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xserver/dix/ptrveloc.c

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#ifdef HAVE_DIX_CONFIG_H
#include <dix-config.h>
#endif
#include <math.h>
#include <ptrveloc.h>
#include <inputstr.h>
#include <assert.h>
/*****************************************************************************
* Predictable pointer ballistics
*
* 2006-2008 by Simon Thum (simon [dot] thum [at] gmx de)
*
* Serves 3 complementary functions:
* 1) provide a sophisticated ballistic velocity estimate to improve
* the relation between velocity (of the device) and acceleration
* 2) make arbitrary acceleration profiles possible
* 3) decelerate by two means (constant and adaptive) if enabled
*
* Important concepts are the
*
* - Scheme
* which selects the basic algorithm
* (see devices.c/InitPointerAccelerationScheme)
* - Profile
* which returns an acceleration
* for a given velocity
*
* The profile can be selected by the user (potentially at runtime).
* the classic profile is intended to cleanly perform old-style
* function selection (threshold =/!= 0)
*
****************************************************************************/
/* fwds */
static inline void
FeedFilterStage(FilterStagePtr s, float value, int tdiff);
extern void
InitFilterStage(FilterStagePtr s, float rdecay, int lutsize);
void
CleanupFilterChain(DeviceVelocityPtr s);
int
SetAccelerationProfile(DeviceVelocityPtr s, int profile_num);
void
InitFilterChain(DeviceVelocityPtr s, float rdecay, float degression,
int stages, int lutsize);
void
CleanupFilterChain(DeviceVelocityPtr s);
static float
SimpleSmoothProfile(DeviceVelocityPtr pVel, float threshold, float acc);
/********************************
* Init/Uninit etc
*******************************/
/**
* Init struct so it should match the average case
*/
void
InitVelocityData(DeviceVelocityPtr s)
{
s->lrm_time = 0;
s->velocity = 0;
s->corr_mul = 10.0; /* dots per 10 milisecond should be usable */
s->const_acceleration = 1.0; /* no acceleration/deceleration */
s->reset_time = 300;
s->last_dx = 0;
s->last_dy = 0;
s->use_softening = 1;
s->min_acceleration = 1.0; /* don't decelerate */
s->coupling = 0.2;
s->profile_private = NULL;
memset(&s->statistics, 0, sizeof(s->statistics));
memset(&s->filters, 0, sizeof(s->filters));
SetAccelerationProfile(s, 0);
InitFilterChain(s, (float)1.0/20.0, 1, 1, 40);
}
/**
* Clean up
*/
static void
FreeVelocityData(DeviceVelocityPtr s){
CleanupFilterChain(s);
SetAccelerationProfile(s, -1);
}
/*
* dix uninit helper, called through scheme
*/
void
AccelerationDefaultCleanup(DeviceIntPtr pDev){
/*sanity check*/
if( pDev->valuator->accelScheme.AccelSchemeProc == acceleratePointerPredictable
&& pDev->valuator->accelScheme.accelData != NULL){
pDev->valuator->accelScheme.AccelSchemeProc = NULL;
FreeVelocityData(pDev->valuator->accelScheme.accelData);
xfree(pDev->valuator->accelScheme.accelData);
pDev->valuator->accelScheme.accelData = NULL;
}
}
/*********************
* Filtering logic
********************/
/**
Initialize a filter chain.
Expected result is a series of filters, each progressively more integrating.
*/
void
InitFilterChain(DeviceVelocityPtr s, float rdecay, float progression, int stages, int lutsize)
{
int fn;
if((stages > 1 && progression < 1.0f) || 0 == progression){
ErrorF("(dix ptracc) invalid filter chain progression specified\n");
return;
}
for(fn = 0; fn < MAX_VELOCITY_FILTERS; fn++){
if(fn < stages){
InitFilterStage(&s->filters[fn], rdecay, lutsize);
}else{
InitFilterStage(&s->filters[fn], 0, 0);
}
rdecay /= progression;
}
}
void
CleanupFilterChain(DeviceVelocityPtr s)
{
int fn;
for(fn = 0; fn < MAX_VELOCITY_FILTERS; fn++)
InitFilterStage(&s->filters[fn], 0, 0);
}
/**
* Adjust weighting decay and lut in sync
* The weight fn is designed so its integral 0->inf is unity, so we end
* up with a stable (basically IIR) filter. It always draws
* towards its more current input values, which have more weight the older
* the last input value is.
