I'm not sure exactly what you mean, but you can both output line primitives directly from the mesh shader or output mitered/capped extruded lines via triangles.

I'm not sure exactly what you mean, but you can both output line primitives directly from the mesh shader or output mitered/capped extruded lines via triangles. As far as other platforms, there's VK_EXT_line_rasterization which is a port of opengl line drawing functionality to vulkan.