Wednesday, February 5, 2014

Returns and Removing Children

Hello everyone!

I don't really have much to report on Winds of Commerce, I wrapped up the transaction list/receipts feature. When you bring up the receipts menu it will show you a list of all the cities you've been to, what day of the journey you visited it on, and how much you spent or earned there. You can then click on a city in the list and it will bring up an itemized list of what commodities you purchased/sold, how much you spent/earned on each commodity, and how much you spent on purchasing information.

The next thing I have to tackle is the navigation system. Right now I'm using exec functions to simulate going between cities. This will probably be the biggest system I've had to tackle developing this game. Unfortunately, before I can even start coding I have to get the routes figured out. That way I know how many days away each city is from one another and try and make the shortest route to each city. The hard part is trying to make it logical. Each time I get a route down I look at it and think, "Is that the most efficient route to that city?" then proceed to convince myself it isn't... and redo it again!


While I was working on getting this game put together I ran into how to use returns in a function. I had only used them a handful of times before, and didn't quite know how to use them. I knew you had to have 'return SomeVariable;' but I guess the usefulness didn't really hit me. Since I read more about them and did some tests I have started to use them more. I find them very useful for doing calculations, conversions, or simply checking if a function has completed running.
Setting up a function to return something is really simple, though it is different in Unrealscript and AS3. In Unrealscript the function setup looks like this:
function ReturnType FunctionName() { local ReturnType SomeVar; //Set SomeVar return SomeVar; }

Here is an example of a function that returns an int:

function int GetSum(int A, int B) { local int Sum; Sum = A + B; return Sum; } //To call use it Total = GetSum(5, 10); //GetSum would return 15

The return type can be any of the standard variable types: bool, int, string, array, and even a class. An example of a class being returned can be found in the GameInfo class, with the SetGameType function. This function returns the GameInfo class to use for the game.
static event class<GameInfo> SetGameType(string MapName, string Options, string Portal) { return Default.Class; }

A bool return can be useful if used in an if statement to make sure that function has ran completely before moving on with the if statement. An example of this is in a lot of the bot AI code that is floating around the internet. It is being used to make sure that a path has been found or not, basically:
if(FindPath()) { //Commence moving }

Return functions work the same in AS3, just with the different declaration. Here is how you would declare a retunr funciton in AS3:
function functionName():ReturnType { var someVar:ReturnType; //Set someVar return someVar; }

Speaking of ActionScript, in my last post I mentioned the different ways to call a function in AS3 from Unrealscript(ActionScriptVoid, ActionScriptBool, AsctionScriptInt, and so on). These are there to allow you to receive a return value from your AS3 function. For instance, if you had the GetSum function in AS3 and needed to call it from Unrealscript it would look like this:
//In AS3 function getSum(a:Number, b:Number):Number { var sum:Number; sum = a + b; return sum; } //In Unrealscript Total = ActionScriptInt("_root.getSum");

Now you have several examples of how to use a function to return a value!

Removing Children

The next code bit I found extends what I talked about in my last post with the removeChild function. Sometimes it is necessary to remove all the children from a MovieClip, and since there isn't a function for removeAllChildren there is a work around using a for loop. It's pretty simple, you get the number of children in the MovieClip, then go backwards through the children and remove them one at a time. Here is an example of what I'm talking about:

for (var i:int = container_mc.numChildren-1; i >= 0; i--) { container_mc.removeChildAt(i); }
I think that is all I have for you this week. Hopefully by my next update I'll have all of the routes figured out.

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