Lamia & Segmented Entity System

Content.Client/DeltaV/Lamiae/SnakeOverlay.cs

@@ -0,0 +1,178 @@
+using Content.Shared.SegmentedEntity;
+using Content.Shared.Humanoid;
+using Content.Shared.Humanoid.Markings;
+using Content.Client.Resources;
+using Robust.Client.ResourceManagement;
+using Robust.Client.Graphics;
+using Robust.Shared.Enums;
+using System.Numerics;
+using System.Linq;
+
+
+namespace Content.Client.Lamiae;
+
+/// <summary>
+/// This draws lamia segments directly from polygons instead of sprites. This is a very novel approach as of the time this is being written (August 2024) but it wouldn't surprise me
+/// if there's a better way to do this at some point. Currently we have a very heavy restriction on the tools we can make, forcing me to make several helpers that may be redundant later.
+/// This will be overcommented because I know you haven't seen code like this before and you might want to copy it.
+/// This is an expansion on some techniques I discovered in (https://github.com/Elijahrane/Delta-v/blob/49d76c437740eab79fc622ab50d628b926e6ddcb/Content.Client/DeltaV/Arcade/S3D/Renderer/S3DRenderer.cs)
+/// </summary>
+public sealed class SnakeOverlay : Overlay
+{
+    private readonly IResourceCache _resourceCache;
+    private readonly IEntityManager _entManager;
+    private readonly SharedTransformSystem _transform;
+    private readonly SharedHumanoidAppearanceSystem _humanoid = default!;
+
+    // Look through these carefully. WorldSpace is useful for debugging. Note that this defaults to "screen space" which breaks when you try and get the world handle.
+    public override OverlaySpace Space => OverlaySpace.WorldSpaceEntities;
+
+    // Overlays are strange and you need this pattern where you define readonly deps above, and then make a constructor with this pattern. Anything that creates this overlay will then
+    // have to provide all the deps.
+    public SnakeOverlay(IEntityManager entManager, IResourceCache resourceCache)
+    {
+        _resourceCache = resourceCache;
+        // we get ent manager from SnakeOverlaySystem turning this on and passing it
+        _entManager = entManager;
+        // with ent manager we can fetch our other entity systems
+        _transform = _entManager.EntitySysManager.GetEntitySystem<SharedTransformSystem>();
+        _humanoid = _entManager.EntitySysManager.GetEntitySystem<SharedHumanoidAppearanceSystem>();
+
+        // draw at drawdepth 3
+        ZIndex = 3;
+    }
+
+    // This step occurs each frame. For some overlays you may want to conisder limiting how often they update, but for player entities that move around fast we'll just do it every frame.
+    protected override void Draw(in OverlayDrawArgs args)
+    {
+        // load the handle, the "pen" we draw with
+        var handle = args.WorldHandle;
+
+        // Get all lamiae the client knows of and their transform in a way we can enumerate over
+        var enumerator = _entManager.AllEntityQueryEnumerator<SegmentedEntityComponent, TransformComponent>();
+
+        // I go over the collection above, pulling out an EntityUid and the two components I need for each.
+        while (enumerator.MoveNext(out var uid, out var lamia, out var xform))
+        {
+            // Skip ones that are off-map. "Map" in this context means interconnected stuff you can travel between by moving, rather than needing e.g. FTL to load a new map.
+            if (xform.MapID != args.MapId)
+                continue;
+
+            // Skip ones where they are not loaded properly, uninitialized, or w/e
+            if (lamia.Segments.Count < lamia.NumberOfSegments)
+            {
+                _entManager.Dirty(uid, lamia); // pls give me an update...
+                continue;
+            }
+
+            // By the way, there's a hack to mitigate overdraw somewhat. Check out whatever is going on with the variable called "bounds" in DoAfterOverlay.
+            // I won't do it here because (1) it's ugly and (2) theoretically these entities can be fucking huge and you'll see the tail end of them when they are way off screen.
+            // On a PVS level I think segmented entities should be all-or-nothing when it comes to PVS range, that is you either load all of their segments or none.
+
