[Effect, HLSL] Lightmapping

One way would be to use a small texture (say 1x1) which is the constant colour you want to multiply by in the absence of a lightmap.

Regards,
ViLiO

I second that, the standard approach would be to just plug in a default white texture. But just be careful with your sampler states and borders, since the default texture will likely be pretty small and you're going to be sampling on the edges a lot.

Thanks, I'll do that then. [smile]

However, there is a BIG problem with that idea. In that case, you are using up an extra texture sampling slot regardless of whether or not you are using a texture.

I recommend creating a second technique (so that you don't have to deal with any branching), which calls the same PS function, and adding a bool parameter to said PS function which tells whether or not a texture is present. This way, it remains very speedy, and you can decide whether or not there is a lightmap (or whether or not you want to USE that lightmap) inside the C++ code. This keeps it speedy, while relatively simple.

Quote:

Original post by generaleskimo However, there is a BIG problem with that idea. In that case, you are using up an extra texture sampling slot regardless of whether or not you are using a texture. I recommend creating a second technique (so that you don't have to deal with any branching), which calls the same PS function, and adding a bool parameter to said PS function which tells whether or not a texture is present. This way, it remains very speedy, and you can decide whether or not there is a lightmap (or whether or not you want to USE that lightmap) inside the C++ code. This keeps it speedy, while relatively simple.

That's another approach. The only reason I didn't mention it was because it's a bit more work than just setting a white texture. It requires an additional code path for every shader that has a toggle-able lightmap, and you have to batch your geometry by primitives that do and don't have lightmaps.