Compositor layers are a powerful and fundamental rendering tool that enhances an app’s visual quality and performance. The compositor’s ability to divide scenes into individual layers means that apps can efficiently render complex scenes and create a more immersive user experience—all without sacrificing performance. While the benefits are clear,
compositor layers are often misunderstood, so we’ve built two new functions into
Meta Quest Developer Hub (MQDH) to help you optimize your apps and understand how the compositor works.
Now in MQDH, you’ll find “Layer Visibility” and “Layer Property” functions to help you build compositor layers into your app. Dive in below to learn how these new functions can help you enhance graphics and optimize rendering.
Using the Layer Visibility Function
The Layer Visibility function provides insights into how different layers interact and affect the overall user experience. When the function is activated, each layer is represented with a control panel of checkboxes that you can toggle to visualize how different parts of your scene correspond to a given layer. Using this information, you can optimize apps' performance and visual quality. We recommend starting with the
Layer Visibility guide while looking at the Performance Analyzer tab in MQDH.
Here are some of the ways you can leverage the Layer Visibility function to improve your projects:
- Performance Optimization: The Layer Visibility tool allows you to manage CPU and GPU resources more efficiently by enabling or disabling specific compositor layers. By toggling the visibility of these layers, you can identify and eliminate unnecessary resource usage to ensure that only the essential layers are rendered. This can lead to significant performance improvements, especially in complex apps with several layers.
- Visual Quality Enhancement: By understanding how different layers contribute to the overall composition, you can enhance the visual quality of 2D layers. In the control panel, you can check or uncheck the boxes to see how each layer affects the visual output in the headset. This is particularly useful for fine-tuning the appearance of layered elements, such as ensuring that important visual components are not occluded by other layers.
- Debugging and Profiling: Toggling layer visibility is also beneficial for debugging purposes. It enables you to discover occluded layers, especially when compositor layers are used as underlays, which might not be visible most of the time. Additionally, you can use this tool to estimate the performance impact of specific layers by comparing performance metrics before and after toggling their visibility. Comparing metrics can be crucial for profiling and optimizing your app to ensure a smooth and efficient operation.
In the graphic above, you can see how toggling the “QUAD” checkbox impacts the rendered compositor layers. On the right side, the “QUAD” box is unchecked, hiding the Horizon Feed layer. This allows you to profile the impact of a single layer's performance.
Using the Layer Property Function
Each layer possesses internal properties that are calculated within the compositor. With the
Layer Property tool, you can view these properties by hovering over individual layer items. The properties include rendered PPD (pixels per degree), texture resolution, recommended texture resolution, and
layer filtering for both eyes. Looking at this information can help you understand the expected parameters from the submitted layers, enabling the compositor to generate a frame with improved quality without incurring additional costs. As demonstrated in the graphic below, when you are close to the browser, the rendered PPD for that quad layer decreases, prompting a sharpening filter.
Conversely, when you are sufficiently distant from the browser, the rendered PPD increases to a level that necessitates the use of a supersampling filter.
For additional details on usage of these tools, please refer to the documentation on
Layer Visibility Control in VR Compositor. If you have any suggestions after using these tools, please send us feedback using the recently launched
Feedback tool in MQDH. We will continue to add more functions to MQDH and look forward to delivering more tools to help you enhance the quality of your apps. For additional tips on improving performance, visual quality, and more, watch our developer sessions from
Meta Connect.
