vehicle.py

"""
Actual implementation of the evolving vehicle. This module contains the base
class Vehicle and all its derivatives (Car, Walker, etc.)


TODO:
    Write class docstrings
    Review (and delete?) the commented code
    Make reproduction parameters class attributes (of Vehicle?)
    More advanced cars, speed instead of torque?
    Implement a walker
"""

import Box2D  # The main library
# Box2D.b2 maps Box2D.b2Vec2 to vec2 (and so on)
from Box2D.b2 import (world, polygonShape, circleShape, staticBody, dynamicBody)
import random
from datetime import datetime

random.seed(datetime.now())

class Vehicle:
    def __init__(self, type_name):
        self.type_name = type_name
        self.genome = {}
        self.bodies = []

    def random_genome(self):
        pass

    def build(self, world):
        pass

    #def get_child(self, mutation_rate, mutation_range):
    #    child = Vehicle(self.type_name)
    #    child.genome = self.genome
    #    for key in child.genome:
    #        prob = random.random()
    #        #mutate if lucky
    #        if prob < mutation_rate:
    #            #change is from -100% to +100% of the gene's value
    #            change = 2.*random.random()-1.
    #            gene = child.genome[key]
    #            gene += change*gene
    #            child.genome[key] = gene

    #    return child


# constants (incorporate as parameters?)
WHEEL_FRICTION = 5.0
MAX_TORQUE = 1e4
SPEED = -6

class Car(Vehicle):
    def __init__(self, randomise_genes=True):
        Vehicle.__init__(self, 'Car')
        self.genome = { 'wheel1_r' : 0,
                        'wheel2_r' : 0,
                        'body_length' : 0,
                        'body_width' : 0 }
        if randomise_genes:
            self.random_genome()

    def random_genome(self):
        for key in self.genome:
            gene = self.genome[key]
            x = random.random()
            gene = 0.2+2*x # sizes from 0.2 to 2.2 metres
            if key == 'body_length':
                # body length is from 2 to 6 m
                gene +=1
                gene *= 2 
            if 'wheel' in key:
                # body length is from 2 to 6 m
                gene +=1
            self.genome[key] = gene

    def build(self, world, x0, y0):
        width = self.genome['body_length']
        height = self.genome['body_width']
        radius1 = self.genome['wheel1_r']
        radius2 = self.genome['wheel2_r']

        # Create a couple dynamic bodies
        carriage = world.CreateDynamicBody(position=(x0, y0))
        carriage.CreatePolygonFixture(box=(width, height), density=1, friction=0.3)

        wheel1 = world.CreateDynamicBody(position=(x0-width*0.95, y0-height*0.85))
        wheel1.CreateCircleFixture(radius=radius1, density=1, friction=WHEEL_FRICTION)
        world.CreateRevoluteJoint(bodyA=carriage, bodyB=wheel1,
                anchor = wheel1.worldCenter,
                maxMotorTorque = MAX_TORQUE, motorSpeed = SPEED,
                enableMotor = True)

        wheel2 = world.CreateDynamicBody(position=(x0+width*0.95, y0-height*0.85))
        wheel2.CreateCircleFixture(radius=radius2, density=1, friction=WHEEL_FRICTION)
        world.CreateRevoluteJoint(bodyA=carriage, bodyB=wheel2,
                anchor = wheel2.worldCenter)#,
                #maxMotorTorque = MAX_TORQUE, motorSpeed = SPEED,
                #enableMotor = True)

        self.bodies = [carriage, wheel1, wheel2]
        self.tracker = carriage.worldCenter
        # return the body object for tracking position
        return carriage

    def get_child(self):
        #print "making a child"
        mutation_rate = 0.2
        child = Car()
        child.genome = dict(self.genome)
        
        for key in child.genome:
            prob = random.random()
            gene = self.genome[key]
            #mutate if lucky
            if prob < mutation_rate:
                #print " mutation occured in", key
                gene = mutate(gene)
                child.genome[key] = gene

        #print "my genome:", self.genome
        #print "child's genome:", child.genome
        return child

def mutate(gene):
    mutated = False
    #print "     old gene", gene
    while not mutated:
        change = random.uniform(-0.15, 0.15)
        gene += change*gene
        if gene > 0.2:
            mutated = True

    #print "     new gene", gene
    return gene



#def mutateparameter(car,paramplace,min,max,mutationfactor):
#    parameter=car(paramplace)
#    while (mutation < min or mutation > max):
#    mutation = (.5-random.random())*mutationfactor+parameter
#    car[paramplace] = mutation
#    return[car]
#    
#    #THIS RUNS THE mutateparameter FUNCTION OVER EACH PARAMETER FOR A GIVEN CAR, IF A RANDOM NUMBER IS < THAN THE mutationrate
#def mutatecar(car):
#    if random.random()<mutationrate:
#        mutateparameter(car,1,heightmin,meightmax,mutationfactor)
#    if random.random()<mutationrate:
#        mutateparameter(car,2,widthmin,widthmax,mutationfactor)
#    if random.random()<mutationrate:
#        mutateparameter(car,3,radiusmin,radiusmax,mutationfactor)
#    if random.random()<mutationrate:
#        mutateparameter(car,4,radiusmin,radiusmax,mutationfactor)
#    if random.random()<mutationrate:
#        mutateparameter(car,5,torquemin,torquemax,mutationfactor)
#    if random.random()<mutationrate:
#        mutateparameter(car,6,torquemin,torquemax,mutationfactor)
#    return[car]
#    
#
#
#
#
#