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我正在尝试创建一个函数来加载 .DDS 格式的纹理文件。当我的程序尝试检测文件的 FourCC 格式时，似乎会出现问题。FOURCC_DXT1、FOURCC_DXT3 和 FOURCC_DXT5 都不会返回 true。我已经尝试了许多纹理，其中一些是 DXT1 根据我从中获取的来源，但问题仍然存在。

GLuint loadDDS(const char * imagepath) {

    unsigned char header[124];

    FILE *fp;
    // open texture data
    fopen_s(&fp, imagepath, "rb");
    if (fp == NULL) return 0;

    std::cout << "file: " << fp << '\n';

    // get the surface desc 
    fread(&header, 124, 1, fp);

    // header data
    unsigned int height = *(unsigned int*)&(header[8]);
    unsigned int width = *(unsigned int*)&(header[12]);
    unsigned int linearSize = *(unsigned int*)&(header[16]);
    unsigned int mipMapCount = *(unsigned int*)&(header[24]);
    unsigned int fourCC = *(unsigned int*)&(header[80]);

    // allocate buffer
    data = (unsigned char*)malloc(width * height * 4);

    // file data
    unsigned char * buffer;
    unsigned int bufsize;

    // how big is it going to be including all mipmaps? 
    bufsize = mipMapCount > 1 ? linearSize * 2 : linearSize;
    buffer = (unsigned char*)malloc(bufsize * sizeof(unsigned char));
    fread(buffer, 1, bufsize, fp);

    // close the file pointer 
    fclose(fp);

    unsigned int components = (fourCC == FOURCC_DXT1) ? 3 : 4;
    unsigned int format;

    // here is where the problem occurs. Switch returns the default case. 
    //At this point fourCC has the value of 4.
    switch (fourCC)
    {
    case FOURCC_DXT1:
        format = GL_COMPRESSED_RGBA_S3TC_DXT1_EXT;
        break;
    case FOURCC_DXT3:
        format = GL_COMPRESSED_RGBA_S3TC_DXT3_EXT;
        break;
    case FOURCC_DXT5:
        format = GL_COMPRESSED_RGBA_S3TC_DXT5_EXT;
        break;
    default:
        std::cout << "Error when trying to read header of texture. Could not find FOURCC component" << '\n';
        free(data);
        return 0;
    }
    // Create one OpenGL texture
    GLuint textureID;
    glGenTextures(1, &textureID);

    // "Bind" the newly created texture : all future texture functions will modify this texture
    glBindTexture(GL_TEXTURE_2D, textureID);

    unsigned int blockSize = (format == GL_COMPRESSED_RGBA_S3TC_DXT1_EXT) ? 8 : 16;
    unsigned int offset = 0;

    // load the mipmaps 
    for (unsigned int level = 0; level < mipMapCount && (width || height); ++level)
    {
        unsigned int size = ((width + 3) / 4)*((height + 3) / 4)*blockSize;
        glCompressedTexImage2D(GL_TEXTURE_2D, level, format, width, height,
            0, size, data + offset);

        offset += size;
        width /= 2;
        height /= 2;
    }
    free(data);

    return textureID;
4

1 回答 1

0

懒得调试你的代码......而且由于这类问题在这里不是主题，所以不要将其作为答案处理（更像是评论，但作为评论，这既不可读也不可能）。

这是我用于将DDS加载到我的OpenGL引擎中的内容：

//------------------------------------------------------------------------------
//--- DDS library ver: 1.03 ----------------------------------------------------
//------------------------------------------------------------------------------
#ifndef _dds_h
#define _dds_h
//------------------------------------------------------------------------------
namespace DDS {
//------------------------------------------------------------------------------
AnsiString _errorlog="";
const DWORD DDS_MAGIC                   =0x20534444;

const DWORD DDSD_CAPS                   =0x00000001;
const DWORD DDSD_HEIGHT                 =0x00000002;
const DWORD DDSD_WIDTH                  =0x00000004;
const DWORD DDSD_PITCH                  =0x00000008;
const DWORD DDSD_PIXELFORMAT            =0x00001000;
const DWORD DDSD_MIPMAPCOUNT            =0x00020000;
const DWORD DDSD_LINEARSIZE             =0x00080000;
const DWORD DDSD_DEPTH                  =0x00800000;

