512 lines
15 KiB
C
512 lines
15 KiB
C
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/// DDS file support, does decoding, _not_ direct uploading
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/// (use SOIL for that ;-)
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/// A bunch of DirectDraw Surface structures and flags
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typedef struct {
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unsigned int dwMagic;
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unsigned int dwSize;
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unsigned int dwFlags;
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unsigned int dwHeight;
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unsigned int dwWidth;
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unsigned int dwPitchOrLinearSize;
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unsigned int dwDepth;
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unsigned int dwMipMapCount;
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unsigned int dwReserved1[ 11 ];
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// DDPIXELFORMAT
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struct {
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unsigned int dwSize;
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unsigned int dwFlags;
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unsigned int dwFourCC;
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unsigned int dwRGBBitCount;
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unsigned int dwRBitMask;
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unsigned int dwGBitMask;
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unsigned int dwBBitMask;
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unsigned int dwAlphaBitMask;
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} sPixelFormat;
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// DDCAPS2
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struct {
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unsigned int dwCaps1;
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unsigned int dwCaps2;
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unsigned int dwDDSX;
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unsigned int dwReserved;
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} sCaps;
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unsigned int dwReserved2;
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} DDS_header ;
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// the following constants were copied directly off the MSDN website
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// The dwFlags member of the original DDSURFACEDESC2 structure
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// can be set to one or more of the following values.
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#define DDSD_CAPS 0x00000001
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#define DDSD_HEIGHT 0x00000002
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#define DDSD_WIDTH 0x00000004
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#define DDSD_PITCH 0x00000008
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#define DDSD_PIXELFORMAT 0x00001000
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#define DDSD_MIPMAPCOUNT 0x00020000
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#define DDSD_LINEARSIZE 0x00080000
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#define DDSD_DEPTH 0x00800000
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// DirectDraw Pixel Format
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#define DDPF_ALPHAPIXELS 0x00000001
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#define DDPF_FOURCC 0x00000004
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#define DDPF_RGB 0x00000040
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// The dwCaps1 member of the DDSCAPS2 structure can be
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// set to one or more of the following values.
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#define DDSCAPS_COMPLEX 0x00000008
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#define DDSCAPS_TEXTURE 0x00001000
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#define DDSCAPS_MIPMAP 0x00400000
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// The dwCaps2 member of the DDSCAPS2 structure can be
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// set to one or more of the following values.
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#define DDSCAPS2_CUBEMAP 0x00000200
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#define DDSCAPS2_CUBEMAP_POSITIVEX 0x00000400
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#define DDSCAPS2_CUBEMAP_NEGATIVEX 0x00000800
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#define DDSCAPS2_CUBEMAP_POSITIVEY 0x00001000
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#define DDSCAPS2_CUBEMAP_NEGATIVEY 0x00002000
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#define DDSCAPS2_CUBEMAP_POSITIVEZ 0x00004000
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#define DDSCAPS2_CUBEMAP_NEGATIVEZ 0x00008000
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#define DDSCAPS2_VOLUME 0x00200000
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static int dds_test(stbi *s)
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{
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// check the magic number
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if (get8(s) != 'D') return 0;
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if (get8(s) != 'D') return 0;
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if (get8(s) != 'S') return 0;
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if (get8(s) != ' ') return 0;
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// check header size
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if (get32le(s) != 124) return 0;
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return 1;
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}
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#ifndef STBI_NO_STDIO
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int stbi_dds_test_file (FILE *f)
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{
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stbi s;
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int r,n = ftell(f);
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start_file(&s,f);
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r = dds_test(&s);
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fseek(f,n,SEEK_SET);
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return r;
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}
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#endif
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int stbi_dds_test_memory (stbi_uc const *buffer, int len)
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{
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stbi s;
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start_mem(&s,buffer, len);
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return dds_test(&s);
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}
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// helper functions
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int stbi_convert_bit_range( int c, int from_bits, int to_bits )
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{
