//$FG,4$You probably want to avoid
$FG$//$FG,4$three dimensional graphics because
$FG$//$FG,4$support is not very good.  There
$FG$//$FG,4$is no support for hidden surface
$FG$//$FG,4$removal.$FG$

#define MAP_WIDTH		1024
#define MAP_HEIGHT		1024
#define MAP_SCALE		20
#define FORSHORTENING		100
#define CONTROLS_SCALE		0.05
#define COORDINATE_SCALE	256
#define COORDINATE_BITS		8

I2 elevations[MAP_HEIGHT][MAP_WIDTH];

double
  phi	=-45.0*pi/180.0,
  theta1=  0.0*pi/180.0,
  theta2=  0.0*pi/180.0,
  speed =  0.2;

I8 x=MAP_WIDTH>>1 *COORDINATE_SCALE*MAP_SCALE,
   y=MAP_HEIGHT>>1*COORDINATE_SCALE*MAP_SCALE,
   z=64  	  *COORDINATE_SCALE*MAP_SCALE;

double grid_size=64.0;

class MPCtrl {
  double phi,theta1,theta2,grid_size;
  I8 x,y,z;
  BoolU4 update,done;
  TssStruct *win_tss;
};

MPCtrl *mp;
void InitMap()
{
  I8 i,j,k1,k2,x,y,xx,yy;
  MemSet(elevations,0,sizeof(elevations));
  for (i=0;i<10000;i++) {
    x=RandU4%MAP_WIDTH;
    y=RandU4%MAP_HEIGHT;
    j=1<<(RandU4%6);
    for (k1=-j;k1<=j;k1++)
      for (k2=-j;k2<=j;k2++) {
	xx=x+k2; yy=y+k1;
	if (xx>=0 && xx<MAP_WIDTH &&
	    yy>=0 && yy<MAP_HEIGHT)
	  elevations[yy][xx]+=AbsI8(j-k1)+AbsI8(j-k2);
      }
  }

  xx=x/MAP_SCALE/COORDINATE_SCALE;
  yy=y/MAP_SCALE/COORDINATE_SCALE;
  z+=elevations[yy][xx]*COORDINATE_SCALE;
}

void DrawIt(TssStruct *tss)
{
  I8 i,j,*r1,*r2,*r3,*r4,*r,x1,y1,z1,x2,y2,z2,xx,yy,grid_s,
    cx=(tss->win_pixel_right-tss->win_pixel_left)>>1,
    cy=(tss->win_pixel_bottom-tss->win_pixel_top)>>1,height;
  double d;
  GrBitMap *base=GrAlias(grbase2,tss);
  I1 buf[128];
  BoolU4 first;

  //Adjust grid size to utilize whole CPU power
  d=1.05*win_refresh/win_max_refresh;
  if (d>1.5) d=1.5;
  if (d<0.666666) d=0.666666;
  grid_size*=0.975+0.025*d;
  if (grid_size<10.0)
    grid_size=10.0;
  grid_s=grid_size;

  //Pass stuff to other CPU
  mp->phi=phi;
  mp->theta1=theta1;
  mp->theta2=theta2;
  mp->x=x;
  mp->y=y;
  mp->z=z;
  mp->update=TRUE;
  mp->grid_size=grid_size;

  xx=x/MAP_SCALE/COORDINATE_SCALE;
  yy=y/MAP_SCALE/COORDINATE_SCALE;
  height=z/COORDINATE_SCALE-elevations[yy][xx];
  if (height<0)
    Sound(1000); //Signal plane crashed

  base->color=BLACK;
  ClearWinText(tss);
  SPrintF(buf,"Theta1:%5.1f Phi:%5.1f Theta2:%5.1f Box:%5.1f",
    theta1*180/pi,phi*180/pi,theta2*180/pi,grid_size);
  GrText(base,0,0,buf);
  SPrintF(buf,"x:%5.1f y:%5.1f z:%5.1f height:%3d",
    x*1.0/COORDINATE_SCALE,y*1.0/COORDINATE_SCALE,z*1.0/COORDINATE_SCALE,
    height);
  GrText(base,0,FONT_HEIGHT,buf);

