When we start using vectors, we want to be able to measure the results. To do this, we will add a visible grid to the environment. Create a new Python script called Grid. py and add the following code to it:
from OpenGL.GL import *
class Grid():
def_init_(self, interval, halfsize, colour):
self. interval $=$ interval
self.halfsize $=$ halfsize
self. colour $=$ colour
def draw(self) :
glColor3fv(self.colour)
glBegin (GL_LINES)
for $x$ in range(-self.halfsize, self.halfsize):
for $y$ in range(-self.halfsize,
self.halfsize):
glVertex3fv((x * self.interval,
y * self.interval - 10,
0))
glVertex3fv((x * self.interval,
y * self.interval + 500,
0))
glVertex3fv((y * self.interval - 10,
x * self.interval, 0))
glVertex3fv((y * self.interval + 500,
x * self.interval, 0))
glEnd()