the `getVertices` example may be outdated

[madjestic]

getVertices :: Gltf -> [V3 Float]
getVertices gltf = concatMap getVertices' (gltf ^. _meshes)
  where getVertices' mesh = concatMap (^. _meshPrimitivePositions) (mesh ^. _meshPrimitives)

produces the following error:

    • Couldn't match type: vector-0.12.3.1:Data.Vector.Vector
                             (V3 Float)
                     with: [b]
      Expected: Getting [b] MeshPrimitive [b]
        Actual: (vector-0.12.3.1:Data.Vector.Vector (V3 Float)
                 -> Data.Functor.Const.Const
                      [b] (vector-0.12.3.1:Data.Vector.Vector (V3 Float)))
                -> MeshPrimitive -> Data.Functor.Const.Const [b] MeshPrimitive
    • In the expression: _meshPrimitivePositions
      In the first argument of ‘concatMap’, namely
        ‘(^. _meshPrimitivePositions)’
      In the expression:
        concatMap (^. _meshPrimitivePositions) (mesh ^. _meshPrimitives)
    • Relevant bindings include
        getVertices' :: Mesh -> [b] (bound at app/Mandelbrot_glTF.hs:380:9)
    |
380 |   where getVertices' mesh = concatMap (^. _meshPrimitivePositions) (mesh ^. _meshPrimitives)

[madjestic]

This seems to work:

import           Text.GLTF.Loader as Gltf
import           Lens.Micro
import           Linear.V3
import qualified Data.Vector as V

getVertices :: Gltf -> V.Vector (V3 Float)
getVertices gltf = V.concatMap getVertices' (gltf ^. _meshes)
  where getVertices' mesh = V.concatMap (^. _meshPrimitivePositions) (mesh ^. _meshPrimitives)

[sgillespie]

You're right, I never updated the docs after I switched to Vectors. Feel free to open a PR with the updated example. If not I'll eventually get to it