# Compute the vertices coordinates of `faces` in a flat `Array[Float]`
	fun vertices(faces: Array[ObjFace]): Array[Float] do
		var obj_def = obj_def

		var vertices = new Array[Float]
		for face in faces do

			# 1st triangle
			var count = 0
			for e in face.vertices do
				var i = e.vertex_point_index - 1
				var v = obj_def.vertex_points[i]

				vertices.add v.x
				vertices.add v.y
				vertices.add v.z

				if count == 2 then break
				count += 1
			end

			# If square, 2nd triangle
			#
			# This may not support all vertices ordering.
			if face.vertices.length > 3 then
				for e in [face.vertices[0], face.vertices[2], face.vertices[3]] do
					var i = e.vertex_point_index - 1
					var v = obj_def.vertex_points[i]

					vertices.add v.x
					vertices.add v.y
					vertices.add v.z
				end
			end

			# TODO use polygon triangulation to support larger polygons
		end
		return vertices
	end