ConstReadonlyALREADY_SIGNALED: 37146GL_ALREADY_SIGNALED.
ReadonlyCONDITION_SATISFIED: 37148GL_CONDITION_SATISFIED.
ReadonlyPIXEL_PACK_BUFFER: 35051GL_PIXEL_PACK_BUFFER — the non-stalling read-back's destination.
ReadonlySTREAM_READ: 35041GL_STREAM_READ — written by GL once, read back by the CPU once.
ReadonlySYNC_FLUSH_COMMANDS_BIT: 1GL_SYNC_FLUSH_COMMANDS_BIT — flush on the first wait, so the fence is reachable.
ReadonlySYNC_GPU_COMMANDS_COMPLETE: 37143GL_SYNC_GPU_COMMANDS_COMPLETE — the only condition fenceSync accepts.
ReadonlyTIMEOUT_EXPIRED: 37147GL_TIMEOUT_EXPIRED — not yet; poll again.
ReadonlyWAIT_FAILED: 37149GL_WAIT_FAILED — the wait itself failed (a lost context, typically).
The GL enumerants only the picking read-back uses — the
PARTICLE_GLprecedent: kept beside their one consumer rather than widening the shared GL object everyWebglRendererbundle carries.