module RSAGL.Scene.WrappedAffine

import RSAGL.Math.Affine
import RSAGL.Scene.CoordinateSystems

-- | WrappedAffine stores up affine transformations that are commited only when
-- the entity is unwrapped.  In this way we can store affine transformations
-- for entities that can not be directly transformed, or for which delaying
-- transformation an optimization.
data WrappedAffine a = WrappedAffine CoordinateSystem a

wrapAffine :: a -> WrappedAffine a
wrapAffine = WrappedAffine root_coordinate_system

unwrapAffine :: (AffineTransformable a) => WrappedAffine a -> a
unwrapAffine (WrappedAffine cs a) = migrateToFrom root_coordinate_system cs a

instance AffineTransformable (WrappedAffine a) where
    transform t (WrappedAffine cs a) = WrappedAffine (transform t cs) a

instance Functor WrappedAffine where
    fmap f (WrappedAffine m a) = WrappedAffine m $ f a