janwas
c1ec44d751
tex: add support for generating mipmaps in software (simplifies ogl_tex_upload) all codecs: change interface, adding "restrict" keyword; rename util functions to tex_util tex_dds: support for decompressing images with mipmaps included This was SVN commit r2909.
84 lines
3.0 KiB
C
84 lines
3.0 KiB
C
#ifndef TEX_CODEC_H__
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#define TEX_CODEC_H__
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#include "tex.h"
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#include "dyn_array.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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// 'template method' to increase code reuse and simplify writing new codecs
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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)(DynArray* restrict da, Tex* restrict t);
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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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//
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// note: <t> cannot be made const because encoding may require a
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// tex_transform.
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int (*encode)(Tex* restrict t, DynArray* restrict da);
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int (*transform)(Tex* t, uint transforms);
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// only guaranteed 4 bytes!
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bool (*is_hdr)(const u8* file);
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// precondition: ext is valid string
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// ext doesn't include '.'; just compare against e.g. "png"
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bool (*is_ext)(const char* ext);
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size_t (*hdr_size)(const u8* file);
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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##_is_hdr, name##_is_ext, name##_hdr_size, #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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// find codec that recognizes the desired output file extension
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extern int tex_codec_for_filename(const char* fn, const TexCodecVTbl** c);
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// find codec that recognizes the header's magic field
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extern int tex_codec_for_header(const u8* file, size_t file_size, 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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//
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// used by PNG and JPG codecs; caller must free() rows when done.
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//
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// note: we don't allocate the data param ourselves because this function is
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// needed for encoding, too (where data is already present).
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typedef const u8* RowPtr;
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typedef RowPtr* RowArray;
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extern int tex_util_alloc_rows(const u8* data, size_t h, size_t pitch,
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uint src_flags, uint dst_orientation, RowArray& rows);
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extern int tex_util_write(Tex* t, uint transforms, const void* hdr, size_t hdr_size, DynArray* da);
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#endif // #ifndef TEX_CODEC_H__
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