+            // Color.White is drawing without modifying color. For clothed tails, we should use White. For skin, we should use the color of the marking.
+            // TODO: Better way to cache this
+            if (_entManager.TryGetComponent<HumanoidAppearanceComponent>(uid, out var humanoid))
+            {
+                if (humanoid.MarkingSet.TryGetCategory(MarkingCategories.Tail, out var tailMarkings))
+                {
+                    var col = tailMarkings.First().MarkingColors.First();
+                    DrawLamia(handle, lamia, col);
+                }
+            }
+            else
+            {
+                DrawLamia(handle, lamia, Color.White);
+            }
+        }
+    }
+
+    // This is where we do the actual drawing.
+    private void DrawLamia(DrawingHandleWorld handle, SegmentedEntityComponent lamia, Color color)
+    {
+        // We're going to store all our verticies in here and then draw them
+        List<DrawVertexUV2D> verts = new List<DrawVertexUV2D>();
+
+        // Radius of the initial segment
+        float radius = lamia.InitialRadius;
+
+        // We're storing the left and right verticies of the last segment so we can start drawing from there without gaps
+        Vector2? lastPtCW = null;
+        Vector2? lastPtCCW = null;
+
+        var tex = _resourceCache.GetTexture(lamia.TexturePath);
+
+        int i = 1;
+        // do each segment except the last one normally
+        while (i < lamia.Segments.Count - 1)
+        {
+            // get centerpoints of last segment and this one
+            var origin = _transform.GetWorldPosition(_entManager.GetEntity(lamia.Segments[i - 1]));
+            var destination = _transform.GetWorldPosition(_entManager.GetEntity(lamia.Segments[i]));
+
+            // get direction between the two points and normalize it
+            var connectorVec = destination - origin;
+            connectorVec = connectorVec.Normalized();
+
+            //get one rotated 90 degrees clockwise
+            var offsetVecCW = new Vector2(connectorVec.Y, 0 - connectorVec.X);
+
+            //and counterclockwise
+            var offsetVecCCW = new Vector2(0 - connectorVec.Y, connectorVec.X);
+
+            /// tri 1: line across first segment and corner of second
+            if (lastPtCW == null)
+            {
+                verts.Add(new DrawVertexUV2D(origin + offsetVecCW * radius, Vector2.Zero));
+            }
+            else
+            {
+                verts.Add(new DrawVertexUV2D((Vector2) lastPtCW, Vector2.Zero));
+            }
+
+            if (lastPtCCW == null)
+            {
+                verts.Add(new DrawVertexUV2D(origin + offsetVecCCW * radius, new Vector2(1, 0)));
+            }
+            else
+            {
+                verts.Add(new DrawVertexUV2D((Vector2) lastPtCCW, new Vector2(1, 0)));
+            }
+
+            verts.Add(new DrawVertexUV2D(destination + offsetVecCW * radius, new Vector2(0, 1)));
+
+            // tri 2: line across second segment and corner of first
+            if (lastPtCCW == null)
+            {
+                verts.Add(new DrawVertexUV2D(origin + offsetVecCCW * radius, new Vector2(1, 0)));
+            }
+            else
+            {
+                verts.Add(new DrawVertexUV2D((Vector2) lastPtCCW, new Vector2(1, 0)));
+            }
+
+            lastPtCW = destination + offsetVecCW * radius;
+            verts.Add(new DrawVertexUV2D((Vector2) lastPtCW, new Vector2(0, 1)));
+            lastPtCCW = destination + offsetVecCCW * radius;
+            verts.Add(new DrawVertexUV2D((Vector2) lastPtCCW, new Vector2(1, 1)));
+
+            // slim down a bit for next segment
+            radius *= lamia.SlimFactor;
+
+            i++;
+        }
+
+        // draw tail (1 tri)
+        if (lastPtCW != null && lastPtCCW != null)
+        {
+            verts.Add(new DrawVertexUV2D((Vector2) lastPtCW, new Vector2(0, 0)));
+            verts.Add(new DrawVertexUV2D((Vector2) lastPtCCW, new Vector2(1, 0)));
+
+            var destination = _transform.GetWorldPosition(_entManager.GetEntity(lamia.Segments.Last()));
+
+            verts.Add(new DrawVertexUV2D(destination, new Vector2(0.5f, 1f)));
+        }
+
+        // Draw all of the triangles we just pit in at once
+        handle.DrawPrimitives(DrawPrimitiveTopology.TriangleList, texture: tex, verts.ToArray().AsSpan(), color);
+    }
+}

