Qualify "coplanar" in the documentation #26
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The code (specifically line https://github.com/evanw/csg.js/blob/a8512afbac3cf503195870f7ef11c0a32f36c6d4/csg.js#L439) uses the word "coplanar" in two ways: coplanarity of polygons with the same direction normal and and coplanarity of polygons with reversed normal directions. The documentation, on the other hand, uses it in one specific way: coplanar polygons with the same normal direction but doesn't quality this word. `clipTo` returns faces with the same normal direction, but removes coplanar polygons with a reversed normal (unless the BSP is degenerate). I think this statement is key to understanding the algorithm correctly, so I think this deserves to be added.
pboyer
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I understand this code isn't actively maintained, but hopefully this pull request will help others understand it correctly.
The code uses the word "coplanar" to refer to two specific conditions: overlapping polygons with the same normal direction and overlapping polygons with reversed normal directions:
csg.js/csg.js
Line 439 in a8512af
The documentation, on the other hand, uses it in one specific way: overlapping polygons with the same normal direction. But, it doesn't doesn't qualify. I think this qualification is key to understanding the algorithm correctly, so it is worth adding.
Namely,
clipTowill return polygons in the argument list with the same normal direction as theCSGNode, but removes coplanar polygons with a reversed normal.