WebGPU Rendering Problems? Troubleshooting PixiJS on Chrome, Pixel, and Ubuntu
Is your WebGPU implementation in PixiJS failing on certain devices? Experiencing rendering glitches on your Google Pixel 9 or Ubuntu 24.04 system with Chrome? You're not alone. This article dives into a common issue affecting WebGPU rendering in PixiJS and, importantly, offers a potential solution. Let's get your graphics back on track!
The WebGPU Glitch: Why PixiJS Rendering Fails on Some Devices
Users are reporting that enabling preference: "webgpu" when using PixiJS examples leads to rendering failures on specific devices. This problem has been observed on Google Pixel 9 devices and Chrome browsers running on Ubuntu 24.04, particularly when manually enabling WebGPU through Chrome flags. The console will likely show errors indicating the rendering process has failed.
- Affected Devices: Google Pixel 9, Ubuntu 24.04 with Chrome (WebGPU enabled via flags).
- Observed Behavior: Rendering fails when
preference: "webgpu"is enabled in PixiJS. - Error Indication: Console logs indicating rendering failure.
Root Cause Analysis: Mismatched Texture Limits and WebGPU
The underlying cause appears to stem from how PixiJS determines the maximum number of textures for WebGPU batching. The code incorrectly relies on WebGL's MAX_TEXTURE_IMAGE_UNITS parameter instead of utilizing WebGPU's device.limits.maxSampledTexturesPerShaderStage. This is a crucial distinction, as these values don't always align across different systems leading to rendering issues.
The problem lies in assuming WebGL limits are appropriate when dealing with WebGPU, resulting in lower texture limits than expected.
Confirmed Texture Limit Mismatch: See the Discrepancy Firsthand
Want to see if this mismatch is affecting your setup? Use this handy JSFiddle: https://jsfiddle.net/hmbf9skw/1/ It allows you to compare the values of MAX_TEXTURE_IMAGE_UNITS and device.limits.maxSampledTexturesPerShaderStage on your device.
- If the values differ, especially if
device.limits.maxSampledTexturesPerShaderStageis significantly higher, you're likely encountering this issue.
The PixiJS Code Culprit: Spotlighting the problematic lines
The code segments believed to be responsible for this issue are likely located within the batcher initialization:
And potentially:
These lines need to be updated to properly fetch and utilize the WebGPU texture limits instead of the WebGL ones.
Solution: Update PixiJS to Prioritize WebGPU Limits
The core solution involves modifying the PixiJS codebase to use WebGPU's device.limits.maxSampledTexturesPerShaderStage for determining texture limits when WebGPU is enabled. This will ensure that the batcher utilizes the correct maximum texture count for the device's WebGPU capabilities.
Actionable steps:
- Locate the code responsible for setting
maxTextureswithin the WebGPU batcher. - Implement a conditional check: if WebGPU is enabled, fetch
device.limits.maxSampledTexturesPerShaderStage. - Otherwise, default to the current method of retrieving texture limits when WebGL is used.
Related Issues: Further Reading on WebGPU and PixiJS
Explore these related GitHub issues for additional context and potential insights:
By addressing this WebGPU texture limit discrepancy, we can overcome rendering failures and ensure a smoother PixiJS experience across a wider range of devices and configurations.
