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authorDavid Thompson <dthompson2@worcester.edu>2013-07-30 00:03:31 -0400
committerDavid Thompson <dthompson2@worcester.edu>2013-07-30 00:03:31 -0400
commit2a7602eb06b7ec78efcec10e283a7a71e995f8a3 (patch)
treee6b82bcf205082093d05bb97ee49e80d88b35e44 /2d
parenta86cd9a0437db2b3cafa6555f6c06defbf830353 (diff)
Only perform sprite rotation math when necessary.
Diffstat (limited to '2d')
-rw-r--r--2d/sprite.scm85
1 files changed, 57 insertions, 28 deletions
diff --git a/2d/sprite.scm b/2d/sprite.scm
index fddfaa4..ebeb3b4 100644
--- a/2d/sprite.scm
+++ b/2d/sprite.scm
@@ -56,42 +56,71 @@
(define (pack-sprite-vertices vertices offset x y width height origin-x origin-y
scale-x scale-y rotation u v u2 v2 color)
(let* ((color (rgba->gl-color color))
- (sin (sin-degrees rotation))
- (cos (cos-degrees rotation))
(local-x1 (* (- origin-x) scale-x))
(local-y1 (* (- origin-y) scale-y))
(local-x2 (* (- width origin-x) scale-x))
(local-y2 (* (- height origin-y) scale-y))
- (x1 (+ x (- (* cos local-x1) (* sin local-y1))))
- (y1 (+ y (* sin local-x1) (* cos local-y1)))
- (x2 (+ x (- (* cos local-x1) (* sin local-y2))))
- (y2 (+ y (* sin local-x1) (* cos local-y2)))
- (x3 (+ x (- (* cos local-x2) (* sin local-y2))))
- (y3 (+ y (* sin local-x2) (* cos local-y2)))
- (x4 (+ x1 (- x3 x2)))
- (y4 (- y3 (- y2 y1)))
(r (vector-ref color 0))
(g (vector-ref color 1))
(b (vector-ref color 2))
(a (vector-ref color 3)))
- ;; Vertices go counter clockwise, starting from the top-left
- ;; corner.
- (pack vertices offset sprite-vertex
- x1 y1
- r g b a
- u v)
- (pack vertices (+ offset 1) sprite-vertex
- x2 y2
- r g b a
- u v2)
- (pack vertices (+ offset 2) sprite-vertex
- x3 y3
- r g b a
- u2 v2)
- (pack vertices (+ offset 3) sprite-vertex
- x4 y4
- r g b a
- u2 v)))
+ (if (= rotation 0)
+ (begin
+ (let ((x1 (+ x local-x1))
+ (y1 (+ y local-y1))
+ (x2 (+ x local-x1))
+ (y2 (+ y local-y2))
+ (x3 (+ x local-x2))
+ (y3 (+ y local-y2))
+ (x4 (+ x local-x2))
+ (y4 (+ y local-y1)))
+ ;; Vertices go counter clockwise, starting from the top-left
+ ;; corner.
+ (pack vertices offset sprite-vertex
+ x1 y1
+ r g b a
+ u v)
+ (pack vertices (+ offset 1) sprite-vertex
+ x2 y2
+ r g b a
+ u v2)
+ (pack vertices (+ offset 2) sprite-vertex
+ x3 y3
+ r g b a
+ u2 v2)
+ (pack vertices (+ offset 3) sprite-vertex
+ x4 y4
+ r g b a
+ u2 v)))
+ (begin
+ (let* ((sin (sin-degrees rotation))
+ (cos (cos-degrees rotation))
+ (x1 (+ x (- (* cos local-x1) (* sin local-y1))))
+ (y1 (+ y (* sin local-x1) (* cos local-y1)))
+ (x2 (+ x (- (* cos local-x1) (* sin local-y2))))
+ (y2 (+ y (* sin local-x1) (* cos local-y2)))
+ (x3 (+ x (- (* cos local-x2) (* sin local-y2))))
+ (y3 (+ y (* sin local-x2) (* cos local-y2)))
+ (x4 (+ x1 (- x3 x2)))
+ (y4 (- y3 (- y2 y1))))
+ ;; Vertices go counter clockwise, starting from the top-left
+ ;; corner.
+ (pack vertices offset sprite-vertex
+ x1 y1
+ r g b a
+ u v)
+ (pack vertices (+ offset 1) sprite-vertex
+ x2 y2
+ r g b a
+ u v2)
+ (pack vertices (+ offset 2) sprite-vertex
+ x3 y3
+ r g b a
+ u2 v2)
+ (pack vertices (+ offset 3) sprite-vertex
+ x4 y4
+ r g b a
+ u2 v))))))
;;;
;;; Sprites