public static MotionResult PhysicsStepHorizontal(ref CharacterPhysicsInfo cpi,
ref Position position, ref ThreeDVelocity velocity,
bool onGround,
int coefficientOfRestitution256,
int groundFriction256,
WorldPhysics physics)
{
MotionResult result = MotionResult.None;
int newPositionX = velocity.X.Update(position.X);
int newPositionZ = velocity.Z.Update(position.Z);
int deltaX = newPositionX - position.X;
int deltaZ = newPositionZ - position.Z;
if (deltaX != 0)
{
if (CharacterPhysics.TryMoveHorizontalDidHitWall(ref cpi, physics, deltaX, 0, onGround, ref position))
{
// Hit wall, bounce:
velocity.X.Scale256(-coefficientOfRestitution256);
result = MotionResult.HitWall;
}
}
// Z-motion just stops if it hits anything
if (deltaZ != 0 && CharacterPhysics.TryMoveHorizontalDidHitWall(ref cpi, physics, 0, deltaZ, onGround, ref position))
{
velocity.Z.Reset();
// NOTE: Currently not even bothering to give a hit result, just carry on...
}
// TODO: Slope handling for rolling objects
if (onGround)
{
// Friction:
velocity.X.Scale256(groundFriction256);
velocity.Z.Scale256(groundFriction256);
}
return(result);
}
/// <summary>Get the Y position of the ground for this actor.</summary>
public int GroundHeight(WorldPhysics physics)
{
var cpi = new CharacterPhysicsInfo(animationSet, this);
return(CharacterPhysics.GroundHeight(ref cpi, physics, position));
}
public static MotionResult PhysicsStepVertical(ref CharacterPhysicsInfo cpi,
ref Position position, ref ThreeDVelocity velocity,
ref bool onGround,
int coefficientOfRestitution256,
int gravityUp256, int gravityDown256, bool lockVertical,
WorldPhysics physics, bool groundIsAPit)
{
if (lockVertical)
{
velocity.Y.Reset();
}
else
{
if (velocity.Y.Velocity256 > 0) // Moving upwards
{
onGround = false;
int startY = position.Y + cpi.height;
position.Y = velocity.Y.Update(position.Y, gravityUp256);
int endY = position.Y + cpi.height;
if (endY > startY)
{
int ceiling = physics.GetCeilingHeightInXRange(position.X + cpi.startX, position.X + cpi.endX, position.Z, startY, endY, cpi.owner);
if (ceiling < endY) // Hit ceiling
{
position.Y = ceiling - cpi.height;
velocity.Y.Velocity256 = -((velocity.Y.Velocity256 * coefficientOfRestitution256) >> 8); // <- Bounce (fixed-point multiply)
return(MotionResult.HitCeiling);
}
}
}
else // Moving downwards
{
int groundHeight = CharacterPhysics.GroundHeight(ref cpi, physics, position);
if (position.Y > groundHeight)
{
onGround = false; // we came off the ground
}
else if (position.Y < groundHeight) // TODO: This needs some rethinking (added to let separation do its thing)
{
onGround = true; // we are embedded in the ground (we may start physics in this state, if we are put here by teleport/animation)
}
else if (position.Y == groundHeight && velocity.Y.Velocity256 == 0)
{
onGround = true; // we were gently placed on the ground (don't trigger OnHitGround)
}
if (!onGround)
{
position.Y = velocity.Y.Update(position.Y, gravityDown256);
if (position.Y <= groundHeight) // Hit the ground
{
position.Y = groundHeight;
if (groundHeight == 0 && groundIsAPit)
{
velocity = new ThreeDVelocity();
return(MotionResult.HitBottomOfPit);
}
else if (velocity.Y.Velocity256 > -128) // <- Kill velocity of we're moving too slowly downwards (start rolling)
{
onGround = true;
velocity.Y.Reset();
}
else
{
onGround = false;
velocity.Y.Scale256(-coefficientOfRestitution256);
velocity.X.Scale256(coefficientOfRestitution256);
velocity.Z.Scale256(coefficientOfRestitution256);
}
return(MotionResult.HitGround);
}
}
}
}
return(MotionResult.None);
}
/// <summary>
/// Add a moving object to the physics system. A moving object may have a heightmap that will be considered for collision (like passing to <see cref="AddCollider"/>),
/// but the moving object itself is a flat plane at the object's origin with the object's physics width and height (depth of one pixel).
/// The moving object will be moved in response to various physics conditions (separation out of walls, movement when stacked, movement on conveyers, etc).
/// </summary>
/// <param name="owner">The object that the mover instance is associated with. Only one mover per actor.</param>
/// <param name="physicsSource">The animation set that provides physics data for the mover.</param>
/// <param name="doNotMove">
/// The mover will not be moved by the physics engine for any reason (eg: separation, stacking, conveyers).
/// Typically used for objects that are moved by the engine on a fixed path, but we still want them to interact with other game objects (eg: things stacked on them will move).
/// </param>
/// <param name="noAutoIgnore">
/// If two movers interpenetrate, then they will automatically ignore each other for collisions, allowing them to move through each other.
/// This disables that behaviour, which will cause interpenetrating objects to get stuck, because every possible movement results in a collision.
/// Typically combined with <see cref="pretendToBeStatic"/>, which causes separation to resolve the interpenetration.
