Source code for examples.arrows
import sys
import pygame
from pygame.locals import *
from pygame.color import *
import pymunk
from pymunk.vec2d import Vec2d
from pymunk.pygame_util import draw_space, from_pygame
[docs]def create_arrow():
vs = [(-30,0), (0,3), (10,0), (0,-3)]
mass = 1
moment = pymunk.moment_for_poly(mass, vs)
arrow_body = pymunk.Body(mass, moment)
arrow_shape = pymunk.Poly(arrow_body, vs)
arrow_shape.friction = .5
arrow_shape.collision_type = 1
return arrow_body, arrow_shape
[docs]def stick_arrow_to_target(arrow_body, target_body, position, space):
pivot_joint = pymunk.PivotJoint(arrow_body, target_body, position)
phase = target_body.angle - arrow_body.angle
gear_joint = pymunk.GearJoint(arrow_body, target_body,phase,1)
space.add(pivot_joint)
space.add(gear_joint)
[docs]def post_solve_arrow_hit(space, arbiter):
if arbiter.total_impulse.length > 300:
a,b = arbiter.shapes
position = arbiter.contacts[0].position
b.collision_type = 0
b.group = 1
other_body = a.body
arrow_body = b.body
space.add_post_step_callback(stick_arrow_to_target, arrow_body, other_body, position, space)
width, height = 800,600
[docs]def main():
### PyGame init
pygame.init()
screen = pygame.display.set_mode((width,height))
clock = pygame.time.Clock()
running = True
font = pygame.font.SysFont("Arial", 16)
### Physics stuff
space = pymunk.Space()
space.gravity = 0,-1000
# walls - the left-top-right walls
static= [pymunk.Segment(space.static_body, (50, 50), (50, 550), 5)
,pymunk.Segment(space.static_body, (50, 550), (750, 550), 5)
,pymunk.Segment(space.static_body, (750, 550), (750, 50), 5)
,pymunk.Segment(space.static_body, (50, 50), (750, 50), 5)
]
b2 = pymunk.Body()
static.append(pymunk.Circle(b2, 30))
b2.position = 300,400
for s in static:
s.friction = 1.
s.group = 1
space.add_static(static)
# "Cannon" that can fire arrows
cannon_body = pymunk.Body(pymunk.inf, pymunk.inf)
cannon_shape = pymunk.Circle(cannon_body, 25)
cannon_shape.sensor = True
cannon_body.position = 100,100
space.add(cannon_shape)
arrow_body,arrow_shape = create_arrow()
space.add(arrow_shape)
space.add_collision_handler(0, 1, post_solve=post_solve_arrow_hit)
flying_arrows = []
while running:
for event in pygame.event.get():
if event.type == QUIT or \
event.type == KEYDOWN and (event.key in [K_ESCAPE, K_q]):
running = False
elif event.type == pygame.MOUSEBUTTONDOWN and event.button == 1:
start_time = pygame.time.get_ticks()
elif event.type == pygame.MOUSEBUTTONUP and event.button == 1:
end_time = pygame.time.get_ticks()
diff = end_time - start_time
power = max(min(diff, 1000), 10) * 1.5
impulse = power * Vec2d(1,0)
arrow_body.apply_impulse(impulse.rotated(arrow_body.angle))
space.add(arrow_body)
flying_arrows.append(arrow_body)
arrow_body, arrow_shape = create_arrow()
space.add(arrow_shape)
keys = pygame.key.get_pressed()
speed = 2.5
if (keys[K_UP]):
cannon_body.position += Vec2d(0,1) * speed
if (keys[K_DOWN]):
cannon_body.position += Vec2d(0,-1) * speed
if (keys[K_LEFT]):
cannon_body.position += Vec2d(-1,0) * speed
if (keys[K_RIGHT]):
cannon_body.position += Vec2d(1,0) * speed
mouse_position = from_pygame( Vec2d(pygame.mouse.get_pos()), screen )
cannon_body.angle = (mouse_position - cannon_body.position).angle
# move the unfired arrow together with the cannon
arrow_body.position = cannon_body.position + Vec2d(cannon_shape.radius + 40, 0).rotated(cannon_body.angle)
arrow_body.angle = cannon_body.angle
for flying_arrow in flying_arrows:
drag_constant = 0.0002
pointing_direction = Vec2d(1,0).rotated(flying_arrow.angle)
flight_direction = Vec2d(flying_arrow.velocity)
flight_speed = flight_direction.normalize_return_length()
dot = flight_direction.dot(pointing_direction)
drag_force_magnitude = (1-abs(dot)) * flight_speed **2 * drag_constant * flying_arrow.mass
arrow_tail_position = Vec2d(-50, 0).rotated(flying_arrow.angle)
flying_arrow.apply_impulse(drag_force_magnitude * -flight_direction, arrow_tail_position)
flying_arrow.angular_velocity *= 0.9
### Clear screen
screen.fill(pygame.color.THECOLORS["black"])
### Draw stuff
draw_space(screen, space)
# Power meter
if pygame.mouse.get_pressed()[0]:
current_time = pygame.time.get_ticks()
diff = current_time - start_time
power = max(min(diff, 1000), 10)
h = power / 2
pygame.draw.line(screen, pygame.color.THECOLORS["red"], (30,550), (30,550-h), 10)
# Info and flip screen
screen.blit(font.render("fps: " + str(clock.get_fps()), 1, THECOLORS["white"]), (0,0))
screen.blit(font.render("Aim with mouse, hold LMB to powerup, release to fire", 1, THECOLORS["darkgrey"]), (5,height - 35))
screen.blit(font.render("Press R to reset, ESC or Q to quit", 1, THECOLORS["darkgrey"]), (5,height - 20))
pygame.display.flip()
### Update physics
fps = 60
dt = 1./fps
space.step(dt)
clock.tick(fps)
if __name__ == '__main__':
sys.exit(main())