Beispiel #1
0
def _get_config(num_ghosts, maze_size):
    """Get environment config."""

    ############################################################################
    # Sprite initialization
    ############################################################################

    # Agent
    agent_factors = dict(shape='circle', scale=0.05, c0=0.33, c1=1., c2=0.66)

    # Prey
    prey_factors = dict(shape='circle', scale=0.025, c0=0.2, c1=1., c2=1.)

    # Ghosts
    ghost_factors = dict(shape='circle',
                         scale=0.05,
                         mass=np.inf,
                         c0=0.,
                         c1=1.,
                         c2=0.8)

    def state_initializer():
        maze = maze_lib.generate_random_maze_matrix(size=maze_size,
                                                    ambient_size=12)
        maze = maze_lib.Maze(np.flip(maze, axis=0))
        walls = maze.to_sprites(c0=0., c1=0., c2=0.8)

        # Sample positions in maze grid of agent and ghosts
        n_ghosts = num_ghosts()
        points = maze.sample_distinct_open_points(1 + n_ghosts)
        positions = [maze.grid_side * (0.5 + np.array(x)) for x in points]

        # Agent
        agent_position = positions[0]
        agent = [
            sprite.Sprite(x=agent_position[1],
                          y=agent_position[0],
                          **agent_factors)
        ]

        # ghosts
        ghosts = []
        for i in range(n_ghosts):
            position = positions[i + 1]
            ghosts.append(
                sprite.Sprite(x=position[1], y=position[0], **ghost_factors))

        # Place prey at every open maze location
        prey = []
        open_maze_points = np.argwhere(maze.maze == 0)
        for p in open_maze_points:
            pos = maze.grid_side * (0.5 + np.array(p))
            prey.append(sprite.Sprite(x=pos[1], y=pos[0], **prey_factors))

        state = collections.OrderedDict([
            ('walls', walls),
            ('prey', prey),
            ('ghosts', ghosts),
            ('agent', agent),
        ])
        return state

    ############################################################################
    # Physics
    ############################################################################

    maze_physics = physics_lib.MazePhysics(
        maze_layer='walls',
        avatar_layers=('agent', 'prey', 'ghosts'),
        constant_speed=0.015,
    )

    physics = physics_lib.Physics(
        (physics_lib.RandomMazeWalk(speed=0.015), ['ghosts']),
        updates_per_env_step=1,
        corrective_physics=[maze_physics],
    )

    ############################################################################
    # Task
    ############################################################################

    ghost_task = tasks.ContactReward(-5,
                                     layers_0='agent',
                                     layers_1='ghosts',
                                     reset_steps_after_contact=0)
    prey_task = tasks.ContactReward(1, layers_0='agent', layers_1='prey')
    reset_task = tasks.Reset(
        condition=lambda state: len(state['prey']) == 0,
        steps_after_condition=5,
    )
    task = tasks.CompositeTask(ghost_task,
                               prey_task,
                               reset_task,
                               timeout_steps=1000)

    ############################################################################
    # Action space
    ############################################################################

    action_space = action_spaces.Grid(
        scaling_factor=0.015,
        action_layers='agent',
        control_velocity=True,
        momentum=0.5,  # Value irrelevant, since maze_physics has constant speed
    )

    ############################################################################
    # Observer
    ############################################################################

    observer = observers.PILRenderer(
        image_size=(256, 256),
        anti_aliasing=1,
        color_to_rgb='hsv_to_rgb',
    )

    ############################################################################
    # Game rules
    ############################################################################

    def _unglue(s):
        s.mass = 1.

    def _unglue_condition(state):
        return not np.all(state['agent'][0].velocity == 0)

    unglue = game_rules.ConditionalRule(
        condition=_unglue_condition,
        rules=game_rules.ModifySprites(('prey', 'ghosts'), _unglue),
    )

    vanish_on_contact = game_rules.VanishOnContact(vanishing_layer='prey',
                                                   contacting_layer='agent')

    rules = (vanish_on_contact, unglue)

    ############################################################################
    # Final config
    ############################################################################

    config = {
        'state_initializer': state_initializer,
        'physics': physics,
        'task': task,
        'action_space': action_space,
        'observers': {
            'image': observer
        },
        'game_rules': rules,
    }
    return config
Beispiel #2
0
def get_config(num_targets):
    """Get environment config.
    
