I would like to be able to write a shader that can generate additional geometry on the fly. Is there a way to do this in Godot? I was hoping Godot 4 would open up this ability.
Does Godot 4 have geometry shaders?
On the source level, yes the vulkan renderer should be able to deal with it. But I'm not aware of godots internal shaderlanguage currently exposing it.
The only instances of geometry_shader in the codebase are related to XR support, as support is queried when setting up an XR context: https://github.com/godotengine/godot/blob/7a0977ce2c558fe6219f0a14f8bd4d05aea8f019/drivers/vulkan/vulkan_context.cpp#L1413
Other than that, it's not exposed to RenderingDevice (unlike tesselation shaders, which are exposed there).