[mutter] background-content: Optimize rounded clipping shader a bit

[Marge Bot <marge-bot src gnome org>]

commit b770ea606aeaea66504649f665e01ac31bfdef44
Author: Jonas Dreßler <verdre v0yd nl>
Date:   Thu Mar 11 22:57:35 2021 +0100

    background-content: Optimize rounded clipping shader a bit
    
    We're using the gtk4 shader for rounded rect clipping here, and gtk just
    introduced a small optimization to make this shader a bit faster, so
    let's do the same.
    
    See https://gitlab.gnome.org/GNOME/gtk/-/commit/57e354c297e1703079c2bc6fb51211b24d884ac3
    
    Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1774>

 src/compositor/meta-background-content.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)
---
diff --git a/src/compositor/meta-background-content.c b/src/compositor/meta-background-content.c
index 73db454407..3afeca4827 100644
--- a/src/compositor/meta-background-content.c
+++ b/src/compositor/meta-background-content.c
@@ -175,16 +175,24 @@ typedef enum
 "      p.x >= bounds.z || p.y >= bounds.w)                                \n"\
 "    return 0.0;                                                          \n"\
 "                                                                         \n"\
-"  vec2 rad_tl = corner_centers_1.xy - bounds.xy;                         \n"\
-"  vec2 rad_tr = corner_centers_1.zw - bounds.zy;                         \n"\
-"  vec2 rad_br = corner_centers_2.xy - bounds.zw;                         \n"\
-"  vec2 rad_bl = corner_centers_2.zw - bounds.xw;                         \n"\
-"                                                                         \n"\
 "  vec2 ref_tl = corner_centers_1.xy;                                     \n"\
 "  vec2 ref_tr = corner_centers_1.zw;                                     \n"\
 "  vec2 ref_br = corner_centers_2.xy;                                     \n"\
 "  vec2 ref_bl = corner_centers_2.zw;                                     \n"\
 "                                                                         \n"\
+"  if (p.x >= ref_tl.x && p.x >= ref_bl.x &&                              \n"\
+"      p.x <= ref_tr.x && p.x <= ref_br.x)                                \n"\
+"    return 1.0;                                                          \n"\
+"                                                                         \n"\
+"  if (p.y >= ref_tl.y && p.y >= ref_tr.y &&                              \n"\
+"      p.y <= ref_bl.y && p.y <= ref_br.y)                                \n"\
+"    return 1.0;                                                          \n"\
+"                                                                         \n"\
+"  vec2 rad_tl = corner_centers_1.xy - bounds.xy;                         \n"\
+"  vec2 rad_tr = corner_centers_1.zw - bounds.zy;                         \n"\
+"  vec2 rad_br = corner_centers_2.xy - bounds.zw;                         \n"\
+"  vec2 rad_bl = corner_centers_2.zw - bounds.xw;                         \n"\
+"                                                                         \n"\
 "  float d_tl = ellipsis_coverage(p, ref_tl, rad_tl);                     \n"\
 "  float d_tr = ellipsis_coverage(p, ref_tr, rad_tr);                     \n"\
 "  float d_br = ellipsis_coverage(p, ref_br, rad_br);                     \n"\