gallium: avoid mapping same vertex buffer in subsequent frames

Quite a few util modules were maintaining a single vertex buffer over multiple
frames, and potentially reusing it in subsequent frames.  Unfortunately that
would force us into syncrhonous rendering as the buffer manager would be
forced to wait for the previous rendering to complete prior to allowing the
map.

This resolves that issue, but requires the state tracker to issue a few new
flush() calls at the end of each frame.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/mesa/state_tracker/st_context.h b/src/mesa/state_tracker/st_context.h
index 5bcb87ce208..695ac4a96f4 100644
--- a/src/mesa/state_tracker/st_context.h
+++ b/src/mesa/state_tracker/st_context.h
@@ -154,6 +154,7 @@ struct st_context
       void *vs;
       float vertices[4][3][4];  /**< vertex pos + color + texcoord */
       struct pipe_buffer *vbuf;
+      unsigned vbuf_slot;       /* next free slot in vbuf */
       struct bitmap_cache *cache;
    } bitmap;
 
@@ -173,6 +174,7 @@ struct st_context
       void *fs;
       float vertices[4][2][4];  /**< vertex pos + color */
       struct pipe_buffer *vbuf;
+      unsigned vbuf_slot;
    } clear;
 
    void *passthrough_fs;  /**< simple pass-through frag shader */