git.mutantstargoat.com Git - retroray/blob - src/gaw/polytmpl.h

   1 #ifdef _MSC_VER
   2 #pragma warning (disable: 4101)
   3 #endif
   4
   5 #if !defined(GOURAUD) && !defined(TEXMAP) && !defined(ZBUF)
   6 #define NOLERP
   7 #endif
   8
   9 void POLYFILL(struct pvertex *varr, int vnum)
  10 {
  11         int i, line, top, bot;
  12         struct pvertex *vlast, *v, *vn, *tab;
  13         int32_t x, y0, y1, dx, dy, slope, fx, fy;
  14         int start, len;
  15         gaw_pixel *fbptr, *pptr, color;
  16 #ifdef GOURAUD
  17         int32_t r, g, b, dr, dg, db, rslope, gslope, bslope;
  18 #ifdef BLEND_ALPHA
  19         int32_t a, da, aslope;
  20 #endif
  21 #endif  /* GOURAUD */
  22 #ifdef TEXMAP
  23         int32_t tu, tv, du, dv, uslope, vslope;
  24         int tx, ty;
  25         gaw_pixel texel;
  26 #endif
  27 #ifdef ZBUF
  28         int32_t z, dz, zslope;
  29         uint32_t *zptr;
  30 #endif
  31
  32 #if !defined(GOURAUD)
  33         /* for flat shading we already know the color, so pack it once */
  34         color = PACK_RGB(varr[0].r, varr[0].g, varr[0].b);
  35 #endif
  36
  37         vlast = varr + vnum - 1;
  38         top = pfill_fb.height;
  39         bot = 0;
  40
  41         for(i=0; i<vnum; i++) {
  42                 /* scan the edge between the current and next vertex */
  43                 v = varr + i;
  44                 vn = VNEXT(v);
  45
  46                 if(vn->y == v->y) continue;     // XXX ???
  47
  48                 if(vn->y >= v->y) {
  49                         /* inrementing Y: left side */
  50                         tab = left;
  51                 } else {
  52                         /* decrementing Y: right side, flip vertices to trace bottom->up */
  53                         tab = right;
  54                         v = vn;
  55                         vn = varr + i;
  56                 }
  57
  58                 /* calculate edge slope */
  59                 dx = vn->x - v->x;
  60                 dy = vn->y - v->y;
  61                 slope = (dx << 8) / dy;
  62
  63 #ifdef GOURAUD
  64                 r = v->r << COLOR_SHIFT;
  65                 g = v->g << COLOR_SHIFT;
  66                 b = v->b << COLOR_SHIFT;
  67                 dr = (vn->r << COLOR_SHIFT) - r;
  68                 dg = (vn->g << COLOR_SHIFT) - g;
  69                 db = (vn->b << COLOR_SHIFT) - b;
  70                 rslope = (dr << 8) / dy;
  71                 gslope = (dg << 8) / dy;
  72                 bslope = (db << 8) / dy;
  73 #ifdef BLEND_ALPHA
  74                 a = v->a << COLOR_SHIFT;
  75                 da = (vn->a << COLOR_SHIFT) - a;
  76                 aslope = (da << 8) / dy;
  77 #endif  /* BLEND_ALPHA */
  78 #endif  /* GOURAUD */
  79 #ifdef TEXMAP
  80                 tu = v->u;
  81                 tv = v->v;
  82                 du = vn->u - tu;
  83                 dv = vn->v - tv;
  84                 uslope = (du << 8) / dy;
  85                 vslope = (dv << 8) / dy;
  86 #endif  /* TEXMAP */
  87 #ifdef ZBUF
  88                 z = v->z;
  89                 dz = vn->z - z;
  90                 zslope = (dz << 8) / dy;
  91 #endif  /* ZBUF */
  92
  93                 y0 = (v->y + 0x100) & 0xffffff00;       /* start from the next scanline */
  94                 fy = y0 - v->y;                                         /* fractional part before the next scanline */
  95                 fx = (fy * slope) >> 8;                         /* X adjust for the step to the next scanline */
  96                 x = v->x + fx;                                          /* adjust X */
  97                 y1 = vn->y & 0xffffff00;                        /* last scanline of the edge <= vn->y */
  98
  99                 /* also adjust other interpolated attributes */
 100 #ifdef GOURAUD
 101                 r += (fy * rslope) >> 8;
 102                 g += (fy * gslope) >> 8;
 103                 b += (fy * bslope) >> 8;
 104 #ifdef BLEND_ALPHA
 105                 a += (fy * aslope) >> 8;
 106 #endif  /* BLEND_ALPHA */
 107 #endif  /* GOURAUD */
