Method 1: Yes you can do by writing equation of 3 lines taking 2 points at a time and finding the sign with the third point.
Suppose: ax+by+c=0 is your first line and (x,y) is the third point then find out the sign of the 3rd point satisfying it on the line. suppose this sign is S (for +ve) Similarly calculate for signs for other 2 lines. Now give a point(p,q) should give the same signs for all the 3 lines .If it gives the same sign for all the 3 lines that means it lies btwn all the 3 lines and all the 3 points.hence proved. Method 2: Area mentioned by praveen Method 3: http://en.wikipedia.org/wiki/Barycentric_coordinates_(mathematics)#Determining_if_a_point_is_inside_a_triangle You can choose the best method. On Mon, Sep 20, 2010 at 9:18 PM, Nicolae Titus <[email protected]>wrote: > there are some approximations involved there, it should be (area(big) - > sum(area small)) < error > a better approach would be to find if the point is on the proper side of > each edge > take all the edges clockwise and calculate the sinus between each edge and > the point, if they are all positive, the point is inside. > > Titus > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]<algogeeks%[email protected]> > . > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- Thanks & Regards Nikhil Agarwal Senior Undergraduate Computer Science & Engineering, National Institute Of Technology, Durgapur,India http://tech-nikk.blogspot.com http://beta.freshersworld.com/communities/nitd -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
