VectorLerp for walking on a path

@jeremydouglass posted this example somewhere on this forum, and I enjoyed porting it to Python mode. That’s the post.

``````# LerpVectorsSimplified
# 2019-04 Processing 3.4 - based on LerpVectorsExample by Jeremy Douglass
# 2020-07 ported to Python Mode by Alexandre Villares

vecs = []

def setup():
size(200, 200)
# mark path points
vecs.append(PVector(10, 10))
vecs.append(PVector(width - 10, 10))
vecs.append(PVector(width - 10, height - 10))
vecs.append(PVector(10, height - 10))
vecs.append(PVector(width / 2, height / 2))
fill(0, 0, 255)

def draw():
background(255)
time = millis() / 2 % 4000    # a clock that counts up to 4000 and starts over
# from -1 to 1, then starts over
sawtoothWave = map(time, 0, 3999, -1, 1)
triangleWave = abs(sawtoothWave)    # bounces 0-1-0-1-0
# find our location in 2D path based on 0-1
loc = lerpVectors(triangleWave, vecs)
ellipse(loc.x, loc.y, 20, 20)    # draw at the location

# based on an amount, find the location along a path made of points
def lerpVectors(amt, vecs):
if len(vecs) == 1:
return vecs[0]
cunit = 1.0 / (len(vecs) - 1)
return PVector.lerp(vecs[floor(amt / cunit)],
vecs[ceil(amt / cunit)],
amt % cunit / cunit)

``````
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