CWE-ou-minkata/Sources/Plasma/PubUtilLib/plAvatar/plPhysicalControllerCore.cpp

/*==LICENSE==*

CyanWorlds.com Engine - MMOG client, server and tools
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*==LICENSE==*/
#include "plPhysicalControllerCore.h"

#include "plArmatureMod.h"
#include "plSwimRegion.h"
#include "plMatrixChannel.h"
#include "../pnSceneObject/plCoordinateInterface.h"
#include "../../NucleusLib/inc/plPhysical.h"
#include "../../NucleusLib/pnMessage/plCorrectionMsg.h"

// Gravity constants
#define kGravity -32.174f
#define kTerminalVelocity kGravity

static inline hsVector3 GetYAxis(hsMatrix44 &mat) { return hsVector3(mat.fMap[1][0], mat.fMap[1][1], mat.fMap[1][2]); }
static float AngleRad2d(float x1, float y1, float x3, float y3);

bool CompareMatrices(const hsMatrix44 &matA, const hsMatrix44 &matB, float tolerance);


// plPhysicalControllerCore
plPhysicalControllerCore::plPhysicalControllerCore(plKey OwnerSceneObject, hsScalar height, hsScalar radius) 
	: fOwner(OwnerSceneObject), 
	fWorldKey(nil), 
	fHeight(height), 
	fRadius(radius), 
	fLOSDB(plSimDefs::kLOSDBNone), 
	fMovementStrategy(nil), 
	fSimLength(0.0f), 
	fLocalRotation(0.0f, 0.0f, 0.0f, 1.0f), 
	fLocalPosition(0.0f, 0.0f, -2000.0f), 
	fLastLocalPosition(0.0f, 0.0f, 0.0f),
	fLinearVelocity(0.0f, 0.0f, 0.0f), 
	fAchievedLinearVelocity(0.0f, 0.0f, 0.0f), 
	fPushingPhysical(nil), 
	fFacingPushingPhysical(false),
	fSeeking(false), 
	fEnabled(false), 
	fEnableChanged(false)
{
	fLastGlobalLoc.Reset();
	fPrevSubworldW2L.Reset();
}

const plCoordinateInterface* plPhysicalControllerCore::GetSubworldCI()
{
	if (fWorldKey)
	{
		plSceneObject* so = plSceneObject::ConvertNoRef(fWorldKey->ObjectIsLoaded());
		if (so)
			return so->GetCoordinateInterface();
	}

	return nil;
}

void plPhysicalControllerCore::IncrementAngle(hsScalar deltaAngle)
{
	hsVector3 axis;
	hsScalar angle;

	fLocalRotation.NormalizeIfNeeded();
	fLocalRotation.GetAngleAxis(&angle, &axis);
	if (axis.fZ < 0)
		angle = (2.0f * hsScalarPI) - angle; // axis is backwards, so reverse the angle too

	angle += deltaAngle;

	// make sure we wrap around
	if (angle < 0.0f)
		angle = (2.0f * hsScalarPI) + angle; // angle is -, so this works like a subtract
	if (angle >= (2.0f * hsScalarPI))
		angle = angle - (2.0f * hsScalarPI);

	// set the new angle
	axis.Set(0.0f, 0.0f, 1.0f);
	fLocalRotation.SetAngleAxis(angle, axis);
}

void plPhysicalControllerCore::IApply(hsScalar delSecs)
{
	fSimLength = delSecs;

	// Match controller to owner if transform has changed since the last frame
	plSceneObject* so = plSceneObject::ConvertNoRef(fOwner->ObjectIsLoaded());
	const hsMatrix44& l2w = so->GetCoordinateInterface()->GetLocalToWorld();
	if (!CompareMatrices(fLastGlobalLoc, l2w, 0.0001f))
		SetGlobalLoc(l2w);

	if (fEnabled)
	{
		// Convert velocity from avatar to world space
		if (!fLinearVelocity.IsEmpty())
		{
			fLinearVelocity = l2w * fLinearVelocity;
		
			const plCoordinateInterface* subworldCI = GetSubworldCI();
			if (subworldCI)
				fLinearVelocity = subworldCI->GetWorldToLocal() * fLinearVelocity;
		}

		fMovementStrategy->Apply(delSecs);
	}
}
void plPhysicalControllerCore::IUpdate(int numSubSteps, hsScalar alpha)
{
	if (fEnabled)
	{
		// Update local position and acheived velocity
		fLastLocalPosition = fLocalPosition;
		GetPositionSim(fLocalPosition);
		hsVector3 displacement = (hsVector3)(fLocalPosition - fLastLocalPosition);
		fAchievedLinearVelocity = displacement / fSimLength;

		displacement /= (hsScalar)numSubSteps;
		fLastLocalPosition = fLocalPosition - displacement;
		hsPoint3 interpLocalPos = fLastLocalPosition + (displacement * alpha);

