def execute(self, obj):
maxforward = obj.maxspeed * obj.heading * 0.5
pressed = pygame.key.get_pressed()
if pressed[K_LEFT]:
desired_velocity = V.rotate(maxforward, -5)
elif pressed[K_RIGHT]:
desired_velocity = V.rotate(maxforward, 5)
else:
desired_velocity = obj.velocity
obj.steering = 0.0
obj.velocity = desired_velocity
obj.heading = V.normalize(obj.velocity)
def execute(self, obj):
maxforward = obj.maxspeed*obj.heading*0.5
pressed = pygame.key.get_pressed()
if pressed[K_LEFT]:
desired_velocity = V.rotate(maxforward, -5)
elif pressed[K_RIGHT]:
desired_velocity = V.rotate(maxforward, 5)
else:
desired_velocity = obj.velocity
obj.steering = 0.0
obj.velocity = desired_velocity
obj.heading = V.normalize(obj.velocity)
def move(self, env):
#physics of forces on sail here
#src:https://en.wikipedia.org/wiki/Forces_on_sails#Effect_of_coefficients_of_lift_and_drag_on_forces
#f: (angle between wind and sail) -> (total force on sail)
# function returns matrix: Matrix * Wind = Total Force
def force_on_sails_matrix(wind, sail):
#1. get angle between wind and sail
orientation = np.sign(np.cross(wind, sail))
angle = v.angle(wind, sail)
if np.pi/2 < angle <= np.pi:
angle = abs(np.pi - angle)
orientation *= -1
#2. get forces on sail (for 0 <= angle <= pi/2)
#every ship has different parameters
#so this is just game model boat
#to test control self-education ability
drag = np.exp(abs(angle)/2) - 1
lift = -orientation * np.exp(-20*(angle - 0.6)**2)
return np.array([[drag, -lift], [lift, drag]])
#1. rotation
k_rotate = 0.05 * v.length(self.speed) #wheel -> rotate coefficient
self.speed = v.rotate(self.speed, (-1) * self.wheel * k_rotate)
#2. friction
k_friction = 0.05
self.speed = self.speed * (1 - k_friction)
#3. acceleration = forces on sails -> projection on boat direction
k_acceleration = 0.1
wind_apparent = env.wind - self.speed
total_force_matrix = force_on_sails_matrix(wind_apparent, v.rotate(self.speed, self.sail))
total_force = np.dot(total_force_matrix, wind_apparent)
self.speed += k_acceleration * v.projection(total_force, self.speed)
#4. move
self.location += self.speed
plt.show()
return True
#draw_vectors([np.array([1,5]), (2, 3)])
def force_on_sails_matrix(wind, sail):
#get angle between wind and sail
orientation = np.sign(np.cross(wind, sail))
angle = v.angle(wind, sail)
if np.pi/2 < angle <= np.pi:
angle = abs(np.pi - angle)
orientation *= -1
#get forces on sail (for 0 <= angle <= pi/2)
drag = np.exp(abs(angle)/2) - 1
lift = -orientation * np.exp(-20*(angle - 0.6)**2)
return np.array([[drag, -lift], [lift, drag]])
wind_apparent = np.array([1, 0])
speed = np.array([1, 0.5])
sail_angle = np.pi/180 * (110)
total_matrix = force_on_sails_matrix(wind_apparent, v.rotate(speed, sail_angle))
total = np.dot(total_matrix, wind)
print('wind=', wind)
draw_vectors([wind, speed, total])