Overlapping edges still a problem

[croonerg]

Look at this codepen:
https://codepen.io/anon/pen/LLdEbM

Polygon 1:

[
	[
		[
			-492.1913921306456,
			-246.09569606532278
		],
		[
			-492.1913921306456,
			246.09569606532278
		],
		[
			328.12759475376373,
			164.06379737688187
		],
		[
			328.12759475376373,
			82.03189868844093
		],
		[
			0,
			98.43827842612912
		],
		[
			0,
			-98.43827842612912
		],
		[
			328.12759475376373,
			-82.03189868844093
		],
		[
			328.12759475376373,
			-164.06379737688187
		],
		[
			-492.1913921306456,
			-246.09569606532278
		]
	]
]

Polygon 2:

[
	[
		[
			118.12593411135472,
			92.53198172056138
		],
		[
			328.12759475376373,
			82.03189868844093
		],
		[
			328.12759475376373,
			92.53198172056136
		],
		[
			118.12593411135472,
			92.53198172056138
		]
	]
]

[w8r]

still not fixed after #42

[liamdebeasi]

Has there been any progress made on this issue? This would be a nice bug to have fixed as it resolves several issues for a project I'm working on.

[w8r]

We tried to tackle it, but so far to no avail. Of course it would be nice!

[mfogel]

I'm running into what I think is this issue as well. Here's a simple test case that demonstrates the problem. Run 'Difference A-B' to see the problem: https://codepen.io/mfogel/pen/jYgxmm

Poly A:

[[
  [0,0],
  [3,0],
  [3,3],
  [0,3],
  [0,0]
]]

Poly B:

[[
  [1,0],
  [2,0],
  [2,4],
  [1,4],
  [1,0]
]]

[w8r]

Thanks for a simple testcase

[mfogel]

@w8r no prob, happy to help

Just want to mention that it appears this bug can also manifest itself as a heap overflow, crashing the browser/node altogether. Here's an example, similar to the case I posted earlier. Run 'Difference A-B': https://codepen.io/mfogel/pen/baXjGO

Poly A: (a Polygon, same as before)

[[  [0,0],  [3,0],  [3,3],  [0,3],  [0,0]  ]]

Poly B: (a MultiPolygon)

[
  [[  [1,0],  [2,0],  [2,4],  [1,4],  [1,0]  ]],
  [[  [2,0],  [3,0],  [3,1],  [2,1],  [2,0]  ]]
]

Seems possible to me that martinez is:

• computing diff(PolyA, PolyB[0]) -> getting invalid coordinate result
• computing diff(that invalid coord. result, PolyB[1]) -> crashing in heap overflow

I'll try to find some time this weekend to help out on this.