    Args:
        num_targets: Int. Number of targets.
    """
    if num_targets == 0 or not isinstance(num_targets, int):
        raise ValueError(
            f'num_targets is {num_targets}, but must be a positive integer')

    ############################################################################
    # State initialization
    ############################################################################

    screen = sprite.Sprite(x=0.5,
                           y=0.5,
                           shape='square',
                           scale=2.,
                           c0=0.6,
                           c1=0.7,
                           c2=0.7)

    target_factor_distrib = distribs.Product(
        [distribs.Continuous('c0', 0., 1.)],
        shape='circle',
        scale=0.085,
        c1=1.,
        c2=1.,
    )
    cover_factors = dict(mass=0.,
                         shape='circle',
                         scale=0.1,
                         c0=0.,
                         c1=0.,
                         c2=0.5,
                         opacity=0)

    def state_initializer():
        """State initializer method to be fed into environment."""

        # Get targets and covers
        sprite_positions = 0.5 + 0.35 * _get_polygon(num_targets, 0.7)
        target_factors = [
            target_factor_distrib.sample() for _ in range(num_targets)
        ]
        targets = [
            sprite.Sprite(x=pos[0], y=pos[1], **factors)
            for pos, factors in zip(sprite_positions, target_factors)
        ]
        covers = [
            sprite.Sprite(x=pos[0], y=pos[1], **cover_factors)
            for pos in sprite_positions
        ]

        # Tag the cover metadata based on whether they are prey or not
        for i, s in enumerate(covers):
            if i == 0:
                s.metadata = {'prey': True}
            else:
                s.metadata = {'prey': False}

        # Make cue have the same factors as the first target, except slightly
        # smaller
        cue_factors = copy.deepcopy(target_factors[0])
        cue_factors['scale'] = 0.7 * target_factors[0]['scale']
        cue = sprite.Sprite(x=0.5,
                            y=0.501,
                            opacity=0,
                            mass=np.inf,
                            **cue_factors)

        agent = sprite.Sprite(x=0.5,
                              y=0.5,
                              shape='circle',
                              scale=0.1,
                              c0=0.4,
                              c1=0.,
                              c2=1.,
                              mass=np.inf)
        annulus_verts = shapes.annulus_vertices(0.34, 0.36)
        annulus = sprite.Sprite(x=0.5,
                                y=0.5,
                                shape=annulus_verts,
                                scale=1.,
                                c0=0.,
                                c1=0.,
                                c2=0.3)

        state = collections.OrderedDict([
            ('annulus', [annulus]),
            ('targets', targets),
            ('covers', covers),
            ('agent', [agent]),
            ('cue', [cue]),
            ('screen', [screen]),
        ])
        return state

    ################################################################################
    # Physics
    ################################################################################

    drag = (physics_lib.Drag(coeff_friction=0.25), ['agent', 'cue'])
    tether_covers = physics_lib.TetherZippedLayers(('targets', 'covers'),
                                                   anchor=np.array([0.5, 0.5]))
    physics = physics_lib.Physics(
        drag,
        updates_per_env_step=1,
        corrective_physics=[tether_covers],
    )

    ################################################################################
    # Task
    ################################################################################

    contact_task = tasks.ContactReward(
        reward_fn=lambda _, s: 1 if s.metadata['prey'] else -1,
        layers_0='agent',
        layers_1='covers',
    )

    def _should_reset(state, meta_state):
        should_reset = (state['covers'][0].opacity == 0
                        and meta_state['phase'] == 'response')
        return should_reset

    reset_task = tasks.Reset(
        condition=_should_reset,
        steps_after_condition=15,
    )

    task = tasks.CompositeTask(contact_task, reset_task, timeout_steps=800)

    ################################################################################
    # Action Space
    ################################################################################

    action_space = action_spaces.Joystick(scaling_factor=0.01,
                                          action_layers=['agent', 'cue'])

    ################################################################################
    # Observer
    ################################################################################