Content.Client/DeltaV/Lamiae/SnakeOverlaySystem.cs

@@ -0,0 +1,26 @@
+using Robust.Client.Graphics;
+using Robust.Client.ResourceManagement;
+
+namespace Content.Client.Lamiae;
+
+/// <summary>
+/// This system turns on our always-on overlay. I have no opinion on this design pattern or the existence of this file.
+/// It also fetches the deps it needs.
+/// </summary>
+public sealed class SnakeOverlaySystem : EntitySystem
+{
+    [Dependency] private readonly IOverlayManager _overlay = default!;
+    [Dependency] private readonly IResourceCache _resourceCache = default!;
+
+    public override void Initialize()
+    {
+        base.Initialize();
+        _overlay.AddOverlay(new SnakeOverlay(EntityManager, _resourceCache));
+    }
+
+    public override void Shutdown()
+    {
+        base.Shutdown();
+        _overlay.RemoveOverlay<SnakeOverlay>();
+    }
+}

Content.Server/Shuttles/Systems/ShuttleSystem.FasterThanLight.cs

@@ -11,6 +11,7 @@
 using Content.Shared.Ghost;
 using Content.Shared.Maps;
 using Content.Shared.Parallax;
+using Content.Shared.SegmentedEntity;
 using Content.Shared.Shuttles.Components;
 using Content.Shared.Shuttles.Systems;
 using Content.Shared.StatusEffect;
@@ -639,7 +640,9 @@ private void KnockOverKids(TransformComponent xform, ref ValueList<EntityUid> to
         var childEnumerator = xform.ChildEnumerator;
         while (childEnumerator.MoveNext(out var child))
         {
-            if (!_buckleQuery.TryGetComponent(child, out var buckle) || buckle.Buckled)
+            if (!_buckleQuery.TryGetComponent(child, out var buckle) || buckle.Buckled
+            || HasComp<SegmentedEntityComponent>(child)
+            || HasComp<SegmentedEntitySegmentComponent>(child))
                 continue;
 
             toKnock.Add(child);

Content.Server/Teleportation/PortalSystem.cs

@@ -1,4 +1,4 @@
-using Content.Shared.Administration.Logs;
+using Content.Shared.Administration.Logs;
 using Content.Shared.Database;
 using Content.Shared.Ghost;
 using Content.Shared.Mind.Components;

Content.Server/Weapons/Ranged/Systems/GunSystem.cs

@@ -203,7 +203,13 @@ public override void Shoot(EntityUid gunUid, GunComponent gun, List<(EntityUid?
                             if (!rayCastResults.Any())
                                 break;
 
-                            var result = rayCastResults[0];
+                            var raycastEvent = new HitScanAfterRayCastEvent(rayCastResults);
+                            RaiseLocalEvent(lastUser, ref raycastEvent);
+
+                            if (raycastEvent.RayCastResults == null)
+                                break;
+
+                            var result = raycastEvent.RayCastResults[0];
                             var hit = result.HitEntity;
                             lastHit = hit;
 

Content.Shared/Roles/StartingGearPrototype.cs

@@ -43,6 +43,7 @@ public string GetGear(string slot, HumanoidCharacterProfile? profile)
             {
                 case "jumpsuit" when profile.Clothing == ClothingPreference.Jumpskirt && !string.IsNullOrEmpty(InnerClothingSkirt):
                 case "jumpsuit" when profile.Species == "Harpy" && !string.IsNullOrEmpty(InnerClothingSkirt):
+                case "jumpsuit" when profile.Species == "Lamia" && !string.IsNullOrEmpty(InnerClothingSkirt):
                     return InnerClothingSkirt;
                 case "back" when profile.Backpack == BackpackPreference.Satchel && !string.IsNullOrEmpty(Satchel):
                     return Satchel;

