/// <summary>
/// Returns the cell, and a rotator for a tile placed near the generator
/// A rotator takes vectors in the tile local space, and returns them in generator local space.
/// It's always an distance presering transform (so it's always one of the symmetries of a cube).
///
/// NB: The cell returned corresponds to offset (0,0,0). The tile may not actually occupy that offset.
/// </summary>
internal static bool GetCell(
Transform transform,
Vector3 center,
Vector3 tileSize,
Vector3Int size,
TesseraTile tile,
Matrix4x4 tileLocalToWorldMatrix,
out Vector3Int cell,
out MatrixInt3x3 rotator)
{
var m = transform.worldToLocalMatrix * tileLocalToWorldMatrix;
Vector3Int Rotate(Vector3Int v)
{
var v1 = m.MultiplyVector(v);
var v2 = new Vector3Int((int)Math.Round(v1.x), (int)Math.Round(v1.y), (int)Math.Round(v1.z));
return(v2);
}
// True if v is a unit vector along an axis
bool Ok(Vector3Int v)
{
return(Math.Abs(v.x) + Math.Abs(v.y) + Math.Abs(v.z) == 1);
}
var rotatedRight = Rotate(Vector3Int.right);
var rotatedUp = Rotate(Vector3Int.up);
var rotatedForward = Rotate(new Vector3Int(0, 0, 1));
if (Ok(rotatedRight) && Ok(rotatedUp) && Ok(rotatedForward))
{
var localPos = m.MultiplyPoint(tile.center);
var min = center - Vector3.Scale(size - Vector3Int.one, tileSize) / 2.0f;
localPos -= min;
var x = (int)Mathf.Round(localPos.x / tileSize.x);
var y = (int)Mathf.Round(localPos.y / tileSize.y);
var z = (int)Mathf.Round(localPos.z / tileSize.z);
cell = new Vector3Int(x, y, z);
rotator = new MatrixInt3x3
{
col1 = rotatedRight,
col2 = rotatedUp,
col3 = rotatedForward,
};
return(true);
}
else
{
cell = default;
rotator = default;
return(false);
}
}
/// <summary>
/// Returns the cell, and a rotator for a tile placed near the generator
/// A rotator takes vectors in the tile local space, and returns them in generator local space.
/// It's always an distance presering transform (so it's always one of the symmetries of a cube).
///
/// NB: The cell returned corresponds to offset (0,0,0). The tile may not actually occupy that offset.
/// </summary>
internal bool GetCell(
TesseraTile tile,
Matrix4x4 tileLocalToWorldMatrix,
out Vector3Int cell,
out MatrixInt3x3 rotator)
{
return(GeometryUtils.GetCell(
transform,
center,
tileSize,
size,
tile, tileLocalToWorldMatrix,
out cell,
out rotator));
}
/// <summary>
/// Given a FaceDetails on given face of the cube,
/// rotates the cube, and returns the new face and correctly oriented FaceDetails
/// </summary>
internal static (FaceDir, FaceDetails) ApplyRotator(FaceDir faceDir, FaceDetails faceDetails, MatrixInt3x3 rotator)
{
var rotatedFaceDirForward = rotator.Multiply(faceDir.Forward());
var rotatedFaceDirUp = rotator.Multiply(faceDir.Up());
var rotatedFaceDirRight = rotator.Multiply(Vector3.Cross(faceDir.Forward(), faceDir.Up()));
var rotatedFaceDir = FromNormal(rotatedFaceDirForward);
var trueUp = rotatedFaceDir.Up();
var trueForward = rotatedFaceDirForward; // = rotatedFaceDir.Forward();
var trueRight = Vector3.Cross(trueForward, trueUp);
// Find the rotation that will map rotatedFaceDirUp to trueUp
// and rotatedFaceDirRight to trueRight
var dot = Vector3.Dot(rotatedFaceDirUp, trueUp);
var cross = Vector3.Dot(rotatedFaceDirUp, trueRight);
Rotation faceRot;
if (dot == 1)
{
faceRot = new Rotation();
}
else if (dot == -1)
{
faceRot = new Rotation(180);
}
else if (cross == 1)
{
faceRot = new Rotation(270);
}
else if (cross == -1)
{
faceRot = new Rotation(90);
}
else
{
throw new Exception();
}
if (Vector3.Dot(Vector3.Cross(rotatedFaceDirForward, rotatedFaceDirUp), rotatedFaceDirRight) < 0)
{
faceRot = new Rotation(360 - faceRot.RotateCw, true);
}
var rotatedFaceDetails = faceDetails.RotateBy(faceRot);
return(rotatedFaceDir, rotatedFaceDetails);
}