		// Update global location
		fLocalRotation.MakeMatrix(&fLastGlobalLoc);
		fLastGlobalLoc.SetTranslate(&interpLocalPos);
		const plCoordinateInterface* subworldCI = GetSubworldCI();
		if (subworldCI)
		{
			const hsMatrix44& subL2W = subworldCI->GetLocalToWorld();
			fLastGlobalLoc = subL2W * fLastGlobalLoc;
			fPrevSubworldW2L = subworldCI->GetWorldToLocal();
		}

		fMovementStrategy->Update(fSimLength);
		ISendCorrectionMessages(true);
	}
	else
	{
		fAchievedLinearVelocity.Set(0.0f, 0.0f, 0.0f);

		// Update global location if in a subworld
		const plCoordinateInterface* subworldCI = GetSubworldCI();
		if (subworldCI)
		{
			hsMatrix44 l2s = fPrevSubworldW2L * fLastGlobalLoc;
			const hsMatrix44& subL2W = subworldCI->GetLocalToWorld();
			fLastGlobalLoc = subL2W * l2s;
			fPrevSubworldW2L = subworldCI->GetWorldToLocal();

			ISendCorrectionMessages();
		}
	}

	if (fEnableChanged)
		IHandleEnableChanged();
}
void plPhysicalControllerCore::IUpdateNonPhysical(hsScalar alpha)
{
	// Update global location if owner transform hasn't changed.
	plSceneObject* so = plSceneObject::ConvertNoRef(fOwner->ObjectIsLoaded());
	const hsMatrix44& l2w = so->GetCoordinateInterface()->GetLocalToWorld();
	if (CompareMatrices(fLastGlobalLoc, l2w, 0.0001f))
	{
		if (fEnabled)
		{
			hsVector3 displacement = (hsVector3)(fLocalPosition - fLastLocalPosition);
			hsPoint3 interpLocalPos = fLastLocalPosition + (displacement * alpha);

			fLocalRotation.MakeMatrix(&fLastGlobalLoc);
			fLastGlobalLoc.SetTranslate(&interpLocalPos);
			const plCoordinateInterface* subworldCI = GetSubworldCI();
			if (subworldCI)
			{
				const hsMatrix44& subL2W = subworldCI->GetLocalToWorld();
				fLastGlobalLoc = subL2W * fLastGlobalLoc;
				fPrevSubworldW2L = subworldCI->GetWorldToLocal();
			}

			ISendCorrectionMessages();
		}
		else
		{
			// Update global location if in a subworld
			const plCoordinateInterface* subworldCI = GetSubworldCI();
			if (subworldCI)
			{
				hsMatrix44 l2s = fPrevSubworldW2L * fLastGlobalLoc;
				const hsMatrix44& subL2W = subworldCI->GetLocalToWorld();
				fLastGlobalLoc = subL2W * l2s;
				fPrevSubworldW2L = subworldCI->GetWorldToLocal();

				ISendCorrectionMessages();
			}
		}
	}
}

void plPhysicalControllerCore::ISendCorrectionMessages(bool dirtySynch)
{
	plCorrectionMsg* corrMsg = TRACKED_NEW plCorrectionMsg();
	corrMsg->fLocalToWorld = fLastGlobalLoc;
	corrMsg->fLocalToWorld.GetInverse(&corrMsg->fWorldToLocal);
	corrMsg->fDirtySynch = dirtySynch;
	corrMsg->AddReceiver(fOwner);
	corrMsg->Send();
}


// Movement Strategy
plMovementStrategy::plMovementStrategy(plPhysicalControllerCore* controller)
	: fController(controller)
{
}

void plMovementStrategy::Reset(bool newAge) { fController->SetMovementStrategy(this); }


