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engine2.py
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engine2.py
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from operator import index
import random as rd
import time
import numpy as np
NUM_PARTICLES = 1
# define two dimentional vector
class vector2:
def __init__(self, x, y):
self.x = x
self.y = y
def vec(self):
return [self.x, self.y]
# two dimentional particle
class Particle:
def __init__(self, position, velocity, mass):
self.position = vector2(x=position[0], y=position[1]).vec()
self.velocity = vector2(x=velocity[0], y=velocity[1]).vec()
self.mass = mass
particles = []
def PrintParticles():
for i in range(NUM_PARTICLES):
particle = particles[i]
print(
f"Particle[{i}] {particle.position}, {particle.velocity}, {particle.mass}")
# print(f"Particle[{i}] {particle.position}")
def InitializeParticles():
for _ in range(NUM_PARTICLES):
particle = Particle(
position=vector2(x=rd.randint(0, 50), y=rd.randint(0, 50)).vec(),
velocity=vector2(x=0, y=0).vec(),
mass=1
)
particles.append(particle)
def ComputeForce(particle):
force = vector2(x=0, y=particle.mass * -9.81)
return force
def RunSimulation():
totalSimulationTime = 10 # simulation length is 10 seconds
currentTime = 0 # simulation starts at time = 0
dt = 0.5 # each step is 1 second
InitializeParticles()
PrintParticles()
while currentTime < totalSimulationTime:
time.sleep(dt)
for i in range(NUM_PARTICLES):
particle = particles[i]
force = ComputeForce(particle).vec()
acceleration = vector2(
x=force[0],
y=force[1]/particle.mass
).vec()
# print(acceleration)
# print(f"x: {particle.position[0]}, {particle.velocity[0]}")
# print(f"y: {particle.position[1], particle.velocity[1]}")
# vel_x
particle.velocity[0] += acceleration[0] * dt
# vel_y
particle.velocity[1] += acceleration[1] * dt
# pos_x
particle.position[0] += particle.velocity[0] * dt
# pos_y
particle.position[1] += particle.velocity[1] * dt
PrintParticles()
currentTime += dt
# RunSimulation()
NUM_RIGID_BODIES = 1
class BoxShape:
def __init__(self, width, height, mass):
self.width = width
self.height = height
self.mass = mass
moi = mass * (width**2 * height**2) / 12
self.momentOfInertia = moi
#def CalculateBoxInertia(boxShape):
# m = boxShape.mass
# w = boxShape.width
# h = boxShape.height
# boxShape.momentOfInertia = m * (w**2 + h**2) / 12
# return boxShape.momentOfInertia
class RigidBody:
def __init__(self, position, linearVelocity, angle, angularVelocity, force, torque, shape):
self.position = vector2(x=position.x, y=position.y).vec()
self.linearVelocity = vector2(x=linearVelocity.x, y=linearVelocity.y).vec()
self.angle = angle
self.angularVelocity = angularVelocity
self.force = vector2(x=force.x, y=force.y).vec()
self.torque = torque
self.shape = BoxShape(width=shape[0], height=shape[1], mass=1)
rigidBodies = []
def PrintRigidBodies():
for i in range(NUM_RIGID_BODIES):
rigidBody = rigidBodies[i]
print(f"body[{i}] position = {rigidBody.position} | angle = {rigidBody.angle}")
print(f" ↪ force = {rigidBody.force} | torque = {rigidBody.torque} | linearv = {rigidBody.linearVelocity}")
def InitializeRigidBodies():
for _ in range(NUM_RIGID_BODIES):
rigidBody = RigidBody(
position=vector2(x=rd.randint(0, 50), y=rd.randint(0, 50)),
linearVelocity=vector2(x=0, y=0),
angle=(rd.randint(0, 360))/360 * np.pi,
angularVelocity=0,
force=vector2(x=0, y=0),
torque=0,
shape=[1 + rd.randint(0, 2), 1 + rd.randint(0, 2), 1]
)
rigidBodies.append(rigidBody)
def ComputeForceAndTorque(rigidBody):
f = vector2(x=0, y=100)
rigidBody.force[0], rigidBody.force[1] = f.x, f.y
r = vector2(x=rigidBody.shape.width / 2, y=rigidBody.shape.height /2)
rigidBody.torque = r.x * f.y - r.y * f.x
#InitializeRigidBodies()
#PrintRigidBodies()
#ComputeForceAndTorque(rigidBodies[0])
#PrintRigidBodies()
def RunRigidBodySimulation():
totalSimulationTime = 10
currentTime = 0
dt = 1
InitializeRigidBodies()
PrintRigidBodies()
while currentTime < totalSimulationTime:
time.sleep(dt)
for i in range(NUM_RIGID_BODIES):
rigidBody = rigidBodies[i]
ComputeForceAndTorque(rigidBody)
linearAcceleration = vector2(
x = rigidBody.force[0] / rigidBody.shape.mass,
y = rigidBody.force[1] / rigidBody.shape.mass
)
rigidBody.linearVelocity[0] += linearAcceleration.x * dt
rigidBody.linearVelocity[1] += linearAcceleration.y * dt
rigidBody.position[0] += rigidBody.linearVelocity[0] * dt
rigidBody.position[1] += rigidBody.linearVelocity[1] * dt
angularAcceleration = rigidBody.torque / rigidBody.shape.momentOfInertia
rigidBody.angularVelocity = angularAcceleration * dt
rigidBody.angle = rigidBody.angularVelocity * dt
PrintRigidBodies()
currentTime += dt