram(new_shader_program);
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glGetShaderiv(new_shader_program, GL_LINK_STATUS, &success);
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if (!success) {
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glGetShaderInfoLog(new_shader_program, 512, NULL, info_log);
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log_error("Shader program linking failed: %s", info_log);
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return 1;
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}
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glDeleteProgram(*shader_program);
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*shader_program = new_shader_program;
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free((void *)fragment_shader_source);
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glDeleteShader(vertex_shader);
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glDeleteShader(fragment_shader);
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log_debug("Shaders compiled successfully");
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return 0;
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}
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/**
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* @brief Callback to adjust the size of the viewport when the window
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* is resized.
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*
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* @param window The current window.
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* @param width The new width.
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* @param height The new height.
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*/
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void framebuffer_size_callback(GLFWwindow *window, int width, int height) {
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UNUSED(window);
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glViewport(0, 0, width, height);
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}
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/**
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* @brief Ensure the window is closed when the user presses the escape
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* key.
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*
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* @param window The current window.
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* @param shader_program Pointer to the shader program to update if needed.
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*/
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void process_input(GLFWwindow *window, unsigned int *shader_program) {
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if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
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log_debug("Quitting");
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glfwSetWindowShouldClose(window, true);
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} else if (glfwGetKey(window, GLFW_KEY_R) == GLFW_PRESS) {
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compile_shaders(shader_program, FRAGMENT_SHADER_FILE);
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}
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}
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/**
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* @brief Reads a file in a heap-allocated buffer.
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*
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* This function computes the length of the file, allocate a buffer of
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* the correct size, and reads the file in the buffer. Returns `NULL`
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* on error.
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*
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* @param filename The file to read.
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* @return A buffer containing the contents of the file, or `NULL` if
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* there was an error.
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*/
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char *read_file(const char *const filename) {
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FILE *fd = fopen(filename, "r");
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if (fd == NULL) {
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log_error("Could not open file %s", filename);
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return NULL;
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}
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if (fseek(fd, 0, SEEK_END) == -1) {
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perror("fseek");
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return NULL;
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}
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long size = ftell(fd);
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if (size == -1) {
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perror("ftell");
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return NULL;
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}
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rewind(fd);
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char *buf = calloc(size + 1, 1);
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if (buf == NULL) {
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log_error("Failed to allocate memory to read file %s", filename);
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return NULL;
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}
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long bytes_read = fread(buf, 1, size, fd);
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if (bytes_read != size) {
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log_error("Failed to read file %s (%ld bytes read out of %ld total)",
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filename, bytes_read, size);
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return NULL;
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}
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fclose(fd);
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return buf;
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}
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