 108 #ifdef TEXMAP
 109                 tu += (fy * uslope) >> 8;
 110                 tv += (fy * vslope) >> 8;
 111 #endif
 112 #ifdef ZBUF
 113                 z += (fy * zslope) >> 8;
 114 #endif
 115
 116                 line = y0 >> 8;
 117                 if(line < top) top = line;
 118                 if((y1 >> 8) > bot) bot = y1 >> 8;
 119
 120                 if(line > 0) tab += line;
 121
 122                 while(line <= (y1 >> 8) && line < pfill_fb.height) {
 123                         if(line >= 0) {
 124                                 int val = x < 0 ? 0 : x >> 8;
 125                                 tab->x = val < pfill_fb.width ? val : pfill_fb.width - 1;
 126 #ifdef GOURAUD
 127                                 tab->r = r;
 128                                 tab->g = g;
 129                                 tab->b = b;
 130 #ifdef BLEND_ALPHA
 131                                 tab->a = a;
 132 #endif  /* BLEND_ALPHA */
 133 #endif  /* GOURAUD */
 134 #ifdef TEXMAP
 135                                 tab->u = tu;
 136                                 tab->v = tv;
 137 #endif
 138 #ifdef ZBUF
 139                                 tab->z = z;
 140 #endif
 141                                 tab++;
 142                         }
 143                         x += slope;
 144 #ifdef GOURAUD
 145                         r += rslope;
 146                         g += gslope;
 147                         b += bslope;
 148 #ifdef BLEND_ALPHA
 149                         a += aslope;
 150 #endif  /* BLEND_ALPHA */
 151 #endif  /* GOURAUD */
 152 #ifdef TEXMAP
 153                         tu += uslope;
 154                         tv += vslope;
 155 #endif  /* TEXMAP */
 156 #ifdef ZBUF
 157                         z += zslope;
 158 #endif  /* ZBUF */
 159                         line++;
 160                 }
 161         }
 162
 163         if(top < 0) top = 0;
 164         if(bot >= pfill_fb.height) bot = pfill_fb.height - 1;
 165
 166         fbptr = pfill_fb.pixels + top * pfill_fb.width;
 167         for(i=top; i<=bot; i++) {
 168                 start = left[i].x;
 169                 len = right[i].x - start;
 170                 /* XXX we probably need more precision in left/right.x */
 171
 172 #ifndef NOLERP
 173                 dx = len == 0 ? 256 : (len << 8);
 174 #endif
 175
 176 #ifdef GOURAUD
 177                 r = left[i].r;
 178                 g = left[i].g;
 179                 b = left[i].b;
 180                 dr = right[i].r - r;
 181                 dg = right[i].g - g;
 182                 db = right[i].b - b;
 183                 rslope = (dr << 8) / dx;
 184                 gslope = (dg << 8) / dx;
 185                 bslope = (db << 8) / dx;
 186 #ifdef BLEND_ALPHA
 187                 a = left[i].a;
 188                 da = right[i].a - a;
 189                 aslope = (da << 8) / dx;
 190 #endif  /* BLEND_ALPHA */
 191 #endif  /* GOURAUD */
 192 #ifdef TEXMAP
 193                 tu = left[i].u;
 194                 tv = left[i].v;
 195                 du = right[i].u - tu;
 196                 dv = right[i].v - tv;
 197                 uslope = (du << 8) / dx;
 198                 vslope = (dv << 8) / dx;
 199 #endif  /* TEXMAP */
 200 #ifdef ZBUF
 201                 z = left[i].z;
 202                 dz = right[i].z - z;
 203                 zslope = (dz << 8) / dx;
 204                 zptr = pfill_zbuf + i * pfill_fb.width + start;
 205 #endif  /* ZBUF */
 206
 207                 pptr = fbptr + start;
 208                 while(len-- > 0) {
 209 #if defined(GOURAUD) || defined(TEXMAP) || defined(BLEND_ALPHA) || defined(BLEND_ADD)
 210                         int cr, cg, cb;
 211 #ifdef BLEND_ALPHA
 212                         int ca;
 213 #endif
 214 #endif
 215 #if defined(BLEND_ALPHA) || defined(BLEND_ADD)
 216                         gaw_pixel fbcol;
 217 #endif
 218 #ifdef BLEND_ALPHA
 219                         int inv_alpha;
 220 #endif
 221 #ifdef ZBUF
 222                         uint32_t cz = z;
 223                         z += zslope;
 224
