Mesa (master): mesa: Support BindBuffer{Base,Offset, Range} with a buffer of 0.

[Kenneth Graunke]

Module: Mesa
Branch: master
Commit: 05b086ce934fa2967da736db8db429d0886735a9
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=05b086ce934fa2967da736db8db429d0886735a9

Author: Kenneth Graunke <kenneth at whitecape.org>
Date:   Mon Jun  4 00:48:23 2012 -0700

mesa: Support BindBuffer{Base,Offset,Range} with a buffer of 0.

_mesa_lookup_bufferobj returns NULL for 0, which caused us to say
"there's no such buffer object" and raise an error, rather than
correctly binding the shared NullBufferObj.

Now you can unbind your buffers.

NOTE: This is a candidate for stable release branches.

Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
Reviewed-by: Brian Paul <brianp at vmware.com>

---

 src/mesa/main/transformfeedback.c |   21 ++++++++++++++++++---
 1 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/src/mesa/main/transformfeedback.c b/src/mesa/main/transformfeedback.c
index f2c1435..1bd76d1 100644
--- a/src/mesa/main/transformfeedback.c
+++ b/src/mesa/main/transformfeedback.c
@@ -470,7 +470,12 @@ _mesa_BindBufferRange(GLenum target, GLuint index,
       return;
    }  
 
-   bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   if (buffer == 0) {
+      bufObj = ctx->Shared->NullBufferObj;
+   } else {
+      bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   }
+
    if (!bufObj) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBindBufferRange(invalid buffer=%u)", buffer);
@@ -518,7 +523,12 @@ _mesa_BindBufferBase(GLenum target, GLuint index, GLuint buffer)
       return;
    }
 
-   bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   if (buffer == 0) {
+      bufObj = ctx->Shared->NullBufferObj;
+   } else {
+      bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   }
+
    if (!bufObj) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBindBufferBase(invalid buffer=%u)", buffer);
@@ -574,7 +584,12 @@ _mesa_BindBufferOffsetEXT(GLenum target, GLuint index, GLuint buffer,
       return;
    }
 
-   bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   if (buffer == 0) {
+      bufObj = ctx->Shared->NullBufferObj;
+   } else {
+      bufObj = _mesa_lookup_bufferobj(ctx, buffer);
+   }
+
    if (!bufObj) {
       _mesa_error(ctx, GL_INVALID_OPERATION,
                   "glBindBufferOffsetEXT(invalid buffer=%u)", buffer);