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openmw-tes3mp/apps/openmw/mwphysics/movementsolver.cpp

533 lines
25 KiB
C++

#include "movementsolver.hpp"
#include <BulletCollision/CollisionDispatch/btCollisionObject.h>
#include <BulletCollision/CollisionDispatch/btCollisionWorld.h>
#include <BulletCollision/CollisionShapes/btCollisionShape.h>
#include <components/esm/loadgmst.hpp>
#include <components/misc/convert.hpp>
#include "../mwbase/world.hpp"
#include "../mwbase/environment.hpp"
#include "../mwworld/class.hpp"
#include "../mwworld/esmstore.hpp"
#include "../mwworld/refdata.hpp"
#include "actor.hpp"
#include "collisiontype.hpp"
#include "constants.hpp"
#include "contacttestwrapper.h"
#include "physicssystem.hpp"
#include "stepper.hpp"
#include "trace.h"
#include <cmath>
namespace MWPhysics
{
static bool isActor(const btCollisionObject *obj)
{
assert(obj);
return obj->getBroadphaseHandle()->m_collisionFilterGroup == CollisionType_Actor;
}
class ContactCollectionCallback : public btCollisionWorld::ContactResultCallback
{
public:
ContactCollectionCallback(const btCollisionObject * me, osg::Vec3f velocity) : mMe(me)
{
m_collisionFilterGroup = me->getBroadphaseHandle()->m_collisionFilterGroup;
m_collisionFilterMask = me->getBroadphaseHandle()->m_collisionFilterMask & ~CollisionType_Projectile;
mVelocity = Misc::Convert::toBullet(velocity);
}
btScalar addSingleResult(btManifoldPoint & contact, const btCollisionObjectWrapper * colObj0Wrap, int partId0, int index0, const btCollisionObjectWrapper * colObj1Wrap, int partId1, int index1) override
{
if (isActor(colObj0Wrap->getCollisionObject()) && isActor(colObj1Wrap->getCollisionObject()))
return 0.0;
// ignore overlap if we're moving in the same direction as it would push us out (don't change this to >=, that would break detection when not moving)
if (contact.m_normalWorldOnB.dot(mVelocity) > 0.0)
return 0.0;
auto delta = contact.m_normalWorldOnB * -contact.m_distance1;
mContactSum += delta;
mMaxX = std::max(std::abs(delta.x()), mMaxX);
mMaxY = std::max(std::abs(delta.y()), mMaxY);
mMaxZ = std::max(std::abs(delta.z()), mMaxZ);
if (contact.m_distance1 < mDistance)
{
mDistance = contact.m_distance1;
mNormal = contact.m_normalWorldOnB;
mDelta = delta;
return mDistance;
}
else
{
return 0.0;
}
}
btScalar mMaxX = 0.0;
btScalar mMaxY = 0.0;
btScalar mMaxZ = 0.0;
btVector3 mContactSum{0.0, 0.0, 0.0};
btVector3 mNormal{0.0, 0.0, 0.0}; // points towards "me"
btVector3 mDelta{0.0, 0.0, 0.0}; // points towards "me"
btScalar mDistance = 0.0; // negative or zero
protected:
btVector3 mVelocity;
const btCollisionObject * mMe;
};
osg::Vec3f MovementSolver::traceDown(const MWWorld::Ptr &ptr, const osg::Vec3f& position, Actor* actor, btCollisionWorld* collisionWorld, float maxHeight)
{
osg::Vec3f offset = actor->getCollisionObjectPosition() - ptr.getRefData().getPosition().asVec3();
ActorTracer tracer;
tracer.findGround(actor, position + offset, position + offset - osg::Vec3f(0,0,maxHeight), collisionWorld);
if (tracer.mFraction >= 1.0f)
{
actor->setOnGround(false);
return position;
}
actor->setOnGround(true);
// Check if we actually found a valid spawn point (use an infinitely thin ray this time).
