From cb4dcc53f14614a434429cfcde23bdee94414b59 Mon Sep 17 00:00:00 2001
From: jbb01 <32650546+jbb01@users.noreply.github.com>
Date: Thu, 8 Aug 2024 19:31:20 +0200
Subject: [PATCH] fix a bug in PdfUtil#getSolidAngle

---
 src/main/java/eu/jonahbauer/raytracing/scene/util/PdfUtil.java | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/main/java/eu/jonahbauer/raytracing/scene/util/PdfUtil.java b/src/main/java/eu/jonahbauer/raytracing/scene/util/PdfUtil.java
index efead20..09c0d4f 100644
--- a/src/main/java/eu/jonahbauer/raytracing/scene/util/PdfUtil.java
+++ b/src/main/java/eu/jonahbauer/raytracing/scene/util/PdfUtil.java
@@ -13,6 +13,7 @@ public final class PdfUtil {
         var j = b.minus(o).unit();
         var k = c.minus(o).unit();
 
-        return 2 * Math.atan(Math.abs(i.times(j.cross(k))) / (1 + i.times(j) + j.times(k) + k.times(i)));
+        var angle = 2 * Math.atan(Math.abs(i.times(j.cross(k))) / (1 + i.times(j) + j.times(k) + k.times(i)));
+        return angle < 0 ? 2 * Math.PI + angle : angle;
     }
 }