1 /* An animation track defines the values of a single scalar over time

2 * and supports various interpolation and extrapolation modes.

3 */

4 #ifndef LIBANIM_TRACK_H_

5 #define LIBANIM_TRACK_H_

6

7 #include <limits.h>

8 #include "config.h"

9

10 enum anm_interpolator {

11 ANM_INTERP_STEP,

12 ANM_INTERP_LINEAR,

13 ANM_INTERP_CUBIC

14 };

15

16 enum anm_extrapolator {

17 ANM_EXTRAP_EXTEND, /* extend to infinity */

18 ANM_EXTRAP_CLAMP, /* clamp to last value */

19 ANM_EXTRAP_REPEAT /* repeat motion */

20 };

21

22 typedef long anm_time_t;

23 #define ANM_TIME_INVAL LONG_MIN

24

25 #define ANM_SEC2TM(x) ((anm_time_t)((x) * 1000))

26 #define ANM_MSEC2TM(x) ((anm_time_t)(x))

27 #define ANM_TM2SEC(x) ((x) / 1000.0)

28 #define ANM_TM2MSEC(x) (x)

29

30 struct anm_keyframe {

31 anm_time_t time;

32 float val;

33 };

34

35 struct anm_track {

36 char *name;

37 int count;

38 struct anm_keyframe *keys;

39

40 float def_val;

41

42 enum anm_interpolator interp;

43 enum anm_extrapolator extrap;

44 };

45

46 /* track constructor and destructor */

47 int anm_init_track(struct anm_track *track);

48 void anm_destroy_track(struct anm_track *track);

49

50 /* helper functions that use anm_init_track and anm_destroy_track internally */

51 struct anm_track *anm_create_track(void);

52 void anm_free_track(struct anm_track *track);

53

54 int anm_set_track_name(struct anm_track *track, const char *name);

55 const char *anm_get_track_name(struct anm_track *track);

56

57 void anm_set_track_interpolator(struct anm_track *track, enum anm_interpolator in);

58 void anm_set_track_extrapolator(struct anm_track *track, enum anm_extrapolator ex);

59

60 anm_time_t anm_remap_time(struct anm_track *track, anm_time_t tm, anm_time_t start, anm_time_t end);

61

62 void anm_set_track_default(struct anm_track *track, float def);

63

64 /* set or update a keyframe */

65 int anm_set_keyframe(struct anm_track *track, struct anm_keyframe *key);

66

67 /* get the idx-th keyframe, returns null if it doesn't exist */

68 struct anm_keyframe *anm_get_keyframe(struct anm_track *track, int idx);

69

70 /* Finds the 0-based index of the intra-keyframe interval which corresponds

71 * to the specified time. If the time falls exactly onto the N-th keyframe

72 * the function returns N.

73 *

74 * Special cases:

75 * - if the time is before the first keyframe -1 is returned.

76 * - if the time is after the last keyframe, the index of the last keyframe

77 * is returned.

78 */

79 int anm_get_key_interval(struct anm_track *track, anm_time_t tm);

80

81 int anm_set_value(struct anm_track *track, anm_time_t tm, float val);

82

83 /* evaluates and returns the value of the track for a particular time */

84 float anm_get_value(struct anm_track *track, anm_time_t tm);

85

86

87

88 #endif /* LIBANIM_TRACK_H_ */