OpenGL VBO 访问冲突

Question

过去几周我一直在学习 OpenGL，在阅读了 Swiftless tuts 和 Nehe 的 tuts 的一部分，以及其他有关法线、场景图、等等的文章之后，我决定创建某种“框架”，以让我更容易插入新学到的代码。因此，我决定创建一个场景图/渲染器组合，不是那么漂亮，也不是那么快（可能），但可以选择添加一个新的派生节点类来渲染我可能刚刚读过的新功能。因此，我在 interwebz 上查看有关如何实现一个基类并确定此基类的各种示例：

#pragma once

#ifndef NODE_H
#define NODE_H

#include <stdlib.h>
#include <stdio.h>      
#include <iostream>
#include <GL/glew.h>
#include <GL/freeglut.h>
#include <GL/glext.h>
#include <math.h>
#include <windows.h>
#include <list>
using namespace std;

class Node
{
public:
        Node(void);
        ~Node(void);

        //Node* parent;

        void addChild(Node* node);
        void removeChilds(Node* node);

        virtual void traverse();

        void kill();

protected:
        std::list<Node*> childs;
};

#endif

....我从中创建了该类：

#pragma once

#ifndef NODESPHERE_H
#define NODESPHERE_H

#include <stdlib.h>
#include <stdio.h>      
#include <iostream>
#include <GL/glew.h>
#include <GL/freeglut.h>
#include <GL/glext.h>
#include <math.h>
#include <windows.h>
#include "Various.h"
#include "Node.h"
class NodeSphere : public Node
{
public:
        NodeSphere(double R, double H, double K, double Z, const int space);
        ~NodeSphere(){delete this;}

        void traverse();

private:
        float out[3];
        int Radius;
        int vhVertexCount;
    Vert *vhVertices;
        Normal *vhNormals,*vhVNormals;
    TexCoord *vhTexCoords;
        unsigned int vhVBOVertices;
    unsigned int vhVBOTexCoords;
        unsigned int vhVBONormals;
    bool Init(void);
        bool Normals(const int nIndex);
        bool ReduceToUnit(void);
};

#endif

现在，我使用 freeglut 来处理窗口创建和循环：

    #include <windows.h>
#include <stdlib.h>
#include <stdio.h>      
#include <iostream>
#include <GL/glew.h>
#include <GL/freeglut.h>
#include <GL/glext.h>
#include <math.h>
#include "Scenegraph.h"
#include "View.h"
#include "Control.h"

#define WIDTH 800
#define HEIGHT 600


Scenegraph *bob;
View *myView;
Control *controler;

.................
.................

void main(int argc, char **argv)
{
        glewInit();
        glutInit(&argc, argv);
        glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB | GLUT_DEPTH);
        glutInitWindowSize(WIDTH,HEIGHT);
        glutInitWindowPosition(0,0);
        glutCreateWindow("Mediensoftware - Finale Übung");
        bob = new Scenegraph();
        myView = new View(WIDTH, HEIGHT, bob);
        controler = new Control(myView);
        glutDisplayFunc(display);
        glutIdleFunc(idle);
        glutReshapeFunc(resize);
        glutKeyboardFunc(keyboard);
        glutSpecialFunc(keyboard_s);

        glutMainLoop();
}

场景图“ bob”像这样处理节点的创建：

Scenegraph::Scenegraph()
{
        this->root = new Node();

        this->sun = new NodeSphere(3,0,0,0,10);
        this->sun_transform = new NodeTransform();
        this->sun_tex = new NodeTexture("sunmap.bmp");
        this->sun_mat = new NodeMaterial(1.0,0,1.0,0.7,0,1.0,1.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0);
        this->planet_earth = new NodeSphere(1,0,0,0,10);
        this->planet_earth_transform = new NodeTransform(6,0,0);
        this->planet_earth_tex = new NodeTexture("earthmap.bmp");
        this->planet_earth_mat = new NodeMaterial(1.0,0,1.0,0.7,0,1.0,1.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0);
        this->moon = new NodeSphere(0.3,0,0,0,10);
        this->moon_tex = new NodeTexture("moonmap.bmp");
        this->moon_transform = new NodeTransform(1.5,0,0);
        this->moon_mat = new NodeMaterial(1.0,0,1.0,0.7,0,1.0,1.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0);
        this->planet_venus = new NodeSphere(0.8,0,0,0,10);
        this->planet_venus_transform = new NodeTransform(3,0,0);
        this->planet_venus_tex = new NodeTexture("venusmap.bmp");
        this->planet_venus_mat = new NodeMaterial(1.0,0,1.0,0.7,0,1.0,1.0,1.0,0.0,0.0,0.0,0.0,0.0,0.0);
        this->planet_mars = new NodeSphere(0.6,0,0,0,10);
................................................................................................
        this->root->addChild(this->sun_transform);
        this->sun_transform->addChild(this->sun_mat);
        this->sun_mat->addChild(this->sun_tex);
        this->sun_tex->addChild(this->sun);
        this->sun->addChild(this->planet_venus_transform);
        this->planet_venus_transform->addChild(this->planet_venus_mat);
        this->planet_venus_mat->addChild(this->planet_venus_tex);
...................................................................................................
        }

