gallium: add start_slot parameter to set_vertex_buffers
This allows updating only a subrange of buffer bindings.
set_vertex_buffers(pipe, start_slot, count, NULL) unbinds buffers in that
range. Binding NULL resources unbinds buffers too (both buffer and user_buffer
must be NULL).
The meta ops are adapted to only save, change, and restore the single slot
they use. The cso_context can save and restore only one vertex buffer slot.
The clients can query which one it is using cso_get_aux_vertex_buffer_slot.
It's currently set to 0. (the Draw module breaks if it's set to non-zero)
It should decrease the CPU overhead when using a lot of meta ops, but
the drivers must be able to treat each vertex buffer slot as a separate
state (only r600g does so at the moment).
I can imagine this also being useful for optimizing some OpenGL use cases.
Reviewed-by: Brian Paul <brianp@vmware.com>
78 files changed