// Required for some broken door destinations in Morrowind.esm, where the spawn point
// intersects with other geometry if the actor's base is taken into account
btVector3 from = Misc::Convert::toBullet(position);
btVector3 to = from - btVector3(0,0,maxHeight);
btCollisionWorld::ClosestRayResultCallback resultCallback1(from, to);
resultCallback1.m_collisionFilterGroup = 0xff;
resultCallback1.m_collisionFilterMask = CollisionType_World|CollisionType_HeightMap;
collisionWorld->rayTest(from, to, resultCallback1);
if (resultCallback1.hasHit() && ((Misc::Convert::toOsg(resultCallback1.m_hitPointWorld) - tracer.mEndPos + offset).length2() > 35*35
|| !isWalkableSlope(tracer.mPlaneNormal)))
{
actor->setOnSlope(!isWalkableSlope(resultCallback1.m_hitNormalWorld));
return Misc::Convert::toOsg(resultCallback1.m_hitPointWorld) + osg::Vec3f(0.f, 0.f, sGroundOffset);
}
actor->setOnSlope(!isWalkableSlope(tracer.mPlaneNormal));
return tracer.mEndPos-offset + osg::Vec3f(0.f, 0.f, sGroundOffset);
}
void MovementSolver::move(ActorFrameData& actor, float time, const btCollisionWorld* collisionWorld,
WorldFrameData& worldData)
{
auto* physicActor = actor.mActorRaw;
const ESM::Position& refpos = actor.mRefpos;
// Early-out for totally static creatures
// (Not sure if gravity should still apply?)
{
const auto ptr = physicActor->getPtr();
if (!ptr.getClass().isMobile(ptr))
return;
}
// Reset per-frame data
physicActor->setWalkingOnWater(false);
// Anything to collide with?
if(!physicActor->getCollisionMode() || actor.mSkipCollisionDetection)
{
actor.mPosition += (osg::Quat(refpos.rot[0], osg::Vec3f(-1, 0, 0)) *
osg::Quat(refpos.rot[2], osg::Vec3f(0, 0, -1))
) * actor.mMovement * time;
return;
}
const btCollisionObject *colobj = physicActor->getCollisionObject();
// Adjust for collision mesh offset relative to actor's "location"
// (doTrace doesn't take local/interior collision shape translation into account, so we have to do it on our own)
// for compatibility with vanilla assets, we have to derive this from the vertical half extent instead of from internal hull translation
// if not for this hack, the "correct" collision hull position would be physicActor->getScaledMeshTranslation()
osg::Vec3f halfExtents = physicActor->getHalfExtents();
actor.mPosition.z() += halfExtents.z(); // vanilla-accurate
static const float fSwimHeightScale = MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fSwimHeightScale")->mValue.getFloat();
float swimlevel = actor.mWaterlevel + halfExtents.z() - (physicActor->getRenderingHalfExtents().z() * 2 * fSwimHeightScale);
ActorTracer tracer;
osg::Vec3f inertia = physicActor->getInertialForce();
osg::Vec3f velocity;
if (actor.mPosition.z() < swimlevel || actor.mFlying)
{
velocity = (osg::Quat(refpos.rot[0], osg::Vec3f(-1, 0, 0)) * osg::Quat(refpos.rot[2], osg::Vec3f(0, 0, -1))) * actor.mMovement;
}
else
{
velocity = (osg::Quat(refpos.rot[2], osg::Vec3f(0, 0, -1))) * actor.mMovement;
if ((velocity.z() > 0.f && physicActor->getOnGround() && !physicActor->getOnSlope())
|| (velocity.z() > 0.f && velocity.z() + inertia.z() <= -velocity.z() && physicActor->getOnSlope()))
inertia = velocity;
else if (!physicActor->getOnGround() || physicActor->getOnSlope())
velocity = velocity + inertia;
}
// Dead and paralyzed actors underwater will float to the surface,
// if the CharacterController tells us to do so
if (actor.mMovement.z() > 0 && actor.mFloatToSurface && actor.mPosition.z() < swimlevel)
velocity = osg::Vec3f(0,0,1) * 25;
if (actor.mWantJump)
actor.mDidJump = true;
// Now that we have the effective movement vector, apply wind forces to it
if (worldData.mIsInStorm)
{
osg::Vec3f stormDirection = worldData.mStormDirection;
float angleDegrees = osg::RadiansToDegrees(std::acos(stormDirection * velocity / (stormDirection.length() * velocity.length())));
static const float fStromWalkMult = MWBase::Environment::get().getWorld()->getStore().get<ESM::GameSetting>().find("fStromWalkMult")->mValue.getFloat();
velocity *= 1.f-(fStromWalkMult * (angleDegrees/180.f));
}
Stepper stepper(collisionWorld, colobj);
osg::Vec3f origVelocity = velocity;
osg::Vec3f newPosition = actor.mPosition;
/*
* A loop to find newPosition using tracer, if successful different from the starting position.
* nextpos is the local variable used to find potential newPosition, using velocity and remainingTime
* The initial velocity was set earlier (see above).
