forked from 0ad/0ad
63 lines
2.4 KiB
C
63 lines
2.4 KiB
C
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#ifndef TEX_CODEC_H__
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#define TEX_CODEC_H__
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#include "tex.h"
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// rationale: no C++ to allow us to store const char* name in vtbl.
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struct TexCodecVTbl
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{
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// pointers aren't const, because the textures
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// may have to be flipped in-place - see "texture orientation".
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// size is guaranteed to be >= 4.
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// (usually enough to compare the header's "magic" field;
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// anyway, no legitimate file will be smaller)
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int (*decode)(u8* data, size_t data_size, Tex* t, const char** perr_msg);
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// rationale: some codecs cannot calculate the output size beforehand
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// (e.g. PNG output via libpng); we therefore require each one to
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// allocate memory itself and return the pointer.
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int (*encode)(const char* ext, Tex* t, u8** out, size_t* out_size, const char** perr_msg);
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int (*transform)(Tex* t, int new_flags);
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const char* name;
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};
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#define TEX_CODEC_REGISTER(name)\
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static const TexCodecVTbl vtbl = { name##_decode, name##_encode, name##_transform, #name};\
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static int dummy = tex_codec_register(&vtbl);
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// the given texture cannot be handled by this codec; pass the buck on to the next one
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const int TEX_CODEC_CANNOT_HANDLE = 1;
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// add this vtbl to the codec list. called at NLSO init time by the
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// TEX_CODEC_REGISTER in each codec file. note that call order and therefore
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// order in the list is undefined, but since each codec only steps up if it
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// can handle the given format, this is not a problem.
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extern int tex_codec_register(const TexCodecVTbl* c);
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// allocate an array of row pointers that point into the given texture data.
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// <file_orientation> indicates whether the file format is top-down or
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// bottom-up; the row array is inverted if necessary to match global
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// orienatation. (this is more efficient than "transforming" later)
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// used by PNG and JPG codecs; caller must free() rows when done.
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typedef const u8* RowPtr;
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typedef RowPtr* RowArray;
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extern int tex_codec_alloc_rows(const u8* data, size_t h, size_t pitch,
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int file_orientation, RowArray& rows);
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extern int tex_codec_set_orientation(Tex* t, int file_orientation);
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// check if the given texture format is acceptable: 8bpp grey,
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// 24bpp color or 32bpp color+alpha (BGR / upside down are permitted).
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// basically, this is the "plain" format understood by all codecs and
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// tex_codec_plain_transform.
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// return 0 if ok or a negative error code.
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extern int tex_codec_validate_format(uint bpp, uint flags);
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#endif // #ifndef TEX_CODEC_H__
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