Content.Shared/SegmentedEntity/SegmentSpawnedEvent.cs

@@ -0,0 +1,11 @@
+namespace Content.Shared.SegmentedEntity;
+
+public sealed class SegmentSpawnedEvent : EntityEventArgs
+{
+    public EntityUid Lamia = default!;
+
+    public SegmentSpawnedEvent(EntityUid lamia)
+    {
+        Lamia = lamia;
+    }
+}

Content.Shared/SegmentedEntity/SegmentedEntityComponent.cs

@@ -0,0 +1,101 @@
+using Robust.Shared.GameStates;
+
+namespace Content.Shared.SegmentedEntity;
+
+/// <summary>
+///     Controls initialization of any Multi-segmented entity
+/// </summary>
+[RegisterComponent, NetworkedComponent]
+[AutoGenerateComponentState]
+public sealed partial class SegmentedEntityComponent : Component
+{
+    /// <summary>
+    ///     A list of each UID attached to the Lamia, in order of spawn
+    /// </summary>
+    [DataField, AutoNetworkedField]
+    public List<NetEntity> Segments = new();
+
+    /// <summary>
+    ///     A clamped variable that represents the number of segments to be spawned
+    /// </summary>
+    [DataField]
+    public int NumberOfSegments = 18;
+
+    /// <summary>
+    ///     How wide the initial segment should be.
+    /// </summary>
+    [DataField]
+    public float InitialRadius = 0.3f;
+
+    /// <summary>
+    ///     Texture of the segment.
+    /// </summary>
+    [DataField(required: true)]
+    public string TexturePath;
+
+    /// <summary>
+    ///     If UseTaperSystem is true, this constant represents the rate at which a segmented entity will taper towards the tip. Tapering is on a logarithmic scale, and will asymptotically approach 0.
+    /// </summary>
+    [DataField]
+    public float OffsetConstant = 1.03f;
+
+    /// <summary>
+    ///     Represents the prototype used to parent all segments
+    /// </summary>
+    [DataField]
+    public string InitialSegmentId = "LamiaInitialSegment";
+
+    /// <summary>
+    ///     Represents the segment prototype to be spawned
+    /// </summary>
+    [DataField]
+    public string SegmentId = "LamiaSegment";
+
+    /// <summary>
+    ///     How much to slim each successive segment.
+    /// </summary>
+    [DataField]
+    public float SlimFactor = 0.93f;
+
+    /// <summary>
+    ///     Set to false for constant width
+    /// </summary>
+    [DataField]
+    public bool UseTaperSystem = true;
+
+    /// <summary>
+    ///     The standard distance between the centerpoint of each segment.
+    /// </summary>
+    [DataField]
+    public float StaticOffset = 0.15f;
+
+    /// <summary>
+    ///     The standard sprite scale of each segment.
+    /// </summary>
+    [DataField]
+    public float StaticScale = 1f;
+
+    /// <summary>
+    ///     Used to more finely tune how much damage should be transfered from tail to body.
+    /// </summary>
+    [DataField]
+    public float DamageModifierOffset = 0.4f;
+
+    /// <summary>
+    ///     A clamped variable that represents how far from the tip should tapering begin.
+    /// </summary>
+    [DataField]
+    public int TaperOffset = 18;
+
+    /// <summary>
+    ///     Coefficient used to finely tune how much explosion damage should be transfered to the body. This is calculated multiplicatively with the derived damage modifier set.
+    /// </summary>
+    [DataField]
+    public float ExplosiveModifierOffset = 0.1f;
+
+    /// <summary>
+    ///     Controls whether or not lamia segments always block bullets, or use the bullet passover system for laying down bodies.
+    /// </summary>
+    [DataField]
+    public bool BulletPassover = true;
+}