GPU instancing shader questions

Posted this in unity answers but maybe it's more appropriate here since there are multiple questions I have.


EDITOR

Do instances work in the editor or only in real time?

PLAYMODE

If I instantiate more objects over time, will they still instance together? Or do all instances have to be ready upon start?

If you can do so, would adding/removing a few thousand instances rapidly and constantly bog down the performance, or is it rather seemless?

How will vertex animation effect instances? Will it work at all? The same?

Can you instance skinned meshes such as characters and animate independently?

 

Awesome, thanks.

 

So, it seems unclear to me. Do I need to instantiate these objects
+ the instanced shader, or do I use Graphics.DrawMeshInstance + instanced shader? Or can it be done either way?

And how can I debug that they are being instanced? Is there something in the profiler?

The graprahics instancing docs don't really go into much depth of how instancing is used.

 

Trying it by just solely using the shader, without calling drawmeshinstance, results in apparently no instancing. Am I doing something wrong or do we have to call drawmeshinstance for everything we want to use it?

 

It is showing instances now. Each batch is like 6 draw calls though but maybe thats normal since it has realtime shadows. And I also noticed you can just use the shader or you can pass Matrix4x4s into Graphics.DrawMeshInstanced (which seems to run much much better). In both cases the bottleneck is on the graphics obviously, but using the shader alone is really performance heavy, which is somewhat expected, but doesnt seem quite right. The 1023 instances per batch is kind of annoying but I suppose we can segment them out.

 

I would like to know, once we get to the oddball remainder amount of instances after segmenting out batches of 1023, if we tell Graphics.DrawMeshInstanced to draw 1023 still, even though there are only say half that in the remaining batch of instances, is this ok to do? Would it still try to draw 1023?

 

In forward using a single directional light with cascaded shadows will be 6 draw calls per object / instance set. One for each cascade, one for the forward camera depth texture pass, and one for finally rendering to the screen.