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Added a really simple wheel spin model for audio effect purposes only. This

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has absolutely no bearing on actual wheel performance and has nothing to do
with the fdm.  It is just a simplistic wheel spin velocity model used to
avoid subsequent squealing when a tire is bouncing, or touches down right after lifting off.  If at some point tire spin is modeled by an FDM we could
transition to using real data.
This commit is contained in:
curt 2001-12-21 04:53:37 +00:00
parent 784d6cd5fc
commit 71bf754fb8
1 changed files with 44 additions and 10 deletions

54
src/Sound/fg_fx.cxx
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@ -169,6 +169,15 @@ FGFX::init ()
_squeal->set_pitch(fgGetFloat("/sim/sounds/squeal/pitch", 1.0));
mgr->add(_squeal, "squeal");
//
// Simplistic wheel spin model for audio effect purposes only. We
// don't want to play a full squeel, if the wheel has only departed
// from the ground for a split second.
//
for (i = 0; i < MAX_GEAR; i++) {
_wheel_spin[i] = 0.0;
}
//
// Create and add the click noise.
_click = new FGSimpleSound(fgGetString("/sim/sounds/click/path",
@ -313,22 +322,47 @@ FGFX::update ()
// FIXME: take rotational velocities
// into account as well.
for (i = 0; i < totalGear; i++) {
// cout << "air speed = " << cur_fdm_state->get_V_equiv_kts();
// cout << " wheel " << i << " speed = " << _wheel_spin[i];
if (cur_fdm_state->get_gear_unit(i)->GetWoW()) {
gearOnGround++;
if (!_gear_on_ground[i]) {
// 3 parts horizontal velocity + 1 part vertical velocity
double squeal_volume = 0.75 * cur_fdm_state->get_V_equiv_kts() / 90.0 +
0.25 * cur_fdm_state->get_V_down() / 5.0;
if (squeal_volume > 0.1) {
_squeal->set_volume(squeal_volume);
_squeal->set_pitch(1.25);
mgr->play_once("squeal");
}
_gear_on_ground[i] = true;
// wheel just touched down
// 3 parts horizontal velocity + 1 part vertical velocity
double squeal_volume = 0.75 * cur_fdm_state->get_V_equiv_kts() / 90.0
+ 0.25 * cur_fdm_state->get_V_down() / 5.0;
// scale volume by difference between wheel spin speed and
// ground speed
double diff = fabs( cur_fdm_state->get_V_equiv_kts()
- _wheel_spin[i] );
// cout << " speed diff = " << diff;
double scale_factor = 0.0;
if ( diff > 10 ) {
scale_factor = ( diff - 10.0 ) / 30.0f;
if ( scale_factor > 1.0 ) { scale_factor = 1.0; }
}
// cout << " scale_factor = " << scale_factor;
squeal_volume *= scale_factor;
if (squeal_volume > 0.1) {
_squeal->set_volume(squeal_volume);
_squeal->set_pitch(1.25);
mgr->play_once("squeal");
}
_gear_on_ground[i] = true;
}
// cout << " wow";
_wheel_spin[i] = cur_fdm_state->get_V_equiv_kts();
} else {
_gear_on_ground[i] = false;
// cout << " airborn";
_gear_on_ground[i] = false;
/* fix me: wheel spindown is currently frame rate dependent which
it shouldn't be */
_wheel_spin[i] -= 0.2;
if ( _wheel_spin[i] < 0.0 ) { _wheel_spin[i] = 0.0; }
}
// cout << endl;
}
// Now, if any of the gear is in