OpenGL之画三角形

OpenGL之画三角形

openGL具有很多扩展，方便进行操作

确保已经安装必要的库，进行正确的链接

glut

#include 

void display()
{
    glClear(GL_COLOR_BUFFER_BIT);
    
    glBegin(GL_TRIANGLES);
    glColor3f(1.0, 0.0, 0.0); // 设置颜色为红色
    glVertex2f(0.0, 0.5); // 第一个顶点
    glVertex2f(-0.5, -0.5); // 第二个顶点
    glVertex2f(0.5, -0.5); // 第三个顶点
    glEnd();
    
    glFlush();
}

int main(int argc, char** argv)
{
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(400, 400);
    glutCreateWindow("Red Triangle");
    glClearColor(1.0, 1.0, 1.0, 1.0); // 设置背景色为白色
    glutDisplayFunc(display);
    glutMainLoop();
    
    return 0;
}

编译命令：

sudo g++ glutTest.cpp -lGL -lglut

glad

#include 
#include 
#include 

void framebuffer_size_callback(GLFWwindow* window, int width, int height)
{
    glViewport(0, 0, width, height);
}

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

const char* vertexShaderSource = R"(
    #version 330 core
    layout (location = 0) in vec3 aPos;
    void main()
    {
        gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
    }
)";

const char* fragmentShaderSource = R"(
    #version 330 core
    out vec4 FragColor;
    void main()
    {
        FragColor = vec4(1.0f, 0.0f, 0.0f, 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);

    GLFWwindow* window = glfwCreateWindow(800, 600, "Red Triangle", nullptr, nullptr);
    if (window == nullptr)
    {
        std::cerr << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }

    glfwMakeContextCurrent(window);

    if (!gladLoadGLLoader((GLADloadproc)glfwGetProcAddress))
    {
        std::cerr << "Failed to initialize GLAD" << std::endl;
        return -1;
    }

    glViewport(0, 0, 800, 600);
    glfwSetFramebufferSizeCallback(window, framebuffer_size_callback);

    unsigned int vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader, 1, &vertexShaderSource, nullptr);
    glCompileShader(vertexShader);

    unsigned int fragmentShader;
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader, 1, &fragmentShaderSource, nullptr);
    glCompileShader(fragmentShader);

    unsigned int shaderProgram;
    shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram, vertexShader);
    glAttachShader(shaderProgram, fragmentShader);
    glLinkProgram(shaderProgram);

    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    float vertices[] = {
        -0.5f, -0.5f, 0.0f,
        0.5f, -0.5f, 0.0f,
        0.0f, 0.5f, 0.0f
    };

    unsigned int VAO, VBO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    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(float), (void*)0);
    glEnableVertexAttribArray(0);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);

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

        glClearColor(1.0f, 1.0f, 1.0f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT);

        glUseProgram(shaderProgram);
        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES, 0, 3);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    glDeleteProgram(shaderProgram);

    glfwTerminate();
    return 0;
}

编译命令

sudo g++ glutTest.cpp /home/long/work/lrn_2/dependencies/glad/src/glad.c -I /home/long/work/lrn_2/dependencies/glad/include/ -I /home/long/work/lrn_2/dependencies/glfw/include/  -ldl -lglfw3  -lpthread