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OpenMW/apps/openmw/mwphysics/movementsolver.cpp
2024-10-28 13:10:16 +03:00

584 lines
27 KiB
C++

#include "movementsolver.hpp"
#include <BulletCollision/CollisionDispatch/btCollisionObject.h>
#include <BulletCollision/CollisionDispatch/btCollisionWorld.h>
#include <BulletCollision/CollisionShapes/btConvexShape.h>
#include <components/esm3/loadgmst.hpp>
#include <components/misc/convert.hpp>
#include "../mwbase/environment.hpp"
#include "../mwworld/esmstore.hpp"
#include "actor.hpp"
#include "collisiontype.hpp"
#include "constants.hpp"
#include "contacttestwrapper.h"
#include "object.hpp"
#include "physicssystem.hpp"
#include "projectile.hpp"
#include "projectileconvexcallback.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;
}
namespace
{
class ContactCollectionCallback : public btCollisionWorld::ContactResultCallback
{
public:
explicit ContactCollectionCallback(const btCollisionObject& me, const osg::Vec3f& velocity)
: mVelocity(Misc::Convert::toBullet(velocity))
{
m_collisionFilterGroup = me.getBroadphaseHandle()->m_collisionFilterGroup;
m_collisionFilterMask = me.getBroadphaseHandle()->m_collisionFilterMask & ~CollisionType_Projectile;
}
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;
};
}
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 = CollisionType_AnyPhysical;
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, const WorldFrameData& worldData)
{
// Reset per-frame data
actor.mWalkingOnWater = false;
// Anything to collide with?
if (actor.mSkipCollisionDetection)
{
actor.mPosition += (osg::Quat(actor.mRotation.x(), osg::Vec3f(-1, 0, 0))
* osg::Quat(actor.mRotation.y(), osg::Vec3f(0, 0, -1)))
* actor.mMovement * time;
return;
}
// 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()
actor.mPosition.z() += actor.mHalfExtentsZ; // vanilla-accurate
float swimlevel = actor.mSwimLevel + actor.mHalfExtentsZ;
ActorTracer tracer;
osg::Vec3f velocity;
// Dead and paralyzed actors underwater will float to the surface,
// if the CharacterController tells us to do so
if (actor.mMovement.z() > 0 && actor.mInert && actor.mPosition.z() < swimlevel)
{
velocity = osg::Vec3f(0, 0, 1) * 25;
}
else if (actor.mPosition.z() < swimlevel || actor.mFlying)
{
velocity = (osg::Quat(actor.mRotation.x(), osg::Vec3f(-1, 0, 0))
* osg::Quat(actor.mRotation.y(), osg::Vec3f(0, 0, -1)))
* actor.mMovement;
}
else
{
velocity = (osg::Quat(actor.mRotation.y(), osg::Vec3f(0, 0, -1))) * actor.mMovement;
if ((velocity.z() > 0.f && actor.mIsOnGround && !actor.mIsOnSlope)
|| (velocity.z() > 0.f && velocity.z() + actor.mInertia.z() <= -velocity.z() && actor.mIsOnSlope))
actor.mInertia = velocity;
else if (!actor.mIsOnGround || actor.mIsOnSlope)
velocity = velocity + actor.mInertia;
}
// Now that we have the effective movement vector, apply wind forces to it
if (worldData.mIsInStorm && velocity.length() > 0)
{
const MWWorld::ESMStore& store = *MWBase::Environment::get().getESMStore();
const float fStromWalkMult = store.get<ESM::GameSetting>().find("fStromWalkMult")->mValue.getFloat();
const float angleCos = worldData.mStormDirection * velocity / velocity.length();
velocity *= 1.f + fStromWalkMult * angleCos;
}
Stepper stepper(collisionWorld, actor.mCollisionObject);
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;
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;
bool underwater = newPosition.z() < swimlevel;
// If not able to fly, don't allow to swim up into the air
if (!actor.mFlying && nextpos.z() > swimlevel && underwater)
{
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(actor.mCollisionObject, newPosition, nextpos, collisionWorld, actor.mIsOnGround);
// 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;
}
bool seenGround = !actor.mFlying && !underwater
&& ((actor.mIsOnGround && !actor.mIsOnSlope) || isWalkableSlope(tracer.mPlaneNormal));
// We hit something. Check if we can step up.
