diff options
Diffstat (limited to '3rdparty/tinygl-0.4-ugfx/src/zdither.c')
| -rw-r--r-- | 3rdparty/tinygl-0.4-ugfx/src/zdither.c | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/3rdparty/tinygl-0.4-ugfx/src/zdither.c b/3rdparty/tinygl-0.4-ugfx/src/zdither.c new file mode 100644 index 00000000..cbe917fd --- /dev/null +++ b/3rdparty/tinygl-0.4-ugfx/src/zdither.c @@ -0,0 +1,158 @@ +/* + * 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)) { + gl_fatal_error("zdither: not enough colors\n"); + } + + 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 |