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filter: make the simpsons accel calculation available through the header

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This is the standard approach for mice and touchpads to calculate the
acceleration based on the last two deltas, let's make that code shareable.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
This commit is contained in:
Peter Hutterer 2018-04-10 16:20:45 +10:00
parent 0ead929838
commit 40c5b64f82
2 changed files with 26 additions and 34 deletions
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8
src/filter-private.h
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@ -106,6 +106,14 @@ tracker_by_offset(struct pointer_trackers *trackers, unsigned int offset);
double
calculate_velocity(struct pointer_trackers *trackers, uint64_t time);
double
calculate_acceleration_simpsons(struct motion_filter *filter,
accel_profile_func_t profile,
void *data,
double velocity,
double last_velocity,
uint64_t time);
/* Convert speed/velocity from units/us to units/ms */
static inline double
v_us2ms(double units_per_us)

52
src/filter.c
View file

@ -295,23 +295,6 @@ calculate_velocity(struct pointer_trackers *trackers, uint64_t time)
return result; /* units/us */
}
/**
* Apply the acceleration profile to the given velocity.
*
* @param accel The acceleration filter
* @param data Caller-specific data
* @param velocity Velocity in device-units per µs
* @param time Current time in µs
*
* @return A unitless acceleration factor, to be applied to the delta
*/
static double
acceleration_profile(struct pointer_accelerator *accel,
void *data, double velocity, uint64_t time)
{
return accel->profile(&accel->base, data, velocity, time);
}
/**
* Calculate the acceleration factor for our current velocity, averaging
* between our current and the most recent velocity to smoothen out changes.
@ -324,23 +307,23 @@ acceleration_profile(struct pointer_accelerator *accel,
*
* @return A unitless acceleration factor, to be applied to the delta
*/
static double
calculate_acceleration(struct pointer_accelerator *accel,
void *data,
double velocity,
double last_velocity,
uint64_t time)
double
calculate_acceleration_simpsons(struct motion_filter *filter,
accel_profile_func_t profile,
void *data,
double velocity,
double last_velocity,
uint64_t time)
{
double factor;
/* Use Simpson's rule to calculate the avarage acceleration between
* the previous motion and the most recent. */
factor = acceleration_profile(accel, data, velocity, time);
factor += acceleration_profile(accel, data, last_velocity, time);
factor += 4.0 *
acceleration_profile(accel, data,
(last_velocity + velocity) / 2,
time);
factor = profile(filter, data, velocity, time);
factor += profile(filter, data, last_velocity, time);
factor += 4.0 * profile(filter, data,
(last_velocity + velocity) / 2,
time);
factor = factor / 6.0;
@ -368,11 +351,12 @@ calculate_acceleration_factor(struct pointer_accelerator *accel,
feed_trackers(&accel->trackers, unaccelerated, time);
velocity = calculate_velocity(&accel->trackers, time);
accel_factor = calculate_acceleration(accel,
data,
velocity,
accel->last_velocity,
time);
accel_factor = calculate_acceleration_simpsons(&accel->base,
accel->profile,
data,
velocity,
accel->last_velocity,
time);
accel->last_velocity = velocity;
return accel_factor;