per-pixel wave reveal mask for lock screen overlay layers

nix/package.nix

@@ -27,10 +27,13 @@ stdenvNoCC.mkDerivation {
     mkdir -p $out/share/nova-shell
     cp -r shell/shell.qml shell/modules shell/services shell/applets shell/lock shell/assets $out/share/nova-shell/
 
-    # Compile fragment shader to Qt RHI format
+    # Compile fragment shaders to Qt RHI format
     qsb --qt6 \
       -o $out/share/nova-shell/modules/hex_wave.frag.qsb \
       shell/modules/hex_wave.frag
+    qsb --qt6 \
+      -o $out/share/nova-shell/modules/reveal_mask.frag.qsb \
+      shell/modules/reveal_mask.frag
 
     mkdir -p $out/bin
     makeWrapper ${lib.getExe quickshell} $out/bin/nova-shell \

shell/lock/LockSurface.qml

@@ -13,9 +13,7 @@ WlSessionLockSurface {
 
     color: S.Theme.base00
 
-    // Wave progress drives blur/dim/hex overlay reveal
     property real _unlockFade: 1
-    readonly property real _waveProgress: (root.width > 0 ? Math.max(0, Math.min(1, _hexWave.wavePhase / root.width)) : 0) * _unlockFade
 
     // Clear desktop screenshot - visible immediately
     ScreencopyView {
@@ -25,12 +23,23 @@ WlSessionLockSurface {
         opacity: _unlockFade
     }
 
-    // Blurred screenshot - fades in as wave passes
+    // Overlay group: blur + dim + hexes, revealed per-pixel by wave position
+    Item {
+        anchors.fill: parent
+        opacity: _unlockFade
+
+        layer.enabled: true
+        layer.effect: ShaderEffect {
+            property real uPhase: _hexWave.wavePhase
+            property real uWidth: root.width
+            fragmentShader: Quickshell.shellPath("modules/reveal_mask.frag.qsb")
+        }
+
+        // Blurred screenshot
         ScreencopyView {
             anchors.fill: parent
             captureSource: root.screen
             visible: S.Modules.lock.screenshot ?? true
-        opacity: root._waveProgress
 
             layer.enabled: true
             layer.effect: MultiEffect {
@@ -41,19 +50,19 @@ WlSessionLockSurface {
             }
         }
 
-    // Dim overlay - fades in with wave
+        // Dim overlay
         Rectangle {
             anchors.fill: parent
             color: Qt.rgba(S.Theme.base00.r, S.Theme.base00.g, S.Theme.base00.b, 0.4)
-        opacity: root._waveProgress
         }
 
-    // Hex wave - fades in with wave progress
+        // Hex wave
         C.HexWaveBackground {
             id: _hexWave
             anchors.fill: parent
             running: root.lock.secure
-        opacity: root._waveProgress * 0.4
+            opacity: 0.4
+        }
     }
 
     // Keyboard input via TextInput - engages Qt's full input pipeline including
@@ -242,13 +251,6 @@ WlSessionLockSurface {
                 duration: 300
                 easing.type: Easing.InCubic
             }
-            NumberAnimation {
-                target: _hexWave
-                property: "opacity"
-                to: 0
-                duration: 300
-                easing.type: Easing.InCubic
-            }
         }
 
         PropertyAction {

shell/modules/reveal_mask.frag

@@ -0,0 +1,21 @@
+#version 440
+
+layout(location = 0) in vec2 qt_TexCoord0;
+layout(location = 0) out vec4 fragColor;
+
+layout(std140, binding = 0) uniform buf {
+    mat4 qt_Matrix;
+    float qt_Opacity;
+    float uPhase;
+    float uWidth;
+};
+
+layout(binding = 1) uniform sampler2D source;
+
+void main() {
+    vec4 tex = texture(source, qt_TexCoord0);
+    float x = qt_TexCoord0.x * uWidth;
+    // Soft reveal edge: fully visible 200px behind wave, fades out 50px ahead
+    float mask = 1.0 - smoothstep(uPhase - 200.0, uPhase + 50.0, x);
+    fragColor = tex * mask * qt_Opacity;
+}