| topology | Topology of the procedural geometry. |
| bufferWithArgs | Buffer with draw arguments. |
| argsOffset | Byte offset where in the buffer the draw arguments are. |
Draws a fully procedural geometry on the GPU.
DrawProceduralIndirect does a draw call on the GPU, without any vertex or index buffers.
The amount of geometry to draw is read from a ComputeBuffer. Typical use
case is generating arbitrary amount of data from a ComputeShader and
then rendering that, without requiring a readback to the CPU.
This is only useful on Shader Model 4.5 level hardware where shaders can read
arbitrary data from ComputeBuffer buffers.
Buffer with arguments, bufferWithArgs, has to have four integer numbers at given argsOffset offset:
vertex count per instance, instance count, start vertex location, start instance location.
This very much maps to Direct3D11 DrawInstancedIndirect and equivalent functions on other graphics APIs. On OpenGL versions before 4.2 and all OpenGL ES versions that support indirect draw, the last argument is reserved and therefore must be zero.
Note that this call executes immediately, similar to Graphics.DrawMeshNow. It uses currently set render target, transformation matrices and currently set shader pass.
There's also a similar functionality in CommandBuffers, see CommandBuffer.DrawProceduralIndirect.
See Also: Graphics.DrawProcedural, ComputeBuffer.CopyCount, SystemInfo.supportsComputeShaders.