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int b = (1 << (from_bits - 1)) + c * ((1 << to_bits) - 1);
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return (b + (b >> from_bits)) >> from_bits;
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}
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void stbi_rgb_888_from_565( unsigned int c, int *r, int *g, int *b )
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{
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*r = stbi_convert_bit_range( (c >> 11) & 31, 5, 8 );
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*g = stbi_convert_bit_range( (c >> 05) & 63, 6, 8 );
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*b = stbi_convert_bit_range( (c >> 00) & 31, 5, 8 );
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}
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void stbi_decode_DXT1_block(
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unsigned char uncompressed[16*4],
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unsigned char compressed[8] )
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{
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int next_bit = 4*8;
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int i, r, g, b;
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int c0, c1;
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unsigned char decode_colors[4*4];
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// find the 2 primary colors
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c0 = compressed[0] + (compressed[1] << 8);
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c1 = compressed[2] + (compressed[3] << 8);
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stbi_rgb_888_from_565( c0, &r, &g, &b );
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decode_colors[0] = r;
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decode_colors[1] = g;
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decode_colors[2] = b;
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decode_colors[3] = 255;
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stbi_rgb_888_from_565( c1, &r, &g, &b );
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decode_colors[4] = r;
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decode_colors[5] = g;
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decode_colors[6] = b;
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decode_colors[7] = 255;
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if( c0 > c1 )
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{
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// no alpha, 2 interpolated colors
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decode_colors[8] = (2*decode_colors[0] + decode_colors[4]) / 3;
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decode_colors[9] = (2*decode_colors[1] + decode_colors[5]) / 3;
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decode_colors[10] = (2*decode_colors[2] + decode_colors[6]) / 3;
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decode_colors[11] = 255;
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decode_colors[12] = (decode_colors[0] + 2*decode_colors[4]) / 3;
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decode_colors[13] = (decode_colors[1] + 2*decode_colors[5]) / 3;
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decode_colors[14] = (decode_colors[2] + 2*decode_colors[6]) / 3;
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decode_colors[15] = 255;
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} else
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{
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// 1 interpolated color, alpha
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decode_colors[8] = (decode_colors[0] + decode_colors[4]) / 2;
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decode_colors[9] = (decode_colors[1] + decode_colors[5]) / 2;
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decode_colors[10] = (decode_colors[2] + decode_colors[6]) / 2;
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decode_colors[11] = 255;
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decode_colors[12] = 0;
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decode_colors[13] = 0;
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decode_colors[14] = 0;
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decode_colors[15] = 0;
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}
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// decode the block
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for( i = 0; i < 16*4; i += 4 )
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{
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int idx = ((compressed[next_bit>>3] >> (next_bit & 7)) & 3) * 4;
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next_bit += 2;
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uncompressed[i+0] = decode_colors[idx+0];
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uncompressed[i+1] = decode_colors[idx+1];
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uncompressed[i+2] = decode_colors[idx+2];
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uncompressed[i+3] = decode_colors[idx+3];
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}
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// done
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}
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void stbi_decode_DXT23_alpha_block(
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unsigned char uncompressed[16*4],
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unsigned char compressed[8] )
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{
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int i, next_bit = 0;
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// each alpha value gets 4 bits
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for( i = 3; i < 16*4; i += 4 )
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{
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uncompressed[i] = stbi_convert_bit_range(
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(compressed[next_bit>>3] >> (next_bit&7)) & 15,
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4, 8 );
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next_bit += 4;
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}
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}
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void stbi_decode_DXT45_alpha_block(
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unsigned char uncompressed[16*4],
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unsigned char compressed[8] )
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{
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int i, next_bit = 8*2;
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unsigned char decode_alpha[8];
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// each alpha value gets 3 bits, and the 1st 2 bytes are the range
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decode_alpha[0] = compressed[0];
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decode_alpha[1] = compressed[1];
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if( decode_alpha[0] > decode_alpha[1] )
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{
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// 6 step intermediate
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decode_alpha[2] = (6*decode_alpha[0] + 1*decode_alpha[1]) / 7;
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decode_alpha[3] = (5*decode_alpha[0] + 2*decode_alpha[1]) / 7;