float hitHeight = tracer.mHitPoint.z() - tracer.mEndPos.z() + actor.mHalfExtentsZ;
osg::Vec3f oldPosition = newPosition;
bool usedStepLogic = false;
if (!isActor(tracer.mHitObject))
{
if (hitHeight < Constants::sStepSizeUp)
{
// 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);
}
auto* ptrHolder = static_cast<PtrHolder*>(tracer.mHitObject->getUserPointer());
if (Object* hitObject = dynamic_cast<Object*>(ptrHolder))
{
hitObject->addCollision(
actor.mIsPlayer ? ScriptedCollisionType_Player : ScriptedCollisionType_Actor);
}
}
if (usedStepLogic)
{
if (actor.mIsAquatic && newPosition.z() + actor.mHalfExtentsZ > 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;
// need to know the unadjusted normal to handle certain types of seams properly
const auto origPlaneNormal = planeNormal;
// 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 for this, we want to use the original plane normal, or else certain types of geometry will
// snag
if (numTimesSlid > 0)
{
auto dotA = lastSlideNormal * origPlaneNormal;
auto dotB = lastSlideNormalFallback * origPlaneNormal;
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 ^ origPlaneNormal; // 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 + origPlaneNormal;
averageNormal.normalize();
tracer.doTrace(actor.mCollisionObject, newPosition,
newPosition + averageNormal * (sCollisionMargin * 2.0), collisionWorld);
newPosition = (newPosition + tracer.mEndPos) / 2.0;
usedSeamLogic = true;
}
}
}
// otherwise just keep the normal vector rejection
// 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)
{
tracer.doTrace(actor.mCollisionObject, newPosition,
newPosition + planeNormal * (sCollisionMargin * 2.0), collisionWorld);
newPosition = (newPosition + tracer.mEndPos) / 2.0;
}
// short circuit if we went backwards, but only if it was mostly horizontal and we're on the ground
if (seenGround && newVelocity * origVelocity <= 0.0f)
{
auto perpendicular = newVelocity ^ origVelocity;
if (perpendicular.length2() > 0.0f)
{
perpendicular.normalize();
if (std::abs(perpendicular.z()) > 0.7071f)
break;
}
}
// Do not allow sliding up steep slopes if there is gravity.
// The purpose of this is to prevent air control from letting you slide up tall, unwalkable slopes.
// For that purpose, it is not necessary to do it when trying to slide along acute seams/crevices (i.e.
// usedSeamLogic) and doing so would actually break air control in some situations where vanilla allows
// air control. Vanilla actually allows you to slide up slopes as long as you're in the "walking"
// animation, which can be true even in the air, so allowing this for seams isn't a compatibility break.
if (newPosition.z() >= swimlevel && !actor.mFlying && !isWalkableSlope(planeNormal) && !usedSeamLogic)
newVelocity.z() = std::min(newVelocity.z(), velocity.z());
numTimesSlid += 1;
lastSlideNormalFallback = lastSlideNormal;
lastSlideNormal = origPlaneNormal;
velocity = newVelocity;
}
}
bool isOnGround = false;
bool isOnSlope = false;
if (forceGroundTest || (actor.mInertia.z() <= 0.f && newPosition.z() >= swimlevel))
{
osg::Vec3f from = newPosition;
auto dropDistance = 2 * sGroundOffset + (actor.mIsOnGround ? sStepSizeDown : 0);
osg::Vec3f to = newPosition - osg::Vec3f(0, 0, dropDistance);
tracer.doTrace(actor.mCollisionObject, from, to, collisionWorld, actor.mIsOnGround);
if (tracer.mFraction < 1.0f)
{
if (!isActor(tracer.mHitObject))
{
isOnGround = true;
isOnSlope = !isWalkableSlope(tracer.mPlaneNormal);
actor.mStandingOn = tracer.mHitObject;
if (actor.mStandingOn->getBroadphaseHandle()->m_collisionFilterGroup == CollisionType_Water)
actor.mWalkingOnWater = true;
if (!actor.mFlying && !isOnSlope)
{
if (tracer.mFraction * dropDistance > sGroundOffset)
newPosition.z() = tracer.mEndPos.z() + sGroundOffset;
else
{
newPosition.z() = tracer.mEndPos.z();
