Vertex tangents.

src/Text/GLTF/Loader/Gltf.hs

@@ -241,6 +241,8 @@ data MeshPrimitive = MeshPrimitive
     meshPrimitiveNormals :: Vector (V3 Float),
     -- | A Vector of vertex positions.
     meshPrimitivePositions :: Vector (V3 Float),
+    -- | A Vector of vertex tangents
+    meshPrimitiveTangents :: Vector (V4 Float),
     -- | A Vector of vertex texture coordinates
     meshPrimitiveTexCoords :: Vector (V2 Float),
     -- | A Vector of vertex colors.

src/Text/GLTF/Loader/Internal/Adapter.hs

@@ -54,6 +54,9 @@ attributePosition = "POSITION"
 attributeNormal :: Text
 attributeNormal = "NORMAL"
 
+attributeTangent :: Text
+attributeTangent = "TANGENT"
+
 attributeTexCoord :: Text
 attributeTexCoord = "TEXCOORD_0"
 
@@ -296,13 +299,15 @@ adaptMeshPrimitive Mesh.MeshPrimitive{..} = do
         meshPrimitiveMode = adaptMeshPrimitiveMode mode,
         meshPrimitiveNormals = maybe mempty (vertexNormals gltf buffers') normals,
         meshPrimitivePositions = maybe mempty (vertexPositions gltf buffers') positions,
+        meshPrimitiveTangents = maybe mempty (vertexTangents gltf buffers') tangents,
         meshPrimitiveTexCoords = maybe mempty (vertexTexCoords gltf buffers') texCoords,
         meshPrimitiveColors =
           maybe mempty (fmap (mapV4 toRatio) . vertexColors gltf buffers') colors
       }
   where
     positions = attributes HashMap.!? attributePosition
     normals = attributes HashMap.!? attributeNormal
+    tangents = attributes HashMap.!? attributeTangent
     texCoords = attributes HashMap.!? attributeTexCoord
     colors = attributes HashMap.!? attributeColors
     toRatio w = fromIntegral w / fromIntegral (maxBound :: Word16)

src/Text/GLTF/Loader/Internal/BufferAccessor.hs

@@ -11,6 +11,7 @@ module Text.GLTF.Loader.Internal.BufferAccessor
     vertexPositions,
     vertexNormals,
     vertexTexCoords,
+    vertexTangents,
     vertexColors,
     imageDataRaw,
   ) where
@@ -109,6 +110,10 @@ vertexPositions = readBufferWithGet getPositions
 vertexNormals :: GlTF -> Vector GltfBuffer -> AccessorIx -> Vector (V3 Float)
 vertexNormals = readBufferWithGet getNormals
 
+-- | Decode vertex tangents
+vertexTangents :: GlTF -> Vector GltfBuffer -> AccessorIx -> Vector (V4 Float)
+vertexTangents = readBufferWithGet getTangents
+
 -- | Decode texture coordinates. Note that we only use the first one.
 vertexTexCoords :: GlTF -> Vector GltfBuffer -> AccessorIx -> Vector (V2 Float)
 vertexTexCoords = readBufferWithGet getTexCoords

src/Text/GLTF/Loader/Internal/Decoders.hs

@@ -4,6 +4,7 @@ module Text.GLTF.Loader.Internal.Decoders
     getIndices32,
     getPositions,
     getNormals,
+    getTangents,
     getTexCoords,
     getColors,
 
@@ -46,6 +47,10 @@ getPositions = getVec3 getFloat
 getNormals :: Get (Vector (V3 Float))
 getNormals = getVec3 getFloat
 
+-- | Vertex tangents binary decoder
+getTangents :: Get (Vector (V4 Float))
+getTangents = getVec4 getFloat
+
 -- | Texture coordinates binary decoder
 getTexCoords :: Get (Vector (V2 Float))
 getTexCoords = getVec2 getFloat