-static uint32_t SCANEDGE(struct pvertex *v0, struct pvertex *v1, struct pvertex *edge)
-{
- int i;
- int32_t x, dx, dy, slope;
-#ifdef GOURAUD
- int r, g, b, dr, dg, db;
- int32_t rslope, gslope, bslope;
-#ifdef BLEND
- int32_t a, da, aslope;
-#endif
-#endif /* GOURAUD */
-#ifdef TEXMAP
- int32_t u, v, du, dv, uslope, vslope;
-#endif
- int32_t start_idx, end_idx;
-
- if(v0->y > v1->y) {
- struct pvertex *tmp = v0;
- v0 = v1;
- v1 = tmp;
- }
-
- x = v0->x;
- dy = v1->y - v0->y;
- dx = v1->x - v0->x;
- slope = (dx << 8) / dy;
-#ifdef GOURAUD
- r = (v0->r << COLOR_SHIFT);
- g = (v0->g << COLOR_SHIFT);
- b = (v0->b << COLOR_SHIFT);
- dr = (v1->r << COLOR_SHIFT) - r;
- dg = (v1->g << COLOR_SHIFT) - g;
- db = (v1->b << COLOR_SHIFT) - b;
- rslope = (dr << 8) / dy;
- gslope = (dg << 8) / dy;
- bslope = (db << 8) / dy;
-#ifdef BLEND
- a = (v0->a << COLOR_SHIFT);
- da = (v1->a << COLOR_SHIFT) - a;
- aslope = (da << 8) / dy;
-#endif /* BLEND */
-#endif /* GOURAUD */
-#ifdef TEXMAP
- u = v0->u;
- v = v0->v;
- du = v1->u - v0->u;
- dv = v1->v - v0->v;
- uslope = (du << 8) / dy;
- vslope = (dv << 8) / dy;
-#endif
-
- start_idx = v0->y >> 8;
- end_idx = v1->y >> 8;
-
- for(i=start_idx; i<end_idx; i++) {
- edge[i].x = x;
- x += slope;
-#ifdef GOURAUD
- /* we'll store the color in the edge tables with COLOR_SHIFT extra bits of precision */
- edge[i].r = r;
- edge[i].g = g;
- edge[i].b = b;
- r += rslope;
- g += gslope;
- b += bslope;
-#ifdef BLEND
- edge[i].a = a;
- a += aslope;
-#endif
-#endif /* GOURAUD */
-#ifdef TEXMAP
- edge[i].u = u;
- edge[i].v = v;
- u += uslope;
- v += vslope;
-#endif
- }
-
- return (uint32_t)start_idx | ((uint32_t)(end_idx - 1) << 16);
-}
-
-void POLYFILL(struct pvertex *pv, int nverts)
-{
- int i, winding;
- int topidx = 0, botidx = 0, sltop = pfill_fb.height, slbot = 0;
- struct pvertex *left, *right;
- g3d_pixel color;
- /* the following variables are used for interpolating horizontally accros scanlines */
-#if defined(GOURAUD) || defined(TEXMAP)
- int mid;
- int32_t dx, tmp;
-#else
- /* flat version, just pack the color now */
- color = G3D_PACK_RGB(pv[0].r, pv[0].g, pv[0].b);
-#endif
-#ifdef GOURAUD
- int32_t r, g, b, dr, dg, db, rslope, gslope, bslope;
-#ifdef BLEND
- int32_t a, da, aslope;
-#endif
-#endif
-#ifdef TEXMAP
- int32_t u, v, du, dv, uslope, vslope;
-#endif
-
- for(i=1; i<nverts; i++) {
- if(pv[i].y < pv[topidx].y) topidx = i;
- if(pv[i].y > pv[botidx].y) botidx = i;
- }
-
- winding = 0;
- for(i=0; i<nverts; i++) {
- int next = NEXTIDX(i);
- winding += ((pv[next].x - pv[i].x) >> 4) * ((pv[next].y + pv[i].y) >> 4);
- }
-
- /* +1 to avoid crashing due to off-by-one rounding errors in the rasterization */
- left = alloca((pfill_fb.height + 1) * sizeof *left);