*/
float remainingTime = time;
bool seenGround = physicActor->getOnGround() && !physicActor->getOnSlope() && !actor.mFlying;
int numTimesSlid = 0;
osg::Vec3f lastSlideNormal(0,0,1);
osg::Vec3f lastSlideNormalFallback(0,0,1);
bool forceGroundTest = false;
for (int iterations = 0; iterations < sMaxIterations && remainingTime > 0.0001f; ++iterations)
{
osg::Vec3f nextpos = newPosition + velocity * remainingTime;
// If not able to fly, don't allow to swim up into the air
if(!actor.mFlying && nextpos.z() > swimlevel && newPosition.z() < swimlevel)
{
const osg::Vec3f down(0,0,-1);
velocity = reject(velocity, down);
// NOTE: remainingTime is unchanged before the loop continues
continue; // velocity updated, calculate nextpos again
}
if((newPosition - nextpos).length2() > 0.0001)
{
// trace to where character would go if there were no obstructions
tracer.doTrace(colobj, newPosition, nextpos, collisionWorld);
// check for obstructions
if(tracer.mFraction >= 1.0f)
{
newPosition = tracer.mEndPos; // ok to move, so set newPosition
break;
}
}
else
{
// The current position and next position are nearly the same, so just exit.
// Note: Bullet can trigger an assert in debug modes if the positions
// are the same, since that causes it to attempt to normalize a zero
// length vector (which can also happen with nearly identical vectors, since
// precision can be lost due to any math Bullet does internally). Since we
// aren't performing any collision detection, we want to reject the next
// position, so that we don't slowly move inside another object.
break;
}
if (isWalkableSlope(tracer.mPlaneNormal) && !actor.mFlying && newPosition.z() >= swimlevel)
seenGround = true;
// We hit something. Check if we can step up.
float hitHeight = tracer.mHitPoint.z() - tracer.mEndPos.z() + halfExtents.z();
osg::Vec3f oldPosition = newPosition;
bool usedStepLogic = false;
if (hitHeight < sStepSizeUp && !isActor(tracer.mHitObject))
{
// Try to step up onto it.
// NOTE: this modifies newPosition and velocity on its own if successful
usedStepLogic = stepper.step(newPosition, velocity, remainingTime, seenGround, iterations == 0);
}
if (usedStepLogic)
{
// don't let pure water creatures move out of water after stepMove
const auto ptr = physicActor->getPtr();
if (ptr.getClass().isPureWaterCreature(ptr) && newPosition.z() + halfExtents.z() > actor.mWaterlevel)
newPosition = oldPosition;
else if(!actor.mFlying && actor.mPosition.z() >= swimlevel)
forceGroundTest = true;
}
else
{
// Can't step up, so slide against what we ran into
remainingTime *= (1.0f-tracer.mFraction);
auto planeNormal = tracer.mPlaneNormal;
// If we touched the ground this frame, and whatever we ran into is a wall of some sort,
// pretend that its collision normal is pointing horizontally
// (fixes snagging on slightly downward-facing walls, and crawling up the bases of very steep walls because of the collision margin)
if (seenGround && !isWalkableSlope(planeNormal) && planeNormal.z() != 0)
{
planeNormal.z() = 0;
planeNormal.normalize();
}
// Move up to what we ran into (with a bit of a collision margin)
if ((newPosition-tracer.mEndPos).length2() > sCollisionMargin*sCollisionMargin)
{
auto direction = velocity;
direction.normalize();
newPosition = tracer.mEndPos;
newPosition -= direction*sCollisionMargin;
}
osg::Vec3f newVelocity = (velocity * planeNormal <= 0.0) ? reject(velocity, planeNormal) : velocity;
bool usedSeamLogic = false;
// check for the current and previous collision planes forming an acute angle; slide along the seam if they do
if(numTimesSlid > 0)
{
auto dotA = lastSlideNormal * planeNormal;
auto dotB = lastSlideNormalFallback * planeNormal;
if(numTimesSlid <= 1) // ignore fallback normal if this is only the first or second slide
dotB = 1.0;
if(dotA <= 0.0 || dotB <= 0.0)
{
osg::Vec3f bestNormal = lastSlideNormal;
// use previous-to-previous collision plane if it's acute with current plane but actual previous plane isn't
if(dotB < dotA)
{
bestNormal = lastSlideNormalFallback;
lastSlideNormal = lastSlideNormalFallback;
}
auto constraintVector = bestNormal ^ planeNormal; // cross product
if(constraintVector.length2() > 0) // only if it's not zero length
{
constraintVector.normalize();
newVelocity = project(velocity, constraintVector);
// version of surface rejection for acute crevices/seams
auto averageNormal = bestNormal + planeNormal;
averageNormal.normalize();
tracer.doTrace(colobj, newPosition, newPosition + averageNormal*(sCollisionMargin*2.0), collisionWorld);
newPosition = (newPosition + tracer.mEndPos)/2.0;
usedSeamLogic = true;
}
}
}
// otherwise just keep the normal vector rejection
// if this isn't the first iteration, or if the first iteration is also the last iteration,
// move away from the collision plane slightly, if possible
// this reduces getting stuck in some concave geometry, like the gaps above the railings in some ald'ruhn buildings
// this is different from the normal collision margin, because the normal collision margin is along the movement path,
// but this is along the collision normal
if(!usedSeamLogic && (iterations > 0 || remainingTime < 0.01f))
{
tracer.doTrace(colobj, newPosition, newPosition + planeNormal*(sCollisionMargin*2.0), collisionWorld);
newPosition = (newPosition + tracer.mEndPos)/2.0;
}
// Do not allow sliding up steep slopes if there is gravity.
