opengl-learn/textures/main.cc

#include <GLFW/glad/glad.h>
#include <GLFW/glfw3.h>
#include <cmath>
#include <cstddef>
#include <iostream>
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
#include "myshader.hh"
#include "stb_image_wrap.h"
float mix_nb = 0.2f;
void framebuffer_size_callback(GLFWwindow* window, int width, int height) {
    glViewport(0, 0, width, height);
}

void process_input(GLFWwindow* window) {
    if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS) {
        glfwSetWindowShouldClose(window, true);
    }
    if (glfwGetKey(window, GLFW_KEY_DOWN) == GLFW_PRESS) {
        mix_nb -= 0.001;
        if (mix_nb <= 0.0f) {
            mix_nb = 0.0f;
        }
    }
    if (glfwGetKey(window, GLFW_KEY_UP) == GLFW_PRESS) {
        mix_nb += 0.001f;
        if (mix_nb >= 1.0f) {
            mix_nb = 1.0f;
        }
    }
}


int main() {
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
#if __APPLE__
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE);
#endif

    GLFWwindow* window = glfwCreateWindow(800, 600, "LearnOpenGL", NULL, NULL);
    if (window == NULL) {
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }
    glfwMakeContextCurrent(window);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);
    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)) {
        std::cout << "Failed to initialize GLAD" << std::endl;
        return -1;
    }

    Shader ourShader("vshader.glsl", "fshader.glsl");
    float vertices[] = {
        //     ---- 位置 ----       ---- 颜色 ----     - 纹理坐标 -
        0.5f,  0.5f, 0.0f,   1.0f, 0.0f, 0.0f,   1.0f, 1.0f,   // 右上
        0.5f, -0.5f, 0.0f,   0.0f, 1.0f, 0.0f,   1.0f, 0.0f,   // 右下
       -0.5f, -0.5f, 0.0f,   0.0f, 0.0f, 1.0f,   0.0f, 0.0f,   // 左下
       -0.5f,  0.5f, 0.0f,   1.0f, 1.0f, 1.0f,   0.0f, 1.0f,    // 左上
   };
    unsigned int indices[] = {
        0, 1, 3,
        1, 2, 3,
    };

    unsigned int VAO, VBO, EBO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    glGenBuffers(1, &EBO);

    glBindVertexArray(VAO);

    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);

    // 顶点
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(0);
    // 颜色
    // glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(3 * sizeof(float)));
    // glEnableVertexAttribArray(1);
    // 纹理
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, 8 * sizeof(float), (void*)(6 * sizeof(float)));
    glEnableVertexAttribArray(2);

    unsigned int texture1;
    glGenTextures(1, &texture1); // 第一个参数都是数量
    glBindTexture(GL_TEXTURE_2D, texture1);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    int width, height, nrChannels;
    stbi_set_flip_vertically_on_load(true);
    unsigned char* data = stbi_load("container.jpg", &width, &height, &nrChannels, 0);
    if (data) {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, width, height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);
        glGenerateMipmap(GL_TEXTURE_2D);
    }
    else {
        std::cout << "Failed to load texture" << std::endl;
    }
    stbi_image_free(data);

    unsigned int texture2;
    glGenTextures(1, &texture2);
    glBindTexture(GL_TEXTURE_2D, texture2);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    data = stbi_load("awesomeface.png", &width, &height, &nrChannels, 0);
    if (data) {
        glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA, width, height, 0, GL_RGBA, GL_UNSIGNED_BYTE, data);
        glGenerateMipmap(GL_TEXTURE_2D);
    }
    stbi_image_free(data);

    ourShader.use();
    glUniform1i(glGetUniformLocation(ourShader.ID, "texture1"), 0);
    ourShader.setInt("texture2", 1);
    ourShader.setFloat("mix_nb", mix_nb);

    while (!glfwWindowShouldClose(window)) {
        process_input(window);
        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

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

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

        glBindVertexArray(VAO);

        glm::mat4 trans = glm::mat4(1.0f);
        trans = glm::translate(trans, glm::vec3(0.5f, -0.5f, 0.0f));
        trans = glm::rotate(trans, (float)glfwGetTime(), glm::vec3(0.0, 0.0, 1.0));
        ourShader.use();
        unsigned int transformLoc = glGetUniformLocation(ourShader.ID, "transform");
        glUniformMatrix4fv(transformLoc, 1, GL_FALSE, glm::value_ptr(trans));
        ourShader.setFloat("mix_nb", mix_nb);

        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);

        glm::mat4 trans1 = glm::mat4(1.0f);
        float scaleAmount = std::abs(static_cast<float>(sin(glfwGetTime())));
        trans1 = glm::translate(trans1, glm::vec3(-0.5f, 0.5f, 0.0f));
        trans1 = glm::scale(trans1, glm::vec3(scaleAmount, scaleAmount, scaleAmount));
        glUniformMatrix4fv(transformLoc, 1, GL_FALSE, glm::value_ptr(trans1));
        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
        glfwSwapBuffers(window);
        glfwPollEvents();
    }
    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteBuffers(1, &EBO);
    glfwTerminate();
    return 0;
}