Merge pull request #43 from JuliaGeometry/sd/meta

preserve meta when converting

Author: SimonDanisch

src/meshes.jl

@@ -110,25 +110,32 @@ function mesh(primitive::Meshable;
         # triangulation.jl
         faces = decompose(facetype, positions)
     end
-    attributes = Dict{Symbol, Any}()
+
+    # We want to preserve any existing attributes!
+    attrs = attributes(primitive)
+    # Make sure this doesn't contain position, we'll add position explicitely via meta!
+    delete!(attrs, :position)
 
     if uv !== nothing
-        attributes[:uv] = decompose(UV(uv), primitive)
+        # this may overwrite an existing :uv, but will only create a copy
+        # if it has a different eltype, otherwise it should replace it
+        # with exactly the same instance - which is what we want here
+        attrs[:uv] = decompose(UV(uv), primitive)
     end
 
     if normaltype !== nothing
         primitive_normals = normals(primitive)
         if primitive_normals !== nothing
-            attributes[:normals] = decompose(normaltype, primitive_normals)
+            attrs[:normals] = decompose(normaltype, primitive_normals)
         else
             # Normals not implemented for primitive, so we calculate them!
-            n = normals(positions, faces)
+            n = normals(positions, faces; normaltype=normaltype)
             if n !== nothing # ok jeez, this is a 2d mesh which cant have normals
-                attributes[:normals] = n
+                attrs[:normals] = n
             end
         end
     end
-    return Mesh(meta(positions; attributes...), faces)
+    return Mesh(meta(positions; attrs...), faces)
 end
 
 """
@@ -231,7 +238,7 @@ Attaches metadata to the coordinates of a mesh
 """
 function pointmeta(mesh::Mesh; meta_data...)
     points = coordinates(mesh)
-    attr = GeometryBasics.attributes(points)
+    attr = attributes(points)
     delete!(attr, :position) # position == metafree(points)
     # delete overlapping attributes so we can replace with `meta_data`
     foreach(k-> delete!(attr, k), keys(meta_data))
@@ -253,7 +260,7 @@ Returns the new mesh, and the property!
 """
 function pop_pointmeta(mesh::Mesh, property::Symbol)
     points = coordinates(mesh)
-    attr = GeometryBasics.attributes(points)
+    attr = attributes(points)
     delete!(attr, :position) # position == metafree(points)
     # delete overlapping attributes so we can replace with `meta_data`
     m = pop!(attr, property)
@@ -268,3 +275,7 @@ Attaches metadata to the faces of a mesh
 function facemeta(mesh::Mesh; meta_data...)
     return Mesh(coordinates(mesh), meta(faces(mesh); meta_data...))
 end
+
+function attributes(hasmeta::Mesh)
+    return Dict{Symbol, Any}((name => getproperty(hasmeta, name) for name in propertynames(hasmeta)))
+end

src/metadata.jl

@@ -4,8 +4,18 @@ Table interface for this functionality. Once this is in e.g. Tables.jl,
 it should be removed from GeometryBasics!
 =#
 
+"""
+    attributes(hasmeta)
+Returns all attributes of meta as a Dict{Symbol, Any}.
+Needs to be overloaded, and returns empty dict for non overloaded types!
+Gets overloaded by default for all Meta types.
+"""
 function attributes(hasmeta)
-    return Dict((name => getproperty(hasmeta, name) for name in propertynames(hasmeta)))
+    return Dict{Symbol, Any}()
+end
+
+function attributes(hasmeta::StructArray)
+    return Dict{Symbol, Any}((name => getproperty(hasmeta, name) for name in propertynames(hasmeta)))
 end
 
 """
@@ -88,6 +98,10 @@ macro meta_type(name, mainfield, supertype, params...)
             return $MetaName(main; meta...)
         end
 
+        function GeometryBasics.attributes(hasmeta::$MetaName)
+            return Dict{Symbol, Any}((name => getproperty(hasmeta, name) for name in propertynames(hasmeta)))
+        end
+
         function GeometryBasics.meta(elements::AbstractVector{T}; meta...) where T <: $supertype
             isempty(meta) && return elements # no meta to add!
             n = length(elements)
@@ -127,6 +141,8 @@ macro meta_type(name, mainfield, supertype, params...)
             ) where {$(params...), Typ, Names, Types}
             $MetaName(metafree, NamedTuple{Names, Types}(args))
         end
+
+
     end
     return esc(expr)
 end

test/runtests.jl

@@ -323,6 +323,27 @@ end
     include("geometrytypes.jl")
 end
 
+@testset "convert mesh + meta" begin
+    m = uv_normal_mesh(FRect3D(Vec3f0(-1), Vec3f0(1, 2, 3)))
+    m_normal = normal_mesh(m)
+    # make sure we don't loose the uv
+    @test hasproperty(m_normal, :uv)
+    @test m == m_normal
+    # Make sure we don't create any copies
+    @test m.position === m_normal.position
+    @test m.normals === m_normal.normals
+    @test m.uv === m_normal.uv
+
+    m = GeometryBasics.mesh(FRect3D(Vec3f0(-1), Vec3f0(1, 2, 3));
+                            uv=Vec2{Float64}, normaltype=Vec3{Float64}, pointtype=Point3{Float64})
+    m_normal = normal_mesh(m)
+    @test hasproperty(m_normal, :uv)
+    @test m.position !== m_normal.position
+    @test m.normals !== m_normal.normals
+    # uv stays untouched, since we don't specify the element type in normalmesh
+    @test m.uv === m_normal.uv
+end
+
 @testset "modifying meta" begin
     xx = rand(10)
     points = rand(Point3f0, 10)