I wrote a custom shader for Conway's Game of Life, using three.js and A-Frame, which does all processing in the fragment shader. It works perfectly in a web browser on desktop. It also appears to work in the Quest browser, but when entering VR mode, the entire screen begins to flicker between the scene and a black screen.

I suspect that the problem is with the RenderTarget settings, or the way in which I switch between render targets, but I am not sure. The relevant code occurs within an A-Frame component tick function, which periodically switches between two render targets and back to the main scene as follows:

this.el.sceneEl.renderer.setRenderTarget(this.renderTarget0);
this.el.sceneEl.renderer.render(this.rtScene0, this.rtCamera);

this.el.sceneEl.renderer.setRenderTarget(this.renderTarget1);
this.el.sceneEl.renderer.render(this.rtScene1, this.rtCamera);

this.el.sceneEl.renderer.setRenderTarget(null);

If it is relevant, I have also disabled the depth buffer on the RenderTarget objects. The full code is available on GitHub at https://github.com/stemkoski/A-Frame-Examples/blob/master/conway-shader.html and a live version is at https://stemkoski.github.io/A-Frame-Examples/conway-shader.html.

My question is: how can I stop the screen from flickering in VR mode, while using RenderTargets in A-Frame?