blob: c1b71d7f0a0d603441955b5d3c3495b7954b0f84 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
|
;;; guile-2d
;;; Copyright (C) 2013 David Thompson <dthompson2@worcester.edu>
;;;
;;; Guile-2d is free software: you can redistribute it and/or modify it
;;; under the terms of the GNU Lesser General Public License as
;;; published by the Free Software Foundation, either version 3 of the
;;; License, or (at your option) any later version.
;;;
;;; Guile-2d is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;;; Lesser General Public License for more details.
;;;
;;; You should have received a copy of the GNU Lesser General Public
;;; License along with this program. If not, see
;;; <http://www.gnu.org/licenses/>.
;;; Commentary:
;;
;; Animations represent a sequence of textures and/or texture regions.
;;
;;; Code:
(define-module (2d animation)
#:use-module (srfi srfi-9)
#:use-module (2d texture))
;;;
;;; Animations
;;;
;; The <animation> type represents a vector of textures or texture
;; regions that are to be played in sequence and possibly looped.
(define-record-type <animation>
(make-animation frames frame-duration loop)
animation?
(frames animation-frames)
(frame-duration animation-frame-duration)
(loop animation-loop?))
(define (animation-frame animation index)
"Return the texture for the given frame INDEX."
(vector-ref (animation-frames animation) index))
(define (animation-length animation)
"Return the number of frames in the ANIMATION."
(vector-length (animation-frames animation)))
(define (animation-duration animation)
"Return the total duration of ANIMATION in ticks."
(* (animation-length animation)
(animation-frame-duration animation)))
(export make-animation
animation?
animation-frames
animation-frame-duration
animation-loop?
animation-frame
animation-length
animation-duration)
;; The <animator> type encapsulates the state for playing an
;; animation.
(define-record-type <animator>
(%make-animator animation frame time playing)
animator?
(animation animator-animation)
(frame animator-frame set-animator-frame!)
(time animator-time set-animator-time!)
(playing animator-playing? set-animator-playing!))
(define (make-animator animation)
"Creates a new animation state object."
(%make-animator animation 0 0 #t))
(define (animator-frame-complete? state)
(>= (animator-time state)
(animation-frame-duration (animator-animation state))))
(define (animator-next-frame state)
"Return the next frame index for the animation STATE. Return -1 when
the animation is complete."
(modulo (1+ (animator-frame state))
(animation-length (animator-animation state))))
(define (animator-texture state)
"Returns the texture for the animation at the current frame index."
(animation-frame (animator-animation state)
(animator-frame state)))
(define (animator-next! state)
"Advance to the next animation frame for the given animation STATE."
(let ((next-frame (animator-next-frame state)))
(define (keep-playing?)
(or (not (= 0 next-frame))
(animation-loop? (animator-animation state))))
(set-animator-time! state 0)
(set-animator-frame! state next-frame)
(set-animator-playing! state (keep-playing?))))
(define (animator-update! state)
"Increments the frame time for the animation STATE and advances to
the next frame in the animation if necessary."
(when (animator-playing? state)
(set-animator-time! state (1+ (animator-time state)))
(when (animator-frame-complete? state)
(animator-next! state))))
(export make-animator
animator?
animator-animation
animator-frame
animator-time
animator-frame-complete?
animator-playing?
animator-next-frame
animator-texture
animator-next!
animator-update!)
|
