rectangle: optimized collision test by removing calls and pushes and calculating...

diff --git a/src/rectangle.s b/src/rectangle.s
index e8c8b776320dc0e7d95cb9e4daf0679b0c409299..99d3a10e81a4f52685a0a38c38139b1d29c30bb6 100644 (file)
--- a/src/rectangle.s
+++ b/src/rectangle.s
@@ -159,20 +159,16 @@ rect_br:
        ;               a == 1: inside
        ;               a == 0: not inside
 rect_point_test:
-       ; TODO: remove store hl
-       ld a, h
-       ld [h2], a
-       ld a, l
-       ld [l2], a
-
        inc hl ; skip mask
 
        ; bottom left
 
        ; load bottom left point
        ld a, [hl+]
+       ; TODO: remove use of d2
+       ld [d2], a ; save y in d2
        ld d, a ; d = y
-       ld a, [hl] 
+       ld a, [hl+] 
        ld e, a ; e = x
 
        ld a, b ; compare y
@@ -182,15 +178,17 @@ rect_point_test:
        cp a, e
        jr c, @no_collision REL
 
-       ; TODO: remove restore hl
-       ld a, [h2]
-       ld h, a
-       ld a, [l2]
-       ld l, a
 
        ; top left
+
+       ; get top left y point
+       ld a, [hl+]
        push hl
-       call rect_tl
+       ld l, a ; TODO: remove use of l to avoid push
+       ld a, d
+       sub a, l ; y-height
+       capunderflow
+       ld d, a ; d = top left y
        pop hl
 
        ld a, b ; compare y points
@@ -203,9 +201,12 @@ rect_point_test:
 
        
        ; top right
-       push hl
-       call rect_tr
-       pop hl
+
+       ; get top right x
+       ld a, [hl]
+       add a, e ; e = x + width
+       capoverflow
+       ld e, a
 
        ld a, b ; compare y
        cp a, d
@@ -216,12 +217,15 @@ rect_point_test:
 
 
        ; bottom right 
-       push hl
-       call rect_br
-       pop hl
+
+       ; remove height from y
+       ; to get bottom right point
+       ld a, [d2] ; d2 = original y point
+       ld d, a
 
        ld a, b ; compare y
-       jr c, @no_collision REL
+       cp a, d
+       jr nc, @no_collision REL
        ld a, c ; compare x
        cp a, e
        jr nc, @no_collision REL