Icons that track world objects. Examples?

#1 GuiShapeNameHud is where you should start. It took me a little under a day to hack in bitmap/icon support for ThinkTanks Xbox.

#2 Turns out I had misunderstood: project/unproject aren't exposed to scripting, so there's no way to do this with scripts by default (except the hard way: doing the whole math in script code, including implementing your own matrix inverter. Not very tempting.).

The good news is that adding scripting support was really easy. To add GameTSCtrl::project and GameTSCtrl::unproject to the console, find engine/game/GameTSCtrl.cc simply add to the end of it something like:

ConsoleMethod( GameTSCtrl, project, const char *, 3, 3, "(Point3F WorldPos")
{
   Point3F src;
   Point3F dst;
   
   dSscanf(argv[2],"%f %f %f",&src.x,&src.y,&src.z);
   object->project(src, &dst);
   char* buff = Con::getReturnBuffer(100);
   dSprintf(buff, 100,"%i %i",(int)(dst.x),(int)(dst.y));
   return buff;
}


ConsoleMethod( GameTSCtrl, unproject, const char *, 3, 3, "(Point2F ScreenPos")
{
   Point3F src;
   Point3F dst;
   
   dSscanf(argv[2],"%f %f",&src.x,&src.y);
   src.z = -1;
   object->unproject(src, &dst);
   char* buff = Con::getReturnBuffer(100);
   dSprintf(buff, 100,"%g %g %g",dst.x,dst.y,dst.z);
   return buff;
}

Caveats:
o This code is not extensively tested; there may well be problems with it. I just wanted to show the general technique .
o I do no checking/odification of the results, so:
- your projected screen position may well be outside the screen if the target is
- if your world point is behind the projection plane "project" will return "0 0", so any such result should be interpreted as invalid.

#3 Here is my tested version:

ConsoleMethod(GuiTSCtrl, project, const char*, 3, 3, "GuiTSCtrl.project(point3F) returns screen space X,Y and Z for world space point")
{
   const Point3F pt;
   Point3F dest;
   char* destbuf = Con::getReturnBuffer(100);

   dSscanf(argv[2], "%f %f %f", &pt.x, &pt.y, &pt.z);

   object->project(pt, &dest);

   dSprintf(destbuf,sizeof(destbuf),"%i %i",(int)(dest.x),(int)(dest.y));
   return destbuf;
}

ConsoleMethod(GuiTSCtrl, unproject, const char*, 3, 3, "GuiTSCtrl.unproject(point3F) returns world space point for X, Y and Z")
{
   const Point3F pt;
   Point3F dest;
   char* destbuf = Con::getReturnBuffer(100);

   dSscanf(argv[2], "%f %f %f", &pt.x, &pt.y, &pt.z);

   object->unproject(pt, &dest);

   dSprintf(destbuf,sizeof(destbuf),"%g %g %g",dest.x,dest.y,dest.z);
   return destbuf;
}