#define BALLS_NUM 7
#define SPRINGS_NUM 3
#define STRETCH 500.0
#define GRAVITY 50.0 //not really gravity
#define BALL_RADIUS 5
#define BASE_SIZE 10
CMass balls[BALLS_NUM];
CSpring springs[SPRINGS_NUM];
F64 collision_t;
U0 DrawIt(CTask *task,CDC *dc)
{
I64 i,
cx=task->pix_width>>1,
cy=task->pix_height>>1;
Bool snd_on=FALSE;
dc->color=BLACK;
GrPrint(dc,0,0,"Protect your base.");
GrRect(dc,cx-BASE_SIZE,cy-BASE_SIZE,BASE_SIZE*2,BASE_SIZE*2);
dc->color=CYAN;
GrRect(dc,cx-BASE_SIZE+2,cy-BASE_SIZE+2,BASE_SIZE*2-4,BASE_SIZE*2-4);
dc->color=YELLOW;
GrLine(dc,balls[0].x,balls[0].y,
ms.pos.x-task->pix_left-task->scroll_x,
ms.pos.y-task->pix_top-task->scroll_y);
for (i=0;i<SPRINGS_NUM;i++)
GrLine(dc,springs[i].end1->x,springs[i].end1->y,
springs[i].end2->x,springs[i].end2->y);
dc->color=LTCYAN;
GrCircle(dc,balls[0].x,balls[0].y,BALL_RADIUS);
GrFloodFill(dc,balls[0].x,balls[0].y,TRUE);
dc->color=BLACK;
GrCircle(dc,balls[0].x,balls[0].y,BALL_RADIUS);
for (i=1;i<BALLS_NUM;i++) {
dc->color=LTPURPLE;
GrCircle(dc,balls[i].x,balls[i].y,BALL_RADIUS);
GrFloodFill(dc,balls[i].x,balls[i].y,TRUE);
if (cx-BASE_SIZE-BALL_RADIUS<=balls[i].x<=cx+BASE_SIZE+BALL_RADIUS &&
cy-BASE_SIZE-BALL_RADIUS<=balls[i].y<=cy+BASE_SIZE+BALL_RADIUS)
snd_on=TRUE;
dc->color=BLACK;
GrCircle(dc,balls[i].x,balls[i].y,BALL_RADIUS);
}
if (snd_on)
Snd(74);
else
Snd;
}
U0 MyDerivative(CMathODE *ode,F64 t,COrder2D3 *,COrder2D3 *)
{
I64 i,j;
F64 d,dd;
CD3 p,p2;
CTask *task=ode->win_task;
D3SubEqu(D3Equ(&p2,
ms.pos.x-task->pix_left-task->scroll_x,
ms.pos.y-task->pix_top-task->scroll_y,0),
&balls[0].state->x);
D3AddEqu(&balls[0].DstateDt->DxDt,D3MulEqu(&p2,STRETCH));
D3Equ(&p2,task->pix_width>>1,task->pix_height>>1,0);
for (i=1;i<BALLS_NUM;i++) {
D3Sub(&p,&p2,&balls[i].state->x);
if (d=D3Norm(&p)) {
//Gravity would be /(d*d*d), but that's too exponential.
D3MulEqu(&p,GRAVITY/d);
D3AddEqu(&balls[i].DstateDt->DxDt,&p);
}
}
for (i=0;i<BALLS_NUM;i++)
for (j=i+1;j<BALLS_NUM;j++) {
D3Sub(&p,&balls[j].state->x,&balls[i].state->x);
dd=D3NormSqr(&p);
if (dd<=(2*BALL_RADIUS)*(2*BALL_RADIUS)) {
if (t-collision_t>0.05) {
Noise(50,102,105);
collision_t=t;
}
d=Sqrt(dd)+0.0001;
dd=10.0*Sqr(Sqr((2*BALL_RADIUS)*(2*BALL_RADIUS)-dd));
D3MulEqu(&p,dd/d);
D3AddEqu(&balls[j].DstateDt->DxDt,&p);
D3SubEqu(&balls[i].DstateDt->DxDt,&p);
}
}
d=balls[0].state->x;
if (d-BALL_RADIUS<0)
balls[0].DstateDt->DxDt+=Sqr(Sqr(Sqr(d-BALL_RADIUS)));
if (d+BALL_RADIUS>task->pix_width)
balls[0].DstateDt->DxDt-=Sqr(Sqr(Sqr((d+BALL_RADIUS)-task->pix_width)));
d=balls[0].state->y;
if (d-BALL_RADIUS<0)
balls[0].DstateDt->DyDt+=Sqr(Sqr(Sqr(d-BALL_RADIUS)));
if (d+BALL_RADIUS>task->pix_height)
balls[0].DstateDt->DyDt-=Sqr(Sqr(Sqr((d+BALL_RADIUS)-task->pix_height)));
}
U0 Whap()
{
I64 i;
CMathODE *ode=ODENew(0,1e-2,ODEF_HAS_MASSES);
SettingsPush; //See SettingsPush
AutoComplete;
WinBorder;
WinMax;
MenuPush(
"File {"
" Abort(,CH_SHIFT_ESC);"
" Exit(,CH_ESC);"
"}"
);
ode->derive=&MyDerivative;
ode->drag_v2=0.002;
ode->drag_v3=0.00001;
ode->acceleration_limit=5e3;
MemSet(balls,0,BALLS_NUM*sizeof(CMass));
D3Equ(&balls[0].x,100,100,0);
for (i=1;i<BALLS_NUM;i++)
D3Equ(&balls[i].x,
RandI16%500+Fs->pix_width>>1,RandI16%500+Fs->pix_height>>1,0);
balls[0].x=ms.pos.x-Fs->pix_left-Fs->scroll_x;
balls[0].y=ms.pos.y-Fs->pix_top-Fs->scroll_y;
for (i=0;i<BALLS_NUM;i++) {
balls[i].mass=1.0;
balls[i].drag_profile_factor=1.0;
QueIns(&balls[i],ode->last_mass);
}
balls[2].x=balls[1].x+15;
balls[2].y=balls[1].y;
balls[3].x=balls[1].x;
balls[3].y=balls[1].y+15;
MemSet(springs,0,SPRINGS_NUM*sizeof(CSpring));
springs[0].end1=&balls[1];
springs[0].end2=&balls[2];
springs[0].rest_len=15;
springs[0].const=10000;
QueIns(&springs[0],ode->last_spring);
springs[1].end1=&balls[1];
springs[1].end2=&balls[3];
springs[1].rest_len=15;
springs[1].const=10000;
QueIns(&springs[1],ode->last_spring);
springs[2].end1=&balls[2];
springs[2].end2=&balls[3];
springs[2].rest_len=sqrt2*15;
springs[2].const=10000;
QueIns(&springs[2],ode->last_spring);
collision_t=0;
QueIns(ode,Fs->last_ode);
DocCursor;
DocClear;
Fs->draw_it=&DrawIt;
GetChar;
SettingsPop;
QueRem(ode);
ODEDel(ode);
MenuPop;
}
Whap;