What is the coordinate system for this algorithm? about cdt HOT 4 CLOSED

Anyway, for other people reading this, I found the answer:

• All triangles are counter-clockwise.
• locatePointTriangle() is processed in order: v1, v2, v3.
• "Right" to the line (negative result) is considered outside of the triangle.
• (p.X - v1.X) * (v1.Y - v2.Y) + (p.Y - v1.Y) * (v2.X - v1.X) returned the same as orient2D()

Therefore the system is X right, Y up. Visualisation:

On DirectX and similar APIs, Y is down, therefore the triangles will be clockwise. Closing this for now.

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The predicates are robust adaptive predicates that use extended precision computations when necessary to guarantee a correct result for every possible floating-point input.
More details can be found in the paper: https://link.springer.com/content/pdf/10.1007/PL00009321.pdf

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Ah I see. I'm porting the library to C# and was trying to find out how many methods can be stripped off. I keep getting point-out-of-triangle errors around the triangle walk stage and thought this was the issue. I'd like to post the results in here once I'm done fixing the bugs (a lot of typo-hunting is involved).

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Thanks, @MWstudios. This is correct. I have slightly updated the README to clarify coordinate system the winding applies to.

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