    _polygon_modifier = observers.polygon_modifiers.FirstPersonAgent(
        agent_layer='agent')
    observer = observers.PILRenderer(
        image_size=(64, 64),
        anti_aliasing=1,
        color_to_rgb='hsv_to_rgb',
        polygon_modifier=_polygon_modifier,
    )

    ############################################################################
    # Game rules
    ############################################################################

    def _make_opaque(s):
        s.opacity = 255

    def _make_transparent(s):
        s.opacity = 0

    # Screen Phase

    screen_phase = gr.Phase(duration=1, name='screen')

    # Visible Phase

    disappear_screen = gr.ModifySprites('screen', _make_transparent)
    visible_phase = gr.Phase(one_time_rules=disappear_screen,
                             duration=2,
                             name='visible')

    # Motion Phase

    def _move(s):
        s.velocity = np.random.uniform(-0.25, 0.25, size=(2, ))

    cover_targets = gr.ModifySprites('covers', _make_opaque)
    begin_motion = BeginMotion(angle_vel_range=(0.1, 0.3))
    motion_phase = gr.Phase(
        one_time_rules=[cover_targets, begin_motion],
        duration=100,
        name='motion',
    )

    # Response Phase

    def _stop(s):
        s.angle_vel = 0.
        s.velocity = np.zeros(2)

    def _unglue(s):
        s.mass = 1.

    appear_cue = gr.ModifySprites('cue', _make_opaque)
    stop_targets = gr.ModifySprites(('targets', 'covers'), _stop)
    unglue_agent = gr.ModifySprites(('agent', 'cue'), _unglue)
    make_targets_discoverable = gr.ModifyOnContact(
        layers_0='agent', layers_1='covers', modifier_1=_make_transparent)

    response_phase = gr.Phase(
        one_time_rules=[appear_cue, stop_targets, unglue_agent],
        continual_rules=make_targets_discoverable,
        name='response',
    )

    phase_sequence = gr.PhaseSequence(
        screen_phase,
        visible_phase,
        motion_phase,
        response_phase,
        meta_state_phase_name_key='phase',
    )

    ############################################################################
    # Final config
    ############################################################################

    config = {
        'state_initializer': state_initializer,
        'physics': physics,
        'task': task,
        'action_space': action_space,
        'observers': {
            'image': observer
        },
        'game_rules': (phase_sequence, ),
        'meta_state_initializer': lambda: {
            'phase': ''
        }
    }
    return config
def _get_config(num_prey, num_predators):
    """Get environment config."""

    ############################################################################
    # Sprite initialization
    ############################################################################

    # Agent
    agent_factors = distribs.Product(
        [distribs.Continuous('x', 0., 1.),
         distribs.Continuous('y', 0., 1.)],
        scale=0.08, c0=0, c1=255, c2=0,
    )

    # Predators
    predator_factors = distribs.Product(
        [distribs.Continuous('x', 0., 1.),
         distribs.Continuous('y', 0., 1.),
         distribs.Continuous('x_vel', -0.02, 0.02),
         distribs.Continuous('y_vel', -0.02, 0.02),],
        scale=0.08, shape='circle', opacity=192, c0=255, c1=0, c2=0,
    )

    # Prey
    prey_factors = distribs.Product(
        [distribs.Continuous('x', 0., 1.),
         distribs.Continuous('y', 0., 1.),
         distribs.Continuous('x_vel', -0.02, 0.02),
         distribs.Continuous('y_vel', -0.02, 0.02),],
        scale=0.08, shape='circle', opacity=192, c0=255, c1=255, c2=0,
    )

    # Create callable initializer returning entire state
    predator_generator = sprite_generators.generate_sprites(
        predator_factors, num_sprites=num_predators)
    prey_generator = sprite_generators.generate_sprites(
        prey_factors, num_sprites=num_prey)

    def state_initializer():
        """Callable returning state at every episode reset."""
        agent = sprite.Sprite(**agent_factors.sample())
        predators = predator_generator(without_overlapping=(agent,))
        prey = prey_generator(without_overlapping=(agent,))

        state = collections.OrderedDict([
            ('prey', prey),
            ('predators', predators),
            ('agent', [agent]),
        ])
        return state

