/* Overload this so as not to change
* velocity as I normally want my walls to be stable and not drift after being dragged. */
/// <summary>
/// There's a collision if pcritter has crossed the wall or if the radius of pcritter is more than
/// the pcritter's distance to the wall. Has code to prevent the pcritter from going through the wall.
/// Returns true if a collision was detected and false otherwise.
/// </summary>
/// <param name="pcritter">The critter to test for a collision with the wall.</param>
/// <returns></returns>
public override bool collide(cCritter pcritter)
{
cVector3 oldlocalpos, newlocalpos;
float newdistance;
int oldoutcode, newoutcode;
bool crossedwall;
oldlocalpos = globalToLocalPosition(pcritter.OldPosition);
oldoutcode = _pskeleton.outcode(oldlocalpos);
newlocalpos = globalToLocalPosition(pcritter.Position);
newdistance = _pskeleton.distanceToOutcode(newlocalpos,
out newoutcode); //Sets the newoutcode as well.
crossedwall = crossed(oldoutcode, newoutcode);
if (newdistance >= pcritter.Radius && !crossedwall) //No collision
{
return(false); /*See if there's a collision at all. We
* say there's a collision if crossedwall or if the
* cCritterWall.distance is less than radius. Remember that
* cCritterWall.distance measures the distance to the OUTSIDE
* PERIMETER of the box, not the distance to the box's center. */
}
/* I collided, so I need to move back further into the last good
* zone I was in outside the wall. I want to set newlocalpos so
* the rim of its critter is touching the wall. The idea is to back
* up in the direction of oldlocalpos. To allow the possibility
* of skidding along the wall, we plan to back up from the
* the face (or edge or corner) facing oldlocalpos. This works
* only if oldlocalpos was a good one, not inside the box. In
* principle this should always be true, but some rare weird circumstance
* (like a triple collsion) might mess this up, so we check for the
* bad case before starting. */
if (oldoutcode == cRealBox3.BOX_INSIDE) //Note that this almost never happens.
{
cVector3 insidepos = new cVector3();
insidepos.copy(oldlocalpos);
oldlocalpos -= pcritter.Tangent * _pskeleton.MaxSize;
//Do a brutally large backup to get out of the box for sure.
oldoutcode = _pskeleton.outcode(oldlocalpos);
//Recalculate outcode at this new position.
oldlocalpos = _pskeleton.closestSurfacePoint(oldlocalpos, oldoutcode,
insidepos, cRealBox3.BOX_INSIDE, false);
//Go to the closest surface point from there.
oldoutcode = _pskeleton.outcode(oldlocalpos);
//Recalculate outcode one more time to be safe.
crossedwall = crossed(oldoutcode, newoutcode);
//Recalculate crossedwall
}
/* I find that with this code, the mouse can drag things through walls,
* so I do a kludge to block it by setting crossedwall to TRUE, this
* affects the action of cRealBox.closestSurfacePoint, as modified
* in build 34_4. */
if (pcritter.Listener is cListenerCursor)
{
crossedwall = true; //Don't trust the mouse listener.
}
newlocalpos = _pskeleton.closestSurfacePoint(oldlocalpos, oldoutcode,
newlocalpos, newoutcode, crossedwall);
/* This call to closestSurfacePoint will move the newlocal pos
* from the far new side (or inside, or overlapping) of the box back to
* the surface, usually on the old near side, edge, or corner given by
* oldoutcode. This prevents going through the wall.
* If oldoutcode is a corner position and you are in fact heading
* towards a face near the corner, we used to bounce off the corner
* even though visually you can see you should bounce off the
* face. This had the effect of making a scooter player get hung up on
* a corner sometimes. As of build 34_3, I'm moving the
* newlocalpos to the newoutocode side in the case where oldlocalpos
* is an edge or a corner, and where crossedwall isn't TRUE. I
* have to force in a TRUE for the cCursorLIstener case. The USEJIGGLE
* code below also helps keep non-player critters from getting stuck
* on corners. */
//Now back away from the box.
newoutcode = _pskeleton.outcode(newlocalpos);
cVector3 avoidbox = _pskeleton.escapeVector(newlocalpos, newoutcode);
newlocalpos += avoidbox * pcritter.Radius;
newoutcode = _pskeleton.outcode(newlocalpos);
pcritter.moveTo(localToGlobalPosition(newlocalpos), true);
//TRUE means continuous motion, means adjust tangent etc.
//Done with position, now change the velocity
cVector3 localvelocity = globalToLocalDirection(pcritter.Velocity);
cVector3 oldlocalvelocity = new cVector3();
oldlocalvelocity.copy(localvelocity);
_pskeleton.reflect(localvelocity, newoutcode);
/* I rewrote the reflect code on Feb 22, 2004 for VErsion 34_3, changing
* it so that when you reflect off an edge or corner, you only bounce
* the smallest of your three velocity components. Balls stll seem to
* get hung up on the corner once is awhile. */
/* Now decide, depending on the pcritter's absorberflag and bounciness,
* how much you want to use the new localvelocity vs. the
* oldlocalvelocity. We decompose the new localvelocity into the
* tangentvelocity parallel to the wall and the normalvelocity
* away from the wall. Some pencil and paper drawings convince
* me that the tangent is half the sum of the oldlocalvelocity
* and the reflected new localvelocity. */
cVector3 tangentvelocity = (localvelocity + oldlocalvelocity) * 0.5f;
cVector3 normalvelocity = localvelocity - tangentvelocity;
float bouncefactor = 1.0f;
if (pcritter.AbsorberFlag)
{
bouncefactor = 0.0f;
}
else
{
bouncefactor = pcritter.Bounciness;
}
localvelocity = tangentvelocity + normalvelocity * bouncefactor;
/* Maybe the rotation should depend on the kind of edge or corner.
* Right now let's just use critter's binormal. Don't to it
* to the player or viewer as it's confusing. */
if (!(cRealBox3.isFaceOutcode(newoutcode)) && //edge or corner
!(pcritter is cCritterViewer) && //not viewer
!(pcritter is cCritterArmedPlayer))
//Not player. Note that cPlayer inherits from cCritterArmedPlayer,
//so don't use cCritterPlayer as the base class here.
{
localvelocity.rotate(new cSpin(
Framework.randomOb.randomReal(
-cCritterWall.CORNERJIGGLETURN,
cCritterWall.CORNERJIGGLETURN), //A random turn
pcritter.Binormal)); //Around the critter's binormal
localvelocity *= cCritterWall.CORNERJIGGLEKICK; //Goose it a little
}
pcritter.Velocity = localToGlobalDirection(localvelocity);
return(true);
}