/// </param>
/// <param name="pretendToBeStatic">
/// Makes the mover act like a part of the static scenery. Affects query results that specifically ask for static collisions,
/// but is mostly used to make the mover object considered for separation. Should typically only be set on objects that have
/// <see cref="doNotMove"/> set, otherwise the separation system can get into messy looping situations.
/// </param>
/// <param name="updateBeforeSeparation">
/// The state of the world for collisions is based on what it was at the beginning of the frame. This causes the mover's entry to be
/// updated immediately before separation is processed, so that separation from moving objects happens based on their position at the
/// end of the frame, rather than the beginning. Combine with <see cref="pretendToBeStatic"/> for meaningful results.
/// </param>
public void AddMover(Actor owner, AnimationSet physicsSource, bool doNotMove = false, bool noAutoIgnore = false, bool pretendToBeStatic = false, bool updateBeforeSeparation = false)
{
//
// Add collider:
if (physicsSource.Heightmap != null)
{
if (physicsSource.Heightmap.DefaultHeight != 0)
{
return; // Refuse to add objects with non-zero default heights (only valid for levels and shadow-receivers)
}
AddCollider(owner, new HeightmapView(physicsSource.Heightmap, owner.position, owner.facingLeft), pretendToBeStatic);
if (updateBeforeSeparation)
{
collidersToUpdateBeforeSeparation.Add(colliderCount - 1);
}
}
//
// Add mover:
EnsureMoverCapacity();
actorToMoverIndex.Add(owner, moverCount); // <- Ensure movers are unique
moverWeDoNotMove[moverCount] = doNotMove;
moverNoAutoIgnore[moverCount] = noAutoIgnore;
moverActors[moverCount] = owner;
Position position = moverInitialPositions[moverCount] = owner.position;
bool facingLeft = moverInitialFacingLeft[moverCount] = owner.facingLeft;
moverBoundsX[moverCount] = new Range(physicsSource.physicsStartX, physicsSource.physicsEndX).MaybeFlip(facingLeft) + position.X;
moverBoundsZ[moverCount] = ((physicsSource.Heightmap == null) ? new Range(0, 1) : new Range(physicsSource.physicsStartZ, physicsSource.physicsEndZ)) + position.Z; // Flat for characters
// NOTE: We assume that heightmap'd objects have their auto-generated physics sizes here:
if (physicsSource.Heightmap != null && physicsSource.physicsHeight >= Heightmap.Infinity)
{
moverBoundsY[moverCount] = new Range(0, MaximumHeight);
}
else
{
moverBoundsY[moverCount] = new Range(position.Y, position.Y + physicsSource.physicsHeight);
}
moverHeightmaps[moverCount] = physicsSource.Heightmap; // May be null
// TODO: Make this a parameter of the animation set
moverCharacterPhysics[moverCount] = new CharacterPhysicsInfo(physicsSource, owner);
Debug.Assert(physicsSource.Heightmap == null || physicsSource.Heightmap.DefaultHeight == 0); // If we have a heightmap, it must be a standard object heightmap
//
// Stacking and intersection-ignores:
moverParentIndex[moverCount] = -1;
moverFirstChildIndex[moverCount] = -1;
moverNextSiblingIndex[moverCount] = -1;
for (int i = 0; i < moverCount; i++)
{
if (!Range.Overlaps(moverBoundsX[moverCount], moverBoundsX[i]) || !Range.Overlaps(moverBoundsZ[moverCount], moverBoundsZ[i]))
{
continue;
}
// PERF: We're touching each heightmap twice for stacking and intersection. Can probably reduce down to one check.
// (Then again, once we cache it, is spinning on it longer such a big deal?)
// Handle stacking:
if (moverBoundsY[moverCount].end < MaximumHeight && moverBoundsY[i].end < MaximumHeight) // <- infinite height things, or things above the world, do not stack
{
if (moverHeightmaps[i] != null && moverParentIndex[moverCount] == -1 && moverBoundsY[moverCount].start > moverBoundsY[i].start && moverBoundsY[moverCount].start <= moverBoundsY[i].end) // added can rest on existing
{
TryAddRestingOn(moverCount, i);
}
else if (moverHeightmaps[moverCount] != null && moverParentIndex[i] == -1 && moverBoundsY[i].start > moverBoundsY[moverCount].start && moverBoundsY[i].start <= moverBoundsY[moverCount].end) // existing can rest on added
{
TryAddRestingOn(i, moverCount);
}
}
// Handle intersection:
if (!noAutoIgnore && !moverNoAutoIgnore[i] && Range.Overlaps(moverBoundsY[moverCount], moverBoundsY[i]))
{
bool hasIntersection = false;
if (moverHeightmaps[i] != null)
{
if (moverHeightmaps[moverCount] != null)
{
hasIntersection = SolidVsSolidIntersection(i, moverCount);
}
else
{
hasIntersection = SolidVsCharacterIntersection(i, moverCount);
}
}
else if (moverHeightmaps[moverCount] != null)
{
hasIntersection = SolidVsCharacterIntersection(moverCount, i);
}
if (hasIntersection)
{
AddIgnoredPair(moverActors[i], moverActors[moverCount]);
}
}
}
moverCount++;
}