SDL_SetRowStretchCode, SDL_PutRowStretchCode, SDL_RunRowStretchCode, SDL_StretchRow1, SDL_StretchRow2, SDL_StretchRow3, SDL_StretchRow4 — (src/SDL_stretchcode.h)
#include <SDL_stretch.h>
unsigned char* SDL_SetRowStretchCode( | , | |
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); |
int src_w;int dst_w;int bpp;unsigned char* SDL_PutRowStretchCode( | , | |
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); |
unsigned char* buffer;int buflen;int src_w;int dst_w;int bpp;void SDL_RunRowStretchCode( | , | |
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); |
unsigned char* buffer;unsigned char* src;unsigned char* dst;void SDL_StretchRow1( | , | |
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); |
Uint8 *src;int src_w;Uint8 *dst;int dst_w;void SDL_StretchRow2( | , | |
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); |
Uint16 *src;int src_w;Uint16 *dst;int dst_w;void SDL_StretchRow3( | , | |
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); |
Uint8 *src;int src_w;Uint8 *dst;int dst_w;void SDL_StretchRow4( | , | |
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); |
Uint32 *src;int src_w;Uint32 *dst;int dst_w;The SetRowStretchCode is a wrapper around PutRowStretchCode that uses the Adress and Size of the shared SDL_TheRowStretchCode buffer. The PutRowStretchCode will fill the given buffer with an assembler stream that should be called with SDL_RunRowStretchCode. The assembler stream is usually faster as all the scale decisions are done in advance of the execution. This helps when a RunCode is done multiple times with the same src_w/dst_w/bpp pair. All the pixel-get and pixel-set calls are unrolled in that buffer. Therefore, the buffer should be big enough - as a rule of thumb use a buffer of size (src_w+dst_w)*5
If PutCode or SetCode fails, a NULL is returned and SDL_SetError. Otherwise, the start adress of the machine code buffer is returned, which is also the input argument of PutCode and RunCode.
If SDL_SetRowStretchCode fails, the SDL_StretchRow1 function must be used instead.
The SDL_StretchRow1 function and its cousins are singular routines that work in
a tight loop to scale a single row. The number specifies the
byte-width of each pixel (it is not a bit-width!).