if (newPosition.z() >= swimlevel && !actor.mFlying && !isWalkableSlope(planeNormal))
newVelocity.z() = std::min(newVelocity.z(), velocity.z());
if (newVelocity * origVelocity <= 0.0f)
break;
numTimesSlid += 1;
lastSlideNormalFallback = lastSlideNormal;
lastSlideNormal = planeNormal;
velocity = newVelocity;
}
}
bool isOnGround = false;
bool isOnSlope = false;
if (forceGroundTest || (inertia.z() <= 0.f && newPosition.z() >= swimlevel))
{
osg::Vec3f from = newPosition;
auto dropDistance = 2*sGroundOffset + (physicActor->getOnGround() ? sStepSizeDown : 0);
osg::Vec3f to = newPosition - osg::Vec3f(0,0,dropDistance);
tracer.doTrace(colobj, from, to, collisionWorld);
if(tracer.mFraction < 1.0f)
{
if (!isActor(tracer.mHitObject))
{
isOnGround = true;
isOnSlope = !isWalkableSlope(tracer.mPlaneNormal);
const btCollisionObject* standingOn = tracer.mHitObject;
PtrHolder* ptrHolder = static_cast<PtrHolder*>(standingOn->getUserPointer());
if (ptrHolder)
actor.mStandingOn = ptrHolder->getPtr();
if (standingOn->getBroadphaseHandle()->m_collisionFilterGroup == CollisionType_Water)
physicActor->setWalkingOnWater(true);
if (!actor.mFlying && !isOnSlope)
{
if (tracer.mFraction*dropDistance > sGroundOffset)
newPosition.z() = tracer.mEndPos.z() + sGroundOffset;
else
{
newPosition.z() = tracer.mEndPos.z();
tracer.doTrace(colobj, newPosition, newPosition + osg::Vec3f(0, 0, 2*sGroundOffset), collisionWorld);
newPosition = (newPosition+tracer.mEndPos)/2.0;
}
}
}
else
{
// Vanilla allows actors to float on top of other actors. Do not push them off.
if (!actor.mFlying && isWalkableSlope(tracer.mPlaneNormal) && tracer.mEndPos.z()+sGroundOffset <= newPosition.z())
newPosition.z() = tracer.mEndPos.z() + sGroundOffset;
isOnGround = false;
}
}
// forcibly treat stuck actors as if they're on flat ground because buggy collisions when inside of things can/will break ground detection
if(physicActor->getStuckFrames() > 0)
{
isOnGround = true;
isOnSlope = false;
}
}
if((isOnGround && !isOnSlope) || newPosition.z() < swimlevel || actor.mFlying)
physicActor->setInertialForce(osg::Vec3f(0.f, 0.f, 0.f));
else
{
inertia.z() -= time * Constants::GravityConst * Constants::UnitsPerMeter;
if (inertia.z() < 0)
inertia.z() *= actor.mSlowFall;
if (actor.mSlowFall < 1.f) {
inertia.x() *= actor.mSlowFall;
inertia.y() *= actor.mSlowFall;
}
physicActor->setInertialForce(inertia);
}
physicActor->setOnGround(isOnGround);
physicActor->setOnSlope(isOnSlope);
actor.mPosition = newPosition;
// remove what was added earlier in compensating for doTrace not taking interior transformation into account
actor.mPosition.z() -= halfExtents.z(); // vanilla-accurate
}
btVector3 addMarginToDelta(btVector3 delta)
{
if(delta.length2() == 0.0)
return delta;
return delta + delta.normalized() * sCollisionMargin;
}
void MovementSolver::unstuck(ActorFrameData& actor, const btCollisionWorld* collisionWorld)
{
const auto& ptr = actor.mActorRaw->getPtr();
if (!ptr.getClass().isMobile(ptr))
return;
auto* physicActor = actor.mActorRaw;
if(!physicActor->getCollisionMode() || actor.mSkipCollisionDetection) // noclipping/tcl
return;
auto* collisionObject = physicActor->getCollisionObject();
auto tempPosition = actor.mPosition;
if(physicActor->getStuckFrames() >= 10)
{
if((physicActor->getLastStuckPosition() - actor.mPosition).length2() < 100)
return;
else
{
physicActor->setStuckFrames(0);
physicActor->setLastStuckPosition({0, 0, 0});
}
}
