Light positions are off when main camera setRotation is different from 0

[FSDevelop]

Version

• Phaser Version: v3.90.0
• Operating system: Windows 11
• Browser: Electron 33.2.1

Description

Light positions become offset when the main camera rotation is set to any value other than 0.

In LightPipeline.js:200-202, the light position calculation applies scroll and zoom factors manually after using cameraMatrix.transformPoint(). This double-transformation causes incorrect positioning when the camera is rotated, since the camera matrix already handles rotation, scroll, and zoom together.

Additional Information

Current problematic code:

cameraMatrix.transformPoint(light.x, light.y, tempVec2);
this.set2f(lightName + 'position', tempVec2.x - (camera.scrollX * light.scrollFactorX * camera.zoom), height - (tempVec2.y - (camera.scrollY * light.scrollFactorY) * camera.zoom));

Expected behavior: Lights should maintain their correct world positions regardless of camera rotation.

Actual behavior: Lights appear to drift/offset as the camera moves when camera.setRotation() is non-zero.

Fix: Apply scroll factors before matrix transformation when camera is rotated, letting the camera matrix handle all transformations together.

[XWILKINX]

Will this be fixed?

[BenjaminDRichards]

Will this be fixed?

Honestly, it's not a priority. Phaser 3 is unlikely to receive further first-party releases, and Phaser 4 rewrote the lighting code (fixing several other issues), so this class of problem won't recur.

That does mean it's safe to patch a fix into your Phaser 3 projects, as we're unlikely to change the code further. Or use Phaser 4, which I believe to be more stable and robust than Phaser 3 by this point, and is extremely close to release.

[FSDevelop]

@BenjaminDRichards I'm already using Phaser4 because I know this is not an issue there, but people still using Phaser3 (still latest stable version) in their projects and don't have plans to migrate yet may experience this.

[photonstorm]

There are no more updates for v3 planned from us, so they can either migrate, or we may consider a PR if we get enough of them to warrant a point release as a one-off bundle. Or monkey-patch it in.