From 36a1c47bb71614852d21663c17aa375d18e9bb45 Mon Sep 17 00:00:00 2001
From: Robin Deits <robin.deits@gmail.com>
Date: Tue, 22 Sep 2020 23:29:10 -0400
Subject: [PATCH] Support vertexColors for meshes via GeometryBasics.meta

---
 src/MeshCat.jl     |  3 +++
 src/lowering.jl    | 13 ++++++++++---
 test/visualizer.jl | 14 ++++++++++++++
 3 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/src/MeshCat.jl b/src/MeshCat.jl
index 3e09d45..3a80ad5 100644
--- a/src/MeshCat.jl
+++ b/src/MeshCat.jl
@@ -10,6 +10,7 @@ using GeometryBasics: GeometryBasics,
   GeometryPrimitive,
   HyperRectangle,
   HyperSphere,
+  MeshMeta,
   NgonFace,
   OffsetInteger,
   Point,
@@ -18,6 +19,8 @@ using GeometryBasics: GeometryBasics,
   SimplexFace,
   Vec,
   decompose,
+  meta,
+  metafree,
   origin,
   radius,
   texturecoordinates,
diff --git a/src/lowering.jl b/src/lowering.jl
index 443202e..bf023ee 100644
--- a/src/lowering.jl
+++ b/src/lowering.jl
@@ -144,10 +144,17 @@ to_zero_index(f::AbstractNgonFace{N}) where {N} = SVector(raw.(convert(NgonFace{
 
 lower(faces::Vector{<:AbstractFace}) = lower(to_zero_index.(faces))
 
-function lower(mesh::AbstractVector{<:Polytope})
+function lower(mesh_meta::M) where {M <: AbstractMesh}
+    mesh = metafree(mesh_meta)
     attributes = Dict{String, Any}(
-        "position" => lower(convert(Vector{Point3f0}, decompose(Point3f0, mesh)))
+        "position" => lower(convert(Vector{Point3f0}, decompose(Point3f0, mesh))),
     )
+    if M <: MeshMeta
+        metadata = meta(mesh_meta)
+        if hasfield(typeof(metadata), :vertexColors)
+            attributes["color"] = lower(convert(Vector{RGB{Float32}}, metadata.vertexColors))
+        end
+    end
     uv = texturecoordinates(mesh)
     if uv !== nothing
         attributes["uv"] = lower(uv)
@@ -175,7 +182,7 @@ function lower(cloud::PointCloud)
         "position" => lower(convert(Vector{Point3f0}, cloud.position)),
     )
     if !isempty(cloud.color)
-        attributes["color"] = lower(cloud.color)
+        attributes["color"] = lower(convert(Vector{RGB{Float32}}, cloud.color))
     end
     Dict{String, Any}(
         "uuid" => string(uuid1()),
diff --git a/test/visualizer.jl b/test/visualizer.jl
index 575f2eb..b8ed056 100644
--- a/test/visualizer.jl
+++ b/test/visualizer.jl
@@ -160,6 +160,20 @@ end
             settransform!(v[:valkyrie, :head], Translation(0, 0.5, 0.5))
         end
 
+        @testset "mesh with vertex colors" begin
+            # Create a simple mesh with a single triangle
+            geometry = GeometryBasics.Mesh(
+                [Point(0., 0, 0), Point(1., 0, 0), Point(1., 1, 0)],
+                [NgonFace(1, 2, 3)])
+            # Wrap that mesh with metadata encoding the vertex colors
+            mesh_meta = meta(geometry, vertexColors=[RGB(1, 0, 0), RGB(0, 1, 0), RGB(0, 0, 1)])
+            # Create a Gouraud-shaded material with vertex coloring enabled
+            material = MeshLambertMaterial(vertexColors=true)
+            # Add it to the scene
+            setobject!(v[:vertex_color_mesh], mesh_meta, material)
+            settransform!(v[:vertex_color_mesh], Translation(1, -1.5, 0))
+        end
+
     end
 
     @testset "points" begin