[PATCH xserver 2/3] glamor: Scissor CopyArea to the bounds of the drawing.

[Mark Marshall]

On 1 August 2017 at 22:59, Eric Anholt <eric at anholt.net> wrote:
> Like the previous fix to rectangles, this reduces the area drawn on
> tiled renderers by letting the CPU-side tile setup know what tiles
> might be drawn at all.
>
> Surprisingly, it improves x11perf -copypixwin1 -repeat 1 -reps 10000
> on i965 by 2.93185% +/- 1.5561% (n=90).
>
> Signed-off-by: Eric Anholt <eric at anholt.net>
> ---
>  glamor/glamor_copy.c  | 27 +++++++++++++++++++++++----
>  glamor/glamor_utils.h |  9 +++++++++
>  2 files changed, 32 insertions(+), 4 deletions(-)
>
> diff --git a/glamor/glamor_copy.c b/glamor/glamor_copy.c
> index f7d6eb163fac..3296b7b1bf75 100644
> --- a/glamor/glamor_copy.c
> +++ b/glamor/glamor_copy.c
> @@ -351,6 +351,7 @@ glamor_copy_fbo_fbo_draw(DrawablePtr src,
>      const glamor_facet *copy_facet;
>      int n;
>      Bool ret = FALSE;
> +    BoxRec bounds = glamor_no_rendering_bounds();
>
>      glamor_make_current(glamor_priv);
>
> @@ -391,11 +392,20 @@ glamor_copy_fbo_fbo_draw(DrawablePtr src,
>      glVertexAttribPointer(GLAMOR_VERTEX_POS, 2, GL_SHORT, GL_FALSE,
>                            2 * sizeof (GLshort), vbo_offset);
>
> +    if (nbox < 100) {
> +        bounds = glamor_start_rendering_bounds();
> +        for (int i = 0; i < nbox; i++)
> +            glamor_bounds_union_box(&bounds, &box[i]);
> +    }
> +
>      for (n = 0; n < nbox; n++) {
>          v[0] = box->x1; v[1] = box->y1;
>          v[2] = box->x1; v[3] = box->y2;
>          v[4] = box->x2; v[5] = box->y2;
>          v[6] = box->x2; v[7] = box->y1;
> +
> +        glamor_bounds_union_box(&bounds, box);
> +

I'm only looking at the diff, but aren't you doing
glamor_bounds_union_box twice in the n < 100 case, and in the n >= 100
case I guess it does nothing anyway, apart from waste cycles?

>          v += 8;
>          box++;
>      }
> @@ -417,15 +427,24 @@ glamor_copy_fbo_fbo_draw(DrawablePtr src,
>              goto bail_ctx;
>
>          glamor_pixmap_loop(dst_priv, dst_box_index) {
> +            BoxRec scissor = {
> +                .x1 = max(-args.dx, bounds.x1),
> +                .y1 = max(-args.dy, bounds.y1),
> +                .x2 = min(-args.dx + src_box->x2 - src_box->x1, bounds.x2),
> +                .y2 = min(-args.dy + src_box->y2 - src_box->y1, bounds.y2),
> +            };
> +            if (scissor.x1 >= scissor.x2 || scissor.y1 >= scissor.y2)
> +                continue;
> +
>              if (!glamor_set_destination_drawable(dst, dst_box_index, FALSE, FALSE,
>                                                   prog->matrix_uniform,
>                                                   &dst_off_x, &dst_off_y))
>                  goto bail_ctx;
>
> -            glScissor(dst_off_x - args.dx,
> -                      dst_off_y - args.dy,
> -                      src_box->x2 - src_box->x1,
> -                      src_box->y2 - src_box->y1);
> +            glScissor(scissor.x1 + dst_off_x,
> +                      scissor.y1 + dst_off_y,
> +                      scissor.x2 - scissor.x1,
> +                      scissor.y2 - scissor.y1);
>
>              glamor_glDrawArrays_GL_QUADS(glamor_priv, nbox);
>          }
> diff --git a/glamor/glamor_utils.h b/glamor/glamor_utils.h
> index 824be1a09338..81df944b38ba 100644
> --- a/glamor/glamor_utils.h
> +++ b/glamor/glamor_utils.h
> @@ -764,6 +764,15 @@ glamor_bounds_union_rect(BoxPtr bounds, xRectangle *rect)
>      bounds->y2 = max(bounds->y2, rect->y + rect->height);
>  }
>
> +static inline void
> +glamor_bounds_union_box(BoxPtr bounds, BoxPtr box)
> +{
> +    bounds->x1 = min(bounds->x1, box->x1);
> +    bounds->y1 = min(bounds->y1, box->y1);
> +    bounds->x2 = max(bounds->x2, box->x2);
> +    bounds->y2 = max(bounds->y2, box->y2);
> +}
> +
>  /**
>   * Helper function for implementing draws with GL_QUADS on GLES2,
>   * where we don't have them.
> --
> 2.13.3
>
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