Vulkan Static reflections from dynamic shader sky (ViewportTexture)

[RicardRC]

Godot version

master (6882890)

System information

Windows 10 and Linux

Issue description

I expect reflections from sky to change when the sky changes.

Steps to reproduce

Open project and observe that the background is dynamic but the reflections are static

Minimal reproduction project

ViewportBug.zip

[clayjohn]

I can reproduce the issue. It looks like the "background" viewports are updated appropriately each frame, but the sky is not updating the radiance map as it doesn't detect that there has been a change.

We will need to add some logic to the sky setup function to detect if it is using ViewportTextures and if so, to update the sky everytime the ViewportTexture changes.

In the meantime, as a workaround, you can force the sky to update every frame by adding + 0.0 * TIME at the end of one of the lines in the shader. While this is a total hack, it works and won't hurt the shader.

[Calinou]

• Related to Decals using ViewportTexture are not updated #73400, ViewportTexture doesn't update when used as a Light3D projector texture #74352 and ViewportTexture doesn't work within PointLight2D #75868.

[clayjohn]

• Related to Decals using ViewportTexture not updated #73400, ViewportTexture doesn't update when used as a Light3D projector texture #74352 and ViewportTexture doesn't work within PointLight2D #75868.

Those issues aren't really related. In all three of those cases the issue is that the texture atlas is not updated when the Viewport is updated. This issue here is specific to skies and it happens because the radiance map itself is not redrawn each frame when a viewport is used as a texture in the sky's shader and that viewport is updated every frame.