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enable predictive smoothing

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This commit is contained in:
David Rose 2001-10-23 22:54:13 +00:00
parent 47562a9984
commit e328baf2b4
2 changed files with 35 additions and 4 deletions
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34
direct/src/deadrec/smoothMover.cxx
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@ -214,10 +214,15 @@ compute_smooth_position(double timestamp) {
int point_after = -1;
double timestamp_after = 0.0;
// This loop doesn't make any assumptions about the ordering of
// timestamps in the queue. We could probably make it faster by
// assuming timestamps are ordered from oldest to newest (as they
// are generally guaranteed to be, except for the minor detail of
// clients occasionally resetting their clocks).
int num_points = _points.size();
for (int i = 0; i < num_points; i++) {
const SamplePoint &point = _points[i];
if (point._timestamp <= timestamp) {
if (point._timestamp < timestamp) {
// This point is before the desired time. Find the newest of
// these.
if (point_before == -1 || point._timestamp > timestamp_before) {
@ -251,9 +256,30 @@ compute_smooth_position(double timestamp) {
bool result = true;
if (point_after == -1 || timestamp_before == timestamp_after) {
// If we only have a before point, we have to stop there, unless
// we have prediction in effect.
if (point_after == -1 && _prediction_mode != PM_off) {
// With prediction in effect, we're allowed to anticipate where
// the avatar is going by a tiny bit, if we don't have current
// enough data. This works only if we have at least two points of
// old data, and they're not *too* old.
if (point_before > 0 &&
timestamp - timestamp_before <= _max_position_age) {
// To implement simple prediction, we simply back up in time to
// the previous two timestamps, and base our linear
// interpolation off of those two, extending into the future.
int point_before_before = point_before - 1;
const SamplePoint &point = _points[point_before_before];
if (point._timestamp < timestamp_before) {
point_after = point_before;
timestamp_after = timestamp_before;
point_before = point_before_before;
timestamp_before = point._timestamp;
}
}
}
if (point_after == -1) {
// If we only have a before point even after we've checked for the
// possibility of using prediction, then we have to stop there.
const SamplePoint &point = _points[point_before];
set_smooth_pos(point._pos, point._hpr, timestamp);
if (timestamp - point._timestamp > _reset_velocity_age) {

5
direct/src/deadrec/smoothMover.h
View File

@ -100,10 +100,15 @@ PUBLISHED:
enum SmoothMode {
SM_off,
SM_on,
// We might conceivably add more kinds of smooth modes later, for
// instance, SM_spline.
};
enum PredictionMode {
PM_off,
PM_on,
// Similarly for other kinds of prediction modes. I don't know
// why, though; linear interpolation seems to work pretty darn
// well.
};
INLINE static void set_smooth_mode(SmoothMode mode);