Mesa (master): mesa: add/update comments in _mesa_copy_buffer_subdata()

[Brian Paul]

Module: Mesa
Branch: master
Commit: 4c502e05e803dc45bb01510683fb86cf7f30e431
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=4c502e05e803dc45bb01510683fb86cf7f30e431

Author: Brian Paul <brianp at vmware.com>
Date:   Sat Jan  7 14:16:27 2012 -0700

mesa: add/update comments in _mesa_copy_buffer_subdata()

---

 src/mesa/main/bufferobj.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c
index 4625198..5f8071f 100644
--- a/src/mesa/main/bufferobj.c
+++ b/src/mesa/main/bufferobj.c
@@ -504,7 +504,7 @@ _mesa_copy_buffer_subdata(struct gl_context *ctx,
 {
    void *srcPtr, *dstPtr;
 
-   /* buffer should not already be mapped */
+   /* the buffers should not be mapped */
    assert(!_mesa_bufferobj_mapped(src));
    assert(!_mesa_bufferobj_mapped(dst));
 
@@ -514,6 +514,9 @@ _mesa_copy_buffer_subdata(struct gl_context *ctx,
                                        (GL_MAP_WRITE_BIT |
                                         GL_MAP_INVALIDATE_RANGE_BIT), dst);
 
+   /* Note: the src and dst regions will never overlap.  Trying to do so
+    * would generate GL_INVALID_VALUE earlier.
+    */
    if (srcPtr && dstPtr)
       memcpy(dstPtr, srcPtr, size);