Question

如果我将GL函数移动到另一个类，我的GLEW MX会崩溃...说Point类包含我所有的点和所需的VBO函数。

它基本上在第一次GL调用时崩溃，对我来说意味着当GL函数在点类中被调用时，GLEWContext点在某种程度上为空。

我对GLEW MX

缺少什么基础

如果所有东西都在main中，那么它可以正常工作，我可以渲染出一个简单的三角形。

的main.cpp

#include <GL/glew.h>
#include <GLFW/glfw3.h>
#include "Global_variables.h"
#include <thread>
#include <stdlib.h>
#include <stdio.h>

static void error_callback(int error, const char* description)
{
    fputs(description, stderr);
}
static void key_callback(GLFWwindow* window, int key, int scancode, int action, int mods)
{
    if (key == GLFW_KEY_ESCAPE && action == GLFW_PRESS)
        glfwSetWindowShouldClose(window, GL_TRUE);
}
int main(void)
{
    GLFWwindow* window;
    glfwSetErrorCallback(error_callback);
    if (!glfwInit())
        exit(EXIT_FAILURE);
    window = glfwCreateWindow(640, 480, "Simple example", NULL, NULL);
    if (!window)
    {
        glfwTerminate();
        exit(EXIT_FAILURE);
    }
    std::thread::id thread = std::this_thread::get_id();
    glfwMakeContextCurrent(window);

    myGLEWCONTEXT = new GLEWContext();
    GLEWContext* test = glewGetContext();

    Points mPoints = Points();
    mPoints.AddPoint(Point(glm::vec3(-1.0f, -1.0f, 0.0f), glm::vec2(0, 0), glm::vec3(0, 1, 0), glm::vec4(0.1, 0.1, 0.1, 1)));
    mPoints.AddPoint(Point(glm::vec3(1.0f, -1.0f, 0.0f), glm::vec2(0, 0), glm::vec3(0, 1, 0), glm::vec4(0.1, 0.1, 0.1, 1)));

    mPoints.setGLMode(GL_TRIANGLES);
    mPoints.create();
}

Global_variables.h

static GLEWContext* myGLEWCONTEXT;


static GLEWContext* glewGetContext()
{
    std::thread::id thread = std::this_thread::get_id();

    return myGLEWCONTEXT;
}

Points.h

class Points 
{
public:

    //Pack Vertex
    struct PackedVertex{
        glm::vec3 position;
        glm::vec2 uv;
        glm::vec3 normal;
        glm::vec4 color;
        bool operator<(const PackedVertex that) const{
            return memcmp((void*)this, (void*)&that, sizeof(PackedVertex))>0;
        };
    };

    Points();
    Points(int number, glm::vec3 upperleftbound, glm::vec3 lowerrightbound);
    Points(std::vector<Point> & passedinpoints);
    ~Points(void);


    void Print();
    void Render();
    bool create();

.....

更新：-----------------尝试了Singlton

#include <GL/glew.h>

#pragma once
class glewSinglton
{


public:
    glewSinglton (const glewSinglton&) = delete;
    glewSinglton& operator=(const glewSinglton&) = delete;


    GLEWContext* myGLEWCONTEXT;

    GLEWContext* get_value()
    {
        return myGLEWCONTEXT;
    }
    void set_value(GLEWContext* v)
    {
        myGLEWCONTEXT = v;
    }
    static glewSinglton *instance()
    {
        if (!s_instance){
            s_instance = new glewSinglton;
            GLEWContext* myGLEWCONTEXT = new  GLEWContext();
        }
        return s_instance;
    }

    GLEWContext* glewGetContext()
    {
        return myGLEWCONTEXT;
    }


    static glewSinglton *s_instance;

private:
    glewSinglton();
    ~glewSinglton();

};

#endif

但是当我提出

时，这只会给我带来大量的错误

#include "glewSinglton.h"

glewSinglton *mInstance = glewSinglton::instance();

Answer 1

正如评论中所解释的，这可能是您需要做的：

static GLEWContext* glewGetContext()
{
    static GLEWContext* myGLEWCONTEXT = NULL;

    std::thread::id thread = std::this_thread::get_id();

    // Initialize on first use
    if (! myGLEWCONTEXT)
        myGLEWCONTEXT = new GLEWContext();      

    return myGLEWCONTEXT;
}

GLEW MX在尝试渲染时崩溃

1 个答案:

正如评论中所解释的，这可能是您需要做的：