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decode_alpha[4] = (4*decode_alpha[0] + 3*decode_alpha[1]) / 7;
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decode_alpha[5] = (3*decode_alpha[0] + 4*decode_alpha[1]) / 7;
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decode_alpha[6] = (2*decode_alpha[0] + 5*decode_alpha[1]) / 7;
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decode_alpha[7] = (1*decode_alpha[0] + 6*decode_alpha[1]) / 7;
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} else
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{
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// 4 step intermediate, pluss full and none
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decode_alpha[2] = (4*decode_alpha[0] + 1*decode_alpha[1]) / 5;
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decode_alpha[3] = (3*decode_alpha[0] + 2*decode_alpha[1]) / 5;
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decode_alpha[4] = (2*decode_alpha[0] + 3*decode_alpha[1]) / 5;
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decode_alpha[5] = (1*decode_alpha[0] + 4*decode_alpha[1]) / 5;
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decode_alpha[6] = 0;
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decode_alpha[7] = 255;
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}
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for( i = 3; i < 16*4; i += 4 )
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{
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int idx = 0, bit;
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bit = (compressed[next_bit>>3] >> (next_bit&7)) & 1;
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idx += bit << 0;
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++next_bit;
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bit = (compressed[next_bit>>3] >> (next_bit&7)) & 1;
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idx += bit << 1;
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++next_bit;
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bit = (compressed[next_bit>>3] >> (next_bit&7)) & 1;
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idx += bit << 2;
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++next_bit;
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uncompressed[i] = decode_alpha[idx & 7];
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}
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// done
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}
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void stbi_decode_DXT_color_block(
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unsigned char uncompressed[16*4],
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unsigned char compressed[8] )
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{
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int next_bit = 4*8;
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int i, r, g, b;
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int c0, c1;
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unsigned char decode_colors[4*3];
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// find the 2 primary colors
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c0 = compressed[0] + (compressed[1] << 8);
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c1 = compressed[2] + (compressed[3] << 8);
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stbi_rgb_888_from_565( c0, &r, &g, &b );
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decode_colors[0] = r;
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decode_colors[1] = g;
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decode_colors[2] = b;
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stbi_rgb_888_from_565( c1, &r, &g, &b );
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decode_colors[3] = r;
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decode_colors[4] = g;
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decode_colors[5] = b;
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// Like DXT1, but no choicees:
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// no alpha, 2 interpolated colors
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decode_colors[6] = (2*decode_colors[0] + decode_colors[3]) / 3;
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decode_colors[7] = (2*decode_colors[1] + decode_colors[4]) / 3;
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decode_colors[8] = (2*decode_colors[2] + decode_colors[5]) / 3;
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decode_colors[9] = (decode_colors[0] + 2*decode_colors[3]) / 3;
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decode_colors[10] = (decode_colors[1] + 2*decode_colors[4]) / 3;
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decode_colors[11] = (decode_colors[2] + 2*decode_colors[5]) / 3;
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// decode the block
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for( i = 0; i < 16*4; i += 4 )
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{
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int idx = ((compressed[next_bit>>3] >> (next_bit & 7)) & 3) * 3;
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next_bit += 2;
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uncompressed[i+0] = decode_colors[idx+0];
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uncompressed[i+1] = decode_colors[idx+1];
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uncompressed[i+2] = decode_colors[idx+2];
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}
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// done
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}
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static stbi_uc *dds_load(stbi *s, int *x, int *y, int *comp, int req_comp)
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{
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// all variables go up front
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stbi_uc *dds_data = NULL;
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stbi_uc block[16*4];
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stbi_uc compressed[8];
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int flags, DXT_family;
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int has_alpha, has_mipmap;
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int is_compressed, cubemap_faces;
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int block_pitch, num_blocks;
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DDS_header header;
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int i, sz, cf;
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// load the header
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if( sizeof( DDS_header ) != 128 )
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{
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return NULL;
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}
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getn( s, (stbi_uc*)(&header), 128 );
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// and do some checking
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if( header.dwMagic != (('D' << 0) | ('D' << 8) | ('S' << 16) | (' ' << 24)) ) return NULL;
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if( header.dwSize != 124 ) return NULL;
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flags = DDSD_CAPS | DDSD_HEIGHT | DDSD_WIDTH | DDSD_PIXELFORMAT;