const DWORD DDPF_ALPHAPIXELS            =0x00000001;
const DWORD DDPF_FOURCC                 =0x00000004;
const DWORD DDPF_INDEXED                =0x00000020;
const DWORD DDPF_RGB                    =0x00000040;

const DWORD DDSCAPS_COMPLEX             =0x00000008;
const DWORD DDSCAPS_TEXTURE             =0x00001000;
const DWORD DDSCAPS_MIPMAP              =0x00400000;

const DWORD DDSCAPS2_CUBEMAP            =0x00000200;
const DWORD DDSCAPS2_CUBEMAP_POSITIVEX  =0x00000400;
const DWORD DDSCAPS2_CUBEMAP_NEGATIVEX  =0x00000800;
const DWORD DDSCAPS2_CUBEMAP_POSITIVEY  =0x00001000;
const DWORD DDSCAPS2_CUBEMAP_NEGATIVEY  =0x00002000;
const DWORD DDSCAPS2_CUBEMAP_POSITIVEZ  =0x00004000;
const DWORD DDSCAPS2_CUBEMAP_NEGATIVEZ  =0x00008000;
const DWORD DDSCAPS2_VOLUME             =0x00200000;

const DWORD D3DFMT_DXT1                 ='1TXD';
const DWORD D3DFMT_DXT2                 ='2TXD';
const DWORD D3DFMT_DXT3                 ='3TXD';
const DWORD D3DFMT_DXT4                 ='4TXD';
const DWORD D3DFMT_DXT5                 ='5TXD';
//------------------------------------------------------------------------------
#define PF_IS_DXT1(pf) \
  ((pf.dwFlags & DDPF_FOURCC) && \
   (pf.dwFourCC == D3DFMT_DXT1))

#define PF_IS_DXT3(pf) \
  ((pf.dwFlags & DDPF_FOURCC) && \
   (pf.dwFourCC == D3DFMT_DXT3))

#define PF_IS_DXT5(pf) \
  ((pf.dwFlags & DDPF_FOURCC) && \
   (pf.dwFourCC == D3DFMT_DXT5))

#define PF_IS_BGRA8(pf) \
  ((pf.dwFlags & DDPF_RGB) && \
   (pf.dwFlags & DDPF_ALPHAPIXELS) && \
   (pf.dwRGBBitCount == 32) && \
   (pf.dwRBitMask == 0xff0000) && \
   (pf.dwGBitMask == 0xff00) && \
   (pf.dwBBitMask == 0xff) && \
   (pf.dwAlphaBitMask == 0xff000000U))

#define PF_IS_RGBA8(pf) \
  ((pf.dwFlags & DDPF_RGB) && \
   (pf.dwFlags & DDPF_ALPHAPIXELS) && \
   (pf.dwRGBBitCount == 32) && \
   (pf.dwRBitMask == 0xff) && \
   (pf.dwGBitMask == 0xff00) && \
   (pf.dwBBitMask == 0xff0000) && \
   (pf.dwAlphaBitMask == 0xff000000U))

#define PF_IS_BGR8(pf) \
  ((pf.dwFlags & DDPF_RGB) && \
  !(pf.dwFlags & DDPF_ALPHAPIXELS) && \
   (pf.dwRGBBitCount == 24) && \
   (pf.dwRBitMask == 0xff0000) && \
   (pf.dwGBitMask == 0xff00) && \
   (pf.dwBBitMask == 0xff))

#define PF_IS_RGB8(pf) \
  ((pf.dwFlags & DDPF_RGB) && \
  !(pf.dwFlags & DDPF_ALPHAPIXELS) && \
   (pf.dwRGBBitCount == 24) && \
   (pf.dwRBitMask == 0xff) && \
   (pf.dwGBitMask == 0xff00) && \
   (pf.dwBBitMask == 0xff0000))

