commit c75f75e

(screen.c) Macroed boundary checking

 1@@ -17,6 +17,17 @@ WITH REGARD TO THIS SOFTWARE.
 2 
 3 UxnScreen uxn_screen;
 4 
 5+#define BOUNDARY(a, b, c, d, e) \
 6+	{ \
 7+		if(a > 0xfff8) { \
 8+			b = 0, c = 0 - a; \
 9+			if(d > 0x8000) d = 0; \
10+		} else if(a > e) \
11+			return; \
12+		else if(a > e - 8) \
13+			d = e; \
14+	}
15+
16 /* c = !ch ? (color % 5 ? color >> 2 : 0) : color % 4 + ch == 1 ? 0 : (ch - 2 + (color & 3)) % 3 + 1; */
17 
18 static Uint8 blending[4][16] = {
19@@ -45,42 +56,16 @@ screen_2bpp(Uint8 *layer, Uint8 *addr, Uint16 x1, Uint16 y1, Uint16 color, int f
20 static void
21 screen_1bpp(Uint8 *layer, Uint8 *addr, Uint16 x1, Uint16 y1, Uint16 color, int fx, int fy)
22 {
23-	int x, y;
24-	Uint16 top = y1, bottom = y1 + 8, left = x1, right = x1 + 8, offset2 = 0, offset3 = 0;
25-	int row, opaque = (color % 5);
26-	/* find vertical bounds */
27-	if(y1 > 0xfff8){
28-		top = 0;
29-		if(bottom > 0x8000) bottom = 0;
30-		offset2 = 0 - y1;
31-	}
32-	else if(y1 > uxn_screen.height)
33-		return;
34-	else if(y1 >  uxn_screen.height - 8){
35-		bottom =  uxn_screen.height;
36-	}
37-
38-	/* find hor bounds  */
39-	if(x1 > 0xfff8){
40-		left = 0;
41-		if(right > 0x8000) right = 0;
42-		offset3 = 0 - x1;
43-	}
44-	else if(x1 > uxn_screen.width)
45-		return; 
46-	else if(x1 >  uxn_screen.width - 8){
47-		right =  uxn_screen.width;
48-	}
49-	
50+	int x, y, opaque = (color % 5);
51+	Uint16 top = y1, bottom = y1 + 8, left = x1, right = x1 + 8, offx = 0, offy = 0;
52+	BOUNDARY(y1, top, offy, bottom, uxn_screen.height)
53+	BOUNDARY(x1, left, offx, right, uxn_screen.width)
54 	for(y = top; y < bottom; y++) {
55-		int yi = y-top;
56-		int offset = fy < 0 ? 7 - yi : yi;
57-		int byte = addr[offset+(offset2*fy)];
58-		row = y * uxn_screen.width;
59+		int byte = addr[fy < 0 ? 7 - (y - top) : y - top + offy * fy];
60+		int row = y * uxn_screen.width;
61 		for(x = left; x < right; x++) {
62-			int xi = x - left + offset3;
63-			int offx =  fx > 0 ? (7-xi) : xi;
64-			Uint8 ch = (byte >> offx) & 1;
65+			int shift = (fx > 0 ? 7 - (x - left) : x - left) + offx;
66+			int ch = (byte >> shift) & 1;
67 			if((opaque || ch))
68 				layer[x + row] = blending[ch][color];
69 		}