In general, the simplest (and quite optimal) algorithm is checking on which side of the half-plane created by the edges the point is. Here’s some high quality info in this topic on GameDev, including performance issues. And here’s some code to get you started:
How do I determine whether or not two lines intersect, and if they do, at what x,y point?
If you mean the angle that P1 is the vertex of then using the Law of Cosines should work: arccos((P122 + P132 – P232) / (2 * P12 * P13)) where P12 is the length of the segment from P1 to P2, calculated by sqrt((P1x – P2x)2 + (P1y – P2y)2)
A line loop is just an outline. To fill the middle as well, you want to use GL_POLYGON.
The equation of a line is: For a segment, it is exactly the same, except that x is included on an interval I. If you have two segments, defined as follow: The abcisse Xa of the potential point of intersection (Xa,Ya) must be contained in both interval I1 and I2, defined as follow : And … Read more
For div tag there is already default property display:block given by browser. For anchor tag there is not display property given by browser. You need to add display property to it. That’s why use display:block or display:inline-block. It will work.