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);
}
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);
}