I want to super-impose a texture on top of my tiles.
I need my texture to be drawn only where the current render target is NOT transparent.
the current render target starts out transparent, then gets level geometry drawn, and I want to overlay a texture ONLY where geometry is already drawn, NOT the transparent bits.
-NOTE that level geometry can have any shape, so I need overlay - functionality, or some sort of masking.
-Is there some blend-state setup for this? Or would I need some sort of pixel shader?