大小太大时 VBO + glBufferData 崩溃

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【中文标题】大小太大时 VBO + glBufferData 崩溃【英文标题】：VBO + glBufferData crash when size too high 【发布时间】：2012-03-26 15:26:52 【问题描述】：

我正在尝试运行一个简单的 VBO。但是当我打电话时

glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex)*vertexcount, vertices, GL_STATIC_DRAW);

它只是崩溃，但只有当顶点数超过 1531 时。是的，“顶点”数组存储，或者更确切地说，分配了足够的空间，用于超过 1531 个元素。 这是我的顶点结构：

typedef struct
    float x, y, z;
    float nx, ny, nz;
    float u, v;
Vertex, vertex;

所以它应该是 32 字节。 32 字节 * 1531 = 48992 字节 = 48kb。

但是对于普通的 VBO 来说，48kb 似乎不会太高？我不明白发生了什么。

编辑：

Windows Xp 32 位服务包 3

英伟达 GeForce 9800GT 1024mb

编辑2： 我的完整代码的简短版本： （有趣的部分在底部）

#include <windows.h>
#include <glew.h>
#include <wglew.h>
#include <gl3.h>
#include <gl/glu.h>
#define BUFFER_OFFSET(i) ((char *)NULL + (i))

typedef struct
    float x, y, z;
float nx, ny, nz;
float u, v;
Vertex, vertex;

typedef struct
    int first, second, third;
VertexIndex, vertexindex, vindex, Vindex;

typedef struct
    unsigned int vao;
    unsigned int vertexcount, indexcount;
Mesh, mesh;

typedef struct
    HWND hwnd;
    HDC hdc;
    HGLRC hrc;
GLWindow, Window, window;

void WindowShenanigans(Window *w, HINSTANCE *hinstance, WNDPROC WindowProc)

    HWND tmp_hwnd;
    WNDCLASS wndclass;

    ZeroMemory(&wndclass, sizeof(WNDCLASS));
    wndclass.style  = CS_HREDRAW | CS_VREDRAW | CS_OWNDC | CS_GLOBALCLASS;
    wndclass.cbClsExtra = 0;    
    wndclass.cbWndExtra = 0;
    wndclass.lpszMenuName = 0;
    wndclass.hIcon = 0;
    wndclass.hInstance  = *hinstance;
    wndclass.lpszClassName = "glclass";
    wndclass.hbrBackground = (HBRUSH)(COLOR_APPWORKSPACE);
    wndclass.hCursor = LoadCursor(0, IDC_ARROW);
    wndclass.lpfnWndProc = WindowProc;

    if(RegisterClass(&wndclass) == 0)
    
        return;
    

    ShowCursor(TRUE);

    tmp_hwnd = CreateWindowA  ( "glclass",
                            "bla",
                            WS_BORDER | WS_CAPTION | WS_SYSMENU,
                            0, 0,
                            600,
                            800,
                            HWND_DESKTOP,
                            NULL,
                            hinstance,
                            NULL);

    w->hwnd = tmp_hwnd;

    unsigned int PixelFormat;
    PIXELFORMATDESCRIPTOR pfd;

    pfd.nSize = sizeof(PIXELFORMATDESCRIPTOR);
    pfd.nVersion = 1;
    pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
    pfd.iPixelType = PFD_TYPE_RGBA;
    pfd.cColorBits = 32;
    pfd.cDepthBits = 16;
    pfd.cStencilBits = 32;
    pfd.iLayerType = PFD_MAIN_PLANE;

    w->hdc = GetDC(w->hwnd);

    PixelFormat = ChoosePixelFormat(w->hdc, &pfd);
    SetPixelFormat(w->hdc, PixelFormat, &pfd);

    int attrib[] =
    
            WGL_CONTEXT_MAJOR_VERSION_ARB, 3,
            WGL_CONTEXT_MINOR_VERSION_ARB, 2,
            WGL_CONTEXT_FLAGS_ARB, WGL_CONTEXT_FORWARD_COMPATIBLE_BIT_ARB,
            0
    ; //OpenGL Context

    HGLRC tmphrc = wglCreateContext(w->hdc);

    wglMakeCurrent (w->hdc, tmphrc);

    PFNWGLCREATEBUFFERREGIONARBPROC wglCreateContextAttribsARB =      (PFNWGLCREATEBUFFERREGIONARBPROC)wglGetProcAddress( "wglCreateContextAttribsARB" );
    w->hrc = (HGLRC)wglCreateContextAttribsARB( w->hdc, 0, (UINT)attrib ) ;

