Compute to Graphics Dependencies

Question

I am doing a Marching cube algorithm in a Compute shader. The vertices generated by the compute stage will be input to the vertex stage.

Compute -> Vertices -> Render

There is no way of knowing how many vertices that the compute stage will output, so I need a storage buffer looking something like this:

layout(set = 1, binding = 0) buffer Count{
  int value;
} count;

layout(set = 2, binding = 0) buffer Mesh {
  vec4 vertices[1<<15];
} mesh;

The vertices do not need a roundtrip to the CPU, but the count is a variable used by the vkCmdDraw command. So I need to put the count buffer in host visible memory, map that memory and do a memcpy after the compute stage. Is this a good way of solving this problem or is there some other way where I don't have to read back data to the CPU?

[Don't use `vec3` in interface blocks](https://stackoverflow.com/a/38172697/734069). — Nicol Bolas, Mar 30 '20 at 13:31

score 2 · Accepted Answer · answered Mar 30 '20 at 10:47

2

Well, this is exactly what vkCmdDrawIndirect is for. The vertex count is stored in a Vkuffer, which makes the CPU round-trip unnecessary.

answered Mar 30 '20 at 10:47

krOoze

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Compute to Graphics Dependencies

1 Answers1