Decal placement preview (#13460)

Content.Client/Decals/Overlays/DecalOverlay.cs

@@ -0,0 +1,99 @@
+using Content.Shared.Decals;
+using Robust.Client.GameObjects;
+using Robust.Client.Graphics;
+using Robust.Shared.Enums;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Utility;
+
+namespace Content.Client.Decals.Overlays
+{
+    public sealed class DecalOverlay : Overlay
+    {
+        private readonly DecalSystem _decals;
+        private readonly SpriteSystem _sprites;
+        private readonly IEntityManager _entManager;
+        private readonly IPrototypeManager _prototypeManager;
+
+        public override OverlaySpace Space => OverlaySpace.WorldSpaceBelowEntities;
+
+        private readonly Dictionary<string, (Texture Texture, bool SnapCardinals)> _cachedTextures = new(64);
+
+        public DecalOverlay(
+            DecalSystem decals,
+            SpriteSystem sprites,
+            IEntityManager entManager,
+            IPrototypeManager prototypeManager)
+        {
+            _decals = decals;
+            _sprites = sprites;
+            _entManager = entManager;
+            _prototypeManager = prototypeManager;
+        }
+
+        protected override void Draw(in OverlayDrawArgs args)
+        {
+            // Shouldn't need to clear cached textures unless the prototypes get reloaded.
+            var handle = args.WorldHandle;
+            var xformQuery = _entManager.GetEntityQuery<TransformComponent>();
+            var eyeAngle = args.Viewport.Eye?.Rotation ?? Angle.Zero;
+
+            foreach (var (gridId, zIndexDictionary) in _decals.DecalRenderIndex)
+            {
+                if (zIndexDictionary.Count == 0)
+                    continue;
+
+                if (!xformQuery.TryGetComponent(gridId, out var xform))
+                {
+                    Logger.Error($"Tried to draw decals on a non-existent grid. GridUid: {gridId}");
+                    continue;
+                }
+
+                if (xform.MapID != args.MapId)
+                    continue;
+
+                var (_, worldRot, worldMatrix) = xform.GetWorldPositionRotationMatrix(xformQuery);
+
+                handle.SetTransform(worldMatrix);
+
+                foreach (var decals in zIndexDictionary.Values)
+                {
+                    foreach (var decal in decals.Values)
+                    {
+                        if (!_cachedTextures.TryGetValue(decal.Id, out var cache) && _prototypeManager.TryIndex<DecalPrototype>(decal.Id, out var decalProto))
+                        {
+                            var sprite = GetDecalSprite(decal.Id);
+                            cache = (_sprites.Frame0(sprite), decalProto.SnapCardinals);
+                            _cachedTextures[decal.Id] = cache;
+                        }
+
+                        var cardinal = Angle.Zero;
+
+                        if (cache.SnapCardinals)
+                        {
+                            var worldAngle = eyeAngle + worldRot;
+                            cardinal = worldAngle.GetCardinalDir().ToAngle();
+                        }
+
+                        var angle = decal.Angle - cardinal;
+
+                        if (angle.Equals(Angle.Zero))
+                            handle.DrawTexture(cache.Texture, decal.Coordinates, decal.Color);
+                        else
+                            handle.DrawTexture(cache.Texture, decal.Coordinates, angle, decal.Color);
+                    }
+                }
+            }
+
+            handle.SetTransform(Matrix3.Identity);
+        }
+
+        public SpriteSpecifier GetDecalSprite(string id)
+        {
+            if (_prototypeManager.TryIndex<DecalPrototype>(id, out var proto))
+                return proto.Sprite;
+
+            Logger.Error($"Unknown decal prototype: {id}");
+            return new SpriteSpecifier.Texture(new ResourcePath("/Textures/noSprite.png"));
+        }
+    }
+}