--- /dev/null
+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_ALPHA
+ 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_ALPHA
+ a = (v0->a << COLOR_SHIFT);
+ da = (v1->a << COLOR_SHIFT) - a;
+ aslope = (da << 8) / dy;
+#endif /* BLEND_ALPHA */
+#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++) {
+ CHECKEDGE(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 */
+ CHECKEDGE(i);
+ edge[i].r = r;
+ edge[i].g = g;
+ edge[i].b = b;
+ r += rslope;
+ g += gslope;
+ b += bslope;
+#ifdef BLEND_ALPHA
+ CHECKEDGE(i);
+ edge[i].a = a;
+ a += aslope;
+#endif
+#endif /* GOURAUD */
+#ifdef TEXMAP
+ CHECKEDGE(i);
+ 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;
+ 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_ALPHA
+ 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);
+ }
+
+ 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;
+ }
+ CHECKEDGE(idx);
+ 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_ALPHA
+ left[idx].a = pv[i0].a << COLOR_SHIFT;
+ right[idx].a = pv[i1].a << COLOR_SHIFT;
+#endif /* BLEND_ALPHA */
+#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
+ CHECKEDGE(idx);
+ 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;
+ CHECKEDGE(sltop);
+ CHECKEDGE(slbot);
+ CHECKEDGE(mid);
+ 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
+ CHECKEDGE(idx);
+#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_ALPHA
+ da = right[mid].a - left[mid].a;
+ aslope = (da << 8) / dx;
+#endif /* BLEND_ALPHA */
+#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;
+
+ CHECKEDGE(i);
+ 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_ALPHA
+ a = left[i].a;
+#endif /* BLEND_ALPHA */
+#endif
+#ifdef TEXMAP
+ u = left[i].u;
+ v = left[i].v;
+#endif
+ CHECKEDGE(i);
+
+#if defined(HIGH_QUALITY) && (defined(GOURAUD) || defined(TEXMAP))
+ if(!(dx = right[i].x - left[i].x)) dx = 256;
+
+ CHECKEDGE(i);
+#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_ALPHA
+ da = right[i].a - left[i].a;
+ aslope = (da << 8) / dx;
+#endif /* BLEND_ALPHA */
+#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 */
+ CHECKEDGE(i);
+
+ /* go across the scanline interpolating if necessary */
+ while(x <= right[i].x) {
+#if defined(GOURAUD) || defined(TEXMAP) || defined(BLEND_ALPHA) || defined(BLEND_ADD)
+ int cr, cg, cb;
+#endif
+#if defined(BLEND_ALPHA) || defined(BLEND_ADD)
+ g3d_pixel fbcol;
+#endif
+#ifdef BLEND_ALPHA
+ 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_ALPHA
+ a += aslope;
+#else
+ if(cr > 255) cr = 255;
+ if(cg > 255) cg = 255;
+ if(cb > 255) cb = 255;
+#endif /* BLEND_ALPHA */
+#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
+
+#if defined(BLEND_ALPHA) || defined(BLEND_ADD)
+#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
+ fbcol = *pixptr;
+
+#ifdef BLEND_ALPHA
+#ifdef GOURAUD
+ alpha = a >> COLOR_SHIFT;
+#else
+ alpha = pv[0].a;
+#endif
+ 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;
+#else /* !BLEND_ALPHA (so BLEND_ADD) */
+ cr += G3D_UNPACK_R(fbcol);
+ cg += G3D_UNPACK_R(fbcol);
+ cb += G3D_UNPACK_R(fbcol);
+#endif
+ if(cr > 255) cr = 255;
+ if(cg > 255) cg = 255;
+ if(cb > 255) cb = 255;
+#endif /* BLEND(ALPHA|ADD) */
+
+#if defined(GOURAUD) || defined(TEXMAP) || defined(BLEND_ALPHA) || defined(BLEND_ADD)
+ color = G3D_PACK_RGB(cr, cg, cb);
+#endif
+
+#ifdef DEBUG_OVERDRAW
+ *pixptr++ += DEBUG_OVERDRAW;
+#else
+ *pixptr++ = color;
+#endif
+ x += 256;
+ }
+ }
+}
+
projects / dosdemo / blobdiff