Drunk Shader (#8910)

Co-authored-by: Kara D <lunarautomaton6@gmail.com>
Co-authored-by: metalgearsloth <comedian_vs_clown@hotmail.com>

Content.Client/Drunk/DrunkOverlay.cs

@@ -0,0 +1,81 @@
+using Content.Shared.Drunk;
+using Content.Shared.StatusEffect;
+using Robust.Client.Graphics;
+using Robust.Client.Player;
+using Robust.Shared.Enums;
+using Robust.Shared.Prototypes;
+using Robust.Shared.Timing;
+
+namespace Content.Client.Drunk;
+
+public sealed class DrunkOverlay : Overlay
+{
+    [Dependency] private readonly IEntityManager _entityManager = default!;
+    [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
+    [Dependency] private readonly IPlayerManager _playerManager = default!;
+    [Dependency] private readonly IEntitySystemManager _sysMan = default!;
+
+    public override OverlaySpace Space => OverlaySpace.WorldSpace;
+    public override bool RequestScreenTexture => true;
+    private readonly ShaderInstance _drunkShader;
+
+    public float CurrentBoozePower = 0.0f;
+
+    private const float VisualThreshold = 10.0f;
+    private const float PowerDivisor = 250.0f;
+
+    private float _visualScale = 0;
+
+    public DrunkOverlay()
+    {
+        IoCManager.InjectDependencies(this);
+        _drunkShader = _prototypeManager.Index<ShaderPrototype>("Drunk").InstanceUnique();
+    }
+
+    protected override void FrameUpdate(FrameEventArgs args)
+    {
+        var playerEntity = _playerManager.LocalPlayer?.ControlledEntity;
+
+        if (playerEntity == null)
+            return;
+
+        if (!_entityManager.HasComponent<DrunkComponent>(playerEntity)
+            || !_entityManager.TryGetComponent<StatusEffectsComponent>(playerEntity, out var status))
+            return;
+
+        var statusSys = _sysMan.GetEntitySystem<StatusEffectsSystem>();
+        if (!statusSys.TryGetTime(playerEntity.Value, SharedDrunkSystem.DrunkKey, out var time, status))
+            return;
+
+        var timeLeft = (float) (time.Value.Item2 - time.Value.Item1).TotalSeconds;
+        CurrentBoozePower += (timeLeft - CurrentBoozePower) * args.DeltaSeconds / 16f;
+    }
+
+    protected override bool BeforeDraw(in OverlayDrawArgs args)
+    {
+        _visualScale = BoozePowerToVisual(CurrentBoozePower);
+        return _visualScale > 0;
+    }
+
+    protected override void Draw(in OverlayDrawArgs args)
+    {
+        if (ScreenTexture == null)
+            return;
+
+        var handle = args.WorldHandle;
+        _drunkShader.SetParameter("SCREEN_TEXTURE", ScreenTexture);
+        _drunkShader.SetParameter("boozePower", _visualScale);
+        handle.UseShader(_drunkShader);
+        handle.DrawRect(args.WorldBounds, Color.White);
+    }
+
+    /// <summary>
+    ///     Converts the # of seconds the drunk effect lasts for (booze power) to a percentage
+    ///     used by the actual shader.
+    /// </summary>
+    /// <param name="boozePower"></param>
+    private float BoozePowerToVisual(float boozePower)
+    {
+        return Math.Clamp((boozePower - VisualThreshold) / PowerDivisor, 0.0f, 1.0f);
+    }
+}