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authorDavid Thompson <dthompson@member.fsf.org>2013-08-13 07:51:19 -0400
committerDavid Thompson <dthompson@member.fsf.org>2013-08-13 07:51:19 -0400
commit266e42e8d9d523f686255882ece65ae1361be2e6 (patch)
tree17b43ff88322e6b529ee81b61a6aa9ca7c8a0d15 /2d
parent2f11a58328d0ea936e22ad84f803941686c2e09d (diff)
Expand rect module.
Diffstat (limited to '2d')
-rw-r--r--2d/rect.scm36
1 files changed, 30 insertions, 6 deletions
diff --git a/2d/rect.scm b/2d/rect.scm
index 85943db..9abbca5 100644
--- a/2d/rect.scm
+++ b/2d/rect.scm
@@ -36,8 +36,12 @@
rect-move
rect-inflate
rect-union
- rect-contains?
- rect-collides?))
+ rect-within?
+ rect-intesects?
+ rect-contains?))
+
+;; The rect API is very similar to the Pygame rect API, but rects are
+;; immutable.
(define-record-type <rect>
(make-rect x y width height)
@@ -48,10 +52,10 @@
(height rect-height))
(define (rect-x2 rect)
- (+ (rect-x rect) (rect-width rect)))
+ (+ (rect-x rect) (rect-width rect) -1))
(define (rect-y2 rect)
- (+ (rect-y rect) (rect-height rect)))
+ (+ (rect-y rect) (rect-height rect) -1))
(define (rect-move rect x y)
"Moves a rect by the given offset."
@@ -76,7 +80,16 @@ its current center."
(y2 (max (rect-y2 rect1) (rect-y2 rect2))))
(make-rect x1 y1 (- x2 x1) (- y2 y1))))
-(define (rect-contains? rect1 rect2)
+(define (rect-clip rect1 rect2)
+ "Returns the overlapping region of rect1 and rect2. If the rects do
+not overlap, a rect of size 0 is returned."
+ (let ((x1 (max (rect-x rect1) (rect-x rect2)))
+ (x2 (min (rect-x2 rect1) (rect-x2 rect2)))
+ (y1 (max (rect-y rect1) (rect-y rect2)))
+ (y2 (min (rect-y2 rect1) (rect-y2 rect2))))
+ (make-rect x1 y1 (max (- x2 x1) 0) (max (- y2 y1) 0))))
+
+(define (rect-within? rect1 rect2)
"Tests if rect2 is completely within rect1."
(and (>= (rect-x rect2) (rect-x rect1))
(<= (rect-x rect2) (rect-x2 rect1))
@@ -87,7 +100,7 @@ its current center."
(>= (rect-y2 rect2) (rect-y rect1))
(<= (rect-y2 rect2) (rect-y2 rect1))))
-(define (rect-collides? rect1 rect2)
+(define (rect-intersects? rect1 rect2)
"Tests if rect2 overlaps rect1."
(or (and (>= (rect-x rect2) (rect-x rect1))
(<= (rect-x rect2) (rect-x2 rect1)))
@@ -97,3 +110,14 @@ its current center."
(<= (rect-y rect2) (rect-y2 rect1)))
(and (>= (rect-y2 rect2) (rect-y rect1))
(<= (rect-y2 rect2) (rect-y2 rect1)))))
+
+(define (rect-contains? rect x y)
+ "Tests if the given point is within rect."
+ (and (>= x (rect-x rect))
+ (<= x (rect-x2 rect))
+ (>= x (rect-x rect))
+ (<= x (rect-x2 rect))
+ (>= y (rect-y rect))
+ (<= y (rect-y2 rect))
+ (>= y (rect-y rect))
+ (<= y (rect-y2 rect))))