  //World to screen coordinates
  r1=GrTheta(theta1);
  r2=GrPhi(phi);
  r3=GrTheta(theta2);
  r4=GrMulMat(r1,r2);
  r=GrMulMat(r4,r3);
  Free(r1);
  Free(r2);
  Free(r3);
  Free(r4);

  base->pen_width=2;
  base->color=BLACK;
  GrLine3(base,cx+5,cy,0,cx-5,cy,0);
  GrLine3(base,cx,cy+5,0,cx,cy-5,0);

  base->color=GREEN;

  x2=0;y2=0;z2=0;
  for (i=yy-grid_s;i<yy+grid_s;i++) {
    if (i>=0 && i<MAP_HEIGHT) {
      first=TRUE;
      for (j=xx-grid_s;j<xx+grid_s;j++) {
	if (j>=0 && j<MAP_WIDTH) {
	  x1=j*MAP_SCALE-x>>COORDINATE_BITS;
	  y1=i*MAP_SCALE-y>>COORDINATE_BITS;
	  z1=elevations[i][j]-z>>COORDINATE_BITS;
	  GrRotate(r,&x1,&y1,&z1);
	  if (z1<0) {
	    z1=AbsI8(z1)+FORSHORTENING;
	    x1=x1*FORSHORTENING/z1;
	    y1=y1*FORSHORTENING/z1;
 
	    if (!first)
	      GrLine(base,x1+cx,cy-y1,x2+cx,cy-y2);
	  }
	  x2=x1;y2=y1;z2=z1;
	  first=FALSE;
	}
      }
    }
  }
  Free(r);
  GrDel(base);
}

void MPDrawIt(MPCtrl *mp)
{
  TssStruct *tss=mp->win_tss;
  I8 i,j,*r1,*r2,*r3,*r4,*r,x1,y1,z1,x2,y2,z2,xx,yy,
    cx=(tss->win_pixel_right-tss->win_pixel_left)>>1,
    cy=(tss->win_pixel_bottom-tss->win_pixel_top)>>1;
  GrBitMap *base=GrAlias(Gs->grbase,Fs);
  BoolU4 first;
  I8 x=mp->x,y=mp->y,z=mp->z,grid_s=mp->grid_size;

  base->win_tss=tss;

  xx=x/MAP_SCALE/COORDINATE_SCALE;
  yy=y/MAP_SCALE/COORDINATE_SCALE;

  //World to screen coordinates
  r1=GrTheta(mp->theta1);
  r2=GrPhi(mp->phi);
  r3=GrTheta(mp->theta2);
  r4=GrMulMat(r1,r2);
  r=GrMulMat(r4,r3);
  Free(r1);
  Free(r2);
  Free(r3);
  Free(r4);
 
  GrClear(base);
 
  base->color=GREEN^WHITE;
  x2=0;y2=0;z2=0;
  for (j=xx-grid_s;j<xx+grid_s;j++) {
    if (j>=0 && j<MAP_WIDTH) {
      first=TRUE;
      for (i=yy-grid_s;i<yy+grid_s;i++) {
	if (i>=0 && i<MAP_HEIGHT) {
	  x1=j*MAP_SCALE-x>>COORDINATE_BITS;
	  y1=i*MAP_SCALE-y>>COORDINATE_BITS;
	  z1=elevations[i][j]-z>>COORDINATE_BITS;
	  GrRotate(r,&x1,&y1,&z1);
	  if (z1<0) {
	    z1=AbsI8(z1)+FORSHORTENING;
	    x1=x1*FORSHORTENING/z1;
	    y1=y1*FORSHORTENING/z1;
 
	    if (!first)
	      GrLine(base,x1+cx,cy-y1,x2+cx,cy-y2);
	  }
	  x2=x1;y2=y1;z2=z1;
	  first=FALSE;
	}
      }
    }
  }
  Free(r);
  GrDel(base);
}

