how can I check that a point is in a triangle?

问题

Hi also consider that I have 4 points and I will have 4 triangles how can I check these four triangles for each point that is the point within the triangles or not. thanks

回答1:

Polygon implements the Shape interface, which provides several contains() methods. Here's a simple example.

回答2:

You need to find the equation for the line created by each side of the triangle, and then for each side, check whether the point in question is on the same side of this line as the third point in the triangle. If all three are on the same side, it is within the triangle. Add bounds checking for cases of a point falling ON one of your sides.

来源：https://stackoverflow.com/questions/4207318/how-can-i-check-that-a-point-is-in-a-triangle