// Animated Movement Strategy
plAnimatedMovementStrategy::plAnimatedMovementStrategy(plAGApplicator* rootApp, plPhysicalControllerCore* controller)
	: plMovementStrategy(controller),
	fRootApp(rootApp),
	fAnimLinearVel(0.0f, 0.0f, 0.0f),
	fAnimAngularVel(0.0f),
	fTurnStr(0.0f)
{
}

void plAnimatedMovementStrategy::RecalcVelocity(double timeNow, hsScalar elapsed, hsBool useAnim)
{
	if (useAnim)
	{
		// while you may think it would be correct to cache this, what we're actually asking is "what would the animation's
		// position be at the previous time given its *current* parameters (particularly blends)"
		hsMatrix44 prevMat = ((plMatrixChannel *)fRootApp->GetChannel())->Value(timeNow - elapsed, true);		
		hsMatrix44 curMat = ((plMatrixChannel *)fRootApp->GetChannel())->Value(timeNow, true);
		
		IRecalcLinearVelocity(elapsed, prevMat, curMat);
		IRecalcAngularVelocity(elapsed, prevMat, curMat);
	}
	else
	{
		fAnimLinearVel.Set(0.0f, 0.0f, 0.0f);
		fAnimAngularVel = 0.0f;
	}

	// Update controller rotation
	hsScalar zRot = fAnimAngularVel + fTurnStr;
	if (hsABS(zRot) > 0.0001f)
		fController->IncrementAngle(zRot * elapsed);

	// Update controller velocity
	fController->SetLinearVelocity(fAnimLinearVel);
}

void plAnimatedMovementStrategy::IRecalcLinearVelocity(float elapsed, hsMatrix44 &prevMat, hsMatrix44 &curMat)
{
	hsPoint3 startPos(0.0f, 0.0f, 0.0f);					// default position (at start of anim)
	hsPoint3 prevPos = prevMat.GetTranslate();				// position previous frame
	hsPoint3 nowPos = curMat.GetTranslate();				// position current frame

	hsVector3 prev2Now = (hsVector3)(nowPos - prevPos);		// frame-to-frame delta

	if (fabs(prev2Now.fX) < 0.0001f && fabs(prev2Now.fY) < 0.0001f && fabs(prev2Now.fZ) < 0.0001f)
	{
		fAnimLinearVel.Set(0.f, 0.f, 0.f);
	} 
	else 
	{
		hsVector3 start2Now = (hsVector3)(nowPos - startPos);	// start-to-frame delta

		float prev2NowMagSqr = prev2Now.MagnitudeSquared();
		float start2NowMagSqr = start2Now.MagnitudeSquared();

		float dot = prev2Now.InnerProduct(start2Now);

		// HANDLING ANIMATION WRAPPING:
		// the vector from the animation origin to the current frame should point in roughly
		// the same direction as the vector from the previous animation position to the
		// current animation position.
		//
		// If they don't agree (dot < 0,) then we probably mpst wrapped around. 
		// The right answer would be to compare the current frame to the start of
		// the anim loop, but it's cheaper to cheat and use the previous frame's velocity.
		if (dot > 0.0f)
		{
			prev2Now /= elapsed;

			float xfabs = fabs(prev2Now.fX);
			float yfabs = fabs(prev2Now.fY);
			float zfabs = fabs(prev2Now.fZ);
			static const float maxVel = 20.0f;
			hsBool valid = xfabs < maxVel && yfabs < maxVel && zfabs < maxVel;

			if (valid)
			{
				fAnimLinearVel = prev2Now;
			}
		} 
	}
}

void plAnimatedMovementStrategy::IRecalcAngularVelocity(float elapsed, hsMatrix44 &prevMat, hsMatrix44 &curMat)
{
	fAnimAngularVel = 0.0f;
	hsScalar appliedVelocity = 0.0f;
	hsVector3 prevForward = GetYAxis(prevMat);
	hsVector3 curForward = GetYAxis(curMat);

	hsScalar angleSincePrev = AngleRad2d(curForward.fX, curForward.fY, prevForward.fX, prevForward.fY);
	hsBool sincePrevSign = angleSincePrev > 0.0f;
	if (angleSincePrev > hsScalarPI)
		angleSincePrev = angleSincePrev - TWO_PI;

	const hsVector3 startForward = hsVector3(0.0f, -1.0f, 0.0f);	// the Y orientation of a "resting" armature....
	hsScalar angleSinceStart = AngleRad2d(curForward.fX, curForward.fY, startForward.fX, startForward.fY);
	hsBool sinceStartSign = angleSinceStart > 0.0f;
	if (angleSinceStart > hsScalarPI)
		angleSinceStart = angleSinceStart - TWO_PI;