    ShowWindow(w->hwnd, SW_SHOW);
    UpdateWindow(w->hwnd);


LRESULT CALLBACK WindowProc(HWND hwnd, UINT msg, WPARAM wparam, LPARAM lparam)

    switch(msg)
    
        case WM_DESTROY:
        
            PostQuitMessage(0);
            return 0;
        
        case WM_CLOSE:
        
            PostQuitMessage(0);
            return 0;
        
        case WM_CREATE:
        
        
        break;
        case WM_SIZE:
        
        
        break;

        case WM_PAINT:
        
        
        break;
    
    return DefWindowProc(hwnd, msg, wparam, lparam);


BOOL ProcessMessage(MSG *msg)

    if(GetMessage(msg, NULL, 0, 0) != 0)
    
        TranslateMessage(msg);
        DispatchMessage(msg);
        return TRUE;
    
    else
    
        return FALSE;
    


///////////////////////////////////////////////////////////////////////////////////////////
void DataUpload(Mesh *m, Vindex *indices, Vertex *vertices)

    unsigned int vbo, index_vbo;

    glGenVertexArrays(1, &m->vao);
    glBindVertexArray(m->vao);

    glGenBuffers(1, &index_vbo);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, index_vbo);
    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(unsigned int)*3500, indices, GL_STATIC_DRAW);

    glGenBuffers(1, &vbo);
    glBindBuffer(GL_ARRAY_BUFFER, vbo);
    //  MessageBox(HWND_DESKTOP, "3..2..1..", "", MB_OK);
    glBufferData(GL_ARRAY_BUFFER, sizeof(Vertex)*3500, vertices, GL_STATIC_DRAW);
    //  MessageBox(HWND_DESKTOP, "YEA", "", MB_OK);

    glEnableVertexAttribArray(0);
    glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(0));
    glEnableVertexAttribArray(1);
    glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(sizeof(float)*3));
    glEnableVertexAttribArray(2);
    glVertexAttribPointer(2, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), BUFFER_OFFSET(sizeof(float)*6));
    glBindVertexArray(0);


void MeshGenerate(Mesh *m, float x, float y, float z)

        int i;
        Vertex *vertices;
        Vindex *indices;
        m->vertexcount = 3500;
        m->indexcount = 3500;
        vertices = malloc(3500*sizeof(vertex));
        indices = malloc(3500*sizeof(vindex));

        for(i = 0; i<3500; i++)
        
            vertices[i].x = 1.0f;
            vertices[i].y = 1.0f;
            vertices[i].z = 1.0f;
            vertices[i].nx = 1.0f;
            vertices[i].ny = 1.0f;
            vertices[i].nz = 1.0f;
            vertices[i].u = 1.0f;
            vertices[i].v = 1.0f;
        
        for(i = 0; i<3500; i++)
        
            indices[i].first = 1;
            indices[i].second = 1;
            indices[i].third = 1;
        
        DataUpload(m, vertices, indices);
        return;


int WINAPI WinMain(HINSTANCE hinstance, HINSTANCE hprevinstance, LPSTR lpcmdline, int nshowcmd)

    MSG msg;
    BOOL isActive = 1;
    window w;
    WindowShenanigans(&w, &hinstance, WindowProc);

    glewInit();

    Mesh m;
    MeshGenerate(&m, 1.0f, 1.0f, 1.0f);

    while(isActive == 1)
    
        SwapBuffers(w.hdc);
        isActive = ProcessMessage(&msg);
    

    return msg.wParam;

////////////////////////////////////////////////////////////////////////////////

【问题讨论】：

它只是一个好的旧段错误吗？ 发布SSCCE。 看看分配相同的内存是否有帮助？ 多个 MB 的 VBO 在我的机器上工作正常。我怀疑大小只是碰巧暴露了一些其他错误。 什么平台？我认为当 GPU 驱动程序尝试读取存储在数组“顶点”中的数据时，它会遇到某种障碍。没有更多细节很难说。 【参考方案1】： 
ogl.c: In function `MeshGenerate':

ogl.c:200: 警告：从不兼容的指针类型传递 DataUpload' from incompatible pointer type ogl.c:200: warning: passing arg 3 ofDataUpload' 的 arg 2

我没有安装 glew，所以我无法让示例正常工作。但这绝对是个问题。

DataUpload(m, vertices, indices);

应该是

DataUpload(m, indices, vertices);

【讨论】：

是的，我没有注意到 <_>

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