vbo/dlist: use a shared index buffer
Draws can be merged by u_threaded if they share the same IB.
This improves performance in SPECviewperf13 snx-03: tests fps are improved by a 1.2x - 2.0x factor.
Draws can be merged by u_threaded if they share the same IB.
This improves performance in SPECviewperf13 snx-03: tests fps are improved by a 1.2x - 2.0x factor.