tracer.doTrace(actor.mCollisionObject, 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 (actor.mStuckFrames > 0)
{
isOnGround = true;
isOnSlope = false;
}
}
if ((isOnGround && !isOnSlope) || newPosition.z() < swimlevel || actor.mFlying)
actor.mInertia = osg::Vec3f(0.f, 0.f, 0.f);
else
{
actor.mInertia.z() -= time * Constants::GravityConst * Constants::UnitsPerMeter;
if (actor.mInertia.z() < 0)
actor.mInertia.z() *= actor.mSlowFall;
if (actor.mSlowFall < 1.f)
{
actor.mInertia.x() *= actor.mSlowFall;
actor.mInertia.y() *= actor.mSlowFall;
}
}
actor.mIsOnGround = isOnGround;
actor.mIsOnSlope = isOnSlope;
actor.mPosition = newPosition;
// remove what was added earlier in compensating for doTrace not taking interior transformation into account
actor.mPosition.z() -= actor.mHalfExtentsZ; // vanilla-accurate
}
void MovementSolver::move(ProjectileFrameData& projectile, float time, const btCollisionWorld* collisionWorld)
{
btVector3 btFrom = Misc::Convert::toBullet(projectile.mPosition);
btVector3 btTo = Misc::Convert::toBullet(projectile.mPosition + projectile.mMovement * time);
if (btFrom == btTo)
return;
assert(projectile.mProjectile != nullptr);
ProjectileConvexCallback resultCallback(
projectile.mCaster, projectile.mCollisionObject, btFrom, btTo, *projectile.mProjectile);
resultCallback.m_collisionFilterMask = CollisionType_AnyPhysical;
resultCallback.m_collisionFilterGroup = CollisionType_Projectile;
const btQuaternion btrot = btQuaternion::getIdentity();
btTransform from_(btrot, btFrom);
btTransform to_(btrot, btTo);
const btCollisionShape* shape = projectile.mCollisionObject->getCollisionShape();
assert(shape->isConvex());
collisionWorld->convexSweepTest(static_cast<const btConvexShape*>(shape), from_, to_, resultCallback);
projectile.mPosition
= Misc::Convert::toOsg(projectile.mProjectile->isActive() ? btTo : resultCallback.m_hitPointWorld);
}
btVector3 addMarginToDelta(btVector3 delta)
{
if (delta.length2() == 0.0)
return delta;
return delta + delta.normalized() * sCollisionMargin;
}
void MovementSolver::unstuck(ActorFrameData& actor, const btCollisionWorld* collisionWorld)
{
if (actor.mSkipCollisionDetection) // noclipping/tcl
return;
if (actor.mMovement.length2() == 0) // no AI nor player attempted to move, current position is assumed correct
return;
auto tempPosition = actor.mPosition;
if (actor.mStuckFrames >= 10)
{
if ((actor.mLastStuckPosition - actor.mPosition).length2() < 100)
return;
else
{
actor.mStuckFrames = 0;
actor.mLastStuckPosition = { 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, actor.mHalfExtentsZ);
// use a 3d approximation of the movement vector to better judge player intent
auto velocity = (osg::Quat(actor.mRotation.x(), osg::Vec3f(-1, 0, 0))
* osg::Quat(actor.mRotation.y(), 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 (!actor.mIsOnGround || actor.mIsOnSlope)
velocity += actor.mInertia;
// 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 = actor.mCollisionObject->getWorldTransform();
btTransform newTransform = oldTransform;
auto gatherContacts = [&](btVector3 newOffset) -> ContactCollectionCallback {
goodPosition = refPosition + Misc::Convert::toOsg(addMarginToDelta(newOffset));
newTransform.setOrigin(Misc::Convert::toBullet(goodPosition));
actor.mCollisionObject->setWorldTransform(newTransform);
ContactCollectionCallback callback(*actor.mCollisionObject, velocity);
ContactTestWrapper::contactTest(
const_cast<btCollisionWorld*>(collisionWorld), actor.mCollisionObject, 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)
{
++actor.mStuckFrames;
actor.mLastStuckPosition = 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
{
actor.mStuckFrames = 0;
actor.mLastStuckPosition = { 0, 0, 0 };
}
actor.mCollisionObject->setWorldTransform(oldTransform);
actor.mPosition = tempPosition;
}
}