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, 3 insertions, 2 deletions

diff --git a/src/gallium/auxiliary/util/u_draw_quad.c b/src/gallium/auxiliary/util/u_draw_quad.c
index 8ecae71b64..d7bb74b87b 100644
--- a/src/gallium/auxiliary/util/u_draw_quad.c
+++ b/src/gallium/auxiliary/util/u_draw_quad.c
@@ -40,6 +40,7 @@
 void 
 util_draw_vertex_buffer(struct pipe_context *pipe,
                         struct pipe_buffer *vbuf,
+                        uint offset,
                         uint prim_type,
                         uint num_verts,
                         uint num_attribs)
@@ -53,7 +54,7 @@ util_draw_vertex_buffer(struct pipe_context *pipe,
    /* tell pipe about the vertex buffer */
    vbuffer.buffer = vbuf;
    vbuffer.pitch = num_attribs * 4 * sizeof(float);  /* vertex size */
-   vbuffer.buffer_offset = 0;
+   vbuffer.buffer_offset = offset;
    pipe->set_vertex_buffers(pipe, 1, &vbuffer);
 
    /* tell pipe about the vertex attributes */
@@ -124,7 +125,7 @@ util_draw_texquad(struct pipe_context *pipe,
          v[29] = 1.0;
 
          pipe_buffer_unmap(pipe->screen, vbuf);
-         util_draw_vertex_buffer(pipe, vbuf, PIPE_PRIM_TRIANGLE_FAN, 4, 2);
+         util_draw_vertex_buffer(pipe, vbuf, 0, PIPE_PRIM_TRIANGLE_FAN, 4, 2);
       }
 
       pipe_buffer_reference(pipe->screen, &vbuf, NULL);