rectangle: fixed collision breaking during scroll due to rectangle positions overflow...

diff --git a/src/macros.inc b/src/macros.inc
index c0f36f31cf2bc9ba403c6930e6a38169013617d8..3aa5bba1385b437d55c7d4c35981b4bedb9b1ca1 100644 (file)
--- a/src/macros.inc
+++ b/src/macros.inc
@@ -218,4 +218,28 @@ $1:
        ;               $6: w
 #macro recdef
        .db $1, $2, $3, $4, $5, $6
+#endmacro
+       
+       ; caps an underflow when carry is set
+       ; caps value to 0x00
+       ; inputs:
+       ;               af: value and carry flag
+#macro capunderflow
+.beginscope
+       jr nc, @no_underflow REL
+               xor a, a
+@no_underflow:         
+.endscope
+#endmacro
+       
+       ; caps an overflow when carry is set
+       ; caps value to 0xFF
+       ;       inputs:
+       ;               af: value and carry flag
+#macro capoverflow
+.beginscope
+jr nc, @no_overflow REL 
+       ld a, 0xFF
+@no_overflow:
+.endscope      
 #endmacro

diff --git a/src/rectangle.s b/src/rectangle.s
index 3a3e0125fc38564636b6b850c2ff0e3e49f53dd2..c14086fb4f81cc70be0677ca77da929d6ba65125 100644 (file)
--- a/src/rectangle.s
+++ b/src/rectangle.s
@@ -97,6 +97,7 @@ rect_tl:
        ld l, a
        ld a, d
        sub a, l ; y-height
+       capunderflow
        ld d, a ; d = top left y
        ret
        
@@ -122,6 +123,7 @@ rect_tr:
 
        ld a, [hl]
        add a, e ; e = x + width
+       capoverflow
        ld e, a 
 
        dec hl ; go back to height
@@ -129,6 +131,7 @@ rect_tr:
        ld l, a
        ld a, d
        sub a, l ; y-height
+       capunderflow
        ld d, a ; d = top right y
        ret
        
@@ -144,6 +147,7 @@ rect_br:
 
        ld a, [hl]
        add a, e ; e = x + width
+       capoverflow
        ld e, a 
        ret