I have a large array with more than 1 million struct instance. The size is actually dynamic.
It works fine with MTLBuffer, it appears to be a pointer in Metal shader, and I don't have to write some hardcoded size or length.
The problem is, I don't want to bind or set it for each frame. So, I am looking into ArgumentBuffers and Heap. But I didn't find solution or example for my use case. It looks like everything in array inside ArgumentBuffers will take some slot. That's not a good idea for my large array. And I didn't find good example which have pointer in ArgumentBuffers.
After all, what is best practice for my use case?
Let me answer my own question. To support dynamic sized array inside Argument buffer. We need the device supporting Metal 2 Tier 2.
[argumentEncoder setArgumentBuffer:_argumentBuffer startOffset:0 arrayElement:0];
// Then, write some code to fill the data for first element
[argumentEncoder setArgumentBuffer:_argumentBuffer startOffset:0 arrayElement:1];
// Then, write some code to fill the data for second element
While, on the GPU side you can simple use the pointer reference below.
constant TheBufferTypeName* theBuffer [[buffer(0)]]
Then, use it with theBuffer[0] or theBuffer[1].
It's done without any hardcoded size.