X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?p=dosdemo;a=blobdiff_plain;f=src%2Fpolyfill.c;h=215cd785c9ec5ff128b4089d09223362d2e1660e;hp=d8facb5a29271e62b29bfb2cbf0a8fc45be21cdf;hb=633743214adddf6ec20f8b1bee1782e6966023af;hpb=d1a2007e191d68b104e436d1817eafcc99ae21dd

diff --git a/src/polyfill.c b/src/polyfill.c
index d8facb5..215cd78 100644
--- a/src/polyfill.c
+++ b/src/polyfill.c
@@ -6,7 +6,8 @@
 
 void (*fillfunc[])(struct pvertex*, int) = {
 	polyfill_wire,
-	0, 0, 0, 0
+	polyfill_flat,
+	0, 0, 0
 };
 
 void polyfill(int mode, struct pvertex *verts, int nverts)
@@ -23,19 +24,104 @@ void polyfill(int mode, struct pvertex *verts, int nverts)
 
 void polyfill_wire(struct pvertex *verts, int nverts)
 {
-	int i;
+	int i, x0, y0, x1, y1;
 	struct pvertex *v = verts;
 	unsigned short color = ((v->r << 8) & 0xf800) |
 		((v->g << 3) & 0x7e0) | ((v->b >> 3) & 0x1f);
 
-	for(i=0; i<nverts; i++) {
-		int x0, y0, x1, y1;
+	for(i=0; i<nverts - 1; i++) {
 		x0 = v->x >> 8;
 		y0 = v->y >> 8;
 		++v;
 		x1 = v->x >> 8;
 		y1 = v->y >> 8;
-		clip_line(&x0, &y0, &x1, &y1, 0, 0, fb_width, fb_height);
-		draw_line(x0, y0, x1, y1, color);
+		if(clip_line(&x0, &y0, &x1, &y1, 0, 0, fb_width, fb_height)) {
+			draw_line(x0, y0, x1, y1, color);
+		}
+	}
+	x0 = verts[0].x >> 8;
+	y0 = verts[0].y >> 8;
+	if(clip_line(&x1, &y1, &x0, &y0, 0, 0, fb_width, fb_height)) {
+		draw_line(x1, y1, x0, y0, color);
+	}
+}
+
+#define NEXTIDX(x) ((x) ? (x) - 1 : nverts - 1)
+#define PREVIDX(x) (((x) + 1) % nverts)
+
+#define CALC_EDGE(which) \
+	do { \
+		which##_x = pv[which##_beg].x; \
+		which##_dx = pv[which##_end].x - pv[which##_beg].x; \
+		which##_slope = (which##_dx << 8) / which##_dy; \
+	} while(0)
+
+void polyfill_flat(struct pvertex *pv, int nverts)
+{
+	int i, sline, x, slen, top = 0;
+	int left_beg, left_end, right_beg, right_end;
+	int32_t left_dy, left_dx, right_dy, right_dx;
+	int32_t left_slope, right_slope;
+	int32_t left_x, right_x, y;
+	uint16_t color = ((pv->r << 8) & 0xf800) | ((pv->g << 3) & 0x7e0) |
+		((pv->b >> 3) & 0x1f);
+	uint16_t *pixptr;
+
+	/* find topmost */
+	for(i=1; i<nverts; i++) {
+		if(pv[i].y < pv[top].y) {
+			top = i;
+		}
+	}
+	left_beg = right_beg = top;
+	left_end = PREVIDX(left_beg);
+	right_end = NEXTIDX(right_beg);
+
+	if((left_dy = pv[left_end].y - pv[left_beg].y)) {
+		CALC_EDGE(left);
+	}
+
+	if((right_dy = pv[right_end].y - pv[right_beg].y)) {
+		CALC_EDGE(right);
+	}
+
+	y = pv[top].y;
+	sline = pv[top].y >> 8;
+
+	for(;;) {
+		if(y >= pv[left_end].y) {
+			while(y >= pv[left_end].y) {
+				left_beg = left_end;
+				if(left_beg == right_beg) return;
+				left_end = PREVIDX(left_end);
+			}
+
+			left_dy = pv[left_end].y - pv[left_beg].y;
+			CALC_EDGE(left);
+		}
+
+		if(y >= pv[right_end].y) {
+			while(y >= pv[right_end].y) {
+				right_beg = right_end;
+				if(left_beg == right_beg) return;
+				right_end = NEXTIDX(right_end);
+			}
+
+			right_dy = pv[right_end].y - pv[right_beg].y;
+			CALC_EDGE(right);
+		}
+
+		x = left_x >> 8;
+		slen = (right_x >> 8) - (left_x >> 8);
+
+		pixptr = (uint16_t*)fb_pixels + sline * fb_width + x;
+		for(i=0; i<slen; i++) {
+			*pixptr++ = color;
+		}
+
+		++sline;
+		y += 256;
+		left_x += left_slope;
+		right_x += right_slope;
 	}
 }