I’m working on a decal that adjusts its parameters based on the slope of terrain it’s being projected onto. To do this I’m sampling the World Normal in the material. It mostly works really well, but it’s creating some issues because the surfaces of the terrain have normal maps on them that make the World Normal grainy. I’m hoping to get the world normal WITHOUT the normal map textures so that it’s purely slope information. Is that possible? Even just being able to blur or average the world normal would achieve what I want.
Because it’s a decal material, some convenient options like VertexNormalWS do not work.
Not that I’m aware of. The normal data that is passed into the scene texture is the final data that will be used to calculate lighting, so there is traditionally no point in preserving the original vertex normal data at that stage of the buffer.
You can sample the world position and reconstruct a normal vector based on the rate of change in the world position, but this will have some issues like the normal appearing sharp/faceted which will be visible in the final result - but depending on the effect you’re trying to achieve, this may be preferable.
If I am not mistaken, you would take the cross product of the DDX and DDY of the world position and then normalize the resulting vector.
Thanks for this reply. I’m going to try what you suggested and see what it looks like. If it doesn’t quite work, then I suppose I’ll be looking for a different way to use the slope in a landscape as a mask for a Lerp.
