opengl日记8-opengl创建三角形

文章目录

环境
直接上代码
一点小总结
参考

环境

系统：ubuntu20.04
opengl版本：4.6
glfw版本：3.3
glad版本：4.6
cmake版本：3.16.3
gcc版本：10.3.0

直接上代码

CMakeLists.txt

cmake_minimum_required(VERSION 2.8)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 11)
project(helloTriangle)
find_package(glfw3 REQUIRED)
file(GLOB project_file glad.c main.cpp)
add_executable(${PROJECT_NAME} ${project_file})

target_link_libraries(${PROJECT_NAME}
    -lglfw
    -lGL
    -lm
    -lXrandr
    -lX11
    -lpthread
    -ldl
)

main.cpp

#include <glad/glad.h>
#include <GLFW/glfw3.h>

#include <iostream>

const unsigned int SCR_WIDTH = 800;
const unsigned int SCR_HEIGHT = 600;

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

const char *fragmentShaderSource = "#version 330 core\n"
        "out vec4 FragColor;\n"
        "void main()\n"
        "{\n"
        "    FragColor = vec4(1.0f, 0.5f, 0.2f, 1.0f);\n"
        "}\0";

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

    //创建一个窗口
    GLFWwindow *window = glfwCreateWindow(SCR_WIDTH,SCR_HEIGHT,"hello Triangle",NULL,NULL);
    if (window == NULL){
        std::cout << "Failed to create GLFW window" << std::endl;
        glfwTerminate();
        return -1;
    }

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

    //顶点着色器代码
    unsigned int vertexShader;
    vertexShader = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertexShader,1,&vertexShaderSource,NULL);
    glCompileShader(vertexShader);
    // check for shader compile errors
    int success;
    char infoLog[512];
    glGetShaderiv(vertexShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(vertexShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::VERTEX::COMPILATION_FAILED\n" << infoLog << std::endl;
    }

    //片段着色器
    unsigned int fragmentShader;
    fragmentShader = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragmentShader,1,&fragmentShaderSource,NULL);
    glCompileShader(fragmentShader);
    // check for shader compile errors
    glGetShaderiv(fragmentShader, GL_COMPILE_STATUS, &success);
    if (!success)
    {
        glGetShaderInfoLog(fragmentShader, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::FRAGMENT::COMPILATION_FAILED\n" << infoLog << std::endl;
    }

    //着色器程序
    unsigned int shaderProgram;
    shaderProgram = glCreateProgram();
    glAttachShader(shaderProgram,vertexShader);
    glAttachShader(shaderProgram,fragmentShader);
    glLinkProgram(shaderProgram);
    // check for linking errors
    glGetProgramiv(shaderProgram, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(shaderProgram, 512, NULL, infoLog);
        std::cout << "ERROR::SHADER::PROGRAM::LINKING_FAILED\n" << infoLog << std::endl;
    }

    glDeleteShader(vertexShader);
    glDeleteShader(fragmentShader);

    //输入顶点
    float vertices[] = {
        -0.5f,-0.5f,0.0f,
        0.5f,-0.5f,0.0f,
        0.0f,0.5f,0.0f
    };

    //顶点数组对象
    unsigned int VAO;
    glGenVertexArrays(1,&VAO);
    glBindVertexArray(VAO);

    //顶点缓存对象
    unsigned int VBO;
    glGenBuffers(1,&VBO);

    glBindBuffer(GL_ARRAY_BUFFER,VBO);
    glBufferData(GL_ARRAY_BUFFER,sizeof(vertices),vertices,GL_STATIC_DRAW);

    //链接顶点属性
    glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,3*sizeof(float),(void*)0);
    glEnableVertexAttribArray(0);
    
    glBindBuffer(GL_ARRAY_BUFFER, 0); 
    glBindVertexArray(0);

    while(!glfwWindowShouldClose(window)){

        //激活着色器程序
        glUseProgram(shaderProgram);
        glBindVertexArray(VAO);
        glDrawArrays(GL_TRIANGLES,0,3);
        glfwSwapBuffers(window);
        // glfwPollEvents();
    }

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

}