#define PF_IS_BGR5(pf) \
  ((pf.dwFlags & DDPF_RGB) && \
  !(pf.dwFlags & DDPF_ALPHAPIXELS) && \
   (pf.dwRGBBitCount == 16) && \
   (pf.dwRBitMask == 0x00007c00) && \
   (pf.dwGBitMask == 0x000003e0) && \
   (pf.dwBBitMask == 0x0000001f) && \
   (pf.dwAlphaBitMask == 0x00000000))

#define PF_IS_BGR5A1(pf) \
  ((pf.dwFlags & DDPF_RGB) && \
   (pf.dwFlags & DDPF_ALPHAPIXELS) && \
   (pf.dwRGBBitCount == 16) && \
   (pf.dwRBitMask == 0x00007c00) && \
   (pf.dwGBitMask == 0x000003e0) && \
   (pf.dwBBitMask == 0x0000001f) && \
   (pf.dwAlphaBitMask == 0x00008000))

#define PF_IS_BGR565(pf) \
  ((pf.dwFlags & DDPF_RGB) && \
  !(pf.dwFlags & DDPF_ALPHAPIXELS) && \
   (pf.dwRGBBitCount == 16) && \
   (pf.dwRBitMask == 0x0000f800) && \
   (pf.dwGBitMask == 0x000007e0) && \
   (pf.dwBBitMask == 0x0000001f))

#define PF_IS_INDEX8(pf) \
  ((pf.dwFlags & DDPF_INDEXED) && \
   (pf.dwRGBBitCount == 8))
//------------------------------------------------------------------------------
#pragma pack(1)
union DDS_header
    {
    struct
        {
        DWORD dwMagic;
        DWORD dwSize;
        DWORD dwFlags;
        DWORD dwHeight;
        DWORD dwWidth;
        DWORD dwPitchOrLinearSize;
        DWORD dwDepth;
        DWORD dwMipMapCount;
        DWORD dwReserved1[ 11 ];

        //  DDPIXELFORMAT
        struct
            {
            DWORD dwSize;
            DWORD dwFlags;
            DWORD dwFourCC;
            DWORD dwRGBBitCount;
            DWORD dwRBitMask;
            DWORD dwGBitMask;
            DWORD dwBBitMask;
            DWORD dwAlphaBitMask;
            } sPixelFormat;

        //  DDCAPS2
        struct
            {
            DWORD dwCaps1;
            DWORD dwCaps2;
            DWORD dwDDSX;
            DWORD dwReserved;
            } sCaps;
        DWORD dwReserved2;
        };
    BYTE data[128];
    };
#pragma pack()
//------------------------------------------------------------------------------
void load(Graphics::TBitmap *bmp,AnsiString name)
    {
    int hnd,siz,adr;
    BYTE *dat;
    int xs,ys,x,y,i;
    DWORD **p;
    DDS_header hdr;

    hnd=FileOpen(name,fmOpenRead); if (hnd<0) return;
    siz=FileSeek(hnd,0,2);
        FileSeek(hnd,0,0);
    FileRead(hnd,&hdr,sizeof(hdr));


    if (hdr.dwSize!=124) { FileClose(hnd); return; }
    if (hdr.dwMagic!=DDS_MAGIC) { FileClose(hnd); return; }
    if (DWORD(hdr.dwFlags&DDSD_CAPS)==0) { FileClose(hnd); return; }
    if (DWORD(hdr.dwFlags&DDSD_PIXELFORMAT)==0) { FileClose(hnd); return; }

    xs=hdr.dwWidth;
    ys=hdr.dwHeight;
    bmp->Width=xs;
    bmp->Height=ys;
    bmp->PixelFormat=pf32bit;
    bmp->HandleType=bmDIB;
    p=new DWORD*[ys]; if (p==NULL) { FileClose(hnd); return; }
    #ifdef _mmap_h
    if (p) mmap_new('DDS',p,ys*sizeof(DWORD*));
    #endif
    for (y=0;y<ys;y++) p[y]=(DWORD*)bmp->ScanLine[y];
    dat=new BYTE[siz];
    if (dat==NULL)
        {
        #ifdef _mmap_h
        mmap_del('DDS',p);
        #endif
        delete[] p;
        FileClose(hnd);
        return;
        }
    #ifdef _mmap_h
    if (dat) mmap_new('DDS',dat,siz*sizeof(BYTE));
    #endif
    FileRead(hnd,dat,siz);
    FileClose(hnd);

