So I got this nice grass geometry shader going but when I went on to build for WebGL to put it to my portfolio, I just got a pink model. Are geometry shaders supported in webGL? If not, is there any alternative to use shaders to get the same effects in webGL in any way?
to be more specific I got this warning: WARNING: Shader /:9089:3 Unsupported: 'Custom/grass' - Pass '' has no vertex shader any clues about it?
No. Even in WebGL 2.0, which Unity only just started to support in Unity 5.5 and which most browsers don't support yet, does not support geometry shaders.
Most likely using a GPU instancing technique and just changing some per-renderer data on the instances in the array that have been walked over. https://docs.unity3d.com/Manual/GPUInstancing.html