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00006 #include <stdlib.h>
00007 #include <stdio.h>
00008 #include "zbuffer.h"
00009 #include <assert.h>
00010
00011 #if defined(TGL_FEATURE_8_BITS)
00012
00013 #define _R 5
00014 #define _G 9
00015 #define _B 5
00016 #define _DX 4
00017 #define _DY 4
00018 #define _D (_DX*_DY)
00019 #define _MIX(r,g,b) ( ((g)<<6) | ((b)<<3) | (r) )
00020
00021 #define DITHER_TABLE_SIZE (1 << 15)
00022
00023 #define DITHER_INDEX(r,g,b) ((b) + (g) * _B + (r) * (_B * _G))
00024
00025 #define MAXC 256
00026 static int kernel8[_DY*_DX] = {
00027 0 * MAXC, 8 * MAXC, 2 * MAXC, 10 * MAXC,
00028 12 * MAXC, 4 * MAXC, 14 * MAXC, 6 * MAXC,
00029 3 * MAXC, 11 * MAXC, 1 * MAXC, 9 * MAXC,
00030 15 * MAXC, 7 * MAXC, 13 * MAXC, 5 * MAXC,
00031 };
00032
00033
00034
00035 void ZB_initDither(ZBuffer *zb,int nb_colors,
00036 unsigned char *color_indexes,int *color_table)
00037 {
00038 int c,r,g,b,i,index,r1,g1,b1;
00039
00040 if (nb_colors < (_R * _G * _B)) {
00041 fprintf(stderr,"zdither: not enough colors\n");
00042 exit(1);
00043 }
00044
00045 for(i=0;i<nb_colors;i++) color_table[i]=0;
00046
00047 zb->nb_colors=nb_colors;
00048 zb->ctable=gl_malloc(nb_colors * sizeof(int));
00049
00050 for (r = 0; r < _R; r++) {
00051 for (g = 0; g < _G; g++) {
00052 for (b = 0; b < _B; b++) {
00053 r1=(r*255) / (_R - 1);
00054 g1=(g*255) / (_G - 1);
00055 b1=(b*255) / (_B - 1);
00056 index=DITHER_INDEX(r,g,b);
00057 c=(r1 << 16) | (g1 << 8) | b1;
00058 zb->ctable[index]=c;
00059 color_table[index]=c;
00060 }
00061 }
00062 }
00063
00064 zb->dctable=gl_malloc( DITHER_TABLE_SIZE );
00065
00066 for(i=0;i<DITHER_TABLE_SIZE;i++) {
00067 r=(i >> 12) & 0x7;
00068 g=(i >> 8) & 0xF;
00069 b=(i >> 3) & 0x7;
00070 index=DITHER_INDEX(r,g,b);
00071 zb->dctable[i]=color_indexes[index];
00072 }
00073 }
00074
00075 void
00076 ZB_closeDither(ZBuffer *zb) {
00077 gl_free(zb->ctable);
00078 gl_free(zb->dctable);
00079 }
00080
00081 #if 0
00082 int
00083 ZDither_lookupColor(int r,int g,int b) {
00084 unsigned char *ctable=zdither_color_table;
00085 return ctable[_MIX(_DITH0(_R, r), _DITH0(_G, g),_DITH0(_B, b))];
00086 }
00087 #endif
00088
00089
00090 #define DITHER_PIXEL2(a) \
00091 { \
00092 register int v,t,r,g,c; \
00093 v=*(unsigned int *)(pp+(a)); \
00094 g=(v & 0x07DF07DF) + g_d; \
00095 r=(((v & 0xF800F800) >> 2) + r_d) & 0x70007000; \
00096 t=r | g; \
00097 c=ctable[t & 0xFFFF] | (ctable[t >> 16] << 8); \
00098 *(unsigned short *)(dest+(a))=c; \
00099 }
00100
00101
00102
00103
00104
00105 void
00106 ZB_ditherFrameBuffer(ZBuffer *zb,unsigned char *buf,
00107 int linesize) {
00108 int xk,yk,x,y,c1,c2;
00109 unsigned char *dest1;
00110 unsigned short *pp1;
00111 int r_d,g_d,b_d;
00112 unsigned char *ctable=zb->dctable;
00113 register unsigned char *dest;
00114 register unsigned short *pp;
00115
00116 assert( ((long)buf & 1) == 0 && (linesize & 1) == 0);
00117
00118 for(yk=0;yk<4;yk++) {
00119 for(xk=0;xk<4;xk+=2) {
00120 #if BYTE_ORDER == BIG_ENDIAN
00121 c1=kernel8[yk*4+xk+1];
00122 c2=kernel8[yk*4+xk];
00123 #else
00124 c1=kernel8[yk*4+xk];
00125 c2=kernel8[yk*4+xk+1];
00126 #endif
00127 r_d=((c1 << 2) & 0xF800) >> 2;
00128 g_d=(c1 >> 4) & 0x07C0;
00129 b_d=(c1 >> 9) & 0x001F;
00130
00131 r_d|=(((c2 << 2) & 0xF800) >> 2) << 16;
00132 g_d|=((c2 >> 4) & 0x07C0) << 16;
00133 b_d|=((c2 >> 9) & 0x001F) << 16;
00134 g_d=b_d | g_d;
00135
00136 dest1=buf + (yk * linesize) + xk;
00137 pp1=zb->pbuf + (yk * zb->xsize) + xk;
00138
00139 for(y=yk;y<zb->ysize;y+=4) {
00140 dest=dest1;
00141 pp=pp1;
00142 for(x=xk;x<zb->xsize;x+=16) {
00143
00144 DITHER_PIXEL2(0);
00145 DITHER_PIXEL2(1*4);
00146 DITHER_PIXEL2(2*4);
00147 DITHER_PIXEL2(3*4);
00148
00149 pp+=16;
00150 dest+=16;
00151 }
00152 dest1+=linesize*4;
00153 pp1+=zb->xsize*4;
00154 }
00155 }
00156 }
00157 }
00158
00159 #endif