This page describes the optimization techniques for URP projects that target untethered XRAn umbrella term encompassing Virtual Reality (VR), Augmented Reality (AR) and Mixed Reality (MR) applications. Devices supporting these forms of interactive applications can be referred to as XR devices. More info
See in Glossary devices.
Most untethered XR devices use tile-based GPUs. The guidelines on this page help you use this hardware architecture more efficiently and avoid using rendering techniques that are less efficient on those devices.
To learn more about how tiled-based GPUs work, refer to the additional resources section.
Vulkan API is more stable and provides better performance compared to OpenGL ES API in URP projects targeting XR platforms.
Refer to Graphics API support for information on how to change the graphics API to Vulkan.
Use the OpenXR Plugin in projects that target XR platforms.
Enable the following settings in your project: * Multi-view \ Single pass rendering * Foveated rendering
To configure the Render Mode to Single Pass Instanced \ Multi-view:
Starting with Unity 6 Preview, new URP projects use the render graph system. Refer to Benefits of the render graph system to understand the benefits of RenderGraph.
In URP, Deferred rendering generates several render targets for the G-buffer. Unity performs multiple graphics memory loads to access those render targets, which is slow on tile-based GPUs.
Refer to Deferred rendering implementation details for more information on the implementation of the G-buffer in URP.
The Rendering PathThe technique that a render pipeline uses to render graphics. Choosing a different rendering path affects how lighting and shading are calculated. Some rendering paths are more suited to different platforms and hardware than others. More info
See in Glossary settings is in the Rendering section of the Universal Renderer Asset.
Avoid post-processingA process that improves product visuals by applying filters and effects before the image appears on screen. You can use post-processing effects to simulate physical camera and film properties, for example Bloom and Depth of Field. More info post processing, postprocessing, postprocess
See in Glossary on untethered XR devices because of its performance impact.
URP renders post-processing in multiple render passes where the output of one pass is the input of the next one. On tile-based GPUs one of the most resource intensive tasks is performing a GMEM load. Post-processing passes often cause GMEM loads because they might load additional textures or copy the current screen color information to perform certain effects. In certain post-processing effects, for example in bloomA post-processing effect used to reproduce an imaging artifact of real-world cameras. The effect produces fringes of light extending from the borders of bright areas in an image, contributing to the illusion of an extremely bright light overwhelming the camera or eye capturing the scene.
See in Glossary, rendering a pixelThe smallest unit in a computer image. Pixel size depends on your screen resolution. Pixel lighting is calculated at every screen pixel. More info
See in Glossary requires sampling adjacent pixels. This can cause extra GMEM loads for accessing pixels outside a certain tile.
In URP, the post-processing pass executes a final blitA shorthand term for “bit block transfer”. A blit operation is the process of transferring blocks of data from one place in memory to another.
See in Glossary even if there are no effects to execute. This requires another GMEM load because the blit operation copies the current texture in which Unity executes the post-processing pass to the final cameraA component which creates an image of a particular viewpoint in your scene. The output is either drawn to the screen or captured as a texture. More info
See in Glossary texture.
On XR platforms Unity performs such operations once per view which increases the performance impact.
Note: Some effects can cause motion sickness. Refer to section Post-processing in URP for VR for a list of effects that can cause motion sickness.
To disable post-processing for a specific Universal Renderer: 1. Select a Universal Renderer asset. 2. Under Post-processing, ensure that the Enabled checkbox is cleared.
To disable post-processing for a camera:
Avoid using geometry shadersA program that runs on the GPU. More info
See in Glossary on platforms with tile-based GPUs. Some devices don’t support geometry shaders.
The generation of additional primitives and vertices breaks the tiled GPU flow because the division of primitives after the binning pass becomes invalid.
Tile-based GPUs can store more samples in the same tile. This makes Multi-sample Anti-aliasing (MSAA) efficient on mobile and untethered XR platforms. 2X MSAA value provides a good balance between visual quality and performance.
You can change the MSAA settings in the Quality section of the URP Asset.
For more information on MSAA, refer to Anti-aliasing in URP.
Disable depth priming on XR platforms. XR devices have two views, which increases the performance impact from performing the depth pre-pass.
For untethered XR devices there are no benefits of performing the depth priming. You can obtain similar results using hardware optimization features, such as Low-Resolution-Z (LRZ) or Hidden Surface Removal (HSR).
For information on how to configure or disable depth priming, refer to the Depth Priming Mode property description.
Disable the Opaque Texture and Depth Texture properties to improve performance. Enabling those options causes extra texture copy operations, which requires extra GMEM loads.
Refer to the Rendering section of the URP Asset description for more information on these options.
To identify if your current configuration is using intermediate textures, use the Render Graph Viewer window.
Screen-Space Ambient OcclusionA method to approximate how much ambient light (light not coming from a specific direction) can hit a point on a surface.
See in Glossary (SSAO) might have poor performance on mobile and untethered XR devices.
SSAO in URP requires the depth priming pass, two blur passes to reduce the noise, and an additional blit pass to clean the image. Such passes require several GMEM loads which have a high performance impact on tile-based GPUs.
To disable SSAO:
HDR rendering has higher precision and improves graphics fidelity, but requires more bits per pixel to process. Disable HDRhigh dynamic range
See in Glossary to reduce memory bandwidth and improve performance.
Most untethered XR devices don’t support HDR rendering.
To disable HDR: 1. Select a URP Asset. 2. In the Inspector window, in the Quality section, clear the HDR property.