From: Joshua Simmons <josh@nega.tv>
Date: Sun, 19 Oct 2025 10:34:50 +0000 (+0200)
Subject: shark-shaders: Improve how we handle clipping for rects
X-Git-Url: https://git.nega.tv//gitweb.cgi?a=commitdiff_plain;h=31eb91d5167cccb2a590c463e32791ae87e53743;p=josh%2Fnarcissus

shark-shaders: Improve how we handle clipping for rects
---

diff --git a/title/shark-shaders/shaders/draw_2d.slang b/title/shark-shaders/shaders/draw_2d.slang
index 3c668dd..e62a01f 100644
--- a/title/shark-shaders/shaders/draw_2d.slang
+++ b/title/shark-shaders/shaders/draw_2d.slang
@@ -568,17 +568,23 @@ void rasterize(uniform RasterizeConstants constants, uint3 thread_id: SV_Dispatc
                 let cmd_min = cmd_rect.position;
                 let cmd_max = cmd_rect.position + cmd_rect.bound;
 
-                if (all(sample_center >= cmd_min) && all(sample_center <= cmd_max)) {
+                let cmd_min_clipped = max(scissor.offset_min, cmd_min);
+                let cmd_max_clipped = min(scissor.offset_max, cmd_max);
+
+                if (all(sample_center >= cmd_min_clipped) && all(sample_center <= cmd_max_clipped)) {
                     let border_width = float((cmd.packed_type >> 16) & 0xff);
                     let border_radii = unpackUnorm4x8ToFloat(cmd_rect.border_radii) * 255.0;
                     let max_border_radius = max(border_radii.x, max(border_radii.y, max(border_radii.z, border_radii.w)));
                     let shrink = (2.0 - sqrt(2.0)) * max_border_radius;
                     let background_color = unpackUnorm4x8ToFloat(cmd_rect.background_color).bgra;
 
-                    let cmd_min_clipped = max(scissor.offset_min, cmd_min + border_width + shrink);
-                    let cmd_max_clipped = min(scissor.offset_max, cmd_max - border_width - shrink);
+                    // We calculate a safe region where samples are fully inside
+                    // the background. For this region we can just write out the
+                    // background color without any sdf evaluation.
+                    let cmd_min_safe = max(scissor.offset_min, cmd_min + border_width + shrink);
+                    let cmd_max_safe = min(scissor.offset_max, cmd_max - border_width - shrink);
 
-                    if (all(sample_center >= cmd_min_clipped) && all(sample_center <= cmd_max_clipped)) {
+                    if (all(sample_center >= cmd_min_safe) && all(sample_center <= cmd_max_safe)) {
                         primitive_color = background_color;
                     } else {
                         let b = cmd_rect.bound / 2.0;
@@ -601,11 +607,6 @@ void rasterize(uniform RasterizeConstants constants, uint3 thread_id: SV_Dispatc
 
                         let border = lerp(float4(0.0), border_color, alpha_border);
                         primitive_color = lerp(border, background_color, alpha);
-
-                        let clip_b = (scissor.offset_max - scissor.offset_min) / 2.0;
-                        let clip_p = scissor.offset_min + clip_b - sample_center;
-                        d = max(d, sdf::box(clip_p, clip_b));
-                        primitive_color = d < 0.0 ? primitive_color : float4(0.0);
                     }
                 }
                 break;