	// HANDLING ANIMATION WRAPPING:
	// under normal conditions, the angle from rest to the current frame will have the same
	// sign as the angle from the previous frame to the current frame.
	// if it does not, we have (most likely) wrapped the motivating animation from frame n back
	// to frame zero, creating a large angle from the previous frame to the current one
	if (sincePrevSign == sinceStartSign)
	{
		// signs are the same; didn't wrap; use the frame-to-frame angle difference
		appliedVelocity = angleSincePrev / elapsed;	// rotation / time
		if (fabs(appliedVelocity) < 3)
		{
			fAnimAngularVel = appliedVelocity;
		}
	}
}


// Walking Strategy
plWalkingStrategy::plWalkingStrategy(plAGApplicator* rootApp, plPhysicalControllerCore* controller)
	: plAnimatedMovementStrategy(rootApp, controller),
	fSlidingNormals(),
	fImpactVelocity(0.0f, 0.0f, 0.0f),
	fImpactTime(0.0f),
	fTimeInAir(0.0f),
	fControlledFlightTime(0.0f),
	fControlledFlight(0),
	fGroundHit(false),
	fFalseGround(false),
	fHeadHit(false),
	fClearImpact(false),
	fHitGroundInThisAge(false)
{
}

void plWalkingStrategy::Apply(hsScalar delSecs)
{
	hsVector3 velocity = fController->GetLinearVelocity();
	hsVector3 achievedVelocity = fController->GetAchievedLinearVelocity();

	// Add in gravity if the avatar's z velocity isn't being set explicitly
	if (hsABS(velocity.fZ) < 0.001f)
	{
		// Get our previous z velocity.  If we're on the ground, clamp it to zero at
		// the largest, so we won't launch into the air if we're running uphill.
		hsScalar prevZVel = achievedVelocity.fZ;
		if (IsOnGround())
			prevZVel = hsMinimum(prevZVel, 0.0f);

		velocity.fZ = prevZVel + (kGravity * delSecs);
	}

	// If we're airborne and the velocity isn't set, use the velocity from
	// the last frame so we maintain momentum.
	if (!IsOnGround() && velocity.fX == 0.0f && velocity.fY == 0.0f)
	{
		velocity.fX = achievedVelocity.fX;
		velocity.fY = achievedVelocity.fY;
	}

	if (!fGroundHit && fSlidingNormals.Count())
	{
		// We're not on solid ground, so we should be sliding against whatever
		// we're hitting (like a rock cliff). Each vector in fSlidingNormals is
		// the surface normal of a collision that's too steep to be ground, so
		// we project our current velocity onto that plane and slide along the
		// wall.
		//
		// Also, sometimes PhysX reports a bunch of collisions from the wall,
		// but nothing from underneath (when there should be). So if we're not
		// touching ground, we offset the avatar in the direction of the 
		// surface normal(s). This doesn't fix the issue 100%, but it's a hell
		// of a lot better than nothing, and suitable duct tape until a future
		// PhysX revision fixes the issue.
		//
		// Yes, there's room for optimization here if we care.
		hsVector3 offset(0.0f, 0.0f, 0.0f);
		for (int i = 0; i < fSlidingNormals.GetCount(); i++)
		{
			offset += fSlidingNormals[i];
			hsVector3 velNorm = velocity;

			if (velNorm.MagnitudeSquared() > 0.0f)
				velNorm.Normalize();

			if (velNorm * fSlidingNormals[i] < 0.0f)
			{
				hsVector3 proj = (velNorm % fSlidingNormals[i]) % fSlidingNormals[i];
				if (velNorm * proj < 0.0f)
					proj *= -1.0f;

				velocity = velocity.Magnitude() * proj;
			}
		}
		if (offset.MagnitudeSquared() > 0.0f)
		{
			// 5 ft/sec is roughly the speed we walk backwards.
			// The higher the value, the less likely you'll trip
			// the bug, and this seems reasonable.
			offset.Normalize();
			velocity += offset * 5.0f;
		}
	}

	if (velocity.fZ < kTerminalVelocity)
		velocity.fZ = kTerminalVelocity;

