[Mesa-dev] [PATCH 1/2] mesa: Support BindBuffer{Base, Offset, Range} with a buffer of 0.

[Brian Paul]

On 06/04/2012 02:12 AM, Kenneth Graunke wrote:
> _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>
> ---
>   src/mesa/main/transformfeedback.c |   21 ++++++++++++++++++---
>   1 file 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);

Reviewed-by: Brian Paul <brianp at vmware.com>