    ############################################################################
    # Physics
    ############################################################################

    agent_friction_force = physics_lib.Drag(coeff_friction=0.25)
    random_force = physics_lib.RandomForce(max_force_magnitude=0.01)
    predator_attraction = physics_lib.DistanceForce(
        physics_lib.linear_force_fn(zero_intercept=-0.001, slope=0.0005))
    prey_avoid = physics_lib.DistanceForce(
        physics_lib.linear_force_fn(zero_intercept=0.001, slope=-0.0005))

    forces = (
        (agent_friction_force, 'agent'),
        (random_force, ['predators', 'prey']),
        (predator_attraction, 'agent', 'predators'),
        (prey_avoid, 'agent', 'prey'),
    )

    constant_speed = physics_lib.ConstantSpeed(
        layer_names=['prey', 'predators'], speed=0.015)

    physics = physics_lib.Physics(
        *forces,
        updates_per_env_step=10,
        corrective_physics=[constant_speed],
    )

    ############################################################################
    # Task
    ############################################################################

    predator_task = tasks.ContactReward(
        -5, layers_0='agent', layers_1='predators', reset_steps_after_contact=0)
    prey_task = tasks.ContactReward(1, layers_0='agent', layers_1='prey')
    reset_task = tasks.Reset(
        condition=lambda state: len(state['prey']) == 0,
        steps_after_condition=5,
    )
    task = tasks.CompositeTask(
        reset_task, predator_task, prey_task, timeout_steps=300)

    ############################################################################
    # Action space
    ############################################################################

    action_space = action_spaces.Joystick(
        scaling_factor=0.025, action_layers='agent', control_velocity=True)

    ############################################################################
    # Observer
    ############################################################################

    observer = observers.PILRenderer(
        image_size=(64, 64),
        anti_aliasing=1,
        polygon_modifier=polygon_modifiers.TorusGeometry(
            ['agent', 'predators', 'prey']),
    )

    ############################################################################
    # Game rules
    ############################################################################

    prey_vanish = game_rules.VanishOnContact(
        vanishing_layer='prey', contacting_layer='agent')
    def _torus_position_wrap(s):
        s.position = np.remainder(s.position, 1)
    torus_position_wrap = game_rules.ModifySprites(
        ('agent', 'predators', 'prey'), _torus_position_wrap)

    rules = (prey_vanish, torus_position_wrap)

    ############################################################################
    # Final config
    ############################################################################

    config = {
        'state_initializer': state_initializer,
        'physics': physics,
        'task': task,
        'action_space': action_space,
        'observers': {'image': observer},
        'game_rules': rules,
    }
    return config
Beispiel #4
0
def get_config(_):
    """Get environment config."""

    ############################################################################
    # Sprite initialization
    ############################################################################

    # Agents
    agent_factors = distribs.Product(
        [distribs.Continuous('x', 0., 1.),
         distribs.Continuous('y', 0.35, 0.65)],
        shape='circle', scale=0.1, c1=1., c2=0.7,
    )
    agent_0_factors = distribs.Product([agent_factors], c0=0.2)
    agent_1_factors = distribs.Product([agent_factors], c0=0.1)
    agent_2_factors = distribs.Product([agent_factors], c0=0.)

    # Walls
    walls = shapes.border_walls(visible_thickness=0.05, c0=0., c1=0., c2=0.5)

    # Fountains
    fountain_factors = {
        'shape': 'circle', 'scale': 0.05, 'c0': 0.6, 'c1': 1., 'c2': _BAD_VALUE}
    fountains_across = np.linspace(0.1, 0.9, 6)
    fountains_up = np.linspace(0.75, 0.9, 2)
    fountains_grid_x, fountains_grid_y = np.meshgrid(fountains_across,
                                                     fountains_up)
    fountains_positions = zip(np.ravel(fountains_grid_x),
                              np.ravel(fountains_grid_y))
    fountain_sprites = [
        sprite.Sprite(x=x, y=y, **fountain_factors)
        for (x, y) in fountains_positions
    ]

