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;
+ 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;
edge[i].x = x;
x += slope;
#ifdef GOURAUD
- /* we'll store the color in the edge tables with 8 extra bits of precision */
+ /* 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;
uint16_t color;
/* the following variables are used for interpolating horizontally accros scanlines */
#if defined(GOURAUD) || defined(TEXMAP)
- /*int mid;*/
- int32_t dx/*, tmp*/;
+ 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);
if(pv[i].y > pv[botidx].y) botidx = i;
}
- left = alloca(pfill_fb.height * sizeof *left);
- right = alloca(pfill_fb.height * sizeof *right);
+ int winding = 0;
+ for(i=0; i<nverts; i++) {
+ int next = NEXTIDX(i);
+ winding += ((pv[next].x - pv[i].x) >> 8) * ((pv[next].y + pv[i].y) >> 8);
+ }
+
+ /* +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 y1 = pv[next].y;
if((y0 >> 8) == (y1 >> 8)) {
- if(y0 > y1) {
+ /*if(y0 > y1) {*/
+ int i0, i1;
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;
- }
+ 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;
+#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 = y0 > y1 ? left : right;
- uint32_t res = SCANEDGE(pv + i, pv + next, edge);
- uint32_t tmp = (res >> 16) & 0xffff;
+ struct pvertex *edge;
+ uint32_t res, tmp;
+
+ if(winding < 0) {
+ edge = y0 > y1 ? left : right;
+ } else {
+ 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;
}
}
- /* find the mid-point and calculate slopes for all attributes */
-#if 0
+ /* 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;
dx = tmp;
mid = slbot;
}
- if(!dx) {
- dx = 256; /* 1 */
- }
+ if(!dx) dx = 256; /* avoid division by zero */
#endif
#ifdef GOURAUD
dr = right[mid].r - left[mid].r;
uslope = (du << 8) / dx;
vslope = (dv << 8) / dx;
#endif
-#endif /* 0 */
+#endif /* !defined(HIGH_QUALITY) */
+ /* for each scanline ... */
for(i=sltop; i<=slbot; i++) {
uint16_t *pixptr;
int32_t x;
x = left[i].x;
pixptr = pfill_fb.pixels + i * pfill_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;
+#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;
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
+#endif /* HIGH_QUALITY */
+ /* go across the scanline interpolating if necessary */
while(x <= right[i].x) {
#if defined(GOURAUD) || defined(TEXMAP)
int cr, cg, cb;
#endif
#ifdef GOURAUD
- /* drop the extra 8 bits when packing */
- cr = r >> 8;
- cg = g >> 8;
- cb = b >> 8;
+ /* 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);
+ if(cr > 255) cr = 255;
+ if(cg > 255) cg = 255;
+ if(cb > 255) cb = 255;
r += rslope;
g += gslope;
b += bslope;
int ty = (v >> (16 - pfill_tex.yshift)) & pfill_tex.ymask;
uint16_t texel = pfill_tex.pixels[(ty << pfill_tex.xshift) + tx];
#ifdef GOURAUD
- /* XXX this is not correct, should be /255, but it might not make a huge difference */
+ /* 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 * UNPACK_R16(texel)) >> 8;
cg = (cg * UNPACK_G16(texel)) >> 8;
cb = (cb * UNPACK_B16(texel)) >> 8;
projects / dosdemo / blobdiff