Hunter shot: replicated laser beam + X-ray hit flash; snapshot apply in-place reseed

- Laser.shader + HunterLaserBeam: additive HDR beam, fade in/out over opacity
  and thickness, code-driven LineRenderer, tunable emission multiplier.
- FirstPersonMode: TryShoot computes world endpoint, fires beam with lateral
  muzzle offset (right) so it isn't dead-center from hunter view.
- NetworkPlayerSetup: shot relay RPCs (owner->server->all) + hit-flash RPC
  (server->all), flash OR-branch in ComputeXRay.
- MatchManager: hit reveal broadcasts X-ray flash first, delays hider removal
  by hitRevealDelay so the glow is visible before the body vanishes.
- MeshPainter reseed: in-place fast path avoids full GPU backend teardown on
  snapshot apply (no ~70MB RT churn), fixes spawn/paint-load hitch.

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

Assets/Scripts/Components/HunterLaserBeam.cs

@@ -0,0 +1,135 @@
+using UnityEngine;
+using UnityEngine.Rendering;
+
+/// <summary>
+/// Momentary world-space laser beam for a hunter's shot. Purely visual (no networking): a LineRenderer drawn
+/// from the muzzle to the hit point that fades IN fast then OUT over its lifetime, animating both opacity
+/// (via per-vertex colour alpha, read by the Chameleon/Laser shader) and thickness (via widthMultiplier).
+/// Self-contained: it builds its own LineRenderer child + an additive material at runtime, so it can be added
+/// to a hunter avatar purely in code with no prefab authoring. Call <see cref="Fire"/> to trigger; the beam
+/// recycles itself (disables the renderer) once it expires.
+/// </summary>
+[DisallowMultipleComponent]
+public sealed class HunterLaserBeam : MonoBehaviour
+{
+    [Header("Look")]
+    [ColorUsage(true, true)]
+    [Tooltip("HDR beam tint. Its alpha is ignored - the animated opacity envelope drives visibility.")]
+    [SerializeField] private Color color = new Color(1f, 0.25f, 0.25f, 1f);
+
+    [Tooltip("HDR emission multiplier applied to the tint. >1 pushes the beam past LDR into bloom.")]
+    [Min(0f)]
+    [SerializeField] private float emission = 6f;
+
+    [Tooltip("Peak beam thickness in world units (the width envelope scales this).")]
+    [Min(0f)]
+    [SerializeField] private float maxWidth = 0.06f;
+
+    [Tooltip("Optional material override. Empty -> a built-in additive laser material (Chameleon/Laser) is created at runtime.")]
+    [SerializeField] private Material materialOverride;
+
+    [Header("Timing")]
+    [Tooltip("Total beam lifetime in seconds (fade-in + fade-out).")]
+    [Min(0.01f)]
+    [SerializeField] private float lifetime = 0.5f;
+
+    [Tooltip("Fraction of the lifetime spent fading IN (the rest fades out).")]
+    [Range(0f, 1f)]
+    [SerializeField] private float fadeInFraction = 0.2f;
+
+    [Tooltip("Thickness floor as a fraction of maxWidth at the envelope's ends, so the beam never pinches to a dot.")]
+    [Range(0f, 1f)]
+    [SerializeField] private float minWidthFraction = 0.35f;
+
+    private LineRenderer _line;
+    private Material _material;