    if (PF_IS_DXT1  (hdr.sPixelFormat))
        {
        BYTE c[4][4];
        WORD *ptr=(WORD*)(void*)dat;
        DWORD q,a0,a1;
        adr=0;
        ys&=0xFFFFFFFF-3;
        xs&=0xFFFFFFFF-3;
        for (y=0;y<ys;y+=4)
         for (x=xs-1;x>=0;)
            {
            q=ptr[adr]; adr++;
            c[0][0]=(q<<3)&248;
            c[0][1]=(q>>3)&248;
            c[0][2]=(q>>8)&248;
            c[0][3]=0;
            q=ptr[adr]; adr++;
            c[1][0]=(q<<3)&248;
            c[1][1]=(q>>3)&248;
            c[1][2]=(q>>8)&248;
            c[1][3]=0;
            for (i=0;i<4;i++)
                {
                a0=c[0][i];
                a1=c[1][i];
                if (c[0]<c[1])
                    {
                    c[2][i]=DWORD((a0+a0+a1)/3);
                    c[3][i]=DWORD((a0+a1+a1)/3);
                    }
                else{
                    c[2][i]=DWORD((a0+a1)/2);
                    c[3][i]=0;
                    }
                }
            q=ptr[adr]; adr++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x+=3; y++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x+=3; y++;
            q=ptr[adr]; adr++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x+=3; y++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]; x--;  y-=3;
            }
        }
    else if (PF_IS_DXT3  (hdr.sPixelFormat))
        {
        BYTE c[4][4];
        WORD *ptr=(WORD*)(void*)dat;
        DWORD q,a[16],a0,a1;
        adr=0;
        ys&=0xFFFFFFFF-3;
        xs&=0xFFFFFFFF-3;
        for (y=0;y<ys;y+=4)
         for (x=xs-1;x>=0;)
            {
            for (i=0;i<16;)
                {
                q=ptr[adr]; adr++; q<<=16;
                a[i]=q&0x0F0000000; q<<=4; i++;
                a[i]=q&0x0F0000000; q<<=4; i++;
                a[i]=q&0x0F0000000; q<<=4; i++;
                a[i]=q&0x0F0000000; q<<=4; i++;
                }
            q=ptr[adr]; adr++;
            c[0][0]=(q<<3)&248;
            c[0][1]=(q>>3)&248;
            c[0][2]=(q>>8)&248;
            c[0][3]=0;
            q=ptr[adr]; adr++;
            c[1][0]=(q<<3)&248;
            c[1][1]=(q>>3)&248;
            c[1][2]=(q>>8)&248;
            c[1][3]=0;
            for (i=0;i<4;i++)
                {
                a0=c[0][i];
                a1=c[1][i];
                if (c[0]<c[1])
                    {
                    c[2][i]=DWORD((a0+a0+a1)/3);
                    c[3][i]=DWORD((a0+a1+a1)/3);
                    }
                else{
                    c[2][i]=DWORD((a0+a1)/2);
                    c[3][i]=0;
                    }
                }
            q=ptr[adr]; adr++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 1]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 2]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 3]; x+=3; y++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 4]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 5]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 6]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 7]; x+=3; y++;
            q=ptr[adr]; adr++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 8]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 9]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[10]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[11]; x+=3; y++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[12]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[13]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[14]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[15]; x--;  y-=3;
            }
        }
    else if (PF_IS_DXT5  (hdr.sPixelFormat))
        {
        BYTE c[4][4];
        WORD *ptr=(WORD*)(void*)dat;
        DWORD q,ca[8],a[16],a0,a1;
        adr=0;
        ys&=0xFFFFFFFF-3;
        xs&=0xFFFFFFFF-3;
        for (y=0;y<ys;y+=4)
         for (x=xs-1;x>=0;)
            {
            q=ptr[adr]; adr++;
            a0=(q>>8)&255; ca[0]=a0;
            a1=(q   )&255; ca[1]=a1;
            if (a0<a1)
                {
                ca[2]=((6*a0)+(  a1))/7;
                ca[3]=((5*a0)+(2*a1))/7;
                ca[4]=((4*a0)+(3*a1))/7;
                ca[5]=((3*a0)+(4*a1))/7;
                ca[6]=((2*a0)+(5*a1))/7;
                ca[7]=((  a0)+(6*a1))/7;
                }
            else{
                ca[2]=((4*a0)+(  a1))/5;
                ca[3]=((3*a0)+(2*a1))/5;
                ca[4]=((2*a0)+(3*a1))/5;
                ca[5]=((  a0)+(4*a1))/5;
                ca[6]=0;
                ca[7]=255;
                }
            for (i=0;i<8;i++) ca[i]=(ca[i]<<24)&0x00FF000000;
            i=0;
            q=ptr[adr]; adr++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&1;
            q=ptr[adr]; adr++;
            a0|=(q<<1)&6; q>>=2; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&3;
            q=ptr[adr]; adr++;
