forked from KolibriOS/kolibrios
160 lines
3.4 KiB
C
160 lines
3.4 KiB
C
|
/*
|
||
|
* Highly optimised dithering 16 bits -> 8 bits.
|
||
|
* The formulas were taken in Mesa (Bob Mercier mercier@hollywood.cinenet.net).
|
||
|
*/
|
||
|
|
||
|
#include <stdlib.h>
|
||
|
#include <stdio.h>
|
||
|
#include "zbuffer.h"
|
||
|
/*#include <assert.h>*/
|
||
|
|
||
|
#if defined(TGL_FEATURE_8_BITS)
|
||
|
|
||
|
#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) )
|
||
|
|
||
|
#define DITHER_TABLE_SIZE (1 << 15)
|
||
|
|
||
|
#define DITHER_INDEX(r,g,b) ((b) + (g) * _B + (r) * (_B * _G))
|
||
|
|
||
|
#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,
|
||
|
};
|
||
|
|
||
|
/* we build the color table and the lookup table */
|
||
|
|
||
|
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;
|
||
|
|
||
|
if (nb_colors < (_R * _G * _B)) {
|
||
|
fprintf(stderr,"zdither: not enough colors\n");
|
||
|
exit(1);
|
||
|
}
|
||
|
|
||
|
for(i=0;i<nb_colors;i++) color_table[i]=0;
|
||
|
|
||
|
zb->nb_colors=nb_colors;
|
||
|
zb->ctable=gl_malloc(nb_colors * sizeof(int));
|
||
|
|
||
|
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;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
zb->dctable=gl_malloc( DITHER_TABLE_SIZE );
|
||
|
|
||
|
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];
|
||
|
}
|
||
|
}
|
||
|
|
||
|
void ZB_closeDither(ZBuffer *zb)
|
||
|
{
|
||
|
gl_free(zb->ctable);
|
||
|
gl_free(zb->dctable);
|
||
|
}
|
||
|
|
||
|
#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
|
||
|
|
||
|
|
||
|
#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; \
|
||
|
}
|
||
|
|
||
|
/* 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!) */
|
||
|
|
||
|
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;
|
||
|
|
||
|
assert( ((long)buf & 1) == 0 && (linesize & 1) == 0);
|
||
|
|
||
|
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;
|
||
|
|
||
|
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;
|
||
|
|
||
|
dest1=buf + (yk * linesize) + xk;
|
||
|
pp1=zb->pbuf + (yk * zb->xsize) + xk;
|
||
|
|
||
|
for(y=yk;y<zb->ysize;y+=4) {
|
||
|
dest=dest1;
|
||
|
pp=pp1;
|
||
|
for(x=xk;x<zb->xsize;x+=16) {
|
||
|
|
||
|
DITHER_PIXEL2(0);
|
||
|
DITHER_PIXEL2(1*4);
|
||
|
DITHER_PIXEL2(2*4);
|
||
|
DITHER_PIXEL2(3*4);
|
||
|
|
||
|
pp+=16;
|
||
|
dest+=16;
|
||
|
}
|
||
|
dest1+=linesize*4;
|
||
|
pp1+=zb->xsize*4;
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
#endif
|