From cf7a31691e0988c82018e14ca310e999015b4b5a Mon Sep 17 00:00:00 2001
From: Chris Iverach-Brereton <civerachb@clearpathrobotics.com>
Date: Fri, 2 Aug 2024 13:16:31 -0400
Subject: [PATCH] The lidar is mounted sideways; restrict the FoV to the
 robot's front arc, not the sensor's

---
 turtlebot4_description/urdf/sensors/rplidar.urdf.xacro | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/turtlebot4_description/urdf/sensors/rplidar.urdf.xacro b/turtlebot4_description/urdf/sensors/rplidar.urdf.xacro
index 5e0d5c8..ff87edd 100644
--- a/turtlebot4_description/urdf/sensors/rplidar.urdf.xacro
+++ b/turtlebot4_description/urdf/sensors/rplidar.urdf.xacro
@@ -36,11 +36,13 @@
 
   <gazebo reference="${name}_link">
     <!--
-      GPU Ray sensor plugin only supports 180 degrees, so limig to the front arc only
+      GPU Ray sensor plugin only supports 180 degrees, so limit to the "front" arc only
+      The lidar is actually mounted sideways on the robot, with +x to the left, so the
+      front arc is actually 0 to -pi
     -->
     <xacro:ray_sensor sensor_name="${name}" gazebo="${gazebo}" 
                   update_rate="62.0" visualize="1" 
-                  h_samples="640" h_res="1.0" h_min_angle="${-pi/2}" h_max_angle="${pi/2}" 
+                  h_samples="640" h_res="1.0" h_min_angle="${-pi}" h_max_angle="0" 
                   r_min="0.164" r_max="12.0" r_res="0.01">
                   <plugin name="dummy" filename="dummyfile"></plugin>
     </xacro:ray_sensor>