Per-Vertex Normals from perlin noise?
I'm generating terrain in Opengl geometry shader and am having trouble calculating normals for lighting. I'm generating the terrain dynamically each frame with a perlin noise function implemented in the geometry shader. Because of this, I need an efficient way to calculate normals per-vertex based on the noise function (no texture or anything). I am able to take cross product of 2 side to get face normals, but they are generated dynamically with the geometry so I cannot then go back and smooth the face normals for vertex normals. How can I get vertex normals on the fly just using the noise