[Mesa-dev] [PATCH 2/3] mesa/st: Accelerate ARB_clear_buffer_object with clear_buffer

[Brian Paul]

On 03/25/2014 03:36 PM, Ilia Mirkin wrote:
> Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
> ---
>
> Note that this also ensures that the clear size is passed through even when
> the data is null. This preserves the validation done to make sure that size %
> clear size == 0.
>
>   src/mesa/main/bufferobj.c                    |  6 +++---
>   src/mesa/main/bufferobj.h                    |  7 +++++++
>   src/mesa/state_tracker/st_cb_bufferobjects.c | 28 ++++++++++++++++++++++++++++
>   3 files changed, 38 insertions(+), 3 deletions(-)
>
> diff --git a/src/mesa/main/bufferobj.c b/src/mesa/main/bufferobj.c
> index 2e9e059..36acd64 100644
> --- a/src/mesa/main/bufferobj.c
> +++ b/src/mesa/main/bufferobj.c
> @@ -665,7 +665,7 @@ _mesa_buffer_get_subdata( struct gl_context *ctx, GLintptrARB offset,
>    * \sa glClearBufferSubData, glClearBufferData and
>    * dd_function_table::ClearBufferSubData.
>    */
> -static void
> +void
>   _mesa_buffer_clear_subdata(struct gl_context *ctx,
>                              GLintptr offset, GLsizeiptr size,
>                              const GLvoid *clearValue,
> @@ -1458,7 +1458,7 @@ _mesa_ClearBufferData(GLenum target, GLenum internalformat, GLenum format,
>      if (data == NULL) {
>         /* clear to zeros, per the spec */
>         ctx->Driver.ClearBufferSubData(ctx, 0, bufObj->Size,
> -                                     NULL, 0, bufObj);
> +                                     NULL, clearValueSize, bufObj);
>         return;
>      }
>
> @@ -1510,7 +1510,7 @@ _mesa_ClearBufferSubData(GLenum target, GLenum internalformat,
>         /* clear to zeros, per the spec */
>         if (size > 0) {
>            ctx->Driver.ClearBufferSubData(ctx, offset, size,
> -                                        NULL, 0, bufObj);
> +                                        NULL, clearValueSize, bufObj);
>         }
>         return;
>      }
> diff --git a/src/mesa/main/bufferobj.h b/src/mesa/main/bufferobj.h
> index 9814552..c08c4fd 100644
> --- a/src/mesa/main/bufferobj.h
> +++ b/src/mesa/main/bufferobj.h
> @@ -115,6 +115,13 @@ extern void
>   _mesa_buffer_unmap_all_mappings(struct gl_context *ctx,
>                                   struct gl_buffer_object *bufObj);
>
> +extern void
> +_mesa_buffer_clear_subdata(struct gl_context *ctx,
> +                           GLintptr offset, GLsizeiptr size,
> +                           const GLvoid *clearValue,
> +                           GLsizeiptr clearValueSize,
> +                           struct gl_buffer_object *bufObj);
> +
>   /*
>    * API functions
>    */
> diff --git a/src/mesa/state_tracker/st_cb_bufferobjects.c b/src/mesa/state_tracker/st_cb_bufferobjects.c
> index 49c4b90..2706903 100644
> --- a/src/mesa/state_tracker/st_cb_bufferobjects.c
> +++ b/src/mesa/state_tracker/st_cb_bufferobjects.c
> @@ -447,6 +447,33 @@ st_copy_buffer_subdata(struct gl_context *ctx,
>                                 srcObj->buffer, 0, &box);
>   }
>
> +/**
> + * Called via glClearBufferSubData().
> + */
> +static void
> +st_clear_buffer_subdata(struct gl_context *ctx,
> +                        GLintptr offset, GLsizeiptr size,
> +                        const GLvoid *clearValue,
> +                        GLsizeiptr clearValueSize,
> +                        struct gl_buffer_object *bufObj)
> +{
> +   struct pipe_context *pipe = st_context(ctx)->pipe;
> +   struct st_buffer_object *buf = st_buffer_object(bufObj);
> +   char zeros[16] = {0};

that could be static const to avoid runtime setup.


> +
> +   if (!pipe->clear_buffer) {
> +      _mesa_buffer_clear_subdata(
> +            ctx, offset, size, clearValue, clearValueSize, bufObj);

We'd normally wrap a line like that as:

       _mesa_buffer_clear_subdata(ctx, offset, size, clearValue,
                                  clearValueSize, bufObj);

> +      return;
> +   }
> +
> +   if (!clearValue)
> +      clearValue = zeros;
> +
> +   pipe->clear_buffer(pipe, buf->buffer, offset, size,
> +                      clearValue, clearValueSize);
> +}
> +
>
>   /* TODO: if buffer wasn't created with appropriate usage flags, need
>    * to recreate it now and copy contents -- or possibly create a
> @@ -476,6 +503,7 @@ st_init_bufferobject_functions(struct dd_function_table *functions)
>      functions->FlushMappedBufferRange = st_bufferobj_flush_mapped_range;
>      functions->UnmapBuffer = st_bufferobj_unmap;
>      functions->CopyBufferSubData = st_copy_buffer_subdata;
> +   functions->ClearBufferSubData = st_clear_buffer_subdata;
>
>      /* For GL_APPLE_vertex_array_object */
>      functions->NewArrayObject = _mesa_new_vao;
>