[Mesa-dev] [PATCH 1/2] gallium/include/pipe: Added interface for atomic counter buffers in pipe

[Jose Fonseca]

Do we really need a new pipe_context::set_counter_buffer method? 
Shouldn't this case be covered by pipe_context::set_shader_resources ?

If we really need new method, I'd like we have better names for them, so 
we can clearly distinguish them.

IIUC GL_ARB_shader_atomic_counters correctly, this roughly matches 
D3D11s "unordered access views" [1], though D3D11's UAVs can by typed 
[2], or raw [3].

Also, are counter buffers in user memory really supported?  I can't spot 
any mention of that in GL_ARB_shader_atomic_counters.

I think that rather than mimicking pipe_constant_buffer, this feature 
should more closely to sampler views.


I confess I'm not familiar with counter buffers / UAVs, but I think this 
needs a bit more thought to avoid being completely redone in the medium 
term.


Jose


[1] 
http://msdn.microsoft.com/en-gb/library/windows/desktop/ff476335.aspx#Unordered_Access
[2] http://msdn.microsoft.com/en-gb/library/windows/desktop/ff476258.aspx
[3] 
http://msdn.microsoft.com/en-gb/library/windows/desktop/ff476900.aspx#Raw_Buffer_Views

On 04/01/15 21:44, adityaatluri wrote:
> ---
>   src/gallium/include/pipe/p_context.h |  5 +++++
>   src/gallium/include/pipe/p_defines.h |  7 ++++++-
>   src/gallium/include/pipe/p_state.h   | 10 ++++++++++
>   3 files changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/src/gallium/include/pipe/p_context.h b/src/gallium/include/pipe/p_context.h
> index af5674f..bf3be31 100644
> --- a/src/gallium/include/pipe/p_context.h
> +++ b/src/gallium/include/pipe/p_context.h
> @@ -44,6 +44,7 @@ struct pipe_blit_info;
>   struct pipe_box;
>   struct pipe_clip_state;
>   struct pipe_constant_buffer;
> +struct pipe_counter_buffer;
>   struct pipe_depth_stencil_alpha_state;
>   struct pipe_draw_info;
>   struct pipe_fence_handle;
> @@ -201,6 +202,10 @@ struct pipe_context {
>                                   uint shader, uint index,
>                                   struct pipe_constant_buffer *buf );
>
> +   void (*set_counter_buffer)( struct pipe_context *,
> +                               uint shader, uint index,
> +                               struct pipe_counter_buffer *buf );
> +




>      void (*set_framebuffer_state)( struct pipe_context *,
>                                     const struct pipe_framebuffer_state * );
>
> diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
> index 8c4e415..717ab6a 100644
> --- a/src/gallium/include/pipe/p_defines.h
> +++ b/src/gallium/include/pipe/p_defines.h
> @@ -341,6 +341,7 @@ enum pipe_flush_flags {
>   #define PIPE_BIND_VERTEX_BUFFER        (1 << 4) /* set_vertex_buffers */
>   #define PIPE_BIND_INDEX_BUFFER         (1 << 5) /* draw_elements */
>   #define PIPE_BIND_CONSTANT_BUFFER      (1 << 6) /* set_constant_buffer */
> +#define PIPE_BIND_COUNTER_BUFFER       (1 << 7) /* set_counter_buffer */
>   #define PIPE_BIND_DISPLAY_TARGET       (1 << 8) /* flush_front_buffer */
>   #define PIPE_BIND_TRANSFER_WRITE       (1 << 9) /* transfer_map */
>   #define PIPE_BIND_TRANSFER_READ        (1 << 10) /* transfer_map */
> @@ -572,6 +573,8 @@ enum pipe_cap {
>      PIPE_CAP_MAX_VERTEX_ATTRIB_STRIDE = 109,
>      PIPE_CAP_SAMPLER_VIEW_TARGET = 110,
>      PIPE_CAP_CLIP_HALFZ = 111,
> +   PIPE_CAP_USER_COUNTER_BUFFERS = 112,
> +   PIPE_CAP_COUNTER_BUFFER_OFFSET_ALIGNMENT = 113,
>   };
>
>   #define PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_NV50 (1 << 0)
> @@ -631,7 +634,9 @@ enum pipe_shader_cap
>      PIPE_SHADER_CAP_PREFERRED_IR,
>      PIPE_SHADER_CAP_TGSI_SQRT_SUPPORTED,
>      PIPE_SHADER_CAP_MAX_SAMPLER_VIEWS,
> -   PIPE_SHADER_CAP_DOUBLES
> +   PIPE_SHADER_CAP_DOUBLES,
> +   PIPE_SHADER_CAP_MAX_COUNTER_BUFFER_SIZE,
> +   PIPE_SHADER_CAP_MAX_COUNTER_BUFFERS
>   };
>
>   /**
> diff --git a/src/gallium/include/pipe/p_state.h b/src/gallium/include/pipe/p_state.h
> index 43bc48b..49fae5d 100644
> --- a/src/gallium/include/pipe/p_state.h
> +++ b/src/gallium/include/pipe/p_state.h
> @@ -57,6 +57,7 @@ extern "C" {
>   #define PIPE_MAX_CLIP_PLANES       8
>   #define PIPE_MAX_COLOR_BUFS        8
>   #define PIPE_MAX_CONSTANT_BUFFERS 32
> +#define PIPE_MAX_COUNTER_BUFFERS  32
>   #define PIPE_MAX_SAMPLERS         16
>   #define PIPE_MAX_SHADER_INPUTS    32
>   #define PIPE_MAX_SHADER_OUTPUTS   48 /* 32 GENERICs + POS, PSIZE, FOG, etc. */
> @@ -462,6 +463,15 @@ struct pipe_constant_buffer {
>      const void *user_buffer;  /**< pointer to a user buffer if buffer == NULL */
>   };
>
> +/**
> + * A Counter buffer. A new buffer is set everytime a variable with
> + * atomic_uint is defined.
> + */
> +struct pipe_counter_buffer{
> +   struct pipe_resource *buffer; /**< The actual buffer */
> +   unsigned buffer_offset; /**< The offset to start of data in buffer in bytes */
> +   const void *user_buffer; /**< The buffer which is created by the compiler */
> +};
>
>   /**
>    * A stream output target. The structure specifies the range vertices can
>