	// Convert to a displacement vector
	hsVector3 displacement = velocity * delSecs;

	// Reset vars and move the controller
	fController->SetPushingPhysical(nil);
	fController->SetFacingPushingPhysical(false);
	fGroundHit = fFalseGround = fHeadHit = false;
	fSlidingNormals.SetCount(0);

	unsigned int collideResults = 0;
	unsigned int collideFlags = 1<<plSimDefs::kGroupStatic | 1<<plSimDefs::kGroupAvatarBlocker | 1<<plSimDefs::kGroupDynamic;
	if (!fController->IsSeeking())
		collideFlags |= (1<<plSimDefs::kGroupExcludeRegion);

	fController->Move(displacement, collideFlags, collideResults);

	if ((!fGroundHit) && (collideResults & kBottom))
		fFalseGround = true;

	if (collideResults & kTop)
		fHeadHit = true;
}
void plWalkingStrategy::Update(hsScalar delSecs)
{
	if (fGroundHit || fFalseGround)
		fTimeInAir = 0.0f;
	else
	{
		fTimeInAir += delSecs;
		if (fHeadHit)
		{ 
			// If we're airborne and hit our head, override achieved velocity to avoid being shoved sideways
			hsVector3 velocity = fController->GetLinearVelocity();
			hsVector3 achievedVelocity = fController->GetAchievedLinearVelocity();
		
			achievedVelocity.fX = velocity.fX;
			achievedVelocity.fY = velocity.fY;
			if (achievedVelocity.fZ > 0.0f)
				achievedVelocity.fZ = 0.0f;

			fController->OverrideAchievedLinearVelocity(achievedVelocity);
		}
	}

	hsVector3 zeroVelocity(0.f, 0.f, 0.f);
	fController->SetLinearVelocity(zeroVelocity);

	if (!fHitGroundInThisAge && IsOnGround())
		fHitGroundInThisAge = true;

	if (fClearImpact)
	{
		fImpactTime = 0.0f;
		fImpactVelocity.Set(0.0f, 0.0f, 0.0f);
	}

	if (IsOnGround())
		fClearImpact = true;
	else
	{
		fImpactTime = fTimeInAir;
		fImpactVelocity = fController->GetAchievedLinearVelocity();
		// convert orientation from subworld to avatar-local coordinates
		fImpactVelocity = (hsVector3)fController->GetLocalRotation().Rotate(&fImpactVelocity);
		fClearImpact = false;
	}
}

void plWalkingStrategy::AddContactNormals(hsVector3& vec)
{
	hsScalar dot = vec * kAvatarUp;
	if (dot >= 0.5f)
		fGroundHit = true;
	else
		fSlidingNormals.Append(vec);
}

void plWalkingStrategy::Reset(bool newAge)
{
	plMovementStrategy::Reset(newAge);
	fImpactVelocity.Set(0.0f, 0.0f, 0.0f);
	fImpactTime = 0.0f;
	if (newAge)
	{
		fTimeInAir = 0.0f;
		fClearImpact = true;
		fHitGroundInThisAge = false;
		fSlidingNormals.SetCount(0);
	}
}

void plWalkingStrategy::RecalcVelocity(double timeNow, hsScalar elapsed, hsBool useAnim)
{
	if (fControlledFlight != 0)
	{
		if (IsOnGround())
			fControlledFlightTime = fTimeInAir;

		if (fControlledFlightTime > kControlledFlightThreshold)
			EnableControlledFlight(false);
	}

	plAnimatedMovementStrategy::RecalcVelocity(timeNow, elapsed, useAnim);
}

bool plWalkingStrategy::EnableControlledFlight(bool status)
{
	if (status)
	{
		if (fControlledFlight == 0)
			fControlledFlightTime = 0.0f;

