Decrease circleVertexEpsilon in order to increase the fidelity of circle approximation.

[dev7355608]

Environment Details

• Foundry VTT Version: 10.272

Issue Description

The polygonal shape is clearly noticeable in the case of small light sources or with low attenuation light sources or at intersections of dark and normal light sources. Even at maximum performance mode. 0.3 would be a good value for circleVertexEpsilon.

Also I don't think it's a good idea to set circleVertexEpsilon based on the performance mode, because it affects the visibility state of tokens etc. A player with low performance mode won't see some tokens that players with higher settings do in certain situations. I can see this causing a lot of confusion. Imagine the GM (low performance mode) wondering why their player (high performance mode) are able to see and target a token that is not visible if they select the player's token.

[caewok]

I agree that at the moment, the density can affect visibility in rare cases. If #7259 is resolved, this may cease to be an issue because the polygon approximation would use the exact circle-poly intersections. It would be pretty rare, I think, to see visibility affected at that point unless the polygon density is set very large.

Keep in mind, setting it to 1 means a maximum 1 pixel difference between polygon edge and circle circumference.

Thinking about this a bit more... If this continues to be an issue, it is conceivable that the visibility test could check for inclusion in the actual light shape along with the LOS/FOV tests. Not sure it is worth the trouble though.

[dev7355608]

To add to this: lowering the circleVertexEpsilon doesn't really do much, because of the rounding in toClipperPoints (because of the lack of upscaling/downscaling). Both of these circle are generated with circleVertexEpsilon = 0.3. The first circle is not rounded, the second is. The rounded circle is clearly not particularly smooth in comparison.