--- /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;
+#endif
+#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 << 8);
+ g = (v0->g << 8);
+ b = (v0->b << 8);
+ dr = (v1->r << 8) - r;
+ dg = (v1->g << 8) - g;
+ db = (v1->b << 8) - b;
+ rslope = (dr << 8) / dy;
+ gslope = (dg << 8) / dy;
+ bslope = (db << 8) / dy;
+#endif
+#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 8 extra bits of precision */
+ edge[i].r = r;
+ edge[i].g = g;
+ edge[i].b = b;
+ r += rslope;
+ g += gslope;
+ b += bslope;
+#endif
+#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;
+ int topidx = 0, botidx = 0, sltop = pimg_fb.height, slbot = 0;
+ struct pvertex *left, *right;
+ uint16_t 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 = PACK_RGB16(pv[0].r, pv[0].g, pv[0].b);
+#endif
+#ifdef GOURAUD
+ int32_t r, g, b, dr, dg, db, rslope, gslope, bslope;
+#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;
+ }
+
+ left = alloca(pimg_fb.height * sizeof *left);
+ right = alloca(pimg_fb.height * 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 idx = y0 >> 8;
+ left[idx].x = pv[i].x < pv[next].x ? pv[i].x : pv[next].x;
+ right[idx].x = pv[i].x < pv[next].x ? pv[next].x : pv[i].x;
+ }
+ } else {
+ struct pvertex *edge = y0 > y1 ? left : right;
+ uint32_t res = SCANEDGE(pv + i, pv + next, edge);
+ uint32_t tmp = (res >> 16) & 0xffff;
+ if(tmp > slbot) slbot = tmp;
+ if((tmp = res & 0xffff) < sltop) {
+ sltop = tmp;
+ }
+ }
+ }
+
+ /* find the mid-point and calculate slopes for all attributes */
+#if 0
+#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; /* 1 */
+ }
+#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;
+#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 /* 0 */
+
+ for(i=sltop; i<=slbot; i++) {
+ uint16_t *pixptr;
+ int32_t x;
+
+ x = left[i].x;
+ pixptr = pimg_fb.pixels + i * pimg_fb.width + (x >> 8);
+
+#if defined(GOURAUD) || defined(TEXMAP)
+ if(!(dx = right[i].x - left[i].x)) dx = 256; /* 1 */
+#endif
+#ifdef GOURAUD
+ r = left[i].r;
+ g = left[i].g;
+ b = left[i].b;
+ 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;
+#endif
+#ifdef TEXMAP
+ u = left[i].u;
+ v = left[i].v;
+ du = right[i].u - left[i].u;
+ dv = right[i].v - left[i].v;
+ uslope = (du << 8) / dx;
+ vslope = (dv << 8) / dx;
+#endif
+
+ while(x <= right[i].x) {
+#ifdef GOURAUD
+ /* drop the extra 8 bits when packing */
+ int cr = r >> 8;
+ int cg = g >> 8;
+ int cb = b >> 8;
+ color = PACK_RGB16(cr, cg, cb);
+ r += rslope;
+ g += gslope;
+ b += bslope;
+#endif
+#ifdef TEXMAP
+ /* TODO */
+ u += uslope;
+ v += vslope;
+#endif
+
+#ifdef DEBUG_OVERDRAW
+ *pixptr++ += DEBUG_OVERDRAW;
+#else
+ *pixptr++ = color;
+#endif
+ x += 256;
+ }
+ }
+}
+
projects / dosdemo / blobdiff