Fog + Tonemapping

[willeastcott]

Often, you want to fade your scene via a fog color so that it matches the clear color of the camera.

This works fine if you have tonemapping disabled. But let's say you enable linear tonemapping and have 0.1, 0.1, 0.1 clear color set, you need to set the fog color to roughly 0.21, 0.21, 0.21 for the scene to match up with the camera's clear color.

Is this because we need to be applying fog after the tonemap? Or should we be tonemapping the fog color?

[mvaligursky]

I think the problem is that the clear color is not tonemapped. A workaround here would be to render an inverted sphere with a color as this color would be tonemapped. Not surer convenient though.
This should not be an issue if post-effects / CameraFrame rendering is used, as the clear color is used to clear the color and the tone mapping is applied over it as well.