OpenGL 2 and newer do not have the glPolygonMode(..., GL_LINES) API,
so produce the wireframe on our side. It's somewhat slow, and draws
every line three times, but it is cached when the OpenGL 2 renderer
is used, and this should do for a debugging feature.
SurfaceRenderer is a new renderer implementing the Canvas interface
running entirely on the CPU; it projects strokes and triangles
in the exact same way as OpenGL would, and it can be used for
rendering into raster or vector 2d surfaces.