    # Fruits
    fruit_factors = {
        'shape': 'circle', 'scale': 0.05, 'c0': 0.3, 'c1': 1., 'c2': _BAD_VALUE}
    fruits_across = np.linspace(0.1, 0.9, 6)
    fruits_up = np.linspace(0.1, 0.25, 2)
    fruits_grid_x, fruits_grid_y = np.meshgrid(fruits_across, fruits_up)
    fruits_positions = zip(np.ravel(fruits_grid_x), np.ravel(fruits_grid_y))
    fruit_sprites = [
        sprite.Sprite(x=x, y=y, **fruit_factors)
        for (x, y) in fruits_positions
    ]

    # Create callable initializer returning entire state
    agent_0_generator = sprite_generators.generate_sprites(
        agent_0_factors, num_sprites=1)
    agent_1_generator = sprite_generators.generate_sprites(
        agent_1_factors, num_sprites=1)
    agent_2_generator = sprite_generators.generate_sprites(
        agent_2_factors, num_sprites=1)

    def state_initializer():
        agent_0 = agent_0_generator(without_overlapping=walls)
        agent_1 = agent_1_generator(without_overlapping=walls)
        agent_2 = agent_2_generator(without_overlapping=walls)
        state = collections.OrderedDict([
            ('walls', walls),
            ('fountains', fountain_sprites),
            ('fruits', fruit_sprites),
            ('agent_2', agent_2),
            ('agent_1', agent_1),
            ('agent_0', agent_0),
        ])
        return state

    ############################################################################
    # Physics
    ############################################################################

    agent_friction_force = physics_lib.Drag(coeff_friction=0.25)
    asymmetric_collision = physics_lib.Collision(
        elasticity=0.25, symmetric=False)
    
    forces = (
        (agent_friction_force, ['agent_0', 'agent_1', 'agent_2']),
        (asymmetric_collision, ['agent_0', 'agent_1', 'agent_2'], 'walls'),
    )
    
    physics = physics_lib.Physics(*forces, updates_per_env_step=5)

    ############################################################################
    # Task
    ############################################################################

    task = tasks.ContactReward(
        1, layers_0='agent_0', layers_1='fruits',
        condition=lambda s_0, s_1: s_1.c2 > _VALUE_THRESHOLD,
    )

    ############################################################################
    # Action space
    ############################################################################

    action_space = action_spaces.Composite(
        agent_0=action_spaces.Joystick(
            scaling_factor=0.005, action_layers='agent_0'),
        agent_1=action_spaces.Joystick(
            scaling_factor=0.005, action_layers='agent_1'),
        agent_2=action_spaces.Joystick(
            scaling_factor=0.005, action_layers='agent_2'),
    )

    ############################################################################
    # Observer
    ############################################################################

    image_observer = observers.PILRenderer(
        image_size=(64, 64),
        anti_aliasing=1,
        color_to_rgb='hsv_to_rgb',
    )
    raw_state_observer = observers.RawState()  # needed by hand-crafted agents

    ############################################################################
    # Game rules
    ############################################################################

    def _spoil_fruit(sprite):
        sprite.c2 = _BAD_VALUE
    def _ripen_fruit(sprite):
        sprite.c2 = _GOOD_VALUE
    def _poison_fountain(sprite):
        sprite.c2 = _BAD_VALUE
    def _clean_fountain(sprite):
        sprite.c2 = _GOOD_VALUE

    def agents_contacting_layer(state, layer, value):
        n_contact = 0
        for s in state[layer]:
            if s.c2 != value:
                continue
            n_contact += (
                s.overlaps_sprite(state['agent_0'][0]) or 
                s.overlaps_sprite(state['agent_1'][0]) or 
                s.overlaps_sprite(state['agent_2'][0])
            )
        return n_contact
    
    poison_fountains = game_rules.ModifySprites(
        layers='fountains', modifier=_poison_fountain, sample_one=True,
        filter_fn=lambda s: s.c2 > _VALUE_THRESHOLD)
    poison_fountains = game_rules.ConditionalRule(
        condition=lambda s: agents_contacting_layer(s, 'fruits', _GOOD_VALUE),
        rules=poison_fountains,
    )
    ripen_fruits = game_rules.ModifySprites(
        layers='fruits', modifier=_ripen_fruit, sample_one=True,
        filter_fn=lambda s: s.c2 < _VALUE_THRESHOLD)
    ripen_fruits = game_rules.ConditionalRule(
        condition=lambda s: agents_contacting_layer(s, 'fountains', _BAD_VALUE),
        rules=ripen_fruits,
    )

