def __init__(self, entity, mass, gravity, elasticity, friction):
self.entity = entity
self.mass = mass
self.gravity = gravity
self.elasticity = elasticity
self.friction = friction
self.velocity = Vector(0, 0)
self.forces = []
self.last_position = 0, 0
def get_instantaneous_velocity(self):
entity = self.entity
x, y = entity.position
lx, ly = self.last_position
x -= lx
y -= ly
return Vector(x, y)
def integrate_forces(self):
forces = self.forces
self.forces = []
i, j = 0, 0
for f in forces:
i += f.i_hat
j += f.j_hat
acceleration = Vector(i, j).scale(1 / self.mass)
self.velocity.add_vector(acceleration)
def set_vector_image(entity, *args):
if entity.graphics is None:
entity.graphics = GeometryGraphics(entity)
if len(args) > 3:
color, start, end, width = args
else:
color, start, end = args
width = 1
ox, oy = start
if (ox, oy) == (0, 0):
v = Vector(*end)
else:
v = Wall(start, end)
entity.graphics.items.append((v, color, width))
def apply_force(self, i, j):
self.forces.append(Vector(i, j))
class Physics:
def __init__(self, entity, mass, gravity, elasticity, friction):
self.entity = entity
self.mass = mass
self.gravity = gravity
self.elasticity = elasticity
self.friction = friction
self.velocity = Vector(0, 0)
self.forces = []
self.last_position = 0, 0
def get_instantaneous_velocity(self):
entity = self.entity
x, y = entity.position
lx, ly = self.last_position
x -= lx
y -= ly
return Vector(x, y)
def set_mass(self, value):
self.mass = value
def set_elasticity(self, value):
self.elasticity = value
def set_gravity(self, value):
self.gravity = value
def set_friction(self, value):
self.friction = value
def scale_movement_in_direction(self, angle, value):
self.velocity.scale_in_direction(angle, value)
def apply_force(self, i, j):
self.forces.append(Vector(i, j))
def integrate_forces(self):
forces = self.forces
self.forces = []
i, j = 0, 0
for f in forces:
i += f.i_hat
j += f.j_hat
acceleration = Vector(i, j).scale(1 / self.mass)
self.velocity.add_vector(acceleration)
def apply_velocity(self):
self.entity.move(*self.velocity.get_value())
def update(self):
self.last_position = self.entity.position
# gravity
if self.gravity:
g = self.gravity * self.mass
self.apply_force(0, g)
self.integrate_forces()
# movement
self.apply_velocity()
self.velocity.scale(1 - self.friction)
def get_adjustment(o):
x, y = o.get_center_of_mass()
cx, cy = collision
v = Vector(cx - x, cy - y)
return v
def check_orientation(s):
x, y = s.get_center_of_mass()
cx, cy = collision
heading = Vector(cx - x, cy - y)
return s.get_velocity().check_orientation(heading)