找出线段的已知X的Y？

Question

I'm trying to place my hero's feet on a ground made up of line segments.

If I know the X,Y of points A, B, and C and the X of Hero, how do I find the Y of Hero so that his feet touch the ground (assume X is the middle of the Hero and Y is along the bottom)? And do I have to do anything differently if he's standing exactly over a point?

Thanks.

Answer 1

If A and B are two points in a coordinate plane with points (xA, yA) and (xB, yB) respectively - then the slope of the line between them is simple geometry - delta y/delta x, or (yB-yA)/(xB-xA) . The general form of the line can be given as y = yA+(yB-yA)/(xB-xA)*(x-xA)