How to test if a line segment intersects an axis-aligned rectange in 2D?

Question

How to test if a line segment intersects an axis-aligned rectange in 2D? The segment is defined with its two ends: p1, p2. The rectangle is defined with top-left and bottom-

Answer 1

I did a little napkin solution..

Next find m and c and hence the equation y = mx + c

y = (Point2.Y - Point1.Y) / (Point2.X - Point1.X)

Substitute P1 co-ordinates to now find c

Now for a rectangle vertex, put the X value in the line equation, get the Y value and see if the Y value lies in the rectangle bounds shown below

(you can find the constant values X1, X2, Y1, Y2 for the rectangle such that)

X1 <= x <= X2 & 
Y1 <= y <= Y2

If the Y value satisfies the above condition and lies between (Point1.Y, Point2.Y) - we have an intersection. Try every vertex if this one fails to make the cut.