CharacterContactPositionState TrySupportLocation(ConvexCollidable <CylinderShape> queryObject, ref Vector3 position, out float hintOffset,
ref QuickList <CharacterContact> tractionContacts, ref QuickList <CharacterContact> supportContacts, ref QuickList <CharacterContact> sideContacts, ref QuickList <CharacterContact> headContacts)
{
hintOffset = 0;
PrepareQueryObject(queryObject, ref position);
QueryManager.QueryContacts(queryObject, ref tractionContacts, ref supportContacts, ref sideContacts, ref headContacts, true);
bool obstructed = IsObstructed(ref sideContacts, ref headContacts);
if (obstructed)
{
return(CharacterContactPositionState.Obstructed);
}
if (supportContacts.Count > 0)
{
CharacterContactPositionState supportState;
CharacterContact supportContact;
QueryManager.AnalyzeSupportState(ref tractionContacts, ref supportContacts, out supportState, out supportContact);
var down = characterBody.orientationMatrix.Down;
//Note that traction is not tested for; it isn't important for the stance manager.
if (supportState == CharacterContactPositionState.Accepted)
{
//We're done! The guess found a good spot to stand on.
//We need to have fairly good contacts after this process, so only push it up a bit.
hintOffset = Math.Min(0, Vector3.Dot(supportContact.Contact.Normal, down) * (CollisionDetectionSettings.AllowedPenetration * .5f - supportContact.Contact.PenetrationDepth));
return(CharacterContactPositionState.Accepted);
}
else if (supportState == CharacterContactPositionState.TooDeep)
{
//Looks like we have to keep trying, but at least we found a good hint.
hintOffset = Math.Min(0, Vector3.Dot(supportContact.Contact.Normal, down) * (CollisionDetectionSettings.AllowedPenetration * .5f - supportContact.Contact.PenetrationDepth));
return(CharacterContactPositionState.TooDeep);
}
else //if (supportState == SupportState.Separated)
{
//It's not obstructed, but the support isn't quite right.
//It's got a negative penetration depth.
//We can use that as a hint.
hintOffset = -.001f - Vector3.Dot(supportContact.Contact.Normal, down) * supportContact.Contact.PenetrationDepth;
return(CharacterContactPositionState.NoHit);
}
}
else //Not obstructed, but no support.
{
return(CharacterContactPositionState.NoHit);
}
}
CharacterContactPositionState TryDownStepPosition(ref Vector3 position, ref Vector3 down,
ref QuickList <CharacterContact> tractionContacts, ref QuickList <CharacterContact> supportContacts, ref QuickList <CharacterContact> sideContacts, ref QuickList <CharacterContact> headContacts,
out float hintOffset)
{
hintOffset = 0;
PrepareQueryObject(ref position);
QueryManager.QueryContacts(currentQueryObject, ref tractionContacts, ref supportContacts, ref sideContacts, ref headContacts);
if (IsDownStepObstructed(ref sideContacts))
{
return(CharacterContactPositionState.Obstructed);
}
//Note the use of traction contacts. We only want to step down if there are traction contacts to support us.
if (tractionContacts.Count > 0)
{
CharacterContactPositionState supportState;
CharacterContact supportContact;
QueryManager.AnalyzeSupportState(ref tractionContacts, ref supportContacts, out supportState, out supportContact);
if (supportState == CharacterContactPositionState.Accepted)
{
//We're done! The guess found a good spot to stand on.
//The final state doesn't need to actually create contacts, so shove it up
//just barely to the surface.
hintOffset = -Vector3.Dot(supportContact.Contact.Normal, down) * supportContact.Contact.PenetrationDepth;
return(CharacterContactPositionState.Accepted);
}
else if (supportState == CharacterContactPositionState.TooDeep)
{
//Looks like we have to keep trying, but at least we found a good hint.
hintOffset = Math.Min(0, .001f - Vector3.Dot(supportContact.Contact.Normal, down) * supportContact.Contact.PenetrationDepth);
return(CharacterContactPositionState.TooDeep);
}
else //if (supportState == SupportState.Separated)
{
//It's not obstructed, but the support isn't quite right.
//It's got a negative penetration depth.
//We can use that as a hint.
hintOffset = -.001f - Vector3.Dot(supportContact.Contact.Normal, down) * supportContact.Contact.PenetrationDepth;
return(CharacterContactPositionState.NoHit);
}
}
else
{
return(CharacterContactPositionState.NoHit);
}
}
CharacterContactPositionState TryUpStepPosition(ref Vector3 sideNormal, ref Vector3 position, ref Vector3 down,
ref QuickList <CharacterContact> tractionContacts, ref QuickList <CharacterContact> supportContacts, ref QuickList <CharacterContact> sideContacts, ref QuickList <CharacterContact> headContacts,
out float hintOffset)
{
hintOffset = 0;
PrepareQueryObject(ref position);
QueryManager.QueryContacts(currentQueryObject, ref tractionContacts, ref supportContacts, ref sideContacts, ref headContacts);
if (headContacts.Count > 0)
{
//The head is obstructed. This will define a maximum bound.
