source: nagslang/game_object.py @ 140:f36a7075d9a0

import math

import pygame
import pymunk
import pymunk.pygame_util

from nagslang.constants import (
    SWITCH_PUSHERS, COLLISION_TYPE_SWITCH, COLLISION_TYPE_BOX, ZORDER_LOW)
from nagslang.options import options


class PuzzleGlue(object):
    """Glue that holds bits of a puzzle together.
    """
    def __init__(self):
        self._components = {}

    def add_component(self, name, puzzler):
        self._components[name] = puzzler
        puzzler.set_glue(self)

    def get_state_of(self, name):
        return self._components[name].get_state()


class Puzzler(object):
    """Behaviour specific to a puzzle component.
    """
    def set_glue(self, glue):
        self.glue = glue

    def set_game_object(self, game_object):
        self.game_object = game_object

    def get_state(self):
        raise NotImplementedError()


class FloorSwitchPuzzler(Puzzler):
    def get_state(self):
        space = self.game_object.get_space()
        for shape in space.shape_query(self.game_object.get_shape()):
            if shape.collision_type in SWITCH_PUSHERS:
                return True
        return False


class StateProxyPuzzler(Puzzler):
    def __init__(self, state_source):
        self._state_source = state_source

    def get_state(self):
        return self.glue.get_state_of(self._state_source)


class StateLogicalAndPuzzler(Puzzler):
    def __init__(self, *state_sources):
        self._state_sources = state_sources

    def get_state(self):
        for state_source in self._state_sources:
            if not self.glue.get_state_of(state_source):
                return False
        return True


class Physicser(object):
    def __init__(self, space):
        self._space = space

    def get_space(self):
        return self._space

    def set_game_object(self, game_object):
        self.game_object = game_object

    def get_shape(self):
        raise NotImplementedError()

    def add_to_space(self):
        raise NotImplementedError()

    def remove_from_space(self):
        raise NotImplementedError()

    def get_render_position(self, surface):
        raise NotImplementedError()

    def get_angle(self):
        raise NotImplementedError()

    def apply_impulse(self, j, r=(0, 0)):
        raise NotImplementedError()


class SingleShapePhysicser(Physicser):
    def __init__(self, space, shape):
        super(SingleShapePhysicser, self).__init__(space)
        self._shape = shape

    def get_shape(self):
        return self._shape

    def add_to_space(self):
        self.get_space().add(self._shape)
        if not self._shape.body.is_static:
            self.get_space().add(self._shape.body)

    def remove_from_space(self):
        self.get_space().remove(self._shape)
        if not self._shape.body.is_static:
            self.get_space().remove(self._shape.body)

    def get_render_position(self, surface):
        pos = self._shape.body.position
        return pymunk.pygame_util.to_pygame(pos, surface)

    def get_angle(self):
        return self._shape.body.angle

    def apply_impulse(self, j, r=(0, 0)):
        return self._shape.body.apply_impulse(j, r)


class Renderer(object):
    def set_game_object(self, game_object):
        self.game_object = game_object

    def _render_shape(self, surface):
        shape = self.game_object.get_shape()
        # Less general that pymunk.pygame_util.draw, but also a lot less noisy.
        color = getattr(shape, 'color', pygame.color.THECOLORS['lightblue'])
        # We only explicitly draw Circle and Poly shapes. Everything else we
        # forward to pymunk.
        if isinstance(shape, pymunk.Circle):
            centre = pymunk.pygame_util.to_pygame(shape.body.position, surface)
            radius = int(shape.radius)
            pygame.draw.circle(surface, color, centre, radius, 2)
        elif isinstance(shape, pymunk.Poly):
            # polygon bounding box
            points = [pymunk.pygame_util.to_pygame(p, surface)
                      for p in shape.get_vertices()]
            pygame.draw.lines(surface, color, True, points, 2)
        else:
            pymunk.pygame_util.draw(surface, shape)

    def render(self, surface):
        pos = self.game_object.get_render_position(surface)
        angle = self.game_object.get_render_angle()
        if options.debug:
            self._render_shape(surface, pos, angle)


