Ok, I''ve got a really simple question. I have four points (x,y), three form the verticies of a triangle and a forth is the location of a "player" How can i find if the forth point lies within the triangle formed by the first three? Duckbob

Know the winding of the triangle segments (counter-clockwise or clockwise) to begin with. In a clockwise winding, if the point is to the left of any of the segments, it is outside. If it survives all three tests, that is, it is NOT to the left, then the point is inside.

If the signed area * 2 of the triangle defined by the line segment A - B and the point P is > 0.0, then P is to the left of the line segment A - B. Pass the args in as P, A, B.

#define tri2sgnarea2(a,b,c) ( ( ( (b)[0] - (a)[0] ) * ( (c)[1] - (a)[1] ) - ( (c)[0] - (a)[0] ) * ( (b)[1] - (a)[1] ) ) )

Edited by - bishop_pass on June 1, 2001 2:58:29 AM

It mangled my macro. I do not understand why it would do something so inept as that. It''s supposed to render source code, which means don''t do anything to the text, but it has to go and do crap to it.

Unbelievable.