[Mesa-dev] [PATCH] gallium: move clear paths from rgba to a pointer to a color union

[Roland Scheidegger]

Am 15.09.2011 15:35, schrieb Dave Airlie:
> From: Dave Airlie <airlied at redhat.com>
> 
> This moves the gallium interface for clears from using a pointer to 4 floats
> to a pointer to a union of float/unsigned/int values. This is step one
> in allowing integer clears. I've tried to build as many drivers/pieces
> as I could, but I think I missed a couple, (vega for instance seems to
> need a bit more work).

> diff --git a/src/gallium/include/pipe/p_context.h b/src/gallium/include/pipe/p_context.h
> index 49c12ec..b2d5f95 100644
> --- a/src/gallium/include/pipe/p_context.h
> +++ b/src/gallium/include/pipe/p_context.h
> @@ -63,7 +63,7 @@ struct pipe_vertex_element;
>  struct pipe_video_buffer;
>  struct pipe_video_decoder;
>  struct pipe_viewport_state;
> -
> +union pipe_color_union;
>  
>  /**
>   * Gallium rendering context.  Basically:
> @@ -281,23 +281,23 @@ struct pipe_context {
>      * The entire buffers are cleared (no scissor, no colormask, etc).
>      *
>      * \param buffers  bitfield of PIPE_CLEAR_* values.
> -    * \param rgba  pointer to an array of one float for each of r, g, b, a.
> +    * \param color  pointer to a union of fiu array for each of r, g, b, a.
>      * \param depth  depth clear value in [0,1].
>      * \param stencil  stencil clear value
>      */
>     void (*clear)(struct pipe_context *pipe,
>                   unsigned buffers,
> -                 const float *rgba,
> +                 const union pipe_color_union *color,
>                   double depth,
>                   unsigned stencil);
>  
>     /**
>      * Clear a color rendertarget surface.
> -    * \param rgba  pointer to an array of one float for each of r, g, b, a.
> +    * \param color  pointer to an union of fiu array for each of r, g, b, a.
>      */
>     void (*clear_render_target)(struct pipe_context *pipe,
>                                 struct pipe_surface *dst,
> -                               const float *rgba,
> +                               const union pipe_color_union *color,
>                                 unsigned dstx, unsigned dsty,
>                                 unsigned width, unsigned height);
>  

Hmm is it really necessary to change the clear function?
This is sort of a legacy clear, and neither OpenGL nor d3d9(*) allow you
to use anything but floats when specifying clear color.
(Yes I know mesa / mesa state tracker currently use clear and not
clear_render_target/clear_depth_stencil even for the glClearBufferxx
functions right now.)

(*) d3d9 in fact requires the color to be a d3dcolor hence packed 32bit
uint but it can be converted of course without loss to floats.

Roland