OpenGL_6:用两个VBO和VAO分别画2个三角形

#include <stdio.h>#include <GLAD/glad.h>#include <GLFW/glfw3.h>const char *vertexShaderSource =        "#version 330 core\n"                "layout (location = 0) in vec3 aPos;\n"                "void main(){\n"                "gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0f);\n"                "}\n\0";const char *fragmentShaderSource =        "#version 330 core\n"                "out vec4 FragColor;\n"                "void main(){\n"                "FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"                "}\n\0";void processInput(GLFWwindow *glfWwindow);void framebuffer_size_callback(GLFWwindow* glfWwindow, int width, int height);int main() {    glfwInit();    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);    GLFWwindow *glfWwindow = glfwCreateWindow(800, 600, "Square", NULL, NULL);    if (NULL == glfWwindow){        printf("Failed to create window \n");        glfwTerminate();        return -1;    }    glfwMakeContextCurrent(glfWwindow);    glfwSetFramebufferSizeCallback(glfWwindow, framebuffer_size_callback);    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress)){        printf("Failed to initialize GLAD\n");    }    unsigned int vertexShader = glCreateShader(GL_VERTEX_SHADER);    glShaderSource(vertexShader, 1, &vertexShaderSource, NULL);    glCompileShader(vertexShader);    int success;    char infoLog[512];    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);    if (!success){        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);        printf("Failed to compile vertexShader:%s \n", infoLog);    }    unsigned int fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);    glShaderSource(fragmentShader, 1, &fragmentShaderSource, NULL);    glCompileShader(fragmentShader);    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);    if (!success){        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);        printf("Failed to compile fragmentShader:%s \n", infoLog);    }    unsigned int shaderProgram = glCreateProgram();    glAttachShader(shaderProgram, vertexShader);    glAttachShader(shaderProgram, fragmentShader);    glLinkProgram(shaderProgram);    glGetShaderiv(shaderProgram, GL_LINK_STATUS, &success);    if (!success){        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);        printf("Failed to link shaderProgram:%s \n", infoLog);    }    glDeleteShader(vertexShader);    glDeleteShader(fragmentShader);    float vertices_1[] = {            // first triangle            -0.9f, -0.5f, 0.0f,  // left            -0.0f, -0.5f, 0.0f,  // right            -0.45f, 0.5f, 0.0f  // top    };    float vertices_2[] = {            // second triangle            0.0f, -0.5f, 0.0f,  // left            0.9f, -0.5f, 0.0f,  // right            0.45f, 0.5f, 0.0f   // top    };    unsigned int VBO[2], VAO[2];    glGenVertexArrays(2, VAO);    glGenBuffers(2, VBO);    glBindVertexArray(VAO[0]);    glBindBuffer(GL_ARRAY_BUFFER, VBO[0]);    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices_1), vertices_1, GL_STATIC_DRAW);    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);    glEnableVertexAttribArray(0);//    glBindVertexArray(0);  //no need to unbind at all as we directly bind a different VAO the next few lines//    glBindBuffer(GL_ARRAY_BUFFER, 0);    glBindVertexArray(VAO[1]);    glBindBuffer(GL_ARRAY_BUFFER, VBO[1]);    glBufferData(GL_ARRAY_BUFFER, sizeof(vertices_2), vertices_2, GL_STATIC_DRAW);    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);    glEnableVertexAttribArray(0);    // glBindVertexArray(0); // not really necessary as well, but beware of calls that could affect VAOs while this one is bound (like binding element buffer objects, or enabling/disabling vertex attributes)//    glBindBuffer(GL_ARRAY_BUFFER, 0);    /**     * 当目标是GL_ELEMENT_ARRAY_BUFFER的时候，VAO会储存glBindBuffer的函数调用。     * 这也意味着它也会储存解绑调用，所以确保你没有在解绑VAO之前解绑索引数组缓冲，     * 否则它就没有这个EBO配置了。     * */    //glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);    //glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);    while (!glfwWindowShouldClose(glfWwindow)){        processInput(glfWwindow);        glClearColor(0.2f, 0.3f, 0.3f, 1.0f);        glClear(GL_COLOR_BUFFER_BIT);        glUseProgram(shaderProgram);        glBindVertexArray(VAO[0]);        glDrawArrays(GL_TRIANGLES, 0, 3);        glBindVertexArray(VAO[1]);        glDrawArrays(GL_TRIANGLES, 0, 3);//        glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);        glfwSwapBuffers(glfWwindow);        glfwPollEvents();    }    glDeleteVertexArrays(2, VAO);    glDeleteBuffers(2, VBO);    glfwTerminate();    return 0;}void processInput(GLFWwindow *glfWwindow){    if (glfwGetKey(glfWwindow, GLFW_KEY_ESCAPE))        glfwSetWindowShouldClose(glfWwindow, GLFW_TRUE);}void framebuffer_size_callback(GLFWwindow* glfWwindow, int width, int height){    glViewport(0, 0, width, height);}

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