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Se afișează postările cu eticheta pymunk. Afișați toate postările
Se afișează postările cu eticheta pymunk. Afișați toate postările

luni, 21 august 2017

PyGame : The pymunk python module.

First about pymunk python module:
Pymunk is an easy-to-use pythonic 2d physics library that can be used whenever you need 2d rigid body physics from Python. Perfect when you need 2d physics in your game, demo or other application!
I install it with pip and python 2.7 and I test it with one example from the official website.
The source code is this:

import sys, random
import os

description = """
---- Newton's Cradle ----
A screensaver version of Newton's Cradle with an interactive mode
/s - Run in fullscreen screensaver mode
/p #### - Display a preview of the screensaver using a window handler
/i - Interactive mode
"""

if len(sys.argv) < 2:
    print(description)
    sys.exit()

is_interactive = False
display_flags = 0
if sys.argv[1] == "/p":  # preview mode
    os.environ['SDL_VIDEODRIVER'] = 'windib'
    os.environ['SDL_WINDOWID'] = sys.argv[2]
    display_size = (100, 100)
    is_interactive = False

### We must set OS env before the pygame imports..
import pygame
from pygame.locals import *
from pygame.color import *

if sys.argv[1] == "/s":  # fullscreen screensaver mode
    display_size = (0, 0)
    is_interactive = False
    display_flags = display_flags | FULLSCREEN  # FULLSCREEN) # | DOUBLEBUF | HWSURFACE     )
elif sys.argv[1] == "/i":  # interactive
    display_size = (600, 600)
    is_interactive = True

import pymunk as pm
from pymunk import Vec2d


def drawcircle(image, colour, origin, radius, width=0):
    if width == 0:
        pygame.draw.circle(image, colour, origin, int(radius))
    else:
        if radius > 65534 / 5:
            radius = 65534 / 5
        circle = pygame.Surface([radius * 2 + width, radius * 2 + width]).convert_alpha()
        circle.fill([0, 0, 0, 0])
        pygame.draw.circle(circle, colour, [circle.get_width() / 2, circle.get_height() / 2], radius + (width / 2))
        if int(radius - (width / 2)) > 0:
            pygame.draw.circle(circle, [0, 0, 0, 0], [circle.get_width() / 2, circle.get_height() / 2],
                               abs(int(radius - (width / 2))))
        image.blit(circle, [origin[0] - (circle.get_width() / 2), origin[1] - (circle.get_height() / 2)])

def reset_bodies(space):
    for body in space.bodies:
        body.position = Vec2d(body.start_position)
        body.force = 0, 0
        body.torque = 0
        body.velocity = 0, 0
        body.angular_velocity = 0
    color = random.choice(list(THECOLORS.values()))
    for shape in space.shapes:
        shape.color = color

def main():
    pygame.init()
    screen = pygame.display.set_mode(display_size, display_flags)
    width, height = screen.get_size()

    def to_pygame(p):
        """Small hack to convert pymunk to pygame coordinates"""
        return int(p.x), int(-p.y + height)

    def from_pygame(p):
        return to_pygame(p)

    clock = pygame.time.Clock()
    running = True
    font = pygame.font.Font(None, 16)

    ### Physics stuff
    space = pm.Space()
    space.gravity = (0.0, -1900.0)
    space.damping = 0.999  # to prevent it from blowing up.
    mouse_body = pm.Body(body_type=pm.Body.KINEMATIC)

    bodies = []
    for x in range(-100, 150, 50):
        x += width / 2
        offset_y = height / 2
        mass = 10
        radius = 25
        moment = pm.moment_for_circle(mass, 0, radius, (0, 0))
        body = pm.Body(mass, moment)
        body.position = (x, -125 + offset_y)
        body.start_position = Vec2d(body.position)
        shape = pm.Circle(body, radius)
        shape.elasticity = 0.9999999
        space.add(body, shape)
        bodies.append(body)
        pj = pm.PinJoint(space.static_body, body, (x, 125 + offset_y), (0, 0))
        space.add(pj)

    reset_bodies(space)
    selected = None

    if not is_interactive:
        pygame.time.set_timer(USEREVENT + 1, 70000)  # apply force
        pygame.time.set_timer(USEREVENT + 2, 120000)  # reset
        pygame.event.post(pygame.event.Event(USEREVENT + 1))
        pygame.mouse.set_visible(False)

    while running:
        for event in pygame.event.get():
            if event.type == QUIT:
                running = False
            elif event.type == KEYDOWN and event.key == K_p:
                pygame.image.save(screen, "newtons_cradle.png")

            if event.type == pygame.USEREVENT + 1:
                r = random.randint(1, 4)
                for body in bodies[0:r]:
                    body.apply_impulse_at_local_point((-6000, 0))
            if event.type == pygame.USEREVENT + 2:
                reset_bodies(space)

            elif event.type == KEYDOWN and event.key == K_r and is_interactive:
                reset_bodies(space)
            elif event.type == KEYDOWN and event.key == K_f and is_interactive:
                r = random.randint(1, 4)
                for body in bodies[0:r]:
                    body.apply_impulse_at_local_point((-6000, 0))

            elif event.type == MOUSEBUTTONDOWN and is_interactive:
                if selected != None:
                    space.remove(selected)
                p = from_pygame(Vec2d(event.pos))
                hit = space.point_query_nearest(p, 0, pm.ShapeFilter())
                if hit != None:
                    shape = hit.shape
                    rest_length = mouse_body.position.get_distance(shape.body.position)
                    ds = pm.DampedSpring(mouse_body, shape.body, (0, 0), (0, 0), rest_length, 1000, 10)
                    space.add(ds)
                    selected = ds

            elif event.type == MOUSEBUTTONUP and is_interactive:
                if selected != None:
                    space.remove(selected)
                    selected = None

            elif event.type == KEYDOWN:
                running = False
            elif event.type == MOUSEBUTTONDOWN:
                running = False

        mpos = pygame.mouse.get_pos()
        p = from_pygame(Vec2d(mpos))
        mouse_body.position = p

        ### Clear screen
        screen.fill(THECOLORS["black"])

        ### Draw stuff
        for c in space.constraints:
            pv1 = c.a.position + c.anchor_a
            pv2 = c.b.position + c.anchor_b
            p1 = to_pygame(pv1)
            p2 = to_pygame(pv2)
            pygame.draw.aalines(screen, THECOLORS["lightgray"], False, [p1, p2])

        for ball in space.shapes:
            p = to_pygame(ball.body.position)
            drawcircle(screen, ball.color, p, int(ball.radius), 0)
            # pygame.draw.circle(screen, ball.color, p, int(ball.radius), 0)

        ### Update physics
        fps = 50
        iterations = 25
        dt = 1.0 / float(fps) / float(iterations)
        for x in range(iterations):  # 10 iterations to get a more stable simulation
            space.step(dt)

        ### Flip screen
        if is_interactive:
            screen.blit(font.render("fps: " + str(clock.get_fps()), 1, THECOLORS["white"]), (0, 0))
            screen.blit(font.render("Press left mouse button and drag to interact", 1, THECOLORS["darkgrey"]),
                        (5, height - 35))
            screen.blit(font.render("Press R to reset, any other key to quit", 1, THECOLORS["darkgrey"]),
                        (5, height - 20))

        pygame.display.flip()
        clock.tick(fps)

if __name__ == '__main__':
    sys.exit(main()

I test with this command:

C:\Python27>python.exe newtons_cradle.py /i

The result work well, see the next image: