Raycasting in 2D (line segment intersection)

In this video we go over line segment intersection tests and how we can use them in game to create our own 2D raycasting function!

Code:

I also included the line intersection equation in the 2D collision if you want a typed form:

Hope you enjoyed!

[eduardodelagarza]

Thank you very much for the video it was really helpful. I just want to point out that at 9:40 there is a division between 2 vectors which is undefined. The correct procedure is to divide the magnitude of both vectors. This can be seen more clearly when you realise that t is a scalar not a vector. I implemented it in python. Code bellow.


import numpy as np


def func(a, b, c, d):
r = b - a
s = d - c


t = (np.linalg.norm(np.cross(c-a, s))) / np.linalg.norm(np.cross(r, s))
u = (np.linalg.norm(np.cross(a-c, r))) / np.linalg.norm(np.cross(s, r))
print(t, u)


pT = a + t * r
pU = c + u * s
print(pT, pU)


def main():
a = np.array([0, 0])
b = np.array([0, 5])
c = np.array([8, 0])
d = np.array([8, 1])
func(a, b, c, d)


main()

[Thomason]

very useful and well explained! used it in a glsl shader!

[lonelyfloat]

thank you so much for these videos they're so helpful!!!

[RealRobotZer]

Can you please tell me what kind of math book would contain such a problem, many thanks.