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/*
SuperCollider real time audio synthesis system
Copyright (c) 2002 James McCartney. All rights reserved.
http://www.audiosynth.com
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
// some basic physical modeling ugens - julian rohrhuber 1/04
// these are very simple implementations with cartoonification aspects.
#include "SC_PlugIn.h"
static InterfaceTable* ft;
//////////////////////////////////////////////////////////////////////////////////////////////////
struct Spring : public Unit {
float m_pos;
float m_vel;
};
struct Ball : public Unit {
float m_pos;
float m_vel;
float m_prev;
};
struct TBall : public Unit {
double m_pos;
float m_vel;
double m_prev;
};
extern "C" {
void Spring_Ctor(Spring* unit);
void Spring_next(Spring* unit, int inNumSamples);
// void Friction_Ctor(Friction *unit);
// void Friction_next(Friction *unit, int inNumSamples);
void Ball_Ctor(Ball* unit);
void Ball_next(Ball* unit, int inNumSamples);
void TBall_Ctor(TBall* unit);
void TBall_next(TBall* unit, int inNumSamples);
}
////////////////////////////////////////////////////////////////////////////////////////////////////////
void Spring_Ctor(Spring* unit) {
SETCALC(Spring_next);
unit->m_vel = 0.f;
unit->m_pos = 0.f;
Spring_next(unit, 1);
}
// in, spring, damping
void Spring_next(Spring* unit, int inNumSamples) {
float pos = unit->m_pos;
float vel = unit->m_vel;
float* out = ZOUT(0); // out force
float* in = ZIN(0); // in force
float spring = ZIN0(1); // spring constant
float damping = 1.f - ZIN0(2); // damping
float c = SAMPLEDUR;
float rc = SAMPLERATE;
spring = spring * c;
LOOP1(inNumSamples, float force = ZXP(in) * c - pos * spring; vel = (force + vel) * damping; pos += vel;
ZXP(out) = force * rc;);
unit->m_pos = pos;
unit->m_vel = vel;
}
//////////////////////////////////////////////////////////////////////////////////////////
void Ball_Ctor(Ball* unit) {
SETCALC(Ball_next);
unit->m_vel = 0.f;
unit->m_pos = ZIN0(0);
unit->m_prev = ZIN0(0);
Ball_next(unit, 1);
}
void Ball_next(Ball* unit, int inNumSamples) {
float* out = ZOUT(0);
float* in = ZIN(0); // floor position
float g_in = ZIN0(1); // gravity
float damping = 1 - ZIN0(2); // damping
float k = ZIN0(3); // friction
float pos = unit->m_pos;
float vel = unit->m_vel;
float prev_floor = unit->m_prev;
float c = SAMPLEDUR;
float maxvel = c * 1000.f;
float minvel = 0.f - maxvel;
float inter = c * 1000.f;
RGen& rgen = *unit->mParent->mRGen;
float g = c * g_in;
k = (double)k * (double)g_in; // stickyness proportional to gravity
LOOP1(
inNumSamples, float floor = ZXP(in); float floorvel; float dither; vel -= g; pos += vel;
float dist = pos - floor; floorvel = floor - prev_floor; floorvel = sc_clip(floorvel, minvel, maxvel);
float vel_diff = floorvel - vel; if (sc_abs(dist) < k) { // sticky friction: maybe vel dependant?
if (sc_abs(dist) < (k * 0.005)) {
vel = 0.f;
pos = floor + g;
} else {
vel = vel_diff * inter + vel;
pos = (floor - pos) * inter + pos;
}
} else if (dist <= 0.f) {
pos = floor - dist;
vel = vel_diff;
vel *= damping;
dither = rgen.frand() * 0.00005f * g_in; // dither to reduce jitter
// if(sc_abs(dist) < 0.000001) { vel += dither; }
vel += dither;
} prev_floor = floor;
ZXP(out) = pos;);
unit->m_pos = pos;
unit->m_vel = vel;
unit->m_prev = prev_floor;
}
//////////////////////////////////////////////////////////////////////////////////////////
void TBall_Ctor(TBall* unit) {
SETCALC(TBall_next);
unit->m_vel = 0.f;
unit->m_pos = ZIN0(0);
unit->m_prev = ZIN0(0);
TBall_next(unit, 1);
}
void TBall_next(TBall* unit, int inNumSamples) {
float* out = ZOUT(0);
float* in = ZIN(0); // floor position
float g_in = ZIN0(1); // gravity
float damping = 1 - ZIN0(2); // damping
float k = ZIN0(3); // friction
double pos = unit->m_pos;
float vel = unit->m_vel;
double prev_floor = unit->m_prev;
float c = SAMPLEDUR;
float maxvel = c * 1000.f;
float minvel = 0.f - maxvel;
float inter = c * 10000.f;
RGen& rgen = *unit->mParent->mRGen;
float g = c * g_in;
k = (double)k * (double)g_in; // stickyness proportional to gravity
LOOP1(
inNumSamples, double floor = ZXP(in); float floorvel; float outval = 0.f; float dither; vel -= g; pos += vel;
double dist = pos - floor; floorvel = floor - prev_floor; floorvel = sc_clip(floorvel, minvel, maxvel);
float vel_diff = floorvel - vel; if (sc_abs(dist) < k) { // sticky friction: vel dependant?
if (sc_abs(dist) < (k * 0.005)) {
vel = 0.f;
pos = floor + g;
} else {
vel = vel_diff * inter + vel;
pos = (floor - pos) * inter + pos;
}
} else if (dist <= 0.f) {
pos = floor - dist;
vel = floorvel - vel;
vel *= damping;
outval = vel;
dither = rgen.frand() * 0.001f * g_in; // dither to reduce sampling jitter
// if(sc_abs(dist) < 0.003) { vel += dither; }
vel += dither;
} prev_floor = floor;
ZXP(out) = outval;);
unit->m_pos = pos;
unit->m_vel = vel;
unit->m_prev = prev_floor;
}
////////////////////////////////////////////////////////////////////////////////////////////////////////
PluginLoad(PhysicalModeling) {
ft = inTable;
DefineSimpleUnit(Spring);
DefineSimpleUnit(Ball);
DefineSimpleUnit(TBall);
}
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