Week 13 Lab: Putting it All Together

For this lab, you are going to move most of your code from move.py into a class CS104Scribbler and encapsulate information about the Scribbler into that class.

Step 1: Make the lab13 Folder, etc.

• Make sure your workspace is S:\workspace. Make a lab13 folder.
• If you are happy with your lab11's move.py file, then ***copy*** the move.py file over from your lab11 folder into your lab13 folder. Otherwise, you may get my move.py file from our CS104 course moodle page. Copy it to your lab13 folder.
• Rename this move.py file to cs104scrib.py.

Step 2: Make a CS104Scribbler class

We are going to make a new class CS104Scribbler that is a subclass of Scribbler, a class provided by the myro module that we've been using all semester. To do this, do these steps:

• Remove the line at the top of your cs104scrib.py file that imports the scribpoint module. We won't use scribpoint anymore.
• Have cs104scrib.py still must import the myro module.
• After any definition of constants (CENTS_PER_SEC, etc.) write a line of code to create the CS104Scribbler class definition, make this new class a subclass of Scribbler, the class provided by myro.
• With your mouse, select/highlight the rest of the code in your file, and hit the <TAB> key. This will indent all your code so that it is now defined "in" the CS104Scribbler class.
• For each function definition (now a method definition in the CS104Scribbler class), add self as the first parameter.
• For each method call in your code, add self. to the front. E.g., where it says turnRight(1, time) make it say self.turnRight(1, time)

Step 3: Add a constructor method and getters and setters

Next, we need to add a constructor for CS104Scribbler:

• Right after the class definition line, add the constructor definition (__init__). The constructor should take 5 parameters: self, comport, x, y, and angle. These should be optional parameters, with default values: the default value for comport should be "COM40"; the default values for x, y, and angle, should all be 0.
• Write the first line of code in the constructor, which should be a call to the superclass constructor, passing in 2 parameters: self and comport. I've shown you how to do this in your notes from class.
• Write the next lines of code to store x, y, and angle in self. Put the underscore character at the beginning of the attribute names (e.g., _x)
• Write the method definitions for getX(), getY(), getAngle(), setX(), setY(), and setAngle().

Step 4: Fix the goToPoint method

The goToPoint method previously took two parameters, both of them being ScribPoint objects. Now, the CS104Scribbler class stores its current x, y, and angle of the Scribbler robot, so a call to goToPoint does not need to pass in the first parameter -- where the Scribbler robot currently is on the whiteboard. Also, we don't need a ScribPoint class anymore -- we can just pass in the x and y coordinates for where the scribbler robot should move to.

• Change the name of goToPoint() to goTo().
• Make the method take 3 parameters: self, newX, and newY.
• Change your code so that you use self._x and self._y as the "from" point and newX and newY as the "to" point.
• Add code to the end of your method so that you save your new location in self._x and self._y. Because you are writing code that is in the class, you can use self._x and self._y directly, or, you can call self.setX(newValue), etc.
  

Step 5: Test your code

• Create a file lab13.py. At the top of the file, put from cs104scrib import *. (cs104scrib.py will import myro, so you don't have to do that anymore.)
• Add code to :
  • Connect to your robot. This is done by instantiating a CS104Scribbler object. The first parameter to the constructor is optional -- the comport. If you connect with "COM40", you don't have to pass in any argument in the constructor call. Make sure you store the result in a variable called scrib. This is your CS104Scribbler object.
    NOTE: a call to the CS104Scribbler constructor makes a call to the superclass Scribbler() constructor. That constructor will do the init("COM40") call for us. That is why we pass in the comport and we don't call init() ourselves like we've been doing all semester.
  • Write a method call to make your scribbler goTo(10, 10).
  • Write a method call to make your scribbler goTo(10, -10).
  • Write a method call to make your scribbler goTo(-10, -10).
  • Write a method call to make your scribbler goTo(0, 0).

Step 6: Optimize your code

The robot still turns to face east after every move. This is dumb. We can store the angle the robot is facing in the CS104Scribbler object, and then the code can figure out how to turn to get to the next point it needs to go to.

• Remove the line of code in goTo() that makes the robot turn back to face east after it has traveled forward.
• Add a line of code there that stores the current angle the robot is facing in self._angle. So, now we will store the angle the robot used to get from the previous point to the current point, and we'll leave the robot facing that angle.
• A call to atan2() assumes the robot is facing east -- and there is nothing we can do about that. So, after calling that code and figuring out the angle the robot needs to turn to (assuming the robot is facing east), we need to change the result, based on which angle the robot is already facing. To do this, subtract from the computed angle the current angle the robot is facing. That result is passed to the call to self.turnDegrees().
• Now, run your main code again: it should work fine, and the robot should not turn to face east every time.

Step 7: Make your code draw a 5 point star

At the end of lab11 I give you the points necessary to draw a 5-point star. Look in that lab to get those points. Implement this again in your lab13.py main code.

Note: you are done with the lab. But, notice that we really didn't finish our cs104scrib.py code. We really should fix travelForw(), travelBack(), turnLeftDegrees(), and turnRightDegrees() so that they each store the current x, y, and angle of the robot. If we changed those, we wouldn't have to make the changes we did to goTo(). But, we'll just leave the code as it is, for now...

Step 8: Submit your code

• Clean up any code in lab13.py that isn't relevant anymore (old print statements, etc.) Make sure your code is well-documented, indented, hospitable, etc. Make sure you have the correct information in it about you, the author.

To submit your final version of lab13.py and cs104scrib.py, you’ll need to use Windows Explorer.

• Open the Windows Explorer (shortcut: WindowsKey - e)
• Find your lab13.py and cs104scrib.py files down in your lab13 folder.
• Copy lab13.py and cs104scrib.py.
• Now, navigate to T:\CS104\current\<yourid>\.
• Create a folder there called lab13. (Do NOT call it Lab13 or lab 13 or Lab 13 or ISawMommaKissingSantaClaus. Call it lab13.)
• Look again at the folder you just created. Is it called lab13? If not, drop and give me 50 push-ups, and then rename the folder lab13.
• Paste the files (lab13.py and cs104scrib.py) into that folder.

Grading Rubric: 15 points total

10 points: program that runs correctly.  There are many parts to handle in this program, so make sure all work correctly.
1 points: correct comments at the top of the file.
4 points: code is clean and neat and uses good comments and variable names. I.e., the code is hospitable.