190 lines
3.6 KiB
C++
190 lines
3.6 KiB
C++
class MyMass:CMass
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{
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F64 radius;
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};
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class MySpring:CSpring
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{
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};
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CMathODE *ode=NULL;
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U0 DrawIt(CTask *task,CDC *dc)
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{
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Bool old_suspend;
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MyMass *tempm;
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MySpring *temps;
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old_suspend=Suspend(task);
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dc->color=RED;
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temps=ode->next_spring;
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while (temps!=&ode->next_spring) {
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GrLine(dc,temps->end1->x,temps->end1->y,
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temps->end2->x,temps->end2->y);
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temps=temps->next;
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}
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dc->color=BLACK;
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tempm=ode->next_mass;
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while (tempm!=&ode->next_mass) {
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GrCircle(dc,tempm->x,tempm->y,tempm->radius);
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tempm=tempm->next;
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}
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Suspend(task,old_suspend);
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}
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U0 MyDerivative(CMathODE *ode,F64,COrder2D3 *,COrder2D3 *)
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{
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//The forces due to springs and drag are
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//automatically handled by the
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//ode code. We can add new forces
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//here.
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F64 d,dd;
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CD3 p;
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MyMass *tempm1,*tempm2;
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tempm1=ode->next_mass;
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while (tempm1!=&ode->next_mass) {
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tempm2=tempm1->next;
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while (tempm2!=&ode->next_mass) {
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D3Sub(&tempm2->state->x,&tempm1->state->x,&p);
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dd=D3SqrNorm(&p);
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if (dd<=Sqr(tempm1->radius+tempm2->radius)) {
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d=Sqrt(dd)+0.0001;
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dd=10.0*Sqr(Sqr(Sqr(tempm1->radius+tempm2->radius)-dd));
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D3MulEqu(&p,dd/d);
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D3AddEqu(&tempm2->DstateDt->DxDt,&p);
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D3SubEqu(&tempm1->DstateDt->DxDt,&p);
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}
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tempm2=tempm2->next;
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}
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tempm1=tempm1->next;
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}
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}
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U0 PlaceMass(I64 x, I64 y)
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{
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MyMass *tempm=CAlloc(sizeof(MyMass));
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tempm->mass=1.0;
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tempm->drag_profile_factor=100.0;
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tempm->x=x;
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tempm->y=y;
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tempm->radius=10*(Rand+0.25);
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QueIns(tempm,ode->last_mass);
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}
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U0 PlaceSpring(MyMass *tempm1,MyMass *tempm2)
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{
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MySpring *temps=CAlloc(sizeof(MySpring));
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temps->end1=tempm1;
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temps->end2=tempm2;
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temps->constant=10000;
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temps->rest_len=100;
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QueIns(temps,ode->last_spring);
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}
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U0 Init()
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{
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ode=ODENew(0,1e-4,ODEF_HAS_MASSES);
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ode->derivative=&MyDerivative;
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ode->drag_v2=0.002;
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ode->drag_v3=0.00001;
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ode->acceleration_limit=5e3;
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QueIns(ode,Fs->last_ode);
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}
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U0 CleanUp()
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{
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QueRem(ode);
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QueDel(&ode->next_mass,TRUE);
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QueDel(&ode->next_spring,TRUE);
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ODEDel(ode);
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}
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U0 MassSpringDemo()
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{
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I64 msg_code,p1,p2;
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MyMass *tempm1=NULL,*tempm2=NULL;
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PopUpOk("Left-Click to place mas\n"
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"Right-Click and drag to\n"
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"connect with spring.\n\n"
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"Springs are 100 pixels long.\n");
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SettingsPush; //See $LK,"SettingsPush","MN:SettingsPush"$
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WinMax;
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//This Preempt() eliminates a lot of hassles.
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//The concern is about changing
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//que links while the winmgr task
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//is updating the ode or screen.
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//The Window mgr suspends this
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//task while updating the ode. It
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//will not be interrupted and with this
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//preempt, we will not be interrupted.
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//There is little downside to Preempt()
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//since we will yield during GetMsg().
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Preempt(OFF);
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Fs->win_inhibit|=WIF_DBL_CLICK;
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WordStat;
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MenuPush(
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"File {"
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" Abort(,CH_SHIFT_ESC);"
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" Exit(,CH_ESC);"
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"}"
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"Play {"
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" Restart(,'\n');"
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"}"
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);
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Init;
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DocCursor;
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DocClear;
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Fs->draw_it=&DrawIt;
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try {
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while (TRUE) {
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msg_code=GetMsg(&p1,&p2,1<<MSG_IP_L_DOWN|1<<MSG_IP_R_DOWN|1<<MSG_IP_R_UP|1<<MSG_KEY_DOWN);
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switch (msg_code) {
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case MSG_IP_L_DOWN:
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PlaceMass(p1,p2);
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break;
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case MSG_IP_R_DOWN:
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tempm1=MassFind(ode,p1,p2);
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tempm2=NULL;
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break;
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case MSG_IP_R_UP:
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if (tempm1 && (tempm2=MassFind(ode,p1,p2)) && tempm1!=tempm2)
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PlaceSpring(tempm1,tempm2);
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tempm1=tempm2=NULL;
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break;
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case MSG_KEY_DOWN:
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switch (p1) {
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case '\n':
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CleanUp;
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Init;
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break;
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case CH_SHIFT_ESC:
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case CH_ESC:
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goto ms_done;
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}
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break;
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}
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}
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ms_done: //Don't goto out of try
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GetMsg(,,1<<MSG_KEY_UP);
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} catch
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CatchAll;
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SettingsPop;
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CleanUp;
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MenuPop;
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}
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MassSpringDemo;
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