		++fControlledFlight;
	}
	else
		fControlledFlight = __max(--fControlledFlight, 0);

	return status;
}

plPhysical* plWalkingStrategy::GetPushingPhysical() const { return fController->GetPushingPhysical(); }
bool plWalkingStrategy::GetFacingPushingPhysical() const { return fController->GetFacingPushingPhysical(); }

const hsScalar plWalkingStrategy::kAirTimeThreshold = 0.1f;
const hsScalar plWalkingStrategy::kControlledFlightThreshold = 1.0f;


// Swim Strategy
plSwimStrategy::plSwimStrategy(plAGApplicator* rootApp, plPhysicalControllerCore* controller) 
	: plAnimatedMovementStrategy(rootApp, controller),
	fBuoyancy(0.0f),
	fSurfaceHeight(0.0f),
	fCurrentRegion(nil),
	fOnGround(false),
	fHadContacts(false)
{
}

void plSwimStrategy::Apply(hsScalar delSecs)
{
	hsVector3 velocity = fController->GetLinearVelocity();
	hsVector3 achievedVelocity = fController->GetAchievedLinearVelocity();

	IAdjustBuoyancy();
	
	//trying to dampen the oscillations
	hsScalar retardent = 0.0f;
	static hsScalar finalBobSpeed = 0.5f;
	if ((achievedVelocity.fZ > finalBobSpeed) || (achievedVelocity.fZ < -finalBobSpeed))
		retardent = achievedVelocity.fZ * -0.90f;

	hsScalar zacc = (1.0f - fBuoyancy) * kGravity + retardent;
	velocity.fZ += (zacc * delSecs);

	velocity.fZ += achievedVelocity.fZ;

	// Water Current
	if (fCurrentRegion != nil)
	{
		hsScalar angCurrent = 0.0f;
		hsVector3 linCurrent(0.0f, 0.0f, 0.0f);
		fCurrentRegion->GetCurrent(fController, linCurrent, angCurrent, delSecs);

		if (hsABS(angCurrent) > 0.0001f)
			fController->IncrementAngle(angCurrent * delSecs);

		velocity += linCurrent;

		if (velocity.fZ > fCurrentRegion->fMaxUpwardVel)
			velocity.fZ = fCurrentRegion->fMaxUpwardVel;
	}

	if (velocity.fZ < kTerminalVelocity)
		velocity.fZ = kTerminalVelocity;

	// Convert to displacement vector
	hsVector3 displacement = velocity * delSecs;

	// Reset vars and move controller //
	fController->SetPushingPhysical(nil);
	fController->SetFacingPushingPhysical(false);
	fHadContacts = fOnGround = false;

	unsigned int collideResults = 0;
	unsigned int collideFlags = 1<<plSimDefs::kGroupStatic | 1<<plSimDefs::kGroupAvatarBlocker | 1<<plSimDefs::kGroupDynamic;
	if (!fController->IsSeeking())
		collideFlags |= (1<<plSimDefs::kGroupExcludeRegion);

	fController->Move(displacement, collideFlags, collideResults);

	if ((collideResults & kBottom) || (collideResults & kSides))
		fHadContacts = true;
}

void plSwimStrategy::AddContactNormals(hsVector3& vec)
{
	hsScalar dot = vec * kAvatarUp;
	if (dot >= kSlopeLimit)
		fOnGround = true;
}

void plSwimStrategy::SetSurface(plSwimRegionInterface *region, hsScalar surfaceHeight)
{
	fCurrentRegion = region;
	fSurfaceHeight = surfaceHeight;
}
void plSwimStrategy::IAdjustBuoyancy()
{
	// "surface depth" refers to the depth our handle object should be below
	// the surface for the avatar to be "at the surface"
	static const float surfaceDepth = 4.0f;
	// 1.0 = neutral buoyancy
	// 0 = no buoyancy (normal gravity)
	// 2.0 = opposite of gravity, floating upwards
	static const float buoyancyAtSurface = 1.0f;

	if (fCurrentRegion == nil)
	{
		fBuoyancy = 0.f;
		return;
	}

	hsPoint3 posSim;
	fController->GetPositionSim(posSim);
	float depth = fSurfaceHeight - posSim.fZ;

	// this isn't a smooth transition but hopefully it won't be too obvious
	if (depth <= 0.0) //all the away above water
		fBuoyancy = 0.f; // Same as being above ground. Plain old gravity.
	else if (depth >= 5.0f) 
		fBuoyancy = 3.0f; //completely Submereged
	else 
		fBuoyancy = depth / surfaceDepth;
}