*/
void
InitFilterStage(FilterStagePtr s, float rdecay, int lutsize)
{
int x;
float *newlut;
float *oldlut;
s->fading_lut_size = 0; /* prevent access */
/* mb(); concurrency issues may arise */
if(lutsize > 0){
newlut = xalloc (sizeof(float)* lutsize);
if(!newlut)
return;
for(x = 0; x < lutsize; x++)
newlut[x] = pow(0.5, ((float)x) * rdecay);
}else{
newlut = NULL;
}
oldlut = s->fading_lut;
s->fading_lut = newlut;
s->rdecay = rdecay;
s->fading_lut_size = lutsize;
s->current = 0;
if(oldlut != NULL)
xfree(oldlut);
}
static inline void
FeedFilterChain(DeviceVelocityPtr s, float value, int tdiff)
{
int fn;
for(fn = 0; fn < MAX_VELOCITY_FILTERS; fn++){
if(s->filters[fn].rdecay != 0)
FeedFilterStage(&s->filters[fn], value, tdiff);
else break;
}
}
static inline void
FeedFilterStage(FilterStagePtr s, float value, int tdiff){
float fade;
if(tdiff < s->fading_lut_size)
fade = s->fading_lut[tdiff];
else
fade = pow(0.5, ((float)tdiff) * s->rdecay);
s->current *= fade; /* fade out old velocity */
s->current += value * (1.0f - fade); /* and add up current */
}
/**
* Select the most filtered matching result. Also, the first
* mismatching filter will be set to value (coupling).
*/
static inline float
QueryFilterChain(
DeviceVelocityPtr s,
float value,
float maxdiv)
{
int fn, rfn = 0, cfn = -1;
float cur, result = value;
/* try to retrieve most integrated result 'within range'
* Assumption: filter are in order least to most integrating */
for(fn = 0; fn < MAX_VELOCITY_FILTERS; fn++){
if(0.0f == s->filters[fn].rdecay)
break;
cur = s->filters[fn].current;
if (fabs(value - cur) <= 1.0f ||
fabs(value - cur) / (value + cur) <= maxdiv){
result = cur;
rfn = fn; /*remember result determining filter */
} else if(cfn == -1){
cfn = fn; /* rememeber first mismatching filter */
}
}
s->statistics.filter_usecount[rfn]++;
#ifdef SERIOUS_DEBUGGING
ErrorF("(dix ptraccel) result from filter stage %i, input %.2f, output %.2f\n", rfn, value, result);
#endif
/* override one current (coupling) so the filter
* catches up quickly. */
if(cfn != -1)
s->filters[cfn].current = result;
return result;
}
/********************************
* velocity computation
*******************************/
/**
* return the axis if mickey is insignificant and axis-aligned,
* -1 otherwise
* 1 for x-axis
* 2 for y-axis
*/
static inline short
GetAxis(int dx, int dy){
if(dx == 0 || dy == 0){
if(dx == 1 || dx == -1)
return 1;
if(dy == 1 || dy == -1)
return 2;
return -1;
}else{
return -1;
}
}
/**
* Perform velocity approximation
* return true if non-visible state reset is suggested
*/
static short
ProcessVelocityData(DeviceVelocityPtr s, int dx, int dy, int time)
{
float cvelocity;
int diff = time - s->lrm_time;
int cur_ax = GetAxis(dx, dy);
int last_ax = GetAxis(s->last_dx, s->last_dy);
short reset = (diff >= s->reset_time);
if(cur_ax != last_ax && cur_ax != -1 && last_ax != -1 && !reset){
/* correct for the error induced when diagonal movements are
reported as alternating axis mickeys */
dx += s->last_dx;
dy += s->last_dy;
diff += s->last_diff;
s->last_diff = time - s->lrm_time; /* prevent repeating add-up */
#ifdef SERIOUS_DEBUGGING
ErrorF("(dix ptracc) axial correction\n");
#endif
}else{
s->last_diff = diff;
}
/*
* cvelocity is not a real velocity yet, more a motion delta. contant
* acceleration is multiplied here to make the velocity an on-screen
* velocity (px/t as opposed to [insert unit]/t). This is intended to
* make multiple devices with widely varying ConstantDecelerations respond
* similar to acceleration controls.
