0,0 → 1,159 |
/* |
* Highly optimised dithering 16 bits -> 8 bits. |
* The formulas were taken in Mesa (Bob Mercier mercier@hollywood.cinenet.net). |
*/ |
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#include <stdlib.h> |
#include <stdio.h> |
#include "zbuffer.h" |
/*#include <assert.h>*/ |
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#if defined(TGL_FEATURE_8_BITS) |
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#define _R 5 |
#define _G 9 |
#define _B 5 |
#define _DX 4 |
#define _DY 4 |
#define _D (_DX*_DY) |
#define _MIX(r,g,b) ( ((g)<<6) | ((b)<<3) | (r) ) |
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#define DITHER_TABLE_SIZE (1 << 15) |
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#define DITHER_INDEX(r,g,b) ((b) + (g) * _B + (r) * (_B * _G)) |
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#define MAXC 256 |
static int kernel8[_DY*_DX] = { |
0 * MAXC, 8 * MAXC, 2 * MAXC, 10 * MAXC, |
12 * MAXC, 4 * MAXC, 14 * MAXC, 6 * MAXC, |
3 * MAXC, 11 * MAXC, 1 * MAXC, 9 * MAXC, |
15 * MAXC, 7 * MAXC, 13 * MAXC, 5 * MAXC, |
}; |
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/* we build the color table and the lookup table */ |
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void ZB_initDither(ZBuffer *zb,int nb_colors, |
unsigned char *color_indexes,int *color_table) |
{ |
int c,r,g,b,i,index,r1,g1,b1; |
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if (nb_colors < (_R * _G * _B)) { |
fprintf(stderr,"zdither: not enough colors\n"); |
exit(1); |
} |
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for(i=0;i<nb_colors;i++) color_table[i]=0; |
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zb->nb_colors=nb_colors; |
zb->ctable=gl_malloc(nb_colors * sizeof(int)); |
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for (r = 0; r < _R; r++) { |
for (g = 0; g < _G; g++) { |
for (b = 0; b < _B; b++) { |
r1=(r*255) / (_R - 1); |
g1=(g*255) / (_G - 1); |
b1=(b*255) / (_B - 1); |
index=DITHER_INDEX(r,g,b); |
c=(r1 << 16) | (g1 << 8) | b1; |
zb->ctable[index]=c; |
color_table[index]=c; |
} |
} |
} |
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zb->dctable=gl_malloc( DITHER_TABLE_SIZE ); |
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for(i=0;i<DITHER_TABLE_SIZE;i++) { |
r=(i >> 12) & 0x7; |
g=(i >> 8) & 0xF; |
b=(i >> 3) & 0x7; |
index=DITHER_INDEX(r,g,b); |
zb->dctable[i]=color_indexes[index]; |
} |
} |
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void ZB_closeDither(ZBuffer *zb) |
{ |
gl_free(zb->ctable); |
gl_free(zb->dctable); |
} |
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#if 0 |
int ZDither_lookupColor(int r,int g,int b) |
{ |
unsigned char *ctable=zdither_color_table; |
return ctable[_MIX(_DITH0(_R, r), _DITH0(_G, g),_DITH0(_B, b))]; |
} |
#endif |
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#define DITHER_PIXEL2(a) \ |
{ \ |
register int v,t,r,g,c; \ |
v=*(unsigned int *)(pp+(a)); \ |
g=(v & 0x07DF07DF) + g_d; \ |
r=(((v & 0xF800F800) >> 2) + r_d) & 0x70007000; \ |
t=r | g; \ |
c=ctable[t & 0xFFFF] | (ctable[t >> 16] << 8); \ |
*(unsigned short *)(dest+(a))=c; \ |
} |
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/* NOTE: all the memory access are 16 bit aligned, so if buf or |
linesize are not multiple of 2, it cannot work efficiently (or |
hang!) */ |
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void ZB_ditherFrameBuffer(ZBuffer *zb,unsigned char *buf, |
int linesize) |
{ |
int xk,yk,x,y,c1,c2; |
unsigned char *dest1; |
unsigned short *pp1; |
int r_d,g_d,b_d; |
unsigned char *ctable=zb->dctable; |
register unsigned char *dest; |
register unsigned short *pp; |
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assert( ((long)buf & 1) == 0 && (linesize & 1) == 0); |
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for(yk=0;yk<4;yk++) { |
for(xk=0;xk<4;xk+=2) { |
#if BYTE_ORDER == BIG_ENDIAN |
c1=kernel8[yk*4+xk+1]; |
c2=kernel8[yk*4+xk]; |
#else |
c1=kernel8[yk*4+xk]; |
c2=kernel8[yk*4+xk+1]; |
#endif |
r_d=((c1 << 2) & 0xF800) >> 2; |
g_d=(c1 >> 4) & 0x07C0; |
b_d=(c1 >> 9) & 0x001F; |
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r_d|=(((c2 << 2) & 0xF800) >> 2) << 16; |
g_d|=((c2 >> 4) & 0x07C0) << 16; |
b_d|=((c2 >> 9) & 0x001F) << 16; |
g_d=b_d | g_d; |
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dest1=buf + (yk * linesize) + xk; |
pp1=zb->pbuf + (yk * zb->xsize) + xk; |
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for(y=yk;y<zb->ysize;y+=4) { |
dest=dest1; |
pp=pp1; |
for(x=xk;x<zb->xsize;x+=16) { |
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DITHER_PIXEL2(0); |
DITHER_PIXEL2(1*4); |
DITHER_PIXEL2(2*4); |
DITHER_PIXEL2(3*4); |
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pp+=16; |
dest+=16; |
} |
dest1+=linesize*4; |
pp1+=zb->xsize*4; |
} |
} |
} |
} |
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#endif |