From 75af2c15c7adda08fbe49f930cd15b7ecdf26453 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emmanuel=20Beno=C3=AEt?= <tseeker@nocternity.net>
Date: Mon, 20 Nov 2017 11:26:53 +0100
Subject: [PATCH] Overrides - Fixed NaN in camera handling

---
 camera.cc | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/camera.cc b/camera.cc
index 5e0f21a..940ff75 100644
--- a/camera.cc
+++ b/camera.cc
@@ -48,14 +48,19 @@ void T_Camera::cvtAnglesToVectors( ) noexcept
 void T_Camera::cvtVectorsToAngles( ) noexcept
 {
 	dir_ = lookAt_ - pos_;
-	distance_ = glm::length( dir_ );
-	if ( distance_ == 0 ) {
-		angles_ = glm::vec3( 0 );
+	const float distance{ length( dir_ ) };
+	if ( distance == 0 || length( up_ ) == 0 ) {
+		return;
+	}
+	distance_ = distance;
+
+	const glm::vec3 nDir{ - dir_ / distance_ };
+	const glm::vec3 nUp{ normalize( up_ ) };
+	if ( abs( dot( nUp , nDir ) ) == 1 ) {
 		return;
 	}
 
-	const glm::vec3 nDir{ - dir_ / distance_ };
-	const glm::vec3 side{ normalize( cross( normalize( up_ ) , nDir ) ) };
+	const glm::vec3 side{ normalize( cross( nUp , nDir ) ) };
 	const glm::vec3 up{ normalize( cross( nDir , side ) ) };
 	column( rotMat_ , 0 ) = side;
 	column( rotMat_ , 1 ) = up;