Hello,
If you know the *distance* it's a good deal simpler. It's quite easy to
find and store, if you have the position. It looks like you can use
line_segment_point_distance().
Let d1 be the distance to the line at t0.
Let d2 be the distance to the line at t1.
Let x be the spell's position in x.
Let y be the spell's position in y.
Let xD be the speed in the x direction. It is linear.
Let yD be the speed in the y direction. It is linear.
if d2 < radius: #the spell hit the line
#fraction of frame at collision
#I figured this out through linear interpolation. Given constant time
and known distances,
#here's how you find an imaginary frame where distance = radius in the
middle.
portion = float(d1-radius)/float(d1-d2) #multiply by 100 to get % of
time until next frame
position_of_collision = [x + xD*portion,
y + yD*portion]
I hope this is what you're looking for.
Cheers,
Ian
