diff options
| -rw-r--r-- | 2d/rect.scm | 36 |
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)))) |