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(screen.c) Fix sprite draw at screen edge
Problem - Sprites can be drawn at X/Y coordinates >= 0xfff9 to appear
partially over the left/upper screen boundary. But the dirty-rectangle
calculation doesn't account for this, so these updates will only appear
on the screen if something *else* dirties this area of the screen. This
can be observed in /projects/examples/devices/screen.tal where these
edges of the screen show stale content.
Solution - Detect wrapping and expand the dirty rectangle appropriately.
Change screen_change to take Uint16 to make sure values are truncated to
the intended range. Ignore changes that are fully off the screen.
Weeble authored on 29/06/2023 10:44:55
• Devine Lu Linvega committed on 29/06/2023 14:41:42
Showing 1 changed files
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@@ -25,8 +25,12 @@ static Uint8 blending[4][16] = {
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| 25 | 25 |
{2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2, 2, 3, 1, 2}};
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| 26 | 26 |
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| 27 | 27 |
static void |
| 28 |
-screen_change(int x1, int y1, int x2, int y2) |
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+screen_change(Uint16 x1, Uint16 y1, Uint16 x2, Uint16 y2) |
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| 29 | 29 |
{
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+ if(x1 > uxn_screen.width && x2 > x1) return; |
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+ if(y1 > uxn_screen.height && y2 > y1) return; |
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+ if(x1 > x2) x1 = 0; |
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+ if(y1 > y2) y1 = 0; |
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| 30 | 34 |
if(x1 < uxn_screen.x1) uxn_screen.x1 = x1; |
| 31 | 35 |
if(y1 < uxn_screen.y1) uxn_screen.y1 = y1; |
| 32 | 36 |
if(x2 > uxn_screen.x2) uxn_screen.x2 = x2; |