// PRIVATE METHODS
void UpdateMatrix(ref Matrix4x4 matrix, Rect rect, float rotation, Vector2 scale, float depth)
{
// update rotation
Vector3 r = Mathfx.Matrix_GetEulerAngles(matrix);
r.z = rotation * Mathf.Deg2Rad;
Mathfx.Matrix_SetEulerAngles(ref matrix, r);
// update position
Vector3 p = new Vector3(0.0f, 0.0f, depth);
p.x = rect.x + _xOffset;
p.y = (int)ZeroLocation * (-(rect.y - rect.height * 0.5f) + (_yOffset - rect.height * 0.5f));
Mathfx.Matrix_SetPos(ref matrix, p);
// update scale
Vector3 s = Mathfx.Matrix_GetScale(matrix);
s.x *= scale.x;
s.y *= scale.y;
Mathfx.Matrix_SetScale(ref matrix, s);
}