109 lines
2.7 KiB
C
109 lines
2.7 KiB
C
/*
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SDL_gfxBlitFunc: custom blitters (part of SDL_gfx library)
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LGPL (c) A. Schiffler
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*/
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#ifndef _SDL_gfxBlitFunc_h
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#define _SDL_gfxBlitFunc_h
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/* Set up for C function definitions, even when using C++ */
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <stdio.h>
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#include <stdlib.h>
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#include <SDL.h>
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#include <SDL_video.h>
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int SDL_gfxBlitRGBA(SDL_Surface * src, SDL_Rect * srcrect, SDL_Surface * dst, SDL_Rect * dstrect);
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int SDL_gfxSetAlpha(SDL_Surface * src, Uint8 a);
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/* -------- Macros */
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/* Define SDL macros locally as a substitute for a #include "SDL_blit.h", */
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/* which doesn't work since the include file doesn't get installed. */
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/* The structure passed to the low level blit functions */
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typedef struct {
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Uint8 *s_pixels;
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int s_width;
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int s_height;
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int s_skip;
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Uint8 *d_pixels;
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int d_width;
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int d_height;
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int d_skip;
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void *aux_data;
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SDL_PixelFormat *src;
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Uint8 *table;
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SDL_PixelFormat *dst;
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} SDL_gfxBlitInfo;
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#define GFX_RGBA_FROM_PIXEL(pixel, fmt, r, g, b, a) \
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{ \
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r = ((pixel&fmt->Rmask)>>fmt->Rshift)<<fmt->Rloss; \
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g = ((pixel&fmt->Gmask)>>fmt->Gshift)<<fmt->Gloss; \
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b = ((pixel&fmt->Bmask)>>fmt->Bshift)<<fmt->Bloss; \
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a = ((pixel&fmt->Amask)>>fmt->Ashift)<<fmt->Aloss; \
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}
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#define GFX_DISEMBLE_RGBA(buf, bpp, fmt, pixel, r, g, b, a) \
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do { \
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pixel = *((Uint32 *)(buf)); \
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GFX_RGBA_FROM_PIXEL(pixel, fmt, r, g, b, a); \
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pixel &= ~fmt->Amask; \
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} while(0)
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#define GFX_PIXEL_FROM_RGBA(pixel, fmt, r, g, b, a) \
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{ \
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pixel = ((r>>fmt->Rloss)<<fmt->Rshift)| \
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((g>>fmt->Gloss)<<fmt->Gshift)| \
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((b>>fmt->Bloss)<<fmt->Bshift)| \
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((a<<fmt->Aloss)<<fmt->Ashift); \
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}
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#define GFX_ASSEMBLE_RGBA(buf, bpp, fmt, r, g, b, a) \
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{ \
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Uint32 pixel; \
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\
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GFX_PIXEL_FROM_RGBA(pixel, fmt, r, g, b, a); \
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*((Uint32 *)(buf)) = pixel; \
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}
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/* Blend the RGB values of two pixels based on a source alpha value */
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#define GFX_ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB) \
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do { \
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dR = (((sR-dR)*(A))/255)+dR; \
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dG = (((sG-dG)*(A))/255)+dG; \
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dB = (((sB-dB)*(A))/255)+dB; \
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} while(0)
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/* This is a very useful loop for optimizing blitters */
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/* 4-times unrolled loop */
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#define GFX_DUFFS_LOOP4(pixel_copy_increment, width) \
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{ int n = (width+3)/4; \
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switch (width & 3) { \
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case 0: do { pixel_copy_increment; \
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case 3: pixel_copy_increment; \
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case 2: pixel_copy_increment; \
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case 1: pixel_copy_increment; \
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} while ( --n > 0 ); \
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} \
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}
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/* Ends C function definitions when using C++ */
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#ifdef __cplusplus
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}
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#endif
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#endif /* _SDL_gfxBlitFunc_h */
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