 225                         if(cz <= *zptr) {
 226                                 *zptr++ = cz;
 227                         } else {
 228                                 /* ZFAIL: advance all attributes and continue */
 229 #ifdef GOURAUD
 230                                 r += rslope;
 231                                 g += gslope;
 232                                 b += bslope;
 233 #ifdef BLEND_ALPHA
 234                                 a += aslope;
 235 #endif
 236 #endif  /* GOURAUD */
 237 #ifdef TEXMAP
 238                                 tu += uslope;
 239                                 tv += vslope;
 240 #endif  /* TEXMAP */
 241                                 /* skip pixel */
 242                                 pptr++;
 243                                 zptr++;
 244                                 continue;
 245                         }
 246 #endif  /* ZBUF */
 247
 248 #ifdef GOURAUD
 249                         /* we upped the color precision to while interpolating the
 250                          * edges, now drop the extra bits before packing
 251                          */
 252                         cr = r < 0 ? 0 : (r >> COLOR_SHIFT);
 253                         cg = g < 0 ? 0 : (g >> COLOR_SHIFT);
 254                         cb = b < 0 ? 0 : (b >> COLOR_SHIFT);
 255                         r += rslope;
 256                         g += gslope;
 257                         b += bslope;
 258 #ifdef BLEND_ALPHA
 259                         ca = a < 0 ? 0 : (a >> COLOR_SHIFT);
 260                         a += aslope;
 261 #endif  /* BLEND_ALPHA */
 262 #endif  /* GOURAUD */
 263 #ifdef TEXMAP
 264                         tx = (tu >> (16 - pfill_tex.xshift)) & pfill_tex.xmask;
 265                         ty = (tv >> (16 - pfill_tex.yshift)) & pfill_tex.ymask;
 266                         texel = pfill_tex.pixels[(ty << pfill_tex.xshift) + tx];
 267
 268                         tu += uslope;
 269                         tv += vslope;
 270
 271 #ifndef GOURAUD
 272                         /* for flat textured, cr,cg,cb would not be initialized */
 273                         cr = varr[0].r;
 274                         cg = varr[0].g;
 275                         cb = varr[0].b;
 276 #ifdef BLEND_ALPHA
 277                         ca = varr[0].a;
 278 #endif
 279 #endif  /* !GOURAUD */
 280                         /* This is not correct, should be /255, but it's much faster
 281                          * to shift by 8 (/256), and won't make a huge difference
 282                          */
 283                         cr = (cr * UNPACK_R(texel)) >> 8;
 284                         cg = (cg * UNPACK_G(texel)) >> 8;
 285                         cb = (cb * UNPACK_B(texel)) >> 8;
 286 #ifdef BLEND_ALPHA
 287                         ca = (ca * UNPACK_A(texel)) >> 8;
 288 #endif
 289 #endif  /* TEXMAP */
 290
 291 #ifdef BLEND_ALPHA
 292                         inv_alpha = 255 - ca;
 293                         fbcol = *pptr;
 294                         cr = (cr * ca + UNPACK_R(fbcol) * inv_alpha) >> 8;
 295                         cg = (cg * ca + UNPACK_G(fbcol) * inv_alpha) >> 8;
 296                         cb = (cb * ca + UNPACK_B(fbcol) * inv_alpha) >> 8;
 297 #endif  /* BLEND_ALPHA */
 298 #ifdef BLEND_ADD
 299                         fbcol = *pptr;
 300                         cr += UNPACK_R(fbcol);
 301                         cg += UNPACK_G(fbcol);
 302                         cb += UNPACK_B(fbcol);
 303 #endif  /* BLEND_ADD */
 304
 305 #ifdef DEBUG_OVERDRAW
 306                         *pptr++ += DEBUG_OVERDRAW;
 307 #else
 308 #if defined(GOURAUD) || defined(TEXMAP) || defined(BLEND_ALPHA) || defined(BLEND_ADD)
 309                         if(cr >= 255) cr = 255;
 310                         if(cg >= 255) cg = 255;
 311                         if(cb >= 255) cb = 255;
 312                         color = PACK_RGB(cr, cg, cb);
 313 #endif
 314                         *pptr++ = color;
 315 #endif
 316                 }
 317                 fbptr += pfill_fb.width;
 318         }
 319 }
 320
 321 #undef NOLERP