            a0|=(q<<2)&4; q>>=1; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            a0=q&7; q>>=3; a[i]=ca[a0]; i++;
            q=ptr[adr]; adr++;
            c[0][0]=(q<<3)&248;
            c[0][1]=(q>>3)&248;
            c[0][2]=(q>>8)&248;
            c[0][3]=0;
            q=ptr[adr]; adr++;
            c[1][0]=(q<<3)&248;
            c[1][1]=(q>>3)&248;
            c[1][2]=(q>>8)&248;
            c[1][3]=0;
            for (i=0;i<4;i++)
                {
                a0=c[0][i];
                a1=c[1][i];
                if (c[0]<c[1])
                    {
                    c[2][i]=DWORD((a0+a0+a1)/3);
                    c[3][i]=DWORD((a0+a1+a1)/3);
                    }
                else{
                    c[2][i]=DWORD((a0+a1)/2);
                    c[3][i]=0;
                    }
                }
            q=ptr[adr]; adr++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 0]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 1]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 2]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 3]; x+=3; y++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 4]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 5]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 6]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 7]; x+=3; y++;
            q=ptr[adr]; adr++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 8]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[ 9]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[10]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[11]; x+=3; y++;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[12]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[13]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[14]; x--;
            a0=q&3; q>>=2; p[y][x]=((DWORD*)c)[a0]|a[15]; x--;  y-=3;
            }
        }
    else if (PF_IS_BGRA8 (hdr.sPixelFormat))
        {
        DWORD q,*ptr=(DWORD*)(void*)dat;
        adr=0;
        for (y=0;y<ys;y++)
         for (x=xs-1;x>=0;x--)
            {
            q=ptr[adr]; adr++;
            p[y][x]=q;
            }
        }
    else if (PF_IS_BGR8  (hdr.sPixelFormat))
        {
        struct _col { BYTE r,g,b; } *ptr=(_col*)(void*)dat;
        union { _col c; DWORD d; } dc;
        adr=0; dc.d=0;
        for (y=0;y<ys;y++)
         for (x=xs-1;x>=0;x--)
            {
            dc.c=ptr[adr]; adr++;
            p[y][x]=dc.d;
            }
        }
    else if (PF_IS_RGBA8 (hdr.sPixelFormat))
        {
        union { DWORD dd; BYTE db[4]; } w;
        adr=0; w.dd=0;
        for (y=0;y<ys;y++)
         for (x=xs-1;x>=0;x--)
            {
            w.db[2]=dat[adr]; adr++;
            w.db[1]=dat[adr]; adr++;
            w.db[0]=dat[adr]; adr++;
            w.db[3]=dat[adr]; adr++;
            p[y][x]=w.dd;
            }
        }
    else if (PF_IS_RGB8  (hdr.sPixelFormat))
        {
        union { DWORD dd; BYTE db[4]; } w;
        adr=0; w.dd=0;
        for (y=0;y<ys;y++)
         for (x=xs-1;x>=0;x--)
            {
            w.db[2]=dat[adr]; adr++;
            w.db[1]=dat[adr]; adr++;
            w.db[0]=dat[adr]; adr++;
            p[y][x]=w.dd;
            }
        }
    else if (PF_IS_BGR5(hdr.sPixelFormat))
        {
        union { DWORD dd; BYTE db[4]; } w,c;
        adr=0; w.dd=0; c.dd=0;
        for (y=0;y<ys;y++)
         for (x=xs-1;x>=0;x--)
            {
            w.db[1]=dat[adr]; adr++;
            w.db[0]=dat[adr]; adr++;
            c.db[0]=DWORD((w.dd    )&0x1F)<<3;  // B
            c.db[1]=DWORD((w.dd>> 5)&0x1F)<<3;  // G
            c.db[2]=DWORD((w.dd>>10)&0x1F)<<3;  // R
            p[y][x]=c.dd;
            }
        }
    else if (PF_IS_BGR5A1(hdr.sPixelFormat))
        {
        union { DWORD dd; BYTE db[4]; } w,c;
        adr=0; w.dd=0; c.dd=0;
        for (y=0;y<ys;y++)
         for (x=xs-1;x>=0;x--)
            {
            w.db[1]=dat[adr]; adr++;
            w.db[0]=dat[adr]; adr++;
            c.db[0]=DWORD((w.dd    )&0x1F)<<3;  // B
            c.db[1]=DWORD((w.dd>> 5)&0x1F)<<3;  // G
            c.db[2]=DWORD((w.dd>>10)&0x1F)<<3;  // R
            if (DWORD(w.dd&0x8000)) c.db[3]=255;// A
             else c.db[3]=0;
            p[y][x]=c.dd;
            }
        }
    else if (PF_IS_BGR565(hdr.sPixelFormat))
        {
        union { DWORD dd; BYTE db[4]; } w,c;
        adr=0; w.dd=0; c.dd=0;
        for (y=0;y<ys;y++)
         for (x=xs-1;x>=0;x--)
            {
            w.db[1]=dat[adr]; adr++;
            w.db[0]=dat[adr]; adr++;
            c.db[0]=DWORD((w.dd    )&0x1F)<<3;  // B
            c.db[1]=DWORD((w.dd>> 5)&0x3F)<<2;  // G
            c.db[2]=DWORD((w.dd>>11)&0x1F)<<3;  // R
            p[y][x]=c.dd;
            }
        }
//  else if (PF_IS_INDEX8(hdr.sPixelFormat));
    else _errorlog+="DDS::unsuported format \""+name+"\"\n";