*/
cvelocity = (float)sqrt(dx*dx + dy*dy) * s->const_acceleration;
s->lrm_time = time;
if (s->reset_time < 0 || diff < 0) { /* disabled or timer overrun? */
/* simply set velocity from current movement, no reset. */
s->velocity = cvelocity;
return 0;
}
if (diff == 0)
diff = 1; /* prevent div-by-zero, though it shouldn't happen anyway*/
/* translate velocity to dots/ms (somewhat untractable in integers,
so we multiply by some per-device adjustable factor) */
cvelocity = cvelocity * s->corr_mul / (float)diff;
/* short-circuit: when nv-reset the rest can be skipped */
if(reset == TRUE){
s->velocity = cvelocity;
return TRUE;
}
/* feed into filter chain */
FeedFilterChain(s, cvelocity, diff);
/* perform coupling and decide final value */
s->velocity = QueryFilterChain(s, cvelocity, s->coupling);
#ifdef SERIOUS_DEBUGGING
ErrorF("(dix ptracc) guess: vel=%.3f diff=%d |%i|%i|%i|%i|\n",
s->velocity, diff,
s->statistics.filter_usecount[0], s->statistics.filter_usecount[1],
s->statistics.filter_usecount[2], s->statistics.filter_usecount[3]);
#endif
return reset;
}
/**
* this flattens significant ( > 1) mickeys a little bit for more steady
* constant-velocity response
*/
static inline float
ApplySimpleSoftening(int od, int d)
{
float res = d;
if (d <= 1 && d >= -1)
return res;
if (d > od)
res -= 0.5;
else if (d < od)
res += 0.5;
return res;
}
static void
ApplySofteningAndConstantDeceleration(
DeviceVelocityPtr s,
int dx,
int dy,
float* fdx,
float* fdy,
short do_soften)
{
if (do_soften && s->use_softening) {
*fdx = ApplySimpleSoftening(s->last_dx, dx);
*fdy = ApplySimpleSoftening(s->last_dy, dy);
} else {
*fdx = dx;
*fdy = dy;
}
*fdx *= s->const_acceleration;
*fdy *= s->const_acceleration;
}
/*****************************************
* Acceleration functions and profiles
****************************************/
/**
* Polynomial function similar previous one, but with f(1) = 1
*/
static float
PolynomialAccelerationProfile(DeviceVelocityPtr pVel, float ignored, float acc)
{
return pow(pVel->velocity, (acc - 1.0) * 0.5);
}
/**
* returns acceleration for velocity.
* This profile selects the two functions like the old scheme did
*/
static float
ClassicProfile(
DeviceVelocityPtr pVel,
float threshold,
float acc)
{
if (threshold) {
return SimpleSmoothProfile (pVel,
threshold,
acc);
} else {
return PolynomialAccelerationProfile (pVel,
0,
acc);
}
}
/**
* Power profile
* This has a completely smooth transition curve, i.e. no jumps in the
* derivatives.
*
* This has the expense of overall response dependency on min-acceleration.
* In effect, min_acceleration mimics const_acceleration in this profile.
*/
static float
PowerProfile(
DeviceVelocityPtr pVel,
float threshold,
float acc)
{
float vel_dist;
acc = (acc-1.0) * 0.1f + 1.0; /* without this, acc of 2 is unuseable */
if (pVel->velocity <= threshold)
return pVel->min_acceleration;
vel_dist = pVel->velocity - threshold;
return (pow(acc, vel_dist)) * pVel->min_acceleration;
}
/**
* just a smooth function in [0..1] -> [0..1]
* - point symmetry at 0.5
* - f'(0) = f'(1) = 0
* - starts faster than sinoids, C1 (Cinf if you dare to ignore endpoints)
*/
static inline float
CalcPenumbralGradient(float x){
x *= 2.0f;
x -= 1.0f;
return 0.5f + (x * sqrt(1.0f - x*x) + asin(x))/M_PI;
}
/**
* acceleration function similar to classic accelerated/unaccelerated,
* but with smooth transition in between (and towards zero for adaptive dec.).
