int WalkPath(CartesianGridCoordinates startPosition, NativeArray <byte> targetDirections, int pathOffset)
{
var validDirections = CartesianGridOnPlaneShortestPath.LookupDirectionToTarget(startPosition, RowCount, ColCount, targetDirections);
var direction = CartesianGridMovement.PathVariation[((pathOffset & 3) * 16) + validDirections];
if (direction == 0xff) // No path
{
return(0);
}
var nextPosition = new CartesianGridCoordinates();
if (direction == 0)
{
nextPosition = new CartesianGridCoordinates {
x = startPosition.x, y = (short)(startPosition.y + 1)
}
}
;
else if (direction == 1)
{
nextPosition = new CartesianGridCoordinates {
x = startPosition.x, y = (short)(startPosition.y - 1)
}
}
;
else if (direction == 2)
{
nextPosition = new CartesianGridCoordinates {
x = (short)(startPosition.x - 1), y = (short)startPosition.y
}
}
;
else if (direction == 3)
{
nextPosition = new CartesianGridCoordinates {
x = (short)(startPosition.x + 1), y = (short)startPosition.y
}
}
;
else
{
Assert.Fail();
}
// Test no wall in the direction given
if (direction == 0)
{
Assert.IsFalse(TestWallBit(startPosition.x, startPosition.y, CartesianGridDirectionBit.North));
}
else if (direction == 1)
{
Assert.IsFalse(TestWallBit(startPosition.x, startPosition.y, CartesianGridDirectionBit.South));
}
else if (direction == 2)
{
Assert.IsFalse(TestWallBit(startPosition.x, startPosition.y, CartesianGridDirectionBit.West));
}
else if (direction == 3)
{
Assert.IsFalse(TestWallBit(startPosition.x, startPosition.y, CartesianGridDirectionBit.East));
}
return(1 + WalkPath(nextPosition, targetDirections, pathOffset));
}
protected override JobHandle OnUpdate(JobHandle lastJobHandle)
{
int pathOffset = m_PathVariationOffset;
m_PathVariationOffset = (m_PathVariationOffset + 1) & 3;
// Get component data from the GridPlane
var cartesianGridPlane = GetSingleton <CartesianGridOnPlane>();
var rowCount = cartesianGridPlane.Blob.Value.RowCount;
var colCount = cartesianGridPlane.Blob.Value.ColCount;
var trailingOffsets = (float2 *)cartesianGridPlane.Blob.Value.TrailingOffsets.GetUnsafePtr();
var targetEntities = m_TargetQuery.ToEntityArray(Allocator.TempJob);
var targetCoordinates = m_TargetQuery.ToComponentDataArray <CartesianGridCoordinates>(Allocator.TempJob);
var getCartesianGridTargetDirectionFromEntity = GetBufferFromEntity <CartesianGridTargetDirection>(true);
// Offset center to grid cell
var cellCenterOffset = new float2(((float)colCount * 0.5f) - 0.5f, ((float)rowCount * 0.5f) - 0.5f);
// Whenever a CartesianGridFollowTarget reaches a new grid cell, make a decision about what next direction to turn.
lastJobHandle = Entities
.WithName("ChangeDirectionTowardNearestTarget")
.WithNativeDisableUnsafePtrRestriction(trailingOffsets)
.WithEntityQueryOptions(EntityQueryOptions.FilterWriteGroup)
.WithReadOnly(targetCoordinates)
.WithReadOnly(getCartesianGridTargetDirectionFromEntity)
.WithAll <CartesianGridFollowTarget>()
.ForEach((ref CartesianGridDirection gridDirection,
ref CartesianGridCoordinates gridCoordinates,
ref Translation translation) =>
{
var dir = gridDirection.Value;
if (dir != 0xff) // If moving, update grid based on trailing direction.
{
var nextGridPosition = new CartesianGridCoordinates(translation.Value.xz + trailingOffsets[dir], rowCount, colCount);
if (gridCoordinates.Equals(nextGridPosition))
{
// Don't allow translation to drift
translation.Value = CartesianGridMovement.SnapToGridAlongDirection(translation.Value, dir, gridCoordinates, cellCenterOffset);
return; // Still in the same grid cell. No need to change direction.
}
gridCoordinates = nextGridPosition;
}
var targetEntity = FindTargetShortestManhattanDistance(gridCoordinates, rowCount, colCount, targetCoordinates, targetEntities);
if (targetEntity == Entity.Null)
{
// No target for whatever reason, don't move.
gridDirection.Value = 0xff;
return;
}
// Lookup next direction along shortest path to target from table stored in CartesianGridTargetDirection
// - When multiple shortest path available, use pathOffset to select which option.
var targetDirections = getCartesianGridTargetDirectionFromEntity[targetEntity].Reinterpret <byte>().AsNativeArray();
var validDirections = CartesianGridOnPlaneShortestPath.LookupDirectionToTarget(gridCoordinates, rowCount, colCount, targetDirections);
gridDirection.Value = CartesianGridMovement.PathVariation[(pathOffset * 16) + validDirections];
}).Schedule(lastJobHandle);
lastJobHandle = targetEntities.Dispose(lastJobHandle);
lastJobHandle = targetCoordinates.Dispose(lastJobHandle);
return(lastJobHandle);
}