几何着色器，绘制4个房子

#define GLEW_STATIC
#include <GL/glew.h>
#include <GLFW/glfw3.h>

#include "Shader.h"
#include <fstream>
#include <iostream>
using namespace std;

void framebuffer_size_callback(GLFWwindow* window, int width, int height);
void processInput(GLFWwindow *window);


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


// timing
float deltaTime = 0.0f;
float lastFrame = 0.0f;

int main()
{
    // glfw: initialize and configure
    // ------------------------------
    glfwInit();
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 3);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 3);
    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);

#ifdef __APPLE__
    glfwWindowHint(GLFW_OPENGL_FORWARD_COMPAT, GL_TRUE); // uncomment this statement to fix compilation on OS X
#endif

                                                         // glfw window creation
                                                         // --------------------
    GLFWwindow* window = glfwCreateWindow(SCR_WIDTH, SCR_HEIGHT, "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);

    
    glewExperimental = GL_TRUE;
    if (glewInit() != GLEW_OK)
    {
        cout << "Failed to initialize GLEW!" << endl;
        return -1;
    }
    // configure global opengl state
    // -----------------------------

    Shader shader("E:\C++\High_level_GLSL\2.2ver1.txt", "E:\C++\High_level_GLSL\2.2frag1.txt",
        "E:\C++\High_level_GLSL\2.2geo1.txt");

    

    float points[] = {
        -0.5f, 0.5f, 1.0f, 0.0f, 0.0f,
        0.5f, 0.5f, 0.0f, 1.0f, 0.0f,
        0.5f, -0.5f, 0.0f, 0.0f, 1.0f,
        -0.5f, -0.5f, 1.0f, 1.0f, 0.0f
    };

    unsigned int VAO, VBO;
    glGenVertexArrays(1, &VAO);
    glGenBuffers(1, &VBO);
    glBindVertexArray(VAO);
    glBindBuffer(GL_ARRAY_BUFFER, VBO);
    glBufferData(GL_ARRAY_BUFFER, sizeof(points), &points, GL_STATIC_DRAW);
    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)0);
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 5 * sizeof(float), (void*)(2 * sizeof(float)));
    glBindVertexArray(0);

    while (!glfwWindowShouldClose(window))
    {
        processInput(window);
        
        glClearColor(0.1f, 0.1f, 0.1f, 1.0f);
        glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

        shader.use();
        glBindVertexArray(VAO);
        glDrawArrays(GL_POINTS, 0, 4);

        glfwSwapBuffers(window);
        glfwPollEvents();
    }

    glDeleteVertexArrays(1, &VAO);
    glDeleteBuffers(1, &VBO);
    
}

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

    // glfw: whenever the window size changed (by OS or user resize) this callback function executes
    // ---------------------------------------------------------------------------------------------
    void framebuffer_size_callback(GLFWwindow* window, int width, int height)
    {
        // make sure the viewport matches the new window dimensions; note that width and 
        // height will be significantly larger than specified on retina displays.
        glViewport(0, 0, width, height);
    }

    

学习网址：https://learnopengl-cn.github.io/04%20Advanced%20OpenGL/09%20Geometry%20Shader/#_4