小白的OpenGL3.3自学之路(4)OpenGL3.3之EBO跟

最新推荐文章于 2025-06-06 17:59:31 发布

hrq0106

最新推荐文章于 2025-06-06 17:59:31 发布

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CC 4.0 BY-SA版权

分类专栏： OpenGL 文章标签： OpenGL

本文链接：https://blog.youkuaiyun.com/hrq3333/article/details/82800769

本文介绍了OpenGL3.3中EBO（Element Buffer Object）的作用，通过实例展示了如何使用EBO避免绘制时的顶点重复，从而优化效率。同时，文章详细讲解了着色器的写法，包括数据类型、向量和矩阵的概念，以及存储限定符、输入输出变量的使用。最后，阐述了uniform变量在GPU和CPU间传递数据的角色，以及如何为uniform设置颜色值。

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已经有了VAO跟VBO，那还需要EBO干什么。别急，我们画一个矩形来实战一下，代码如下：

#include <glad/glad.h>
#include <iostream>
using namespace std;

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"
"}\n\0";

int main()
{
    glfwInit();
    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "LearnOpenGL", NULL, NULL);

    glfwMakeContextCurrent(window);
    gladLoadGLLoader((GLADloadproc)glfwGetProcAddress);
    float vertices[] = {
        -0.5f,-0.5f,0.0f,
        0.5f,-0.5f,0.0f,
        0.5f,0.5f,0.0f,

        -0.5f, -0.5f, 0.0f,
        0.5f, 0.5f, 0.0f,
        -0.5f, 0.5f, 0.0f,
    };
    unsigned int VBO, VAO;
    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);

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

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

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

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