.. _3 	Known Issues:

3 	Known Issues
===============================

This chapter describes issues identified when using the Pico Unreal SDK. Please check accordingly.  

- "Virtual reality preview" in the scene editor is not supported.

.. image:: _static/3.1.png

Figure 3.1  Does not support virtual reality preview

- Checking HDR option might introduce issues such as fuzzy images, rendering lag (during head movements), screen mosaics etc. Unchecking Mobile HDR is recommended ：

.. image:: _static/3.2.png

Figure 3.2 Uncheck Mobile HDR 

- In Git project management, it is recommended to delete .so and .jar in the file .gitignore. 

.. image:: _static/3.3.png

Figure 3.3 Delete the .so tag

The PicoVR plugin contains .so and .jar files. When using git or other software for project maintenance, developers should not ignore the .so and .jar files in .gitignore. Deleting these two is recommended. 

- Frame rate limitation in UE4.24 will cause time-flow anomalies.

.. image:: _static/3.4.png

Figure 3.4 Unreal frame rate limit option

In version 4.24, if you check the two checkboxes above or use corresponding methods in C++ code to limit frames, it will cause an abnormal time flow rate in the game, which is a problem of version 4.24. It is recommended that developers do not use either of these methods for frame-limiting operations within this release, or choose to use another engine version.

- Version 4.24 has deprecated OpenGLES2, so it is recommended that developers do not use OpenGLES2 for packaging when developing with version 4.24, as this may lead to issues, such as  crashing in certain levels.

- In 4.24 and higher versions, there is the built-in TimeOfDay scene in the newly created scene. It is designed for diplaying the rendering capability of PC end and it is not recommended to use this scene on the mobile end.

- It is recommended to delete Daydream-related settings under Project Settings-Android-Advanced APK Packaging and package for Oculus mobile devices, as shown below:

.. image:: _static/3.5.png

Figure 3.5 Delete related settings

Known issues: 

1. Under non-Shipping mode of version 4.26, adding Landscape and modifying its number of component property will cause a crash.

2. CastModulatedShadows is not supported currently. Using CastModulatedShadows will cause abnormal shadows. Please disable CastModulatedShadows when using Directional light.