src/animation.c


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#include "animation.h"
#include "log.h"
#include "maths.h"

keyframe animation_sample(animation_sampler *sampler, f32 t) {
  size_t previous_index = 0;
  f32 previous_time = 0.0;
  // look forwards
  // DEBUG("%d\n", sampler->animation.values.kind);
  TRACE("Total timestamps %d", sampler->animation.n_timestamps);
  for (u32 i = 0; i < sampler->animation.n_timestamps; i++) {
    f32 current_time = sampler->animation.timestamps[i];
    if (current_time > t) {
      break;
    }
    previous_time = sampler->animation.timestamps[i];
    previous_index = i;
  }

  size_t next_index = (previous_index + 1) % sampler->animation.n_timestamps;
  f32 next_time = sampler->animation.timestamps[next_index];
  printf("%d %f %d %f\n", previous_index, previous_time, next_index, next_time);

  keyframe prev_value = sampler->animation.values.values[previous_index];
  keyframe next_value = sampler->animation.values.values[next_index];

  printf("%d %d\n", previous_index, next_index);

  f32 time_diff =
      sampler->animation.timestamps[next_index] - sampler->animation.timestamps[previous_index];
  f32 percent = (t - previous_time) / time_diff;

  quat interpolated_rot =
      quat_slerp(sampler->animation.values.values[previous_index].rotation,
                 sampler->animation.values.values[next_index].rotation, percent);

  return (keyframe){ .rotation = interpolated_rot };
}