Add more advanced next steps

docs/index.rst

@@ -13,6 +13,7 @@ Welcome to ROBOTC Tutorial's documentation!
    setup
    updating
    first
+   second
 
 
 Indices and tables

docs/second.rst

@@ -0,0 +1,74 @@
+Stepping it up a notch
+======================
+
+Now that you have a basic program, why not work on adding a few more advanced things.
+
+Single-joystick control
+-----------------------
+
+Sometimes it is preferable to control the bot using a single joystick.
+
+Earlier we had:
+
+.. code-block:: c
+
+    motor[leftMotor]  = vexRT[Ch3];   // Left Joystick Y value
+    motor[rightMotor] = vexRT[Ch2];   // Right Joystick Y value
+    
+This allowed us to use the left and right joysticks to control their corresponding wheels.
+However, let's say we only wanted to use the left joystick, more like a video game controller is used to move the player.
+
+Here, we will use some math the calculate the speed at which each wheel should move:
+
+.. code-block:: c
+
+    motor[leftMotor]  = vexRT[Ch3] + vexRT[Ch4];  // Left Joystick Y value + Left Joystick X Value
+    motor[rightMotor] = vexRT[Ch3] - vexRT[Ch4];  // Left Joystick Y value - Left Joystick X Value
+        
+As you can see, we are adding :code:`Ch4` (x-axis) to :code:`Ch3` (y-axis) to move the left motor, 
+and we are subtracting :code:`Ch4` from :code:`Ch3` to move the right motor.
+
+This works because as we push the joystick further right (a positive x-value) we increase the power of the
+left motor while decreasing the power of the right motor, turning the bot rightwards, and vice versa.
+
+Thresholds
+----------
+
+The joysticks are not perfect, and sometimes they will report value (albiet small) even when untouched.
+To prevent this, we can implement a threshold to make sure the wheels (or anything else that uses joystick values)
+only move when the joystick is pushed past a certain value.
+
+First we will create a function called :code:`threshold` at the bottom of our code (below :code:`task main`):
+
+.. code-block:: c
+
+    int threshold(int value, int threshold)
+    {
+	    return abs(value) > abs(threshold) ? value : 0;
+    }
+    
+You may be wondering what the :code:`? :` is, that is a ternary operator, it works essentially like an inline if-else statement.
+They can help us to write out code in a shorter amount of lines, however they should only really be used 
+for basic things. You should never but a ternary operator in a ternary operator.
+
+Next we need to declare our function at the top of our code, since it is at the bottom, 
+any code in :code:`task main` that references it will throw an error since to compiler does not know
+the function exists until it reaches the bottom of the code. A declaration is our way of telling the compiler
+"don't worry, I'll define it later".
+
+So, at the top of your code (right above :code:`task main`), simply add:
+
+.. code-block:: c
+
+    int threshold(int value, int threshold);
+    
+Now we can use our new function in our code! It takes two inputs, the value (an integer), 
+the threshold (an integer) and it outputs an integer (the value if it is greater than the threshold
+or 0 if not).
+
+An example of how we would use it is:
+
+.. code-block: c
+
+    motor[leftMotor]  = threshold(vexRT[Ch3], 15);
+    motor[rightMotor] = threshold(vexRT[Ch2], 15);