vbo: avoid getting buffer_ptr and buffer_map out of sync

1 files changed, 5 insertions, 1 deletions

diff --git a/src/mesa/vbo/vbo_exec_draw.c b/src/mesa/vbo/vbo_exec_draw.c
index 38b6c56f479..4b44b30b325 100644
--- a/src/mesa/vbo/vbo_exec_draw.c
+++ b/src/mesa/vbo/vbo_exec_draw.c
@@ -243,7 +243,10 @@ static void vbo_exec_vtx_unmap( struct vbo_exec_context *exec )
 
       exec->vtx.buffer_used += (exec->vtx.buffer_ptr -
                                 exec->vtx.buffer_map) * sizeof(float);
-            
+
+       
+      assert(exec->vtx.buffer_ptr != NULL);
+      
       ctx->Driver.UnmapBuffer(ctx, target, exec->vtx.bufferobj);
       exec->vtx.buffer_map = NULL;
       exec->vtx.buffer_ptr = NULL;
@@ -296,6 +299,7 @@ void vbo_exec_vtx_map( struct vbo_exec_context *exec )
          (GLfloat *)ctx->Driver.MapBuffer(ctx, target, access, exec->vtx.bufferobj);
    }
 
+   exec->vtx.buffer_ptr = exec->vtx.buffer_map;
    if (0) _mesa_printf("map %d..\n", exec->vtx.buffer_used);
 }