+    private bool _ownsMaterial;
+    private float _age;
+    private bool _active;
+
+    private static readonly int ColorId = Shader.PropertyToID("_Color");
+
+    private void Awake()
+    {
+        var go = new GameObject("LaserBeamLine");
+        go.transform.SetParent(transform, false);
+
+        _line = go.AddComponent<LineRenderer>();
+        _line.useWorldSpace = true;           // endpoints are fixed world points; the beam ignores avatar motion
+        _line.positionCount = 2;
+        _line.numCapVertices = 2;
+        _line.numCornerVertices = 0;
+        _line.alignment = LineAlignment.View;
+        _line.textureMode = LineTextureMode.Stretch;
+        _line.shadowCastingMode = ShadowCastingMode.Off;
+        _line.receiveShadows = false;
+        _line.lightProbeUsage = LightProbeUsage.Off;
+        _line.reflectionProbeUsage = ReflectionProbeUsage.Off;
+
+        if (materialOverride)
+        {
+            _material = materialOverride;
+        }
+        else
+        {
+            _material = new Material(Shader.Find("Chameleon/Laser"));
+            _ownsMaterial = true;
+        }
+        _line.material = _material;
+        if (_material && _material.HasProperty(ColorId))
+        {
+            Color hdr = color * emission;   // push the tint into HDR so bloom picks it up
+            hdr.a = 1f;                     // alpha is unused by the additive shader
+            _material.SetColor(ColorId, hdr);
+        }
+
+        _line.enabled = false;
+    }
+
+    /// <summary>Fires a one-shot beam along the given world-space segment; restarts the animation if already running.</summary>
+    public void Fire(Vector3 start, Vector3 end)
+    {
+        if (!_line) return;
+        _line.SetPosition(0, start);
+        _line.SetPosition(1, end);
+        _age = 0f;
+        _active = true;
+        _line.enabled = true;
+        ApplyEnvelope(0f);
+    }
+
+    private void Update()
+    {
+        if (!_active) return;
+        _age += Time.deltaTime;
+        float t = lifetime > 0f ? _age / lifetime : 1f;
+        if (t >= 1f)
+        {
+            _active = false;
+            _line.enabled = false;
+            return;
+        }
+        ApplyEnvelope(t);
+    }
+
+    // Maps normalized life t (0..1) to opacity + thickness: rises over fadeInFraction, then eases back down.
+    private void ApplyEnvelope(float t)
+    {
+        float inFrac = Mathf.Clamp01(fadeInFraction);
+        float e = t < inFrac
+            ? (inFrac > 0f ? t / inFrac : 1f)
+            : (inFrac < 1f ? 1f - (t - inFrac) / (1f - inFrac) : 1f);
+        e = Mathf.Clamp01(e);
+        e = e * e * (3f - 2f * e); // smoothstep for a softer ramp
+
+        _line.widthMultiplier = maxWidth * Mathf.Lerp(minWidthFraction, 1f, e);
+        var vc = new Color(1f, 1f, 1f, e); // hue from the material _Color; alpha carries the fade envelope
+        _line.startColor = vc;
+        _line.endColor = vc;
+    }
+
+    private void OnDestroy()
+    {
+        if (_ownsMaterial && _material) Destroy(_material);
+    }
+}

Assets/Scripts/Components/HunterLaserBeam.cs.meta

@@ -0,0 +1,2 @@
+fileFormatVersion: 2
+guid: 3755898ae12d28e4585f6e55547c768d

Assets/Scripts/Components/MeshPainter/MeshPainter.Backend.cs

@@ -32,11 +32,27 @@ public partial class MeshPainter
     }
 
     /// <summary>
-    /// Tears down the active backend and rebuilds it from externally supplied canonical maps (load /
-    /// late-join snapshot / undo). Runs the island/dilation seeding path so edge padding is rebuilt for
-    /// the new content. The input arrays are never mutated (SetupBackend clones its seed).
+    /// Re-seeds the backend from externally supplied canonical maps (load / late-join snapshot / undo),
+    /// rebuilding the island/dilation edge padding for the new content. The input arrays are never mutated
+    /// (both seed paths clone before touching a map).
+    ///
+    /// Fast path: when the backend is already built on this same type + size - the common runtime reseed
+    /// (remote snapshot apply, carry/library load, undo/redo) - the existing RTs/textures are re-filled in
+    /// place instead of a full teardown+rebuild. At 1024² a rebuild frees and re-creates nine ARGBHalf RTs
+    /// (~70 MB of GPU allocation) every call, which stalls the frame and shows up as a hitch on every
+    /// observer when a (freshly painted) avatar spawns. Re-seeding reuses the RTs (identical size/format)
+    /// for a bit-identical result. A pending GPU<->CPU switch or an un-built backend falls through to the
+    /// full rebuild.
     /// </summary>
-    private void ReseedCanonical(Color32[][] canonical) => RebuildBackend(useGpu, canonical);
+    private void ReseedCanonical(Color32[][] canonical)
+    {
+        if (_setupValid)
+        {
+            if (useGpu && _gpuActive && _gpu != null) { ReseedGpuInPlace(canonical); _hasLastScreen = false; return; }
+            if (!useGpu && !_gpuActive && _cpu != null) { ReseedCpuInPlace(canonical); _hasLastScreen = false; return; }
+        }
+        RebuildBackend(useGpu, canonical);
+    }
 
     /// <summary>Tears down the active backend and sets up the requested one on the given maps.</summary>
     private void RebuildBackend(bool gpu, Color32[][] canonical)

Assets/Scripts/Components/MeshPainter/MeshPainter.Cpu.cs

@@ -43,6 +43,27 @@ public partial class MeshPainter
         return px;
     }
 
+    /// <summary>
+    /// Re-seeds the ALREADY-built CPU maps from canonical data without recreating the Texture2D mirrors:
+    /// each map's pixel buffer + island guard are re-seeded and re-uploaded into the existing texture,
+    /// mirroring SetupCpu but reusing the textures. The GPU counterpart is ReseedGpuInPlace. Callers ensure
+    /// !_gpuActive && _cpu != null.
+    /// </summary>
+    private void ReseedCpuInPlace(Color32[][] canonical)
+    {
+        for (int mi = 0; mi < MAP_COUNT; mi++)
+        {
+            var cm = _cpu[mi];
+            cm.pixels = SeedCpuPixels(mi, canonical);
+            cm.painted = (bool[])GetIslandMask().Clone();
+            if (cm.fillStamp != null) System.Array.Clear(cm.fillStamp, 0, cm.fillStamp.Length);
+            cm.dilateStamp = 0;
+            cm.dx0 = textureSize; cm.dy0 = textureSize; cm.dx1 = -1; cm.dy1 = -1; // no pending dirty region
+            cm.tex.SetPixels32(cm.pixels);
+            cm.tex.Apply(false);
+        }
+    }
+
     private void TeardownCpu()
     {
         if (_cpu == null) return;

Assets/Scripts/Components/MeshPainter/MeshPainter.Gpu.cs

@@ -100,6 +100,23 @@ public partial class MeshPainter
         }
     }
 
+    /// <summary>
+    /// Re-seeds the ALREADY-built GPU maps from canonical data without recreating the RenderTextures or
+    /// materials: each map's display RT is re-uploaded + re-stamped (MSO re-packed) exactly as SetupGpu
+    /// does, but the existing RTs (same size/format) are reused, so the fur/albedo RTs a sibling
+    /// FurShellRenderer samples keep their references. Avoids the per-apply ~70 MB RT alloc/free churn a
+    /// full RebuildBackend incurs at 1024². Callers ensure _gpuActive && _gpu != null.
+    /// </summary>
+    private void ReseedGpuInPlace(Color32[][] canonical)
+    {
+        for (int mi = 0; mi < MAP_COUNT; mi++)
+        {
+            SeedGpuMap(mi, canonical);
+            var gm = _gpu[mi];
+            AssignMapTexture(mi, gm.final != null ? gm.final : gm.display);
+        }
+    }
+
     /// <summary>
     /// Stamps the dilation coverage guard into a map's alpha: rasterizes the mesh with the brush
     /// shader's coverage pass (pass 1), writing alpha = 1 on exactly the texels the GPU brush can