def __init__(self, x, y):
self.acceleration = vec2(0, 0)
angle = random.uniform(0, 2 * math.pi)
self.velocity = vec2(math.cos(angle), math.sin(angle))
self.position = vec2(x, y)
self.r = 2.0
self.max_velocity = 2
self.max_acceleration = 0.03
def cohesion(self, boids):
neighbor_dist = 50
sum = vec2(0, 0) # Start with empty vector to accumulate all positions
count = 0
for other in boids:
d = (self.position - other.position).length()
if 0 < d < neighbor_dist:
sum += other.position # Add position
count += 1
if count > 0:
sum /= count
return self.seek(sum)
else:
return vec2(0, 0)
def separate(self, boids):
desired_separation = 25.0
steer = vec2(0, 0)
count = 0
# For every boid in the system, check if it's too close
for other in boids:
d = (self.position - other.position).length()
# If the distance is greater than 0 and less than an arbitrary
# amount (0 when you are yourself)
if 0 < d < desired_separation:
# Calculate vector pointing away from neighbor
diff = self.position - other.position
diff = diff.normalized()
steer += diff / d # Weight by distance
count += 1 # Keep track of how many
# Average - divide by how many
if count > 0:
steer /= count
# As long as the vector is greater than 0
if steer.length() > 0:
# Implement Reynolds: Steering = Desired - Velocity
steer = steer.normalized()
steer *= self.max_velocity
steer -= self.velocity
steer = steer.limited(self.max_acceleration)
return steer
def update(self):
# Update velocity
self.velocity += self.acceleration
# Limit speed
self.velocity = self.velocity.limited(self.max_velocity)
self.position += self.velocity
# Reset acceleration to 0 each cycle
self.acceleration = vec2(0, 0)
def align(self, boids):
neighbor_dist = 50
sum = vec2(0, 0)
count = 0
for other in boids:
d = (self.position - other.position).length()
if 0 < d < neighbor_dist:
sum += other.velocity
count += 1
if count > 0:
sum /= count
# Implement Reynolds: Steering = Desired - Velocity
sum = sum.normalized()
sum *= self.max_velocity
steer = sum - self.velocity
steer = steer.limited(self.max_acceleration)
return steer
else:
return vec2(0, 0)
def borders(self):
x, y = self.position
x = (x + self.width) % self.width
y = (y + self.height) % self.height
self.position = vec2(x, y)