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);
}
}
- /* 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;