Infinite mirror grid

[nwpointer]

helper to tile a terrain sector in an grid, using mirroring to avoid sharp edged between sectors.

usefull for faking infinite terrain in self similar environments (mountains, sand dunes etc)

[nwpointer]

proposal:

      <SplatMaterial
        splats={[textures[11], textures[12]]}
        surfaces={[rock, clif, mud, grass1, grass2, mud]}
        orientation={[-1,1]}
      />

[nwpointer]

orientation is multiplied with uv whenever referenced to effectively flip x and or y sampling direction