3 files changed, 18 insertions, 4 deletions
diff --git a/sway/desktop/fx_renderer/shaders/meson.build b/sway/desktop/fx_renderer/shaders/meson.build
index 83119963..7a27de80 100644
--- a/sway/desktop/fx_renderer/shaders/meson.build
+++ b/sway/desktop/fx_renderer/shaders/meson.build
@@ -8,6 +8,7 @@ shaders = [
     'corner.frag',
     'quad.frag',
     'quad_round.frag',
+    'stencil_mask.frag',
     'tex.frag',
 ]
 
diff --git a/sway/desktop/fx_renderer/shaders/quad_round.frag b/sway/desktop/fx_renderer/shaders/quad_round.frag
index 4099e60a..02e99028 100644
--- a/sway/desktop/fx_renderer/shaders/quad_round.frag
+++ b/sway/desktop/fx_renderer/shaders/quad_round.frag
@@ -36,8 +36,4 @@ void main() {
     float dist = min(max(q.x,q.y), 0.0) + length(max(q, 0.0)) - radius;
     float smoothedAlpha = 1.0 - smoothstep(-1.0, 0.5, dist);
     gl_FragColor = mix(vec4(0), v_color, smoothedAlpha);
-
-    if (gl_FragColor.a == 0.0) {
-        discard;
-    }
 }
diff --git a/sway/desktop/fx_renderer/shaders/stencil_mask.frag b/sway/desktop/fx_renderer/shaders/stencil_mask.frag
new file mode 100644
index 00000000..496981ef
--- /dev/null
+++ b/sway/desktop/fx_renderer/shaders/stencil_mask.frag
@@ -0,0 +1,17 @@
+precision mediump float;
+varying vec2 v_texcoord;
+
+uniform vec2 half_size;
+uniform vec2 position;
+uniform float radius;
+
+void main() {
+    vec2 q = abs(gl_FragCoord.xy - position - half_size) - half_size + radius;
+    float dist = min(max(q.x,q.y), 0.0) + length(max(q, 0.0)) - radius;
+    float smoothedAlpha = 1.0 - smoothstep(-1.0, 0.5, dist);
+    gl_FragColor = mix(vec4(0.0), vec4(1.0), smoothedAlpha);
+
+    if (gl_FragColor.a == 0.0) {
+        discard;
+    }
+}