    spoil_fruits = game_rules.ModifyOnContact(
        layers_0='fruits',
        layers_1=('agent_0', 'agent_1', 'agent_2'),
        modifier_0=_spoil_fruit,
        filter_0=lambda s: s.c2 > _VALUE_THRESHOLD)
    clean_fountains = game_rules.ModifyOnContact(
        layers_0='fountains',
        layers_1=('agent_0', 'agent_1', 'agent_2'),
        modifier_0=_clean_fountain,
        filter_0=lambda s: s.c2 < _VALUE_THRESHOLD)
    
    rules = (poison_fountains, spoil_fruits, ripen_fruits, clean_fountains)

    ############################################################################
    # Final config
    ############################################################################

    config = {
        'state_initializer': state_initializer,
        'physics': physics,
        'task': task,
        'action_space': action_space,
        'observers': {'image': image_observer, 'state': raw_state_observer},
        'game_rules': rules,
    }
    return config
def get_config(num_targets):
    """Get environment config.
    
    Args:
        num_targets: Int. Number of targets.
    """

    ############################################################################
    # Sprite initialization
    ############################################################################

    # Target circles
    target_factors = distribs.Product(
        [
            distribs.Continuous('x', 0.1, 0.9),
            distribs.Continuous('y', 0.1, 0.9),
            RadialVelocity(speed=0.01),
        ],
        scale=0.1,
        shape='circle',
        c0=0.,
        c1=0.,
        c2=0.9,
    )

    # Target bars
    bar_factors = dict(scale=0.1,
                       shape='square',
                       aspect_ratio=0.3,
                       c0=0.,
                       c1=0.,
                       c2=0.2)

    # Walls
    bottom_wall = [[-1, 0], [2, 0], [2, -1], [-1, -1]]
    top_wall = [[-1, 1], [2, 1], [2, 2], [-1, 2]]
    left_wall = [[0, -1], [0, 4], [-1, 4], [-1, -1]]
    right_wall = [[1, -1], [1, 4], [2, 4], [2, -1]]
    walls = [
        sprite.Sprite(shape=np.array(v), x=0, y=0, c0=0., c1=0., c2=0.5)
        for v in [bottom_wall, top_wall, left_wall, right_wall]
    ]

    # Occluder
    occluder_factors = dict(x=0.5, y=0.5, c0=0.6, c1=0.25, c2=0.5, opacity=0)

    # Cross shape for agent and fixation cross
    cross_shape = 0.1 * np.array([[-5, 1], [-1, 1], [-1, 5], [1, 5], [1, 1],
                                  [5, 1], [5, -1], [1, -1], [1, -5], [-1, -5],
                                  [-1, -1], [-5, -1]])

    def state_initializer():

        fixation = sprite.Sprite(x=0.5,
                                 y=0.5,
                                 shape=cross_shape,
                                 scale=0.1,
                                 c0=0.,
                                 c1=0.,
                                 c2=0.)
        screen = sprite.Sprite(x=0.5,
                               y=0.5,
                               shape='square',
                               scale=2.,
                               c0=0.,
                               c1=0.,
                               c2=1.)

        agent = sprite.Sprite(x=0.5,
                              y=0.5,
                              scale=0.04,
                              shape=cross_shape,
                              c0=0.33,
                              c1=1.,
                              c2=1.)
        occluder_shape = shapes.annulus_vertices(0.13, 2.)
        occluder = sprite.Sprite(shape=occluder_shape, **occluder_factors)

        targets = [
            sprite.Sprite(**target_factors.sample())
            for _ in range(num_targets)
        ]

        bar_angles = 0.5 * np.pi * np.random.binomial(1, 0.5, (num_targets))
        bars = [
            sprite.Sprite(x=s.x,
                          y=s.y,
                          x_vel=s.x_vel,
                          y_vel=s.y_vel,
                          angle=angle,
                          **bar_factors)
            for s, angle in zip(targets, bar_angles)
        ]

        state = collections.OrderedDict([
            ('walls', walls),
            ('targets', targets),
            ('bars', bars),
            ('occluder', [occluder]),
            ('screen', [screen]),
            ('fixation', [fixation]),
            ('agent', [agent]),
        ])
        return state