def image_pos(image, pos):
    return (pos[0] - image.get_width() / 2,
            pos[1] - image.get_height() / 2)


class ImageRenderer(Renderer):
    def __init__(self, image):
        self._image = image

    def render(self, surface):
        pos = self.game_object.get_render_position(surface)
        surface.blit(self._image, image_pos(self._image, pos))
        super(ImageRenderer, self).render(surface)


class FacingImageRenderer(Renderer):
    def __init__(self, left_image, right_image):
        self._images = {
            'left': left_image,
            'right': right_image,
        }

    def get_image(self, angle):
        if abs(angle) < math.pi / 2:
            return self._images['right']
        return self._images['left']

    def render(self, surface):
        pos = self.game_object.get_render_position(surface)
        image = self.get_image(self.game_object.get_render_angle())
        surface.blit(image, image_pos(image, pos))
        super(FacingImageRenderer, self).render(surface)


class ShapeRenderer(Renderer):
    def render(self, surface):
        self._render_shape(surface)
        super(ShapeRenderer, self).render(surface)


class ShapeStateRenderer(ShapeRenderer):
    """Renders the shape in a different colour depending on the state.

    Requires the game object it's attached to to have a puzzler.
    """
    def render(self, surface):
        if self.game_object.puzzler.get_state():
            color = pygame.color.THECOLORS['green']
        else:
            color = pygame.color.THECOLORS['red']

        self.game_object.get_shape().color = color
        super(ShapeStateRenderer, self).render(surface)


def damping_velocity_func(body, gravity, damping, dt):
    """Apply custom damping to this body's velocity.
    """
    damping = getattr(body, 'damping', damping)
    return pymunk.Body.update_velocity(body, gravity, damping, dt)


def make_body(mass, moment, position, damping=None):
    body = pymunk.Body(mass, moment)
    body.position = position
    if damping is not None:
        body.damping = damping
        body.velocity_func = damping_velocity_func
    return body


class GameObject(object):
    """A representation of a thing in the game world.

    This has a rendery thing, physicsy things and maybe some other things.
    """

    def __init__(self, physicser, renderer, puzzler=None):
        self.physicser = physicser
        physicser.set_game_object(self)
        self.physicser.add_to_space()
        self.renderer = renderer
        renderer.set_game_object(self)
        self.puzzler = puzzler
        if puzzler is not None:
            puzzler.set_game_object(self)
        self.zorder = ZORDER_LOW

    def get_space(self):
        return self.physicser.get_space()

    def get_shape(self):
        return self.physicser.get_shape()

    def get_render_position(self, surface):
        return self.physicser.get_render_position(surface)

    def get_render_angle(self):
        return self.physicser.get_angle()

    def render(self, surface):
        return self.renderer.render(surface)


class FloorSwitch(GameObject):
    def __init__(self, space, position):
        body = pymunk.Body()
        body.position = position
        self.shape = pymunk.Circle(body, 30)
        self.shape.collision_type = COLLISION_TYPE_SWITCH
        self.shape.sensor = True
        super(FloorSwitch, self).__init__(
            SingleShapePhysicser(space, self.shape),
            ShapeStateRenderer(),
            FloorSwitchPuzzler(),
        )


class FloorLight(GameObject):
    def __init__(self, space, position, state_source):
        body = pymunk.Body()
        body.position = position
        self.shape = pymunk.Circle(body, 10)
        self.shape.collision_type = COLLISION_TYPE_SWITCH
        self.shape.sensor = True
        super(FloorLight, self).__init__(
            SingleShapePhysicser(space, self.shape),
            ShapeStateRenderer(),
            StateProxyPuzzler(state_source),
        )


class Box(GameObject):
    def __init__(self, space, position):
        body = make_body(10, 10000, position, damping=0.5)
        self.shape = pymunk.Poly(
            body, [(-20, -20), (20, -20), (20, 20), (-20, 20)])
        self.shape.collision_type = COLLISION_TYPE_BOX
        super(Box, self).__init__(
            SingleShapePhysicser(space, self.shape),
            ShapeRenderer(),
        )