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

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

			# 1st triangle
			var count = 0
			for e in face.vertices do
				var i = e.texture_coord_index
				if i == null then
					coords.add 0.0
					coords.add 0.0
				else
					var tc = obj_def.texture_coords[i-1]
					coords.add tc.u
					coords.add tc.v
				end

				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.texture_coord_index
					if i == null then
						coords.add 0.0
						coords.add 0.0
					else
					var tc = obj_def.texture_coords[i-1]
					coords.add tc.u
					coords.add tc.v
					end
				end
			end
		end
		return coords
	end