*/
static float
SimpleSmoothProfile(
DeviceVelocityPtr pVel,
float threshold,
float acc)
{
float velocity = pVel->velocity;
if(velocity < 1.0f)
return CalcPenumbralGradient(0.5 + velocity*0.5) * 2.0f - 1.0f;
if(threshold < 1.0f)
threshold = 1.0f;
if (velocity <= threshold)
return 1;
velocity /= threshold;
if (velocity >= acc)
return acc;
else
return 1.0f + (CalcPenumbralGradient(velocity/acc) * (acc - 1.0f));
}
/**
* This profile uses the first half of the penumbral gradient as a start
* and then scales linearly.
*/
static float
SmoothLinearProfile(
DeviceVelocityPtr pVel,
float threshold,
float acc)
{
if(acc > 1.0f)
acc -= 1.0f; /*this is so acc = 1 is no acceleration */
else
return 1.0f;
float nv = (pVel->velocity - threshold) * acc * 0.5f;
float res;
if(nv < 0){
res = 0;
}else if(nv < 2){
res = CalcPenumbralGradient(nv*0.25f)*2.0f;
}else{
nv -= 2.0f;
res = nv * 2.0f / M_PI /* steepness of gradient at 0.5 */
+ 1.0f; /* gradient crosses 2|1 */
}
res += pVel->min_acceleration;
return res;
}
static float
LinearProfile(
DeviceVelocityPtr pVel,
float threshold,
float acc)
{
return acc * pVel->velocity;
}
/**
* Set the profile by number.
* Intended to make profiles exchangeable at runtime.
* If you created a profile, give it a number here to make it selectable.
* In case some profile-specific init is needed, here would be a good place,
* since FreeVelocityData() also calls this with -1.
* returns FALSE (0) if profile number is unknown.
*/
int
SetAccelerationProfile(
DeviceVelocityPtr s,
int profile_num)
{
PointerAccelerationProfileFunc profile;
switch(profile_num){
case -1:
profile = NULL; /* Special case to uninit properly */
break;
case 0:
profile = ClassicProfile;
break;
case 1:
if(NULL == s->deviceSpecificProfile)
return FALSE;
profile = s->deviceSpecificProfile;
break;
case 2:
profile = PolynomialAccelerationProfile;
break;
case 3:
profile = SmoothLinearProfile;
break;
case 4:
profile = SimpleSmoothProfile;
break;
case 5:
profile = PowerProfile;
break;
case 6:
profile = LinearProfile;
break;
default:
return FALSE;
}
if(s->profile_private != NULL){
/* Here one could free old profile-private data */
xfree(s->profile_private);
s->profile_private = NULL;
}
/* Here one could init profile-private data */
s->Profile = profile;
s->statistics.profile_number = profile_num;
return TRUE;
}
/**
* device-specific profile
*
* The device-specific profile is intended as a hook for a driver
* which may want to provide an own acceleration profile.
* It should not rely on profile-private data, instead
* it should do init/uninit in the driver (ie. with DEVICE_INIT and friends).
* Users may override or choose it.
*/
extern void
SetDeviceSpecificAccelerationProfile(
DeviceIntPtr pDev,
PointerAccelerationProfileFunc profile)
{
/*sanity check*/
if( pDev->valuator &&
pDev->valuator->accelScheme.AccelSchemeProc ==
acceleratePointerPredictable &&
pDev->valuator->accelScheme.accelData != NULL){
((DeviceVelocityPtr)
(pDev->valuator->accelScheme.accelData))->deviceSpecificProfile
= profile;
}
}
/********************************
* acceleration schemes
*******************************/
/**
* Modifies valuators in-place.
* This version employs a velocity approximation algorithm to
* enable fine-grained predictable acceleration profiles.
