Mesa (master): mesa: Avoid segfault when getting an unbound transform feedback buffer name.

[Paul Berry]

Module: Mesa
Branch: master
Commit: 4357f8b4dcaaef4843d4b34923383a2b045638b1
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=4357f8b4dcaaef4843d4b34923383a2b045638b1

Author: Paul Berry <stereotype441 at gmail.com>
Date:   Tue Jan  3 13:59:13 2012 -0800

mesa: Avoid segfault when getting an unbound transform feedback buffer name.

Previously we were using
gl_transform_feedback_object::Buffers[i]->Name to service an indexed
get request for GL_TRANSFORM_FEEDBACK_BUFFER_BINDING.  However, if no
buffer has been bound, gl_transform_feedback_object::Buffers[i] is
NULL, so this was causing a segfault.

This patch switches to using
gl_transform_feedback_object::BufferNames[i], which is equal to
gl_transform_feedback_object::Buffers[i]->Name if
gl_transform_feedback_object::Buffers[i] is not NULL, and 0 if it is
NULL.

Fixes piglit test "EXT_transform_feedback/get-buffer-state
indexed_binding".

Reviewed-by: Eric Anholt <eric at anholt.net>
Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>

---

 src/mesa/main/get.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/src/mesa/main/get.c b/src/mesa/main/get.c
index 0c9d6b3..5ad6012 100644
--- a/src/mesa/main/get.c
+++ b/src/mesa/main/get.c
@@ -2498,7 +2498,7 @@ find_value_indexed(const char *func, GLenum pname, int index, union value *v)
 	 goto invalid_value;
       if (!ctx->Extensions.EXT_transform_feedback)
 	 goto invalid_enum;
-      v->value_int = ctx->TransformFeedback.CurrentObject->Buffers[index]->Name;
+      v->value_int = ctx->TransformFeedback.CurrentObject->BufferNames[index];
       return TYPE_INT;
    }