Android

• Unreal Engine Setup
• Plugin Setup
  • Handler
  • Material
  • Entities
• Single Channel

This tutorial explains how to enable LFOW for an Android project. However, all the provided instructions can also apply to laptops or consoles. It requires LFOW v1.5.0 and a complete Android setup (Android Studio, SDK, NDK, JDK, etc...).

Supporting Android is challenging, not because of the CPU, but due to the GPU load. Texture sampling and dynamic branching are too heavy for most mobile GPUs. To reduce usage, certain features have been disabled for mobile. If you follow this tutorial, the following features will not be available:

• Multifloor: Previously used textures to pass data; this is replaced with Material Parameter Collections.
• 4 Channels: Reduced to limit dynamic branches.
• SubFog mandatory: Sub Fog Texture must be enabled. Dynamic branching to toggle it has been removed.
• Stylized Fog: Disabled due to excessive texture sampling.
• Debug Commands: FOW.r.SubFogDebugMask no longer works with Sub Fog Texture.

Note: All suggested values are not final. They should be adjusted based on profiling results and performance tuning.

Unreal Engine Setup

I based my setup on this video, and everything worked as expected.
I also installed the Android Game Development Extension, though USB debugging worked better in my case. By following the video, you should have:

• Installed Android Studio
• Installed SDK, NDK & Command Line Tools
• Enabled Android support in UE5
• Verified your Environment Variables
• Run SetupAndroid.bat to configure your environment

Plugin Setup

Now that everything is ready, let's adjust the plugin to reduce GPU load. The goal is to minimize the number of texture samples.

• Remove the MultiFloor feature and replace it with a fast-access SingleFloor system
• Use a simplified version of the Blur algorithm. Sub Fog Texture becomes mandatory, only 4 Channels supported, and debug commands will no longer work
• Reduce blur complexity using the MPC variables, which affects visual quality but improves performance
• Lower PixelSize to increase pixel density and improve visual clarity

Handler

Let's start with the FOWHandler settings:

• Ensure that EnableSubFogTexture is checked doc
• Set SubFogCompression to 2
• Reduce PixelSize to 12

Finding the right balance here is key. The Sub Fog Texture is a really powerful tool, the smaller the SubFogCompression and PixelSize values, the better the performance. However,lowering PixelSize too much can strain the CPU.

Material

Now let's modify the materials. There are two ways to enable GPU optimization:

• You can apply the modifications directly in each Material and Material Instance you're using
• Or you can apply them in the plugin's Material Function. /!\ Be careful, these changes will be reset every time the plugin is updated /!\

Let's start with the first approach. Open MPP_FOW_Floors and in the parameter list, toggle:

• EnableFastFloorAccess: Floor data will now be sent via MPC vector parameters instead of through a texture
• EnableMobileFastBlur: The blur will include fewer features and fewer dynamic branches, which improves performance

If you want to change the default values in the Material Function, open MF_FOWComputeFloorIdx and set EnableFastFloorAccess to true.

Then open MF_FOW_SpiralBlur-Texture_All and set EnableMobileFastBlur to true.

Now that the materials are ready, let's reduce the blur complexity:

• BlurDistance must always be <= the SubFogCompression value set in the FOWHandler
• Set Blur_DistanceStep to 8
• Set Blur_RadialStep to 4

To get an idea of how expensive the blur is: multiply Blur_DistanceStep by Blur_RadialStep. That's the number of texture samples per pixel rendered on screen.

Entities

Finally, if you want to support a large number of entities, it's a good idea to tweak the Layer system a bit.The goal is to reduce the number of entities processed in a single thread/task.

Create a new Blueprint child of FOW_FOVLayer and call it BP_FOVLayer. Once opened, set SharedDrawerMaxEntities to 75.

Next, create a new Blueprint child of FOW_LayerHandler, unless you already have one for your game. Call it BP_LayerHandler. Once opened, add a row to ComputationLayerOrderClass and assign your new BP_FOVLayer. Don't forget to reorder it to fit the screen layout or your game logic.

Finally, change the LayerHandler_Class used by the FOW_Handler.

You should now be able to build your application with the plugin enabled and get good performance!

Single Channel

Another good way to reduce GPU usage is to design your game to use a Single Channel like a typical MOBA style Fog of War. To enable this setup, change the FOWFloor Tiles Class in the FOW_Handler to TFOW_T128b_1Chan_PCK_Class.

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