编译器没有看到任何错误并执行代码，但它在这里收到访问冲突：

bool NodeSphere::Init(void){
        glGenBuffersARB(1, &vhVBOVertices); // DERP here
    glBindBufferARB(GL_ARRAY_BUFFER_ARB, this->vhVBOVertices);
    glBufferDataARB(GL_ARRAY_BUFFER_ARB, this->vhVertexCount * 3 * sizeof(float), this->vhVertices, GL_STATIC_DRAW_ARB);
        glGenBuffersARB(1, &vhVBONormals);
    glBindBufferARB(GL_ARRAY_BUFFER_ARB, this->vhVBONormals);
    glBufferDataARB(GL_ARRAY_BUFFER_ARB, this->vhVertexCount * 3 * sizeof(float), this->vhVNormals, GL_STATIC_DRAW_ARB);
    glGenBuffersARB(1, &vhVBOTexCoords);
        glBindBufferARB(GL_ARRAY_BUFFER_ARB, this->vhVBOTexCoords);
    glBufferDataARB(GL_ARRAY_BUFFER_ARB, this->vhVertexCount * 2 * sizeof(float), this->vhTexCoords, GL_STATIC_DRAW_ARB);

        delete [] vhVertices;
    vhVertices = NULL;
    delete [] vhTexCoords;
    vhTexCoords = NULL;
        delete [] vhNormals;
        vhNormals = NULL;
        delete [] vhVNormals;
        vhVNormals = NULL;
        return true;
}

扩展在 View::initExtensions() 中调用，场景图的 init 是在窗口创建之后完成，所以......我很确定它与指针有关......

在以前的程序中，我使用完全相同的代码来创建VBO并且它有效。唯一的区别是这里使用的代码是在 Node* 中使用的，而之前的代码只是在 Node 中使用（没有指针）。但无论如何，我要检查一下 glew 是否启动良好。 至于我使用的显卡，在笔记本电脑上我有一个蹩脚的 Intel 集成卡，它应该支持 OpenGL 1.5，但甚至没有 GLSL，而在 PC 上，我有 6850。问题是，由于教师和其他方面的原因，我经常在笔记本电脑上工作。

但无论如何，创建 VBO 的代码可以工作，我的意思是，它可以用于以下用途：

#include <stdlib.h> 
#include <windows.h>
#include <iostream>
#include <stdio.h>
#include <GL/glew.h>
#include <GL/gl.h>                                                              // Header File For The OpenGL32 Library
#include <GL/glu.h>                                                             // Header File For The GLu32 Library
#include <GL/glext.h>
#include <math.h>

#define PI 3.14159265f


class Vert{
public:
        float x;
        float y;
    float z;
};

class Normal{
public:
        float x;
        float y;
    float z;
};

class TexCoord{
    public:
                float u;
                float v;
};

class Scenegraph {
private:
        float out[3];
        int Radius;
        GLuint tID[2];
        int vhVertexCount;
    Vert *vhVertices;
        Normal *vhNormals,*vhVNormals;
    TexCoord *vhTexCoords;
        unsigned int vhVBOVertices;
    unsigned int vhVBOTexCoords;
        unsigned int vhVBONormals;
    bool Init(void);
        bool Normals(const int nIndex);
        bool ReduceToUnit(void);


public:
        bool Create(double R, double H, double K, double Z, const int space);

        void Render();

};

它与 NodeSphere 相同，只是它是静态声明的。提前致谢。

Answer 1

最有可能的是，发生错误的原因是当您尝试调用 init() 时，NodeSphere 不存在（或不再有效）。

您可能应该将资源初始化代码移至构造函数中（这通常是它们的用途），除非您稍后需要它发生。 VBO 与对象具有相似的生命周期是有意义的，因此在 ctor/dtor 中创建和销毁它们应该可以工作，并节省显式初始化的复杂性。