void MPFSim()
{
  while (!mp->done) {
    while (!mp->update && !mp->done)
      SwapInNext;
    MPDrawIt(mp);
    mp->update=FALSE;
  }
  GrClear(Gs->grbase);
  mp->done=FALSE;
}

void AnimateTsk()
{
  I8 *r1,*r2,*r3,*r4,*r,x1,y1,z1;
  while (TRUE) {

    //Screen to world coordinates
    r1=GrTheta(-theta2);
    r2=GrPhi(-phi);
    r3=GrTheta(-theta1);
    r4=GrMulMat(r1,r2);
    r=GrMulMat(r4,r3);

    x1=0;y1=0;z1=-1.0*speed*COORDINATE_SCALE;
    GrRotate(r,&x1,&y1,&z1);
    x+=x1;
    y+=y1;
    z+=z1;
    Free(r1);
    Free(r2);
    Free(r3);
    Free(r4);
    Free(r);
    Sleep(1);
  }
}

void SongEndTsk()
{
  Sound(0);
  Exit;
}

void SongTsk()
{
  Fs->end_task_cb=&SongEndTsk;
  ResetMusicSettings;
  while (TRUE) {
    Play("3etDCDqDetABFsFBFBqC2G3BeDF");
    Play("etDCDqDetABFsFBFBqC2G3BeDF");
    Play("qReFDqDeF2GqR3sABABqFetREA");
    Play("qReFDqDeF2GqR3sABABqFetREA");
  }
}

void EndFSim()
{
  mp->done=TRUE;
  while (mp->done)
    SwapInNext;
  FreeHC(mp,mp_heap);
}

void EndFSimCB()
{
  //We need this to shut-down CPU#1 task
  //in case of CPU0 task getting terminated
  //irregularly.
  EndFSim;
  Exit;
}



void FlightSim()
{
  I8 ch,sc;
  double pp,tt1,tt2;
  void *old_update=Fs->update_win;
  TssStruct *animate_tss,song_tss;
  BoolU4 old_border=WinBorder(OFF);
  BoolU4 old_wordstat=WordStat(OFF);

  //Set callback for irregular aborts
  Fs->end_task_cb=&EndFSimCB;

  WinMax;
  InitMap;
  Fs->update_win=&DrawIt;
  animate_tss=Spawn(&AnimateTsk,"FlightSim Animate",Fs);
  song_tss=Spawn(&SongTsk,"FlightSim Song",Fs);

  //This heap is uncached
  mp=MAllocHCZ(sizeof(MPCtrl),mp_heap);
  WbInvd; //Write mp out of cache

  mp->win_tss=Fs;
  if (mp_cnt>1)
    MPQueueJob(&MPFSim,NULL,1<<MPCf_FREE_ON_COMPLETE,TRUE);
  try
  do {
    ch=GetKey(&sc);
    pp=phi; tt1=theta1; tt2=theta2;
    switch (ch) {
      case 0:
	switch (sc.u1[0]) {
	  case SC_CURSOR_DOWN:
	    phi   +=-CONTROLS_SCALE*Cos(tt1);
	    theta2+=-CONTROLS_SCALE*Sin(tt1)*Sin(phi);
	    break;
	  case SC_CURSOR_UP:
	    phi   -=-CONTROLS_SCALE*Cos(tt1);
	    theta2-=-CONTROLS_SCALE*Sin(tt1)*Sin(phi);
	    break;
	  case SC_CURSOR_RIGHT:
	    theta1+=CONTROLS_SCALE;
	    break;
	  case SC_CURSOR_LEFT:
	    theta1-=CONTROLS_SCALE;
	    break;
	}
	break;
    }
    theta1=Unwrap(theta1);
    phi   =Unwrap(phi);
    theta2=Unwrap(theta2);
  } while (ch!=CH_CTRLQ && ch!=CH_ESC);
  catch
    Fs->catch_except=TRUE;

  Kill(animate_tss);
  Kill(song_tss);
  Fs->update_win=old_update;
  Fs->end_task_cb=NULL;
  WinBorder(old_border);
  WordStat(old_wordstat);
 
  EndFSim;
}

FlightSim;