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 <[email protected]>
Reviewed-by: Brian Paul <[email protected]>

1 files changed, 18 insertions, 3 deletions

diff --git a/src/mesa/main/transformfeedback.c b/src/mesa/main/transformfeedback.c
index f2c1435d9e7..1bd76d130fd 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);