    #ifdef _mmap_h
    mmap_del('DDS',dat);
    mmap_del('DDS',p);
    #endif
    delete[] dat;
    delete[] p;
    }
//---------------------------------------------------------------------------
#undef PF_IS_DXT1
#undef PF_IS_DXT3
#undef PF_IS_DXT5
#undef PF_IS_BGRA8
#undef PF_IS_RGBA8
#undef PF_IS_BGR8
#undef PF_IS_RGB8
#undef PF_IS_BGR5
#undef PF_IS_BGR5A1
#undef PF_IS_BGR565
#undef PF_IS_INDEX8
//---------------------------------------------------------------------------
};
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------
#endif
//---------------------------------------------------------------------------
//---------------------------------------------------------------------------

它基于C++/VCL，因此您可以提取/移植它以检测文件格式……如果我没记错的话，我很久以前就写过这篇文章，VCL中唯一使用的东西是Bitmap文件访问和AnsiString. 是能够进行字符串算术的AnsiString自分配字符串变量。注意它的字母是从1. 这里描述了位图的使用：

而且文件访问很简单，因此移植它应该不会造成任何问题。

因此，要么移植/使用它，要么与您的检测进行比较以定位您的错误...如您所见，我不支持所有格式，但它是一个工作起点。

于 2018-06-26T07:50:39.033 回答