C++ OpenGL glTexImage2D访问冲突

Question

我正在使用OpenGL(freeglut和glew)编写应用程序.

我也想要纹理,所以我对Bitmap文件格式进行了一些研究,并为主标题写了一个结构,为DIB标题写了另一个结构(info标题).

然后我开始编写加载器.它会自动将纹理绑定到OpenGL.这是功能:

static unsigned int ReadInteger(FILE *fp)
{
    int a, b, c, d;

    // Integer is 4 bytes long.
    a = getc(fp);  
    b = getc(fp);  
    c = getc(fp);  
    d = getc(fp);

    // Convert the 4 bytes to an integer.
    return ((unsigned int) a) + (((unsigned int) b) << 8) +
           (((unsigned int) c) << 16) + (((unsigned int) d) << 24);
}

static unsigned int ReadShort(FILE *fp)
{
    int a, b;

    // Short is 2 bytes long.
    a = getc(fp);  
    b = getc(fp);

    // Convert the 2 bytes to a short (int16).
    return ((unsigned int) a) + (((unsigned int) b) << 8);
}

    GLuint LoadBMP(const char* filename)
{
    FILE* file;

    // Check if a file name was provided.
    if (!filename)
        return 0;

    // Try to open file.
    fopen_s(&file, filename, "rb");

    // Return if the file could not be open.
    if (!file)
    {
        cout << "Warning: Could not find texture '" << filename << "'." << endl;
        return 0;
    }

    // Read signature.
    unsigned char signature[2];
    fread(&signature, 2, 1, file);

    // Use signature to identify a valid bitmap.
    if (signature[0] != BMPSignature[0] || signature[1] != BMPSignature[1])
    {
        fclose(file);
        return 0;
    }

    // Read width and height.
    unsigned long width, height;
    fseek(file, 16, SEEK_CUR); // After the signature we have 16bytes until the width.
    width = ReadInteger(file);
    height = ReadInteger(file);

    // Calculate data size (we'll only support 24bpp).
    unsigned long dataSize;
    dataSize = width * height * 3;

    // Make sure planes is 1.
    if (ReadShort(file) != 1)
    {
        cout << "Error: Could not load texture '" << filename << "' (planes is not 1)." << endl;
        return 0;
    }

    // Make sure bpp is 24.
    if (ReadShort(file) != 24)
    {
        cout << "Error: Could not load texture '" << filename << "' (bits per pixel is not 24)." << endl;
        return 0;
    }

    // Move pointer to beggining of data. (after the bpp we have 24 bytes until the data)
    fseek(file, 24, SEEK_CUR);

    // Allocate memory and read the image data.
    unsigned char* data = new unsigned char[dataSize];

    if (!data)
    {
        fclose(file);
        cout << "Warning: Could not allocate memory to store data of '" << filename << "'." << endl;
        return 0;
    }

    fread(data, dataSize, 1, file);

    if (data == NULL)
    {
        fclose(file);
        cout << "Warning: Could no load data from '" << filename << "'." << endl;
        return 0;
    }

    // Close the file.
    fclose(file);

    // Create the texture.
    GLuint texture;
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR); //NEAREST);
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_MODULATE); 

    gluBuild2DMipmaps(GL_TEXTURE_2D, GL_RGB, width, height, GL_BGR_EXT, GL_UNSIGNED_BYTE, data);

    return texture;
}

我知道位图的数据是正确读取的,因为我将它的数据输出到控制台并与在paint中打开的图像进行比较.

这里的问题是这一行:

glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB, dibheader.width,
    dibheader.height, 0, GL_RGB, GL_UNSIGNED_BYTE, data);

大多数情况下,我运行应用程序时此行崩溃并出现错误:

GunsGL.exe中0x008ffee9处的未处理异常:0xC0000005:访问冲突读取位置0x00af7002.

这是发生错误的位置的反汇编:

movzx       ebx,byte ptr [esi+2]

我的装载机不是错误,因为我已经下载了其他装载机.我使用的下载装载机是这样一个从讷河.

编辑:(上面的代码更新)

我重写了装载机,但我仍然在同一条线上崩溃.而不是崩溃,有时我在mlock.c上崩溃(我记得正确的错误信息):

void __cdecl _lock (
        int locknum
        )
{

        /*
         * Create/open the lock, if necessary
         */
        if ( _locktable[locknum].lock == NULL ) {

            if ( !_mtinitlocknum(locknum) )
                _amsg_exit( _RT_LOCK );
        }

        /*
         * Enter the critical section.
         */

        EnterCriticalSection( _locktable[locknum].lock );
}

在线上:

EnterCriticalSection( _locktable[locknum].lock );

此外,这里是应用程序没有崩溃的一次屏幕截图(纹理显然不对):http: //i.stack.imgur.com/4Mtso.jpg

EDIT2:

使用新的工作代码更新了代码.(标记为答案的答复不包含此工作所需的全部内容,但这一点至关重要)

Answer 1

glPixelStorei(GL_UNPACK_ALIGNMENT, 1)在glTexImage2D()通话前试试.