- right = alloca((pfill_fb.height + 1) * sizeof *right);
-
- for(i=0; i<nverts; i++) {
- int next = NEXTIDX(i);
- int32_t y0 = pv[i].y;
- int32_t y1 = pv[next].y;
-
- if((y0 >> 8) == (y1 >> 8)) {
- /*if(y0 > y1) {*/
- int i0, i1;
- int idx = y0 >> 8;
- if(pv[i].x < pv[next].x) {
- i0 = i;
- i1 = next;
- } else {
- i0 = next;
- i1 = i;
- }
- left[idx].x = pv[i0].x;
- right[idx].x = pv[i1].x;
-#ifdef GOURAUD
- left[idx].r = pv[i0].r << COLOR_SHIFT;
- left[idx].g = pv[i0].g << COLOR_SHIFT;
- left[idx].b = pv[i0].b << COLOR_SHIFT;
- right[idx].r = pv[i1].r << COLOR_SHIFT;
- right[idx].g = pv[i1].g << COLOR_SHIFT;
- right[idx].b = pv[i1].b << COLOR_SHIFT;
-#ifdef BLEND
- left[idx].a = pv[i0].a << COLOR_SHIFT;
- right[idx].a = pv[i1].a << COLOR_SHIFT;
-#endif /* BLEND */
-#endif
-#ifdef TEXMAP
- left[idx].u = pv[i0].u;
- left[idx].v = pv[i0].v;
- right[idx].u = pv[i1].u;
- right[idx].v = pv[i1].v;
-#endif
- if(idx > slbot) slbot = idx;
- if(idx < sltop) sltop = idx;
- /*}*/
- } else {
- struct pvertex *edge;
- uint32_t res, tmp;
-
- if(winding < 0) {
- /* clockwise */
- edge = y0 > y1 ? left : right;
- } else {
- /* counter-clockwise */
- edge = y0 > y1 ? right : left;
- }
- res = SCANEDGE(pv + i, pv + next, edge);
- tmp = (res >> 16) & 0xffff;
- if(tmp > slbot) slbot = tmp;
- if((tmp = res & 0xffff) < sltop) {
- sltop = tmp;
- }
- }
- }
-
- /* calculate the slopes of all attributes across the largest span out
- * of the three: middle, top, or bottom.
- */
-#ifndef HIGH_QUALITY
-#if defined(GOURAUD) || defined(TEXMAP)
- mid = (sltop + slbot) >> 1;
- dx = right[mid].x - left[mid].x;
- if((tmp = right[sltop].x - left[sltop].x) > dx) {
- dx = tmp;
- mid = sltop;
- }
- if((tmp = right[slbot].x - left[slbot].x) > dx) {
- dx = tmp;
- mid = slbot;
- }
- if(!dx) dx = 256; /* avoid division by zero */
-#endif
-#ifdef GOURAUD
- dr = right[mid].r - left[mid].r;
- dg = right[mid].g - left[mid].g;
- db = right[mid].b - left[mid].b;
- rslope = (dr << 8) / dx;
- gslope = (dg << 8) / dx;
- bslope = (db << 8) / dx;
-#ifdef BLEND
- da = right[mid].a - left[mid].a;
- aslope = (da << 8) / dx;
-#endif /* BLEND */
-#endif
-#ifdef TEXMAP
- du = right[mid].u - left[mid].u;
- dv = right[mid].v - left[mid].v;
- uslope = (du << 8) / dx;
- vslope = (dv << 8) / dx;
-#endif
-#endif /* !defined(HIGH_QUALITY) */
-
- /* for each scanline ... */
- for(i=sltop; i<=slbot; i++) {
- g3d_pixel *pixptr;
- int32_t x;
-
- x = left[i].x;
- pixptr = pfill_fb.pixels + i * pfill_fb.width + (x >> 8);
-
-#ifdef GOURAUD
- r = left[i].r;
- g = left[i].g;
- b = left[i].b;
-#ifdef BLEND
- a = left[i].a;
-#endif /* BLEND */
-#endif
-#ifdef TEXMAP
- u = left[i].u;
- v = left[i].v;
-#endif
-
