dgt.animation source code

1 /**
2 Allows storing instances of a looping, linear animation
3 */
4 module dgt.animation;
5 
6 import dgt.array, dgt.texture;
7 
8 /**
9 A frame in an animation
10 */
11 struct Frame
12 {
13     public:
14     /**
15     The actual thing to draw when this frame is active
16     */
17     Texture image;
18     /**
19     The number of animation ticks this frame remains active
20 
21     An animation tick occurs once a frame, to a default of 60 times a second
22     */
23     int delay;
24 }
25 
26 /**
27 An animated instance
28 
29 It progresses linearly from frame to frame and loops when it finishes.
30 */
31 struct Animation
32 {
33     private:
34     const(Frame[]) frames;
35     int currentFrame = 0, currentTime = 0;
36 
37     @nogc nothrow public:
38     /**
39     Create an animation from an array of frames
40     */
41     pure this(in Frame[] frames)
42     {
43         this.frames = frames;
44     }
45 
46 
47     /**
48     Tick the animation forward one frame
49 
50     Returns: The current frame of the animation
51     */
52     pure ref const(Texture) update()
53     {
54         currentTime++;
55         if (currentTime >= frames[currentFrame].delay)
56         {
57             currentTime = 0;
58             currentFrame = cast(int)((currentFrame + 1) % frames.length);
59         }
60         return frames[currentFrame].image;
61     }
62 
63     /**
64     Returns: The current frame of the animation
65     */
66     pure @property ref const(Texture) texture() const
67     {
68         return frames[currentFrame].image;
69     }
70 }