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code/Tool.Preview.cs

@@ -0,0 +1,92 @@
+using System.Collections.Generic;
+
+namespace Sandbox.Tools
+{
+	public partial class BaseTool
+	{
+		internal List<PreviewEntity> Previews;
+
+		protected virtual bool IsPreviewTraceValid( TraceResult tr )
+		{
+			if ( !tr.Hit )
+				return false;
+
+			if ( !tr.Entity.IsValid() )
+				return false;
+
+			return true;
+		}
+
+		public virtual void CreatePreviews()
+		{
+			// Nothing
+		}
+
+		public virtual void DeletePreviews()
+		{
+			if ( Previews == null || Previews.Count == 0 )
+				return;
+
+			foreach ( var preview in Previews )
+			{
+				preview.Delete();
+			}
+
+			Previews.Clear();
+		}
+
+
+		public virtual bool TryCreatePreview( ref PreviewEntity ent, string model )
+		{
+			if ( !ent.IsValid() )
+			{
+				ent = new PreviewEntity();
+				ent.SetModel( model );
+			}
+
+			if ( Previews == null )
+			{
+				Previews = new List<PreviewEntity>();
+			}
+
+			if ( !Previews.Contains( ent ) )
+			{
+				Previews.Add( ent );
+			}
+
+			return ent.IsValid();
+		}
+
+
+		private void UpdatePreviews()
+		{
+			if ( Previews == null || Previews.Count == 0 )
+				return;
+
+			if ( !Owner.IsValid() )
+				return;
+
+			var startPos = Owner.EyePos;
+			var dir = Owner.EyeRot.Forward;
+
+			var tr = Trace.Ray( startPos, startPos + dir * 10000.0f )
+				.Ignore( Owner )
+				.Run();
+
+			foreach ( var preview in Previews )
+			{
+				if ( !preview.IsValid() )
+					continue;
+
+				if ( IsPreviewTraceValid( tr ) && preview.UpdateFromTrace( tr ) )
+				{
+					preview.RenderAlpha = 0.5f;
+				}
+				else
+				{
+					preview.RenderAlpha = 0.0f;
+				}
+			}
+		}
+	}
+}