// Dynamic Walking Strategy
plDynamicWalkingStrategy::plDynamicWalkingStrategy(plAGApplicator* rootApp, plPhysicalControllerCore* controller)
	: plWalkingStrategy(rootApp, controller)
{
}

void plDynamicWalkingStrategy::Apply(hsScalar delSecs)
{
	hsVector3 velocity = fController->GetLinearVelocity();
	hsVector3 achievedVelocity = fController->GetAchievedLinearVelocity();

	// Add in gravity if the avatar's z velocity isn't being set explicitly
	if (hsABS(velocity.fZ) < 0.001f)
	{
		// Get our previous z velocity.  If we're on the ground, clamp it to zero at
		// the largest, so we won't launch into the air if we're running uphill.
		hsScalar prevZVel = achievedVelocity.fZ;
		if (IsOnGround())
			prevZVel = hsMinimum(prevZVel, 0.f);

		velocity.fZ = prevZVel + (kGravity * delSecs);
	}

	if (velocity.fZ < kTerminalVelocity)
		velocity.fZ = kTerminalVelocity;

	fController->SetPushingPhysical(nil);
	fController->SetFacingPushingPhysical(false);
	fGroundHit = fFalseGround = false;

	hsScalar groundZVelocity;
	if (ICheckForGround(groundZVelocity))
		velocity.fZ += groundZVelocity;

	fController->SetLinearVelocitySim(velocity);
}

bool plDynamicWalkingStrategy::ICheckForGround(hsScalar& zVelocity)
{
	std::vector<plControllerSweepRecord> groundHits;
	UInt32 collideFlags = 1<<plSimDefs::kGroupStatic | 1<<plSimDefs::kGroupAvatarBlocker | 1<<plSimDefs::kGroupDynamic;

	hsPoint3 startPos;
	fController->GetPositionSim(startPos);
	hsPoint3 endPos = startPos;

	// Set sweep length
	startPos.fZ += 0.05f;
	endPos.fZ -= 0.05f;

	int possiblePlatformCount = fController->SweepControllerPath(startPos, endPos, true, true, collideFlags, groundHits);
	if (possiblePlatformCount)
	{
		zVelocity = -FLT_MAX;

		std::vector<plControllerSweepRecord>::iterator curRecord; 
		for (curRecord = groundHits.begin(); curRecord != groundHits.end(); ++curRecord)
		{
			if (curRecord->ObjHit != nil)
			{
				hsVector3 objVelocity;
				curRecord->ObjHit->GetLinearVelocitySim(objVelocity);
				if (objVelocity.fZ > zVelocity)
					zVelocity = objVelocity.fZ;

				fGroundHit = true;
			}
		}
	}

	return fGroundHit;
}


//////////////////////////////////////////////////////////////////////////

/*
Purpose:

ANGLE_RAD_2D returns the angle in radians swept out between two rays in 2D.

Discussion:

Except for the zero angle case, it should be true that

ANGLE_RAD_2D(X1,Y1,X2,Y2,X3,Y3)
+ ANGLE_RAD_2D(X3,Y3,X2,Y2,X1,Y1) = 2 * PI

Modified:

19 April 1999

Author:

John Burkardt

Parameters:

Input, float X1, Y1, X2, Y2, X3, Y3, define the rays
( X1-X2, Y1-Y2 ) and ( X3-X2, Y3-Y2 ) which in turn define the
angle, counterclockwise from ( X1-X2, Y1-Y2 ).

Output, float ANGLE_RAD_2D, the angle swept out by the rays, measured
in radians.  0 <= ANGLE_DEG_2D < 2 PI.  If either ray has zero length,
then ANGLE_RAD_2D is set to 0.
*/

static float AngleRad2d( float x1, float y1, float x3, float y3 )
{
	float value;
	float x;
	float y;

	x = ( x1 ) * ( x3 ) + ( y1 ) * ( y3 );
	y = ( x1 ) * ( y3 ) - ( y1 ) * ( x3 );

	if ( x == 0.0 && y == 0.0 ) {
		value = 0.0;
	}
	else 
	{
		value = atan2 ( y, x );

		if ( value < 0.0 ) 
		{
			value = (float)(value + TWO_PI);
		}
	}
	return value;
}