class MyMass:CMass
{
F64 radius;
};
class MySpring:CSpring
{
};
CMathODE *ode=NULL;
U0 DrawIt(CTask *,CDC *dc)
{
MyMass *tmpm;
MySpring *tmps;
dc->color=RED;
tmps=ode->next_spring;
while (tmps!=&ode->next_spring) {
GrLine(dc,tmps->end1->x,tmps->end1->y,tmps->end2->x,tmps->end2->y);
tmps=tmps->next;
}
dc->color=BLACK;
tmpm=ode->next_mass;
while (tmpm!=&ode->next_mass) {
GrCircle(dc,tmpm->x,tmpm->y,tmpm->radius);
tmpm=tmpm->next;
}
}
U0 MyDerivative(CMathODE *ode,F64,COrder2D3 *,COrder2D3 *)
{//The forces due to springs and drag are
//automatically handled by the ode code.
//We can add new forces here.
F64 d,dd;
CD3 p;
MyMass *tmpm1,*tmpm2;
tmpm1=ode->next_mass;
while (tmpm1!=&ode->next_mass) {
tmpm2=tmpm1->next;
while (tmpm2!=&ode->next_mass) {
D3Sub(&p,&tmpm2->state->x,&tmpm1->state->x);
dd=D3NormSqr(&p);
if (dd<=Sqr(tmpm1->radius+tmpm2->radius)) {
d=Sqrt(dd)+0.0001;
dd=10.0*Sqr(Sqr(Sqr(tmpm1->radius+tmpm2->radius)-dd));
D3MulEqu(&p,dd/d);
D3AddEqu(&tmpm2->DstateDt->DxDt,&p);
D3SubEqu(&tmpm1->DstateDt->DxDt,&p);
}
tmpm2=tmpm2->next;
}
tmpm1=tmpm1->next;
}
}
U0 PlaceMass(I64 x, I64 y)
{
MyMass *tmpm=CAlloc(sizeof(MyMass));
tmpm->mass=1.0;
tmpm->drag_profile_factor=100.0;
tmpm->x=x;
tmpm->y=y;
tmpm->radius=10*(Rand+0.25);
QueIns(tmpm,ode->last_mass);
}
U0 PlaceSpring(MyMass *tmpm1,MyMass *tmpm2)
{
MySpring *tmps=CAlloc(sizeof(MySpring));
tmps->end1=tmpm1;
tmps->end2=tmpm2;
tmps->const=10000;
tmps->rest_len=100;
QueIns(tmps,ode->last_spring);
}
U0 Init()
{
ode=ODENew(0,1e-4,ODEF_HAS_MASSES);
ode->derive=&MyDerivative;
ode->drag_v2=0.002;
ode->drag_v3=0.00001;
ode->acceleration_limit=5e3;
QueIns(ode,Fs->last_ode);
}
U0 CleanUp()
{
QueRem(ode);
QueDel(&ode->next_mass,TRUE);
QueDel(&ode->next_spring,TRUE);
ODEDel(ode);
}
U0 MassSpringDemo()
{
I64 msg_code,arg1,arg2;
MyMass *tmpm1=NULL,*tmpm2=NULL;
PopUpOk("Left-Click to place mas\n"
"Right-Click and drag to\n"
"connect with spring.\n\n"
"Springs are 100 pixs long.\n");
SettingsPush; //See SettingsPush
AutoComplete;
WinBorder;
WinMax;
DocCursor;
DocClear;
Fs->win_inhibit|=WIG_DBL_CLICK;
MenuPush(
"File {"
" Abort(,CH_SHIFT_ESC);"
" Exit(,CH_ESC);"
"}"
"Play {"
" Restart(,'\n');"
"}"
);
Init;
Fs->draw_it=&DrawIt;
try {
while (TRUE) {
msg_code=GetMsg(&arg1,&arg2,
1<<MSG_MS_L_DOWN|1<<MSG_MS_R_DOWN|1<<MSG_MS_R_UP|1<<MSG_KEY_DOWN);
switch (msg_code) {
case MSG_MS_L_DOWN:
PlaceMass(arg1,arg2);
break;
case MSG_MS_R_DOWN:
tmpm1=MassFind(ode,arg1,arg2);
tmpm2=NULL;
break;
case MSG_MS_R_UP:
if (tmpm1 && (tmpm2=MassFind(ode,arg1,arg2)) && tmpm1!=tmpm2)
PlaceSpring(tmpm1,tmpm2);
tmpm1=tmpm2=NULL;
break;
case MSG_KEY_DOWN:
switch (arg1) {
case '\n':
CleanUp;
Init;
break;
case CH_SHIFT_ESC:
case CH_ESC:
goto ms_done;
}
break;
}
}
ms_done: //Don't goto out of try
GetMsg(,,1<<MSG_KEY_UP);
} catch
PutExcept;
SettingsPop;
CleanUp;
MenuPop;
}
MassSpringDemo;