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if( (header.dwFlags & flags) != flags ) return NULL;
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/* According to the MSDN spec, the dwFlags should contain
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DDSD_LINEARSIZE if it's compressed, or DDSD_PITCH if
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uncompressed. Some DDS writers do not conform to the
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spec, so I need to make my reader more tolerant */
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if( header.sPixelFormat.dwSize != 32 ) return NULL;
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flags = DDPF_FOURCC | DDPF_RGB;
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if( (header.sPixelFormat.dwFlags & flags) == 0 ) return NULL;
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if( (header.sCaps.dwCaps1 & DDSCAPS_TEXTURE) == 0 ) return NULL;
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// get the image data
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s->img_x = header.dwWidth;
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s->img_y = header.dwHeight;
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s->img_n = 4;
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is_compressed = (header.sPixelFormat.dwFlags & DDPF_FOURCC) / DDPF_FOURCC;
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has_alpha = (header.sPixelFormat.dwFlags & DDPF_ALPHAPIXELS) / DDPF_ALPHAPIXELS;
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has_mipmap = (header.sCaps.dwCaps1 & DDSCAPS_MIPMAP) && (header.dwMipMapCount > 1);
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cubemap_faces = (header.sCaps.dwCaps2 & DDSCAPS2_CUBEMAP) / DDSCAPS2_CUBEMAP;
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/* I need cubemaps to have square faces */
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cubemap_faces &= (s->img_x == s->img_y);
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cubemap_faces *= 5;
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cubemap_faces += 1;
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block_pitch = (s->img_x+3) >> 2;
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num_blocks = block_pitch * ((s->img_y+3) >> 2);
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/* let the user know what's going on */
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*x = s->img_x;
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*y = s->img_y;
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*comp = s->img_n;
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/* is this uncompressed? */
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if( is_compressed )
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{
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/* compressed */
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// note: header.sPixelFormat.dwFourCC is something like (('D'<<0)|('X'<<8)|('T'<<16)|('1'<<24))
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DXT_family = 1 + (header.sPixelFormat.dwFourCC >> 24) - '1';
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if( (DXT_family < 1) || (DXT_family > 5) ) return NULL;
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/* check the expected size...oops, nevermind...
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those non-compliant writers leave
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dwPitchOrLinearSize == 0 */
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// passed all the tests, get the RAM for decoding
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sz = (s->img_x)*(s->img_y)*4*cubemap_faces;
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dds_data = (unsigned char*)malloc( sz );
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/* do this once for each face */
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for( cf = 0; cf < cubemap_faces; ++ cf )
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{
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// now read and decode all the blocks
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for( i = 0; i < num_blocks; ++i )
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{
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// where are we?
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int bx, by, bw=4, bh=4;
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int ref_x = 4 * (i % block_pitch);
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int ref_y = 4 * (i / block_pitch);
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// get the next block's worth of compressed data, and decompress it
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if( DXT_family == 1 )
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{
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// DXT1
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getn( s, compressed, 8 );
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stbi_decode_DXT1_block( block, compressed );
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} else if( DXT_family < 4 )
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{
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// DXT2/3
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getn( s, compressed, 8 );
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stbi_decode_DXT23_alpha_block ( block, compressed );
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getn( s, compressed, 8 );
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stbi_decode_DXT_color_block ( block, compressed );
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} else
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{
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// DXT4/5
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getn( s, compressed, 8 );
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stbi_decode_DXT45_alpha_block ( block, compressed );
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getn( s, compressed, 8 );
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stbi_decode_DXT_color_block ( block, compressed );
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}
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// is this a partial block?
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if( ref_x + 4 > s->img_x )
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{
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bw = s->img_x - ref_x;
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}
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if( ref_y + 4 > s->img_y )
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{
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bh = s->img_y - ref_y;
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}
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// now drop our decompressed data into the buffer
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for( by = 0; by < bh; ++by )
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{
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int idx = 4*((ref_y+by+cf*s->img_x)*s->img_x + ref_x);
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for( bx = 0; bx < bw*4; ++bx )
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{
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dds_data[idx+bx] = block[by*16+bx];
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}
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}
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}
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/* done reading and decoding the main image...
