Add setting for near plane distance. (#6395)

* Allow setting the near plane

* - Add near_plane limit of 0.5 to prevent x-ray.
- Add more details to near_plane setting.

builtin/settingtypes.txt

@@ -532,6 +532,12 @@ pause_fps_max (FPS in pause menu) int 20
 #    View distance in nodes.
 viewing_range (Viewing range) int 100 20 4000
 
+#   Camera near plane distance in nodes, between 0 and 0.5
+#   Most users will not need to change this.
+#   Increasing can reduce artifacting on weaker GPUs.
+#   0.1 = Default, 0.25 = Good value for weaker tablets.
+near_plane (Near plane) float 0.1 0 0.5
+
 #    Width component of the initial window size.
 screen_w (Screen width) int 1024
 

src/camera.cpp

@@ -549,7 +549,9 @@ void Camera::update(LocalPlayer* player, f32 frametime, f32 busytime, f32 tool_r
 void Camera::updateViewingRange()
 {
 	f32 viewing_range = g_settings->getFloat("viewing_range");
+	f32 near_plane = g_settings->getFloat("near_plane");
 	m_draw_control.wanted_range = viewing_range;
+	m_cameranode->setNearValue(rangelim(near_plane, 0.0f, 0.5f) * BS);
 	if (m_draw_control.range_all) {
 		m_cameranode->setFarValue(100000.0);
 		return;

src/defaultsettings.cpp

@@ -149,6 +149,7 @@ void set_default_settings(Settings *settings)
 	settings->setDefault("fps_max", "60");
 	settings->setDefault("pause_fps_max", "20");
 	settings->setDefault("viewing_range", "100");
+	settings->setDefault("near_plane", "0.1");
 	settings->setDefault("screen_w", "1024");
 	settings->setDefault("screen_h", "600");
 	settings->setDefault("autosave_screensize", "true");