Unity is a multi-platform game development engine used by the majority of game developers. It enables you to create and distribute 2D and 3D games and other graphics applications.
At ARM, we care about game developers. We know we can now achieve console quality games on mobile platforms and we therefore compiled the “ARM Guide for Unity Developers”, a compilation of best practises and optimized techniques to get the most from an ARM mobile platform. Whether you are anything from a beginner to an advanced Unity user, you will find the advice you need to increase the FPS in your graphics app.
The guide starts by covering the optimization process, so that developers learn the optimal quality settings and the fundamentals of the optimization process. It showcases how to use the Unity Profiler and Debugger as well as the ARM developer tools (ARM Mali Graphics Debugger and Streamline).
The profiler is used as a first step, to take measurements of the graphics application and analyze the data to locate any code bottlenecks. Then, we determine the relevant optimization to apply, and finally the developer needs to verify that the optimization works.
The guide dedicates a whole sub-chapter to another very useful ARM tool for Unity developers; the Mali Offline Shader Compiler, which enables developers to compile vertex, fragment and compute shaders into a binary form. Also, it provides information about the number of cycles the shaders are required to execute in each pipeline of the Mali GPU, so that developers can analyze and optimize for ARM Mali GPUs.
The optimizations chapter includes everything from ARM Cortex application processor optimizations with code snippets and settings examples, to Mali GPU optimizations as well as asset optimizations.
The Mali GPU optimization techniques include:
LOD group settings
Developers can optimize their application further by using asset optimizations and a whole sub-chapter addresses this, covering how to most effectively prepare textures and texture atlases, meshes and animations.
The Unity engine supports Global Illumination (GI) using Enlighten from v5 onwards. Enlighten is the Geomerics real-time GI solution.
Enlighten in Unity can be used for baking light maps, light probes and for real-time, indirect lighting. The Enlighten components are not explicitly exposed in Unity, but they are referenced in the user interface and the guide therefore also explains what they are and how they work together.
The Enlighten section also explains how to configure Enlighten in custom shaders, the code flow and what developers need to do to set up Enlighten in the vertex and fragment shader code. It showcases a version of the Unity Standard Shader that is modified to include directional global illumination.
Enlighten Lightmap Images: above left - Ice Cave demo, above right – its UV Chart lightmap, below left – its Irradiance lightmap, below right – its directionality lightmap
Chapter 6, the longest chapter of the guide, explains Advanced Graphics Techniques. These techniques are mainly implemented using “Custom Shaders” as the Unity source code of built-in shaders does not include the majority of advanced effects. The chapter starts by describing how to write and debug custom shaders and then goes on to explain how to implement advanced graphics techniques used in the Ice Cave and Chess Room demos. It also shows source code snippets:
Combining Different Types of Reflections
Last but not least, the last chapter of the guide covers the best coding practises when developing graphics applications for Mobile Virtual Reality.
Unity natively supports some VR devices like the Samsung Gear VR and plug-ins can enable support of other devices like the Google Cardboard. The guide describes how to port a graphics application onto native Unity VR.
Screenshot from a VR application running in Samsung Gear VR developer mode
VR creates a more immersive user experienced compared to running the graphics application from your smartphone or tablet and therefore, camera animations might not feel comfortable for the user in VR. Also, VR can benefit from controllers that connect to the VR device using Bluetooth. Tips and methods to create the ultimate user experience are described in the guide.
A whole sub-chapter is dedicated to how to implement reflections in VR. They can use the same local cubemap technique explained earlier in the Advanced Graphics Techniques chapter. However, the technique must be modified to work with the stereo visual output that a user sees. This chapter therefore explains how to implement stereo reflections as well as combining different types of reflections.
ARM guide for Unity developers