This tutorial is meant for the more advanced cogger, interested in unlocking one of MotS' most powerful features.  (what, you ask, there is something better then colored lighting?!)

PlayerAction? huh?  Why's it Gods' gift to MotS editors?  Simple:  it allows you to use the player's existing buttons instead of having to make new items to act as additional buttons.  Examples:  (all in MotS) the cameras, EWeb, STRifle zooming.  Anytime you ask 'how did they do that with my existing buttons?' the answer is undoubtedly by the use of the SetActionCog command.  It acts very similar to 'key trapping', where a programmer is able to intercept a key stroke before it reaches its destination.

Now that you have been enlightened, you now need to know the full extent of this command.  The following is the list of all the buttons i know of that can be trapped.

Jump Key
Crouch Key
Activate Key
2nd Fire Key
left/Right Strafe Keys
Left/Right Turn Keys/Mouse
Forward/Backward movement Keys
Weapon Switching Keys
Up/Down Pitch Keys/Mouse
Inventory Menu Selection Keys
Force Power Selection Keys
Inventory Use Key
Force Power Use Key
Cycle Camera Key
Talk Key
Quick Save Key
Screen Size Adjustment Keys
Gamma Level Keys
Score Tally Key
Screen Shot Key

Get my jist? SetActionCog is VERY powerful (and 1 key is still at large.  More on it later).

Well, now that you are wetting your pants (I almost did when I discovered it and its potential) you are wondering 'How the hell do I use it!!'

It is very simple actually (if you know what you are doing).

SetActionCog(cog, flags);

This is the command used to initiate the key trapping and all its goodness.  This is the command that tells what COG to send the trapped key messages to, and which keys to trap.  The COG in the command refers to the specific cog that it sends the message to.  More often then not, you will use/find GetSelfCog() in this spot (it gets ID of the very cog that called GetSelfCog) as it cuts down on the confusion of chasing down which messages go to what cog.  In the FLAGS spot goes the hex flags of the keys you wish to trap.  I will post a chart I made (awhile ago, back in August) at the bottom of the tutorial and include it with the zip that has all the parameters, IDs, flags, and anything else you can shake a stick at.  To stop the trapping of keys, one mearly has to call SetActionCog again and use -1 for the cog and 0 for the flags (SetActionCog(-1, 0);)

PlayerAction:

This is the message where SetActionCog sends the information it traps.  By using its Param's, you can find out everything you need about what button they pushed, how fast they're moving, what direction they're moving, what weapon they selected, their head pitch, and the list goes on.  The chart below tells all of them.

ReturnEx(1/0);

This is another command used for the PlayerAction message.  Returning 0 means that the action the key performs WILL NOT happen.  example:

If(GetParam(0) == 0)     // if he presses the jump key
{
   Print("No Jump for You!");
   ReturnEx(0);    // Makes the player NOT jump, even though he pressed the jump key.
   return;
}

That will Print "No Jump For you!" to the console, and the player will not jump.  However, by replacing the 0 with a 1 in the ReturnEx command, it will print "No Jump for You!" and the player will jump.

There are some commands, such as jump and crouch, that send 2 messages to PlayerAction:.  2 of them are Jump and Crouch.  The first is sent when they press the jump key (found out by using GetParam(2), it will be 1 if they jump), and second when they land (found out also by GetParam(2), however it will be 0 if they are landing).  Same deal with crouch, value of 1 is when they first crouch, value of 0 is when they get up.

Here is the chart you've heard a bit about above.  There is a unique case with the misc. keys (gamma, screen size, print screen, ect) where they will all return a Param(0) of 14.  They are separated by their Param(2), each has a different value for it.  Enough talk, more chart.
 
 

Param(0)	Param(1)	Param(2)	Param(3)	Hex Key Flag	Key	Notes
0	n/a	1/0	n/a	0x1	Jump	1 is takeoff, 0 is landing
1	n/a	1/0	n/a	0x2	Crouch	1 is crouch, 0 is getting up
2	n/a	n/a	n/a	0x3	Activate
3	n/a	n/a	n/a	0x4	2nd Fire
4	n/a	Speed	n/a	0x10	L/R Strafe	- speed is left, + speed is right
5	n/a	Direction	n/a	0x20	L/R Turn	-1 is right, +1 is left
6	n/a	Speed	n/a	0x40	For/Back (movement)	- speed is left, + speed is right
7	n/a	Key Num	n/a	0x80	Weap Keys	13-22 (13=1, 14=2, 15=3, ect)
8	Speed	Head Pitch	n/a	0x100	Head Pitch	+ is up, - is down
9	???	???	n/a	0x200?	???	The key i haven't found yet
10	1	Direction	n/a	0x400	Inv Menu	-1 for left, +1 for right (dir). Param 1 is always 1.
11	1	Direction	n/a	0x800	Force Menu	See Inv Menu
12	n/a	n/a	n/a	0x1000	Inv Use
13	n/a	n/a	n/a	0x2000	Force Use
14	n/a	SB	SB	0x4000	Misc Keys	See Below table for params

 

Param(2)	Param(3)	Key
0	n/a	Cycle Camera
1	n/a	Talk
2	n/a	Quick Save
3	-1/+1	Screen Size Adjustment
4	n/a	Gamma Level
5	n/a	Score Tally
6	n/a	Screen Shot

That's about all there is to it.  The acute minded may realize that this is the key to
*cough*driveable vehicles*cough* *Obsidian walks away whistling*