How to determine a point in a triangle?

Answer

And here's some code to get you started:

float sign (fPoint p1, fPoint p2, fPoint p3){return(p1.x - p3.x)*(p2.y - p3.y)-(p2.x - p3.x)*(p1.y - p3.y);}boolPointInTriangle(fPoint pt, fPoint v1, fPoint v2, fPoint v3){bool b1, b2, b3;

    b1 = sign(pt, v1, v2)<0.0f;
    b2 = sign(pt, v2, v3)<0.0f;
    b3 = sign(pt, v3, v1)<0.0f;return((b1 == b2)&&(b2 == b3));}