WebGLRenderer: Calling dispose() does not trigger dispose() on geometries, materials etc.

Each time Pass.FullScreenQuad is used in a new WebGLRenderer, a dispose listener is attached to geometry. But when WebGLRenderer is disposed, geometry is not disposed, therefore the reference to the dispose listener is retained.

https://github.com/mrdoob/three.js/blob/b0a1e8ca7863aa399c31692fa5b76c40feca2485/examples/jsm/postprocessing/Pass.js#L37-L40

The listener holds a reference to info and bindingStates, which further refers to many other objects.

https://github.com/mrdoob/three.js/blob/4944e56c06ed284abe11b7654348fb1ea3ac04d4/src/renderers/webgl/WebGLGeometries.js#L5

[gkjohnson]

I guess one question is whether or not there’s another way to approach this that affords using two renderers at once or will it always be impossible to fully dispose of one renderer without incurring a reinitialization cost of shared geometry in the second.

One approach would be to enable disposing of objects directly on the renderer itself rather than with a dispose function:

renderer.disposeObject( geometry );

Or of course using a Map rather than WeakMap in WebGLGeometries. What is the benefit of using a WeakMap right now? It will let the geometry objects be garbage collected in JS but it will never allow for the gl bindings to be disposed of which will leave unreferenced VAOs in memory until the renderer is disposed of.

I guess it seems like there’s never a case where a user should feel comfortable with letting a BufferGeometry get garbage collected without calling dispose except for maybe just using a single renderer and having just disposed of the renderer. But even then they have to be sure that all of the geometry is left unreferenced or the renderer context can’t actually get cleaned up. If users are being told to call “dispose” on something it should actually properly dispose of the object. Are there strong feelings against using a Map rather than WeakMap in WebGLGeometries (and similar classes)?

Maybe WeakRef will make this all a bit simpler but we’ll see. In the mean time I can look into clarifying the wording on WebGLRenderer.dispose.

[Mugen87]

dispose on the renderer and all geometry and materials in order to fully clean things up.

Yes, this is intended. You’ve already pointed out the reason (non-iterable WeakMaps) for why this is the case.

Perhaps those docs should be clarified if this is intended behavior?

Improving the docs is always good!