From 6834ea10320ab9a479bc511af540dedeecaa5629 Mon Sep 17 00:00:00 2001
From: Pascal Grittmann <grittmann@cg.uni-saarland.de>
Date: Thu, 8 Aug 2024 17:03:54 +0200
Subject: [PATCH] docs

---
 SeeSharp/Shading/Background/Background.cs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/SeeSharp/Shading/Background/Background.cs b/SeeSharp/Shading/Background/Background.cs
index a6730a4..5ea816a 100644
--- a/SeeSharp/Shading/Background/Background.cs
+++ b/SeeSharp/Shading/Background/Background.cs
@@ -13,6 +13,12 @@ public abstract class Background {
 
     public abstract BackgroundSample SampleDirection(Vector2 primary);
     public abstract Vector2 SampleDirectionInverse(Vector3 Direction);
+
+    /// <summary>
+    /// Computes the PDF for sampling a given direction from the background
+    /// </summary>
+    /// <param name="Direction">Direction from the scene towards the background</param>
+    /// <returns>Solid angle PDF</returns>
     public abstract float DirectionPdf(Vector3 Direction);
     public abstract (Ray, RgbColor, float) SampleRay(Vector2 primaryPos, Vector2 primaryDir);
     public abstract (Vector2, Vector2) SampleRayInverse(Vector3 dir, Vector3 pos);