-#if defined(HIGH_QUALITY) && (defined(GOURAUD) || defined(TEXMAP))
- if(!(dx = right[i].x - left[i].x)) dx = 256;
-
-#ifdef GOURAUD
- dr = right[i].r - left[i].r;
- dg = right[i].g - left[i].g;
- db = right[i].b - left[i].b;
- rslope = (dr << 8) / dx;
- gslope = (dg << 8) / dx;
- bslope = (db << 8) / dx;
-#ifdef BLEND
- da = right[i].a - left[i].a;
- aslope = (da << 8) / dx;
-#endif /* BLEND */
-#endif /* GOURAUD */
-#ifdef TEXMAP
- du = right[i].u - left[i].u;
- dv = right[i].v - left[i].v;
- uslope = (du << 8) / dx;
- vslope = (dv << 8) / dx;
-#endif
-#endif /* HIGH_QUALITY */
-
- /* go across the scanline interpolating if necessary */
- while(x <= right[i].x) {
-#if defined(GOURAUD) || defined(TEXMAP) || defined(BLEND)
- int cr, cg, cb;
-#endif
-#ifdef BLEND
- g3d_pixel fbcol;
- int alpha, inv_alpha;
-#endif
-#ifdef GOURAUD
- /* we upped the color precision to while interpolating the
- * edges, now drop the extra bits before packing
- */
- cr = r < 0 ? 0 : (r >> COLOR_SHIFT);
- cg = g < 0 ? 0 : (g >> COLOR_SHIFT);
- cb = b < 0 ? 0 : (b >> COLOR_SHIFT);
- r += rslope;
- g += gslope;
- b += bslope;
-#ifdef BLEND
- a += aslope;
-#else
- if(cr > 255) cr = 255;
- if(cg > 255) cg = 255;
- if(cb > 255) cb = 255;
-#endif /* BLEND */
-#endif /* GOURAUD */
-#ifdef TEXMAP
- {
- int tx = (u >> (16 - pfill_tex.xshift)) & pfill_tex.xmask;
- int ty = (v >> (16 - pfill_tex.yshift)) & pfill_tex.ymask;
- g3d_pixel texel = pfill_tex.pixels[(ty << pfill_tex.xshift) + tx];
-#ifdef GOURAUD
- /* This is not correct, should be /255, but it's much faster
- * to shift by 8 (/256), and won't make a huge difference
- */
- cr = (cr * G3D_UNPACK_R(texel)) >> 8;
- cg = (cg * G3D_UNPACK_G(texel)) >> 8;
- cb = (cb * G3D_UNPACK_B(texel)) >> 8;
-#else
- cr = G3D_UNPACK_R(texel);
- cg = G3D_UNPACK_G(texel);
- cb = G3D_UNPACK_B(texel);
-#endif
- }
- u += uslope;
- v += vslope;
-#endif
-
-#ifdef BLEND
-#if !defined(GOURAUD) && !defined(TEXMAP)
- /* flat version: cr,cg,cb are uninitialized so far */
- cr = pv[0].r;
- cg = pv[0].g;
- cb = pv[0].b;
-#endif
-#ifdef GOURAUD
- alpha = a >> COLOR_SHIFT;
-#else
- alpha = pv[0].a;
-#endif
- fbcol = *pixptr;
- inv_alpha = 255 - alpha;
- cr = (cr * alpha + G3D_UNPACK_R(fbcol) * inv_alpha) >> 8;
- cg = (cg * alpha + G3D_UNPACK_G(fbcol) * inv_alpha) >> 8;
- cb = (cb * alpha + G3D_UNPACK_B(fbcol) * inv_alpha) >> 8;
- if(cr > 255) cr = 255;
- if(cg > 255) cg = 255;
- if(cb > 255) cb = 255;
-#endif /* BLEND */
-
-#if defined(GOURAUD) || defined(TEXMAP) || defined(BLEND)
- color = G3D_PACK_RGB(cr, cg, cb);
-#endif
-
-#ifdef DEBUG_OVERDRAW
- *pixptr++ += DEBUG_OVERDRAW;
-#else
- *pixptr++ = color;
-#endif
- x += 256;
- }
- }
-}
-
projects / dosdemo / blobdiff