How to write a driver module

First, you should import the obstacles and actions modules from rose.common package:

from rose.common import obstacles, actions

The obstacles modules is needed for detecting obstacles on the racing track. The actions module is needed for the drive function.

Define the driver_name variable - this string is rendered below your car on everyone’s screen.

driver_name = "Michael Schumacher"

Write a drive function. This function accepts a world object, which you can use to find obstacles, and must return one of the actions constants in the actions module.

Here is the simplest possible drive function:

def drive(world):
    return actions.NONE

To find your car position, you can access the car.x and car.y of the world object:

x = world.car.x
y = world.car.y

In the next game iteration, your car will be at x, y - 1. World coordinates start at the top left of the screen. You would like to check if there is an obstacle at this location, and return the best action for this obstacle.

To check for obstacles, use the world.get() function. This function accept a tuple (x, y) with the required location.

obstacle = world.get((x, y - 1))

Note that if you try to access a position which is out of the racing track, this function will raise an IndexError. You must handle this exception when checking for obstacles:

try:
    obstacle = world.get((x, y - 1))
except IndexError:
    # x, y - 1 is not a valid position
else:
    # Choose the best action for obstacle

The game has 2 lanes and each lane has 3 routes in which you can drive. On game start, each car starts at the center route of its lane. The car can pass to other lane, but will be punished for collisions with the lane owner.

<------ Car#1 lane ------><------ Car#2 lane ---->

|       |       |       |X|       |       |      |
|       |       |       |X|       |       |      |
|       |       |       |X|       |       |      |
|       |       |       |X|       |       |      |
|       |       |       |X|       |       |      |
|       |       |       |X|       |       |      |
|       |       |       |X|       |       |      |
|       |       |       |X|       |       |      |
|       |       |       |X|       |       |      |
|       | car#1 |       |X|       | Car#2 |      |
|       |       |       |X|       |       |      |
|       |       |       |X|       |       |      |

Here are the possible obstacles and the action you should take when hitting them:

• obstacles.NONE there is no obstacle at this position. You can return any action. Score : 0

• obstacles.PENGUIN return actions.PICKUP and move 1 step forward. You will not move backward if you do not pick up the penguin. Score : 10 for PICKUP otherwise 0

• obstacles.WATER return actions.BRAKE if you want to continue forward. return actions.RIGHT or actions.LEFT if you like to bypass the obstacle. Any other action will cause you to move backward. Score: 4 for BRAKE, 0 for LEFT/RIGHT otherwise -10

• obstacles.CRACK return actions.JUMP if you want to continue forward return actions.RIGHT or actions.LEFT if you like to bypass the obstacle. Any other action will cause you to move backward. Score: 5 for JUMP, 0 for LEFT/RIGHT otherwise -10

• obstacles.TRASH you must return actions.RIGHT or actions.LEFT to bypass the obstacle. Any other action will cause you to move backward. Score: 0 for LEFT/RIGHT otherwise -10

• obstacles.BIKE you must return actions.RIGHT or actions.LEFT to bypass the obstacle. Any other action will cause you to move backward. Score: 0 for LEFT/RIGHT otherwise -10

• obstacles.BARRIER you must return actions.RIGHT or actions.LEFT to bypass the obstacle. Any other action will cause you to move backward. Score: 0 for LEFT/RIGHT otherwise -10

NOTE : If you are driving out of your lane and have a collision with the lane owner, you will punished by -10 points and be moved to other free place.

Please check and test drive the examples drivers modules in this directory. Then go ahead and write the fastest driver!