*/
void
acceleratePointerPredictable(DeviceIntPtr pDev, int first_valuator,
int num_valuators, int *valuators, int evtime)
{
float mult = 0.0;
int dx = 0, dy = 0;
int *px = NULL, *py = NULL;
DeviceVelocityPtr velocitydata =
(DeviceVelocityPtr) pDev->valuator->accelScheme.accelData;
float fdx, fdy; /* no need to init */
if (!num_valuators || !valuators || !velocitydata)
return;
if (first_valuator == 0) {
dx = valuators[0];
px = &valuators[0];
}
if (first_valuator <= 1 && num_valuators >= (2 - first_valuator)) {
dy = valuators[1 - first_valuator];
py = &valuators[1 - first_valuator];
}
if (dx || dy){
/* reset nonvisible state? */
if (ProcessVelocityData(velocitydata, dx , dy, evtime)) {
/* set to center of pixel */
pDev->last.remainder[0] = pDev->last.remainder[1] = 0.5f;
/* prevent softening (somewhat quirky solution,
as it depends on the algorithm) */
velocitydata->last_dx = dx;
velocitydata->last_dy = dy;
}
if (pDev->ptrfeed && pDev->ptrfeed->ctrl.num) {
/* invoke acceleration profile to determine acceleration */
mult = velocitydata->Profile(velocitydata,
pDev->ptrfeed->ctrl.threshold,
(float)(pDev->ptrfeed->ctrl.num) /
(float)(pDev->ptrfeed->ctrl.den));
#ifdef SERIOUS_DEBUGGING
ErrorF("(dix ptracc) resulting speed multiplier : %.3f\n", mult);
#endif
/* enforce min_acceleration */
if (mult < velocitydata->min_acceleration) {
#ifdef SERIOUS_DEBUGGING
ErrorF("(dix ptracc) enforced min multiplier : %.3f\n",
velocitydata->min_acceleration);
#endif
mult = velocitydata->min_acceleration;
}
if(mult != 1.0 || velocitydata->const_acceleration != 1.0) {
ApplySofteningAndConstantDeceleration( velocitydata,
dx, dy,
&fdx, &fdy,
mult > 1.0);
if (dx) {
pDev->last.remainder[0] = mult * fdx + pDev->last.remainder[0];
*px = (int)pDev->last.remainder[0];
pDev->last.remainder[0] = pDev->last.remainder[0] - (float)*px;
}
if (dy) {
pDev->last.remainder[1] = mult * fdy + pDev->last.remainder[1];
*py = (int)pDev->last.remainder[1];
pDev->last.remainder[1] = pDev->last.remainder[1] - (float)*py;
}
}
}
}
/* remember last motion delta (for softening/slow movement treatment) */
velocitydata->last_dx = dx;
velocitydata->last_dy = dy;
}
/**
* Originally a part of xf86PostMotionEvent; modifies valuators
* in-place. Retained mostly for embedded scenarios.
*/
void
acceleratePointerClassic(DeviceIntPtr pDev, int first_valuator,
int num_valuators, int *valuators, int ignored)
{
float mult = 0.0;
int dx = 0, dy = 0;
int *px = NULL, *py = NULL;
if (!num_valuators || !valuators)
return;
if (first_valuator == 0) {
dx = valuators[0];
px = &valuators[0];
}
if (first_valuator <= 1 && num_valuators >= (2 - first_valuator)) {
dy = valuators[1 - first_valuator];
py = &valuators[1 - first_valuator];
}
if (!dx && !dy)
return;
if (pDev->ptrfeed && pDev->ptrfeed->ctrl.num) {
/* modeled from xf86Events.c */
if (pDev->ptrfeed->ctrl.threshold) {
if ((abs(dx) + abs(dy)) >= pDev->ptrfeed->ctrl.threshold) {
pDev->last.remainder[0] = ((float)dx *
(float)(pDev->ptrfeed->ctrl.num)) /
(float)(pDev->ptrfeed->ctrl.den) +
pDev->last.remainder[0];
if (px) {
*px = (int)pDev->last.remainder[0];
pDev->last.remainder[0] = pDev->last.remainder[0] -
(float)(*px);
}
pDev->last.remainder[1] = ((float)dy *
(float)(pDev->ptrfeed->ctrl.num)) /
(float)(pDev->ptrfeed->ctrl.den) +
pDev->last.remainder[1];
if (py) {
*py = (int)pDev->last.remainder[1];
pDev->last.remainder[1] = pDev->last.remainder[1] -
(float)(*py);
}
}
}
else {
mult = pow((float)dx * (float)dx + (float)dy * (float)dy,
((float)(pDev->ptrfeed->ctrl.num) /
(float)(pDev->ptrfeed->ctrl.den) - 1.0) /
2.0) / 2.0;
if (dx) {
pDev->last.remainder[0] = mult * (float)dx +
pDev->last.remainder[0];
*px = (int)pDev->last.remainder[0];
pDev->last.remainder[0] = pDev->last.remainder[0] -
(float)(*px);
}
if (dy) {
pDev->last.remainder[1] = mult * (float)dy +
pDev->last.remainder[1];
*py = (int)pDev->last.remainder[1];
pDev->last.remainder[1] = pDev->last.remainder[1] -
(float)(*py);
}
}
}
}
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