1 files changed, 9 insertions, 1 deletions
diff --git a/shaders/overlay.frag.glsl b/shaders/overlay.frag.glsl
index 86c0188b..b5ac8d5a 100644
--- a/shaders/overlay.frag.glsl
+++ b/shaders/overlay.frag.glsl
@@ -1,9 +1,17 @@
 #version 450
 
+layout(std140, set = 3, binding = 0) uniform UiUniforms {
+    float background_opacity;
+} u_ui;
+
 layout(location = 0) in vec4 v_color;
 
 layout(location = 0) out vec4 o_col;
 
 void main() {
-    o_col = v_color;
+    // Preserve shape coverage for destination subtraction. The pipeline uses
+    // the matching opacity blend constant for source alpha, so graphics laid
+    // over a background with the same opacity do not accumulate opaque seams.
+    // Text/cursor draw groups bind opacity 1 instead.
+    o_col = vec4(v_color.rgb * clamp(u_ui.background_opacity, 0.0, 1.0), v_color.a);
 }