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-rw-r--r--2d/sprite.scm53
1 files changed, 36 insertions, 17 deletions
diff --git a/2d/sprite.scm b/2d/sprite.scm
index a4a0719..21e27de 100644
--- a/2d/sprite.scm
+++ b/2d/sprite.scm
@@ -30,6 +30,7 @@
#:use-module ((sdl sdl) #:prefix SDL:)
#:use-module (2d animation)
#:use-module (2d helpers)
+ #:use-module (2d math)
#:use-module (2d texture)
#:use-module (2d gl)
#:use-module (2d vector))
@@ -204,12 +205,14 @@ bound."
(tex-coords (sprite-texture-coords sprite)))
(%sprite-batch-draw *sprite-batch*
texture
- (- (vx pos) (vx anchor))
- (- (vy pos) (vy anchor))
+ (vx pos)
+ (vy pos)
(vx size)
(vy size)
#:color (sprite-color sprite)
#:rotation (sprite-rotation sprite)
+ #:origin-x (vx anchor)
+ #:origin-y (vy anchor)
#:scale-x (vx scale)
#:scale-y (vy scale)
#:u (first tex-coords)
@@ -302,46 +305,62 @@ bound."
(%make-sprite-batch max-size 0 #f (make-packed-array sprite-vertex (* 4 max-size))))
(define (sprite-batch-draw . args)
- "Adds a textured quad to the sprite batch."
+ "Adds a textured quad to the current zsprite batch."
(apply %sprite-batch-draw *sprite-batch* args))
-(define* (%sprite-batch-draw batch texture x y width height
- #:optional #:key
- (scale-x 1) (scale-y 1) (rotation 0)
- (u 0) (v 0) (u2 1) (v2 1)
- (color #xffffffff))
+(define* (%sprite-batch-draw batch texture x y width height #:optional #:key
+ (origin-x 0) (origin-y 0) (scale-x 1) (scale-y 1)
+ (rotation 0) (u 0) (v 0) (u2 1) (v2 1)
+ (color #xffffffff))
"Adds a textured quad to the sprite batch."
;; Render the batch when it's full or the texture changes.
(cond ((= (sprite-batch-size batch) (sprite-batch-max-size batch))
(sprite-batch-render batch))
((not (equal? texture (sprite-batch-texture batch)))
(sprite-batch-switch-texture batch texture)))
- ;; Add 4 new vertices.
+
+ ;; Add 4 new vertices, taking into account scaling and rotation.
(let* ((base (* 4 (sprite-batch-size batch)))
(vertices (sprite-batch-vertices batch))
(color (rgba->gl-color color))
- (x2 (+ x width))
- (y2 (+ y height))
+ (sin (sin-degrees rotation))
+ (cos (cos-degrees rotation))
+ (world-origin-x (+ origin-x x))
+ (world-origin-y (+ origin-y y))
+ (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 (+ world-origin-x (- (* cos local-x1) (* sin local-y1))))
+ (y1 (+ world-origin-y (* sin local-x1) (* cos local-y1)))
+ (x2 (+ world-origin-x (- (* cos local-x1) (* sin local-y2))))
+ (y2 (+ world-origin-y (* sin local-x1) (* cos local-y2)))
+ (x3 (+ world-origin-x (- (* cos local-x2) (* sin local-y2))))
+ (y3 (+ world-origin-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 base sprite-vertex
- x y
+ x1 y1
r g b a
u v)
(pack vertices (+ base 1) sprite-vertex
- x2 y
+ x2 y2
r g b a
- u2 v)
+ u v2)
(pack vertices (+ base 2) sprite-vertex
- x2 y2
+ x3 y3
r g b a
u2 v2)
(pack vertices (+ base 3) sprite-vertex
- x y2
+ x4 y4
r g b a
- u v2))
+ u2 v))
;; Increment batch size
(set-sprite-batch-size! batch (1+ (sprite-batch-size batch))))