Panda3D
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00001 /* 00002 * Highly optimised dithering 16 bits -> 8 bits. 00003 * The formulas were taken in Mesa (Bob Mercier mercier@hollywood.cinenet.net). 00004 */ 00005 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 /* we build the color table and the lookup table */ 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 /* NOTE: all the memory access are 16 bit aligned, so if buf or 00102 linesize are not multiple of 2, it cannot work efficiently (or 00103 hang!) */ 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