main.cpp

#include <iostream>
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>

#include "Shader.h"
#include "stb_image.h"

void framebuffer_size_callback(GLFWwindow* window, const int w, const int h) {
    glViewport(0, 0, w, h);
}

void process_input(GLFWwindow* window) {
    if (glfwGetKey(window, GLFW_KEY_GRAVE_ACCENT) == GLFW_PRESS) {
        glfwSetWindowShouldClose(window, true);
    }
}

int main() {
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

    GLFWwindow* window = glfwCreateWindow(800, 600, "Learning OpenGL", nullptr, nullptr);
    if (!window) {
        std::cout << "Window creation failed" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    if (!gladLoadGLLoader(reinterpret_cast<GLADloadproc>(glfwGetProcAddress))) {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }
    glViewport(0, 0, 800, 600);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);


    stbi_set_flip_vertically_on_load(true);
    int img_w, img_h, img_ch;
    unsigned char* img_data = stbi_load("../container.jpg", &img_w, &img_h, &img_ch, 0);
    unsigned int texture1, texture2;
    glGenTextures(1, &texture1);
    glBindTexture(GL_TEXTURE_2D, texture1);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img_w, img_h, 0, GL_RGB, GL_UNSIGNED_BYTE, img_data);
    glGenerateMipmap(GL_TEXTURE_2D);
    stbi_image_free(img_data);
    img_data = stbi_load("../awesomeface.png", &img_w, &img_h, &img_ch, 0);
    glGenTextures(1, &texture2);
    glBindTexture(GL_TEXTURE_2D, texture2);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, img_w, img_h, 0, GL_RGBA, GL_UNSIGNED_BYTE, img_data);
    glGenerateMipmap(GL_TEXTURE_2D);
    stbi_image_free(img_data);


    const Shader shader("../VShader.vert", "../FShader.frag");

    float verts[] = {
        -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,
         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,
        -0.5f,  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,
         0.5f,  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,
         0.5f, -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,
         0.5f,  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
    };
    glm::vec3 cubePositions[] = {
        glm::vec3( 0.0f,  0.0f,  0.0f),
        glm::vec3( 2.0f,  5.0f, -15.0f),
        glm::vec3(-1.5f, -2.2f, -2.5f),
        glm::vec3(-3.8f, -2.0f, -12.3f),
        glm::vec3( 2.4f, -0.4f, -3.5f),
        glm::vec3(-1.7f,  3.0f, -7.5f),
        glm::vec3( 1.3f, -2.0f, -2.5f),
        glm::vec3( 1.5f,  2.0f, -2.5f),
        glm::vec3( 1.5f,  0.2f, -1.5f),
        glm::vec3(-1.3f,  1.0f, -1.5f)
    };

    unsigned int vao, vbo;
    glGenVertexArrays(1, &vao);
    glGenBuffers(1, &vbo);
    glBindVertexArray(vao);

    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    glBufferData(GL_ARRAY_BUFFER, sizeof(verts), &verts, GL_STATIC_DRAW);

    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), nullptr);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), reinterpret_cast<void *>(3 * sizeof(float)));
    glEnableVertexAttribArray(2);

    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

    shader.use();
    shader.set("texture1", 0);
    shader.set("texture2", 1);

    glEnable(GL_DEPTH_TEST);

    while (!glfwWindowShouldClose(window)) {
        process_input(window);

        glClearColor(.2, .3, .3, 1.);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        shader.use();

        glm::mat4 view(1.0f);
        view = glm::translate(view, {0.0f, 0.0f, -3.0f});

        glm::mat4 projection(1.0f);
        projection = glm::perspective(glm::radians(45.0f), 800.0f / 600.0f, 0.1f, 100.0f);

        shader.set("view", view);
        shader.set("projection", projection);

        glActiveTexture(GL_TEXTURE0);
        glBindTexture(GL_TEXTURE_2D, texture1);
        glActiveTexture(GL_TEXTURE1);
        glBindTexture(GL_TEXTURE_2D, texture2);

        glBindVertexArray(vao);
        for (unsigned int i = 0; i < 10; i++) {
            glm::mat4 model(1.0f);
            model = glm::translate(model, cubePositions[i]);
            const float angle = 20.0f * i;
            model = glm::rotate(model, glm::radians(angle), {1.0f, 0.3f, 0.5f});
            shader.set("model", model);

            glDrawArrays(GL_TRIANGLES, 0, 36);
        }

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &vao);
    glDeleteBuffers(1, &vbo);
    glfwTerminate();
    return 0;
}