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skip MIPmaps if present */
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if( has_mipmap )
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{
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int block_size = 16;
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if( DXT_family == 1 )
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{
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block_size = 8;
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}
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for( i = 1; i < header.dwMipMapCount; ++i )
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{
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int mx = s->img_x >> (i + 2);
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int my = s->img_y >> (i + 2);
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if( mx < 1 )
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{
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mx = 1;
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}
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if( my < 1 )
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{
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my = 1;
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}
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skip( s, mx*my*block_size );
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}
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}
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}/* per cubemap face */
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} else
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{
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/* uncompressed */
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DXT_family = 0;
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s->img_n = 3;
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if( has_alpha )
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{
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s->img_n = 4;
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}
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*comp = s->img_n;
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sz = s->img_x*s->img_y*s->img_n*cubemap_faces;
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dds_data = (unsigned char*)malloc( sz );
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/* do this once for each face */
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for( cf = 0; cf < cubemap_faces; ++ cf )
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{
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/* read the main image for this face */
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getn( s, &dds_data[cf*s->img_x*s->img_y*s->img_n], s->img_x*s->img_y*s->img_n );
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/* done reading and decoding the main image...
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skip MIPmaps if present */
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if( has_mipmap )
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{
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for( i = 1; i < header.dwMipMapCount; ++i )
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{
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int mx = s->img_x >> i;
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int my = s->img_y >> i;
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if( mx < 1 )
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{
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mx = 1;
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}
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if( my < 1 )
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{
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my = 1;
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}
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skip( s, mx*my*s->img_n );
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}
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}
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}
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/* data was BGR, I need it RGB */
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for( i = 0; i < sz; i += s->img_n )
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{
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unsigned char temp = dds_data[i];
|
|
dds_data[i] = dds_data[i+2];
|
|
dds_data[i+2] = temp;
|
|
}
|
|
}
|
|
/* finished decompressing into RGBA,
|
|
adjust the y size if we have a cubemap
|
|
note: sz is already up to date */
|
|
s->img_y *= cubemap_faces;
|
|
*y = s->img_y;
|
|
// did the user want something else, or
|
|
// see if all the alpha values are 255 (i.e. no transparency)
|
|
has_alpha = 0;
|
|
if( s->img_n == 4)
|
|
{
|
|
for( i = 3; (i < sz) && (has_alpha == 0); i += 4 )
|
|
{
|
|
has_alpha |= (dds_data[i] < 255);
|
|
}
|
|
}
|
|
if( (req_comp <= 4) && (req_comp >= 1) )
|
|
{
|
|
// user has some requirements, meet them
|
|
if( req_comp != s->img_n )
|
|
{
|
|
dds_data = convert_format( dds_data, s->img_n, req_comp, s->img_x, s->img_y );
|
|
*comp = s->img_n;
|
|
}
|
|
} else
|
|
{
|
|
// user had no requirements, only drop to RGB is no alpha
|
|
if( (has_alpha == 0) && (s->img_n == 4) )
|
|
{
|
|
dds_data = convert_format( dds_data, 4, 3, s->img_x, s->img_y );
|
|
*comp = 3;
|
|
}
|
|
}
|
|
// OK, done
|
|
return dds_data;
|
|
}
|
|
|
|
#ifndef STBI_NO_STDIO
|
|
stbi_uc *stbi_dds_load_from_file (FILE *f, int *x, int *y, int *comp, int req_comp)
|
|
{
|
|
stbi s;
|
|
start_file(&s,f);
|
|
return dds_load(&s,x,y,comp,req_comp);
|
|
}
|
|
|
|
stbi_uc *stbi_dds_load (char *filename, int *x, int *y, int *comp, int req_comp)
|
|
{
|
|
stbi_uc *data;
|
|
FILE *f = fopen(filename, "rb");
|
|
if (!f) return NULL;
|
|
data = stbi_dds_load_from_file(f,x,y,comp,req_comp);
|
|
fclose(f);
|
|
return data;
|
|
}
|
|
#endif
|
|
|
|
stbi_uc *stbi_dds_load_from_memory (stbi_uc const *buffer, int len, int *x, int *y, int *comp, int req_comp)
|
|
{
|
|
stbi s;
|
|
start_mem(&s,buffer, len);
|
|
return dds_load(&s,x,y,comp,req_comp);
|
|
}
|