Strange CG Behaviour

Unity Engine
1

Hi guys,

I encountered some really strange errors today from my CG program in my Surface Shader.
Here’s what I mean:

Works.

o.Albedo = tex2D(_WaterBase, i.uv_WaterBase).rgb;
o.Alpha = 1;

Works.

o.Albedo = 1;
o.Alpha = i.uv_WaterBase.r;

Does not work.

o.Albedo = tex2D(_WaterBase, i.uv_WaterBase).rgb;
o.Alpha = i.uv_WaterBase.r;

The first one uses the texture coords to determine color, and has a constant alpha.
The second one uses the texture coords to determine alpha, and has a constant color.
The third one tries to use the texture coords to determine both color AND alpha,
but it ends up being completely transparent.

Also, I can’t use the isnan function. Even when I call isnan(1.0), it says there is no
matching overloaded function found!

This is all very frustrating. Could someone please lend a hand?

2

Can you post full shader that has those problems?

About the isnan - what is the exact error you’re getting? And does it go away if you add “#pragma exclude_renderers gles” to the shader? It might be that we did not add support for this function to the GLSL cross-compiler. FYI, not all GPUs support full IEEE floats, so relying on NaNs, denormals other funky things might not work depending on the GPU.

3

Thank you, Aras. It’s solved now. Turns out the sample tiling factor was the problem. :slight_smile: