Fix render target caching in overlays (#40181)

Many newer overlays use IRenderTextures that are sized to the rendered viewport. This was completely broken, because a single viewport can be rendered on multiple viewports in a single frame.

The end result of this was that in the better case, constant render targets were allocated and freed, which is  extremely inefficient. In the worse case, many of these overlays completely failed to Dispose() their render targets, leading to *extremely* swift VRAM OOMs.

This fixes all the overlays to properly cache resources per viewport. This uses new engine functionality, so it requires engine master.

This is still a pretty lousy way to do GPU resource management but, well, anything better needs a render graph, so...

Content.Client/Overlays/StencilOverlay.cs

@@ -1,4 +1,5 @@
 using System.Numerics;
+using Content.Client.Graphics;
 using Content.Client.Parallax;
 using Content.Client.Weather;
 using Content.Shared.Salvage;
@@ -34,7 +35,7 @@ public sealed partial class StencilOverlay : Overlay
 
     public override OverlaySpace Space => OverlaySpace.WorldSpaceBelowFOV;
 
-    private IRenderTexture? _blep;
+    private readonly OverlayResourceCache<CachedResources> _resources = new();
 
     private readonly ShaderInstance _shader;
 
@@ -55,10 +56,12 @@ public sealed partial class StencilOverlay : Overlay
         var mapUid = _map.GetMapOrInvalid(args.MapId);
         var invMatrix = args.Viewport.GetWorldToLocalMatrix();
 
-        if (_blep?.Texture.Size != args.Viewport.Size)
+        var res = _resources.GetForViewport(args.Viewport, static _ => new CachedResources());
+
+        if (res.Blep?.Texture.Size != args.Viewport.Size)
         {
-            _blep?.Dispose();
-            _blep = _clyde.CreateRenderTarget(args.Viewport.Size, new RenderTargetFormatParameters(RenderTargetColorFormat.Rgba8Srgb), name: "weather-stencil");
+            res.Blep?.Dispose();
+            res.Blep = _clyde.CreateRenderTarget(args.Viewport.Size, new RenderTargetFormatParameters(RenderTargetColorFormat.Rgba8Srgb), name: "weather-stencil");
         }
 
         if (_entManager.TryGetComponent<WeatherComponent>(mapUid, out var comp))
@@ -69,16 +72,33 @@ public sealed partial class StencilOverlay : Overlay
                     continue;
 
                 var alpha = _weather.GetPercent(weather, mapUid);
-                DrawWeather(args, weatherProto, alpha, invMatrix);
+                DrawWeather(args, res, weatherProto, alpha, invMatrix);
             }
         }
 
         if (_entManager.TryGetComponent<RestrictedRangeComponent>(mapUid, out var restrictedRangeComponent))
         {
-            DrawRestrictedRange(args, restrictedRangeComponent, invMatrix);
+            DrawRestrictedRange(args, res, restrictedRangeComponent, invMatrix);
         }
 
         args.WorldHandle.UseShader(null);
         args.WorldHandle.SetTransform(Matrix3x2.Identity);
     }
+
+    protected override void DisposeBehavior()
+    {
+        _resources.Dispose();
+
+        base.DisposeBehavior();
+    }
+
+    private sealed class CachedResources : IDisposable
+    {
+        public IRenderTexture? Blep;
+
+        public void Dispose()
+        {
+            Blep?.Dispose();
+        }
+    }
 }