Make the x-ray pulse an asymmetric rising curve

Replace the symmetric sine with a raised cosine raised to
_XRayPulseShape: a long near-zero plateau, a slow rise and a short
full peak. Both shader halves use the identical formula to stay in
phase.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Assets/Shaders/PlayerCamo.hlsl

@@ -55,7 +55,8 @@ float4 _OcclusionMap_TexelSize;
 // the separate XRayOverlay pass (SRPDefaultUnlit) covers the OCCLUDED parts. See CamoForwardFragment.
 half4 _XRayColor;
 half _XRayPulseSpeed;    // 0 = steady; otherwise breathing pulse via _Time (see CamoForwardFragment)
-half _XRayPulseStrength; // modulation depth of the pulse around the authored intensity
+half _XRayPulseStrength; // modulation depth: how far the trough dims below the full-intensity peak
+half _XRayPulseShape;    // >1 bends the pulse: longer near-off plateau, rising to a brief full peak
 
 // Remaps the painted occlusion/height value into surface AO + a relief normal. Runs after URP's
 // InitializeStandardLitSurfaceData (uv is already parallax-displaced) and before InitializeInputData,
@@ -298,9 +299,12 @@ void CamoForwardFragment(
     // same additive term here reveals the glow on the visible parts too. Visible (here) and occluded
     // (overlay, ZTest Greater) are mutually exclusive by depth => no double contribution. Added
     // post-fog to match the overlay, which outputs the raw color.
-    // Breathing pulse (sin over _Time) on the glow master, matching the XRayOverlay pass exactly so the
-    // visible and occluded halves stay in phase. Speed 0 => term is 1 => identical to no pulse.
-    half xrayPulse = 1.0h + sin(_Time.y * _XRayPulseSpeed) * _XRayPulseStrength;
+    // Asymmetric breathing pulse on the glow master, matching the XRayOverlay pass exactly so the visible
+    // and occluded halves stay in phase. A raised cosine (0..1, peak once per cycle) raised to _XRayPulseShape
+    // rises from a long near-off plateau to a brief peak; _XRayPulseStrength sets how deep the trough dims
+    // (peak stays at the authored intensity). Speed 0 => cos term constant => steady glow.
+    half xrayCurve = pow(0.5h - 0.5h * cos(_Time.y * _XRayPulseSpeed), _XRayPulseShape);
+    half xrayPulse = 1.0h - _XRayPulseStrength * (1.0h - xrayCurve);
     color.rgb += _XRayColor.rgb * (_XRayColor.a * xrayPulse);
 
     color.a = OutputAlpha(color.a, IsSurfaceTypeTransparent(_Surface));

Assets/Shaders/PlayerCamoLit.shader

@@ -62,10 +62,13 @@ Shader "Custom/PlayerCamoLit"
         [HDR] _XRayColor("X-Ray Overlay Color", Color) = (0,0,0,0)
 
         // Optional breathing pulse for the X-ray glow (driven by _Time). Speed 0 => steady, identical to
-        // no pulse; strength = modulation depth around the authored intensity. Applied identically to the
-        // visible (ForwardLit) and occluded (XRayOverlay) halves so they stay in phase.
+        // no pulse; strength = modulation depth (how far the trough dims below the peak). Shape bends the
+        // pulse into an asymmetric curve: 1 = smooth (raised-cosine) breathe, higher = a longer near-off
+        // plateau that rises to a brief full-intensity peak. Applied identically to the visible (ForwardLit)
+        // and occluded (XRayOverlay) halves so they stay in phase.
         _XRayPulseSpeed("X-Ray Pulse Speed", Float) = 3
         _XRayPulseStrength("X-Ray Pulse Strength", Range(0,1)) = 0.5
+        _XRayPulseShape("X-Ray Pulse Shape", Range(1,8)) = 3
 
         _DetailMask("Detail Mask", 2D) = "white" {}
         _DetailAlbedoMapScale("Scale", Range(0.0, 2.0)) = 1.0
@@ -260,7 +263,8 @@ Shader "Custom/PlayerCamoLit"
             // SRP batcher, see PlayerCamo.hlsl), so there is no CBUFFER-layout match to keep here.
             half4 _XRayColor;
             half _XRayPulseSpeed;    // 0 = steady; otherwise breathing pulse via _Time (same math as the forward half)
-            half _XRayPulseStrength; // modulation depth of the pulse around the authored intensity
+            half _XRayPulseStrength; // modulation depth: how far the trough dims below the full-intensity peak
+            half _XRayPulseShape;    // >1 bends the pulse: longer near-off plateau, rising to a brief full peak
 
             struct XRayAttributes
             {
@@ -289,10 +293,11 @@ Shader "Custom/PlayerCamoLit"
             {
                 UNITY_SETUP_INSTANCE_ID(input);
                 UNITY_SETUP_STEREO_EYE_INDEX_POST_VERTEX(input);
-                // Flat additive glow: HDR rgb is the reveal color, alpha the fade/opacity master.
-                // Breathing pulse (sin over _Time) on the alpha master; kept in phase with the forward
-                // half via the shared _Time and identical math. Speed 0 => term is 1 => steady glow.
-                half xrayPulse = 1.0h + sin(_Time.y * _XRayPulseSpeed) * _XRayPulseStrength;
+                // Flat additive glow: HDR rgb is the reveal color, alpha the fade/opacity master. Asymmetric
+                // breathing pulse on the alpha master; kept in phase with the forward half via the shared
+                // _Time and identical math. Speed 0 => term is 1 => steady glow. See CamoForwardFragment.
+                half xrayCurve = pow(0.5h - 0.5h * cos(_Time.y * _XRayPulseSpeed), _XRayPulseShape);
+                half xrayPulse = 1.0h - _XRayPulseStrength * (1.0h - xrayCurve);
                 return half4(_XRayColor.rgb, _XRayColor.a * xrayPulse);
             }
             ENDHLSL