    ############################################################################
    # Physics
    ############################################################################

    elastic_collision = physics_lib.Collision(elasticity=1.,
                                              symmetric=False,
                                              update_angle_vel=False)
    tether = physics_lib.TetherZippedLayers(layer_names=('targets', 'bars'),
                                            update_angle_vel=False)
    physics = physics_lib.Physics(
        (elastic_collision, 'targets', 'walls'),
        updates_per_env_step=10,
        corrective_physics=[tether],
    )

    ############################################################################
    # Task
    ############################################################################

    def _reward_condition(_, meta_state):
        return meta_state['phase'] == 'reward'

    task = tasks.Reset(
        condition=_reward_condition,
        reward_fn=lambda _: 1,
        steps_after_condition=10,
    )

    ############################################################################
    # Action space
    ############################################################################

    action_space = action_spaces.SetPosition(action_layers=('agent',
                                                            'occluder'))

    ############################################################################
    # Observer
    ############################################################################

    observer = observers.PILRenderer(
        image_size=(64, 64),
        anti_aliasing=1,
        color_to_rgb=observers.color_maps.hsv_to_rgb,
    )

    ############################################################################
    # Game rules
    ############################################################################

    # Fixation phase

    fixation_rule = gr.Fixation('agent', 'fixation', _FIXATION_THRESHOLD,
                                'fixation_duration')

    def _should_end_fixation(_, meta_state):
        return meta_state['fixation_duration'] >= 15

    fixation_phase = gr.Phase(
        continual_rules=fixation_rule,
        end_condition=_should_end_fixation,
        name='fixation',
    )

    # Visible Phase

    vanish_fixation = gr.VanishByFilter('fixation', lambda _: True)
    vanish_screen = gr.VanishByFilter('screen', lambda _: True)

    visible_phase = gr.Phase(
        one_time_rules=[vanish_fixation, vanish_screen],
        duration=5,
        name='visible',
    )

    # Tracking Phase

    def _make_opaque(s):
        s.opacity = 255

    appear_occluder = gr.ModifySprites('occluder', _make_opaque)

    tracking_phase = gr.Phase(
        one_time_rules=appear_occluder,
        duration=lambda: np.random.randint(40, 80),
        name='tracking',
    )

    # Change Phase

    fixation_response_rule = gr.Fixation('agent', 'targets',
                                         _FIXATION_THRESHOLD,
                                         'response_duration')

    def _should_end_change(_, meta_state):
        return meta_state['response_duration'] >= 30

    change_phase = gr.Phase(
        one_time_rules=ChangeTargetFeature(),
        continual_rules=fixation_response_rule,
        name='change',
        end_condition=_should_end_change,
    )

    # Reward Phase

    def _make_transparent(s):
        s.opacity = 0

    disappear_occluder = gr.ModifySprites('occluder', _make_transparent)

    def _glue(s):
        s.velocity = np.zeros(2)

    glue_targets = gr.ModifySprites(('targets', 'bars'), _glue)

    reward_phase = gr.Phase(
        one_time_rules=(disappear_occluder, glue_targets),
        name='reward',
    )

    phase_sequence = gr.PhaseSequence(
        fixation_phase,
        visible_phase,
        tracking_phase,
        change_phase,
        reward_phase,
        meta_state_phase_name_key='phase',
    )

    ############################################################################
    # Final config
    ############################################################################

    config = {
        'state_initializer': state_initializer,
        'physics': physics,
        'task': task,
        'action_space': action_space,
        'observers': {
            'image': observer,
            'state': observers.RawState()
        },
        'game_rules': (phase_sequence, ),
        'meta_state_initializer': lambda: {
            'phase': ''
        },
    }
    return config