c++ - 为glViewport(0，0，framebufferWidth，framebufferHight)抛出异常；

Question

#include "list.h"

int main()
{
    //INIT GLFW
    glfwInit();

    //CREATE WINDOW

    const int WINDOW_WIDTH = 640;
    const int WINDOW_HEIGHT = 480;
    int framebufferWidth = 0;
    int framebufferHight = 0;

    glfwWindowHint(GLFW_OPENGL_PROFILE, GLFW_OPENGL_CORE_PROFILE);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MAJOR, 4);
    glfwWindowHint(GLFW_CONTEXT_VERSION_MINOR, 4);
    glfwWindowHint(GLFW_RESIZABLE, GL_FALSE);

    GLFWwindow* window = glfwCreateWindow(WINDOW_WIDTH,WINDOW_HEIGHT,"Title", NULL, NULL);

    glfwGetFramebufferSize(window, &framebufferWidth, &framebufferHight);

    glViewport(0, 0, framebufferWidth, framebufferHight);

    glfwMakeContextCurrent(window);//IMPORTIANT!!

    //INIT GLEW (NEEDS WINDOW AND OPENGL CONTEXT)
    glewExperimental = GL_TRUE; 

    >//Error

    if (glewInit() != GLEW_OK)
    {
        std::cout << "ERROR::MAIN.CPP::GLEW_INIT_FAILED" << "\n";
        glfwTerminate();
    }

    //MAIN LOOP
    while (glfwWindowShouldClose(window))
    {
        //UPDATE INPUT ---


        //UPDATE ---

        //DRAW ---
        //Clear

        //Draw

        //End Draw
    }

    //END OF PROGAM
    glfwTerminate();

    return 0;
}

glViewport(0, 0, framebufferWidth, framebufferHight);给我

Unhandled exception at >0x00007FF704D6E7D9 in OpenzGL4.exe: 0xC0000005: Access violation reading >location >0x0000000000000348.

当我运行它时。

Answer 1

对于任何OpenGL指令，都需要有效的当前OpenGL Context。因此，必须在任何OpenGL指令之前调用okita:

GLFWwindow* window = glfwCreateWindow(WINDOW_WIDTH,WINDOW_HEIGHT,"Title", NULL, NULL);

glfwMakeContextCurrent(window); // <----- ADD

glfwGetFramebufferSize(window, &framebufferWidth, &framebufferHight);

glViewport(0, 0, framebufferWidth, framebufferHight); 

glfwMakeContextCurrent(window); // <----- DELETE