Renderer: Set stencil to false by default.

[Mugen87]

Related issue: #27799

Description

As suggested in #27799 (comment), the stencil parameter of WebGLRenderer and the new Renderer.stencil property are now false by default. That means applications have to set the value to true now if they rely on stencil related logic.

The motivation behind this change is to only request resources if they are required. Since stencil is only used in special circumstances, the new default value seems more appropriate.

Note: Not enabling stencil for the default drawing buffer does not exclude depth textures or render targets of having stencil types/formats or attachments.

@cabanier I've seen WebXRManager also evaluates the stencil property for its layer related logic. Do you see any issues with this change?

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

Filesize dev	Filesize PR	Diff
669.7 kB (166.2 kB)	669.7 kB (166.1 kB)	+0 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

Filesize dev	Filesize PR	Diff
449.9 kB (108.8 kB)	449.9 kB (108.8 kB)	+0 B

[cabanier]

@cabanier I've seen WebXRManager also evaluates the stencil property for its layer related logic. Do you see any issues with this change?

No, this change looks fine. No WebXR browser implementations use the stencil buffer so it's ok to disable by default.

[mrdoob]

/fyi @sunag @RenaudRohlinger

[RenaudRohlinger]

Should we also consider eliminating the clear stencil operation? Given that the stencil buffer is now disabled by default, its clear operation appears unnecessary in both WebGLRenderer and WebGPURenderer.

Additionally, should we default stencil = false in both getDepthBuffer and RenderContext as well?

[Mugen87]

Should we also consider eliminating the clear stencil operation? Given that the stencil buffer is now disabled by default, its clear operation appears unnecessary in both WebGLRenderer and WebGPURenderer.

That sounds good. We can do this by evaluating the stencil context attribute in WebGLRenderer and the respective stencil property in WebGPURenderer and then perform the clear if required.

Additionally, should we default stencil = false in both getDepthBuffer and RenderContext as well?

Sounds good to me as well. We should only keep in might that UnsignedInt248Type might have more depth precision than UnsignedIntType. If we see issues with depth precision on app level, we might want to use a different configuration for depth textures.

@RenaudRohlinger Would you file a PR with your suggested changes?

[RenaudRohlinger]

Ok will do!