// use vanilla-accurate collision hull position hack (do same hitbox offset hack as movement solver)
// if vanilla compatibility didn't matter, the "correct" collision hull position would be physicActor->getScaledMeshTranslation()
const auto verticalHalfExtent = osg::Vec3f(0.0, 0.0, physicActor->getHalfExtents().z());
// use a 3d approximation of the movement vector to better judge player intent
auto velocity = (osg::Quat(actor.mRefpos.rot[0], osg::Vec3f(-1, 0, 0)) * osg::Quat(actor.mRefpos.rot[2], osg::Vec3f(0, 0, -1))) * actor.mMovement;
// try to pop outside of the world before doing anything else if we're inside of it
if (!physicActor->getOnGround() || physicActor->getOnSlope())
velocity += physicActor->getInertialForce();
// because of the internal collision box offset hack, and the fact that we're moving the collision box manually,
// we need to replicate part of the collision box's transform process from scratch
osg::Vec3f refPosition = tempPosition + verticalHalfExtent;
osg::Vec3f goodPosition = refPosition;
const btTransform oldTransform = collisionObject->getWorldTransform();
btTransform newTransform = oldTransform;
auto gatherContacts = [&](btVector3 newOffset) -> ContactCollectionCallback
{
goodPosition = refPosition + Misc::Convert::toOsg(addMarginToDelta(newOffset));
newTransform.setOrigin(Misc::Convert::toBullet(goodPosition));
collisionObject->setWorldTransform(newTransform);
ContactCollectionCallback callback{collisionObject, velocity};
ContactTestWrapper::contactTest(const_cast<btCollisionWorld*>(collisionWorld), collisionObject, callback);
return callback;
};
// check whether we're inside the world with our collision box with manually-derived offset
auto contactCallback = gatherContacts({0.0, 0.0, 0.0});
if(contactCallback.mDistance < -sAllowedPenetration)
{
physicActor->setStuckFrames(physicActor->getStuckFrames() + 1);
physicActor->setLastStuckPosition(actor.mPosition);
// we are; try moving it out of the world
auto positionDelta = contactCallback.mContactSum;
// limit rejection delta to the largest known individual rejections
if(std::abs(positionDelta.x()) > contactCallback.mMaxX)
positionDelta *= contactCallback.mMaxX / std::abs(positionDelta.x());
if(std::abs(positionDelta.y()) > contactCallback.mMaxY)
positionDelta *= contactCallback.mMaxY / std::abs(positionDelta.y());
if(std::abs(positionDelta.z()) > contactCallback.mMaxZ)
positionDelta *= contactCallback.mMaxZ / std::abs(positionDelta.z());
auto contactCallback2 = gatherContacts(positionDelta);
// successfully moved further out from contact (does not have to be in open space, just less inside of things)
if(contactCallback2.mDistance > contactCallback.mDistance)
tempPosition = goodPosition - verticalHalfExtent;
// try again but only upwards (fixes some bad coc floors)
else
{
// upwards-only offset
auto contactCallback3 = gatherContacts({0.0, 0.0, std::abs(positionDelta.z())});
// success
if(contactCallback3.mDistance > contactCallback.mDistance)
tempPosition = goodPosition - verticalHalfExtent;
else
// try again but fixed distance up
{
auto contactCallback4 = gatherContacts({0.0, 0.0, 10.0});
// success
if(contactCallback4.mDistance > contactCallback.mDistance)
tempPosition = goodPosition - verticalHalfExtent;
}
}
}
else
{
physicActor->setStuckFrames(0);
physicActor->setLastStuckPosition({0, 0, 0});
}
collisionObject->setWorldTransform(oldTransform);
actor.mPosition = tempPosition;
}
}