UI fix

shaders/feedback-highlight-accumulator/shader.slang

@@ -3,45 +3,37 @@ float luminance(float3 color)
     return dot(color, float3(0.2126, 0.7152, 0.0722));
 }
 
-float4 buildHistory(ShaderContext context)
+float4 updateBackgroundModel(ShaderContext context)
 {
-    float4 previousFeedback = sampleFeedback(context.uv);
-    float4 previousHistory = context.feedbackAvailable > 0
-        ? previousFeedback
-        : float4(0.0, 0.0, 0.0, 0.0);
+    float3 liveColor = context.sourceColor.rgb;
+    if (context.feedbackAvailable <= 0)
+        return float4(liveColor, 1.0);
 
-    // Highlight selection is always based on the live source image only.
-    // The stored feedback never feeds back into the threshold test.
-    float currentLuma = luminance(context.sourceColor.rgb);
-    float thresholdWidth = max(softness, 0.0001);
-    float brightMask = smoothstep(highlightThreshold - thresholdWidth, highlightThreshold + thresholdWidth, currentLuma);
-
-    // Treat RGBA as a 4-slot rolling scalar history:
-    // R = current frame, G = 1 frame ago, B = 2 frames ago, A = 3 frames ago.
-    // Each frame shifts the history forward and drops the oldest sample.
-    float currentContribution = currentLuma * brightMask * max(accumulateAmount, 0.0);
-    float4 nextHistory = float4(
-        currentContribution,
-        previousHistory.r,
-        previousHistory.g,
-        previousHistory.b
-    );
-
-    return saturate(nextHistory);
+    float3 previousBackground = sampleFeedback(context.uv).rgb;
+    float rate = saturate(learnRate);
+    float3 nextBackground = lerp(previousBackground, liveColor, rate);
+    return float4(saturate(nextBackground), 1.0);
 }
 
-float4 displayHistory(ShaderContext context)
+float4 displayBackgroundDifference(ShaderContext context)
 {
-    // In the display pass, context.sourceColor is the same-frame historyBuffer
-    // produced by buildHistory().
-    float4 history = context.sourceColor;
-    float recentEnergy = history.r + history.g + history.b;
-    float3 originalColor = sampleLayerInput(context.uv).rgb;
-    float highlightBoost = recentEnergy * max(displayGain, 0.0);
-    float3 sourceHue = originalColor / max(max(originalColor.r, originalColor.g), max(originalColor.b, 0.0001));
-    float3 displayColor =
-        originalColor +
-        sourceHue * highlightBoost * 1.5;
+    // In the display pass, context.sourceColor is the same-frame background
+    // model produced by updateBackgroundModel().
+    float3 backgroundModel = context.sourceColor.rgb;
+    float3 liveColor = sampleLayerInput(context.uv).rgb;
+
+    float3 delta = abs(liveColor - backgroundModel);
+    float difference = max(delta.r, max(delta.g, delta.b));
+    float thresholdWidth = max(softness, 0.0001);
+    float motionMask = smoothstep(
+        differenceThreshold - thresholdWidth,
+        differenceThreshold + thresholdWidth,
+        difference);
+
+    float3 baseColor = lerp(liveColor, backgroundModel, saturate(backgroundMix));
+    float3 overlayColor = overlayTint.rgb * max(luminance(liveColor), 0.15);
+    float overlayAmount = motionMask * saturate(overlayOpacity) * overlayTint.a;
+    float3 displayColor = lerp(baseColor, baseColor + overlayColor, overlayAmount);
 
     return float4(saturate(displayColor), 1.0);
 }