//Find the deepest contact on the head and use it to provide a hint.
float dot;
Vector3.Dot(ref down, ref headContacts.Elements[0].Contact.Normal, out dot);
hintOffset = -dot * headContacts.Elements[0].Contact.PenetrationDepth;
for (int i = 1; i < headContacts.Count; i++)
{
Vector3.Dot(ref down, ref headContacts.Elements[i].Contact.Normal, out dot);
dot *= -headContacts.Elements[i].Contact.PenetrationDepth;
if (dot > hintOffset)
{
hintOffset = dot;
}
}
return(CharacterContactPositionState.HeadObstructed);
}
bool obstructed = IsUpStepObstructedBySideContacts(ref sideNormal, ref sideContacts);
if (!obstructed && supportContacts.Count > 0)
{
CharacterContactPositionState supportState;
CharacterContact supportContact;
QueryManager.AnalyzeSupportState(ref tractionContacts, ref supportContacts, out supportState, out supportContact);
if (supportState == CharacterContactPositionState.Accepted)
{
if (tractionContacts.Count > 0)
{
//We're done! The guess found a good spot to stand on.
//Unlike down stepping, upstepping DOES need good contacts in the final state.
//Push it up if necessary, but don't push it too far.
//Putting it into the middle of the allowed penetration makes it very likely that it will properly generate contacts.
//Choosing something smaller than allowed penetration ensures that the search makes meaningful progress forward when the sizes get really tiny;
//we wouldn't want it edging every closer to AllowedPenetration and then exit because too many queries were made.
hintOffset = Math.Min(0, Vector3.Dot(supportContact.Contact.Normal, down) * (CollisionDetectionSettings.AllowedPenetration * .5f - supportContact.Contact.PenetrationDepth));
return(CharacterContactPositionState.Accepted);
}
else
{
//No traction... Before we give up and reject the step altogether, let's try one last thing. It's possible that the character is trying to step up onto the side of a ramp or something.
//In this scenario, the top-down ray cast detects a perfectly walkable slope. However, the contact queries will find a contact with a normal necessarily
//steeper than the one found by the ray cast because it is an edge contact. Not being able to step up in this scenario doesn't feel natural to the player
//even if it is technically consistent.
//So, let's try to ray cast down to the a point just barely beyond the contact (to ensure we don't land right on the edge, which would invite numerical issues).
//Note that this is NOT equivalent to the ray cast we performed earlier to test for an initial step height and surface normal.
//This one is based on the QUERY state and the QUERY's contact position.
//Find the down test ray's position.
Ray downRay;
downRay.Position = supportContact.Contact.Position + sideNormal * .001f;
float verticalOffset = Vector3.Dot(downRay.Position - position, down);
verticalOffset = characterBody.Height * .5f + verticalOffset;
downRay.Position -= verticalOffset * down;
downRay.Direction = down;
//First, we must ensure that the ray cast test origin is not obstructed. Starting very close to the very top of the character is safe because the process has already validated
//this location as accepted, just without traction.
Ray obstructionTestRay;
obstructionTestRay.Position = position - down * (characterBody.Height * .5f);
obstructionTestRay.Direction = downRay.Position - obstructionTestRay.Position;
if (!QueryManager.RayCastHitAnything(obstructionTestRay, 1))
{
//Okay! it's safe to cast down, then.
RayHit hit;
if (QueryManager.RayCast(downRay, characterBody.Height, out hit))
{
//Got a hit!
if (characterBody.Height - maximumStepHeight < hit.T)
{
//It's in range!
float dot;
hit.Normal.Normalize();
Vector3.Dot(ref hit.Normal, ref down, out dot);
if (Math.Abs(dot) > ContactCategorizer.TractionThreshold)
{
//Slope is shallow enough to stand on!
hintOffset = Math.Min(0, Vector3.Dot(supportContact.Contact.Normal, down) * (CollisionDetectionSettings.AllowedPenetration * .5f - supportContact.Contact.PenetrationDepth));
//ONE MORE thing to check. The new position of the center ray must be able to touch the ground!
downRay.Position = position;
if (QueryManager.RayCast(downRay, characterBody.Height * .5f + maximumStepHeight, out hit))
{
//It hit.. almost there!
hit.Normal.Normalize();
Vector3.Dot(ref hit.Normal, ref down, out dot);
if (Math.Abs(dot) > ContactCategorizer.TractionThreshold)
{
//It has traction! We can step!
return(CharacterContactPositionState.Accepted);
}
}
}
}
}
}
//If it didn't have traction, and this was the most valid location we could find, then there is no support.
return(CharacterContactPositionState.Rejected);
}
}
else if (supportState == CharacterContactPositionState.TooDeep)
{
//Looks like we have to keep trying, but at least we found a good hint.
hintOffset = Math.Min(0, Vector3.Dot(supportContact.Contact.Normal, down) * (CollisionDetectionSettings.AllowedPenetration * .5f - supportContact.Contact.PenetrationDepth));
return(CharacterContactPositionState.TooDeep);
}
else //if (supportState == SupportState.Separated)
{
//It's not obstructed, but the support isn't quite right.
//It's got a negative penetration depth.
//We can use that as a hint.
hintOffset = -.001f - Vector3.Dot(supportContact.Contact.Normal, down) * supportContact.Contact.PenetrationDepth;
return(CharacterContactPositionState.NoHit);
}
}
else if (obstructed)
{
return(CharacterContactPositionState.Obstructed);
}
else
{
return(CharacterContactPositionState.NoHit);
}
}