Move Multiple Directions

[Halsafar]

This has to do with direct input.

Now, I notice in some amatuer source code, or if the game works fine with this method, some people just go
(typing this in english, not code)

if button=left

else if button = right

else if button = left

ect

Now this leaves little for play, and one cannot move on diangols...
So A few if then statements would be nice, no else...the only else there should be on each if statement is to make sure the button is up.

Now how would one go about getting multiple directions. I have chosen a method, and seen a few others.
Here is my method, using c++ string

Direction is a string
The player pressed a button
if button = left then
Direction += Direction + "left"

if button = right then
Direction += Direction + "right"

Then we the motion is carried out I just
if (Direction.find("left",0) != string:npos)
move the stuff

Now I have also seen it done with ints, but an int representing a direcetion can get confusing to other programmers looking at yer stuff. I have seen individual key BOOLS for each key, which is consuming...Anyone have any nice methods they wish to explain.

Note: in my game I use north, south, east, west, up, down.

[Shell]

I think using bools is less consuming compared to the string stuff you do at the moment. What I usually do is declare a boolean variable for every key that my game uses, then I create a function that checks for the states of all those keys, and stores true if the key is pressed, and false if it's not. Using this method, you can check the input anywhere in your program. Something like this:

// global
bool keyUp = false;
bool keyDown = false;
bool keyLeft = false;
bool keyRight = false;

// Get the states of the keys we're interested in
void getInput()
{
   keyUp = GetKeyState(VK_UP) <  0;
   keyDown = GetKeyState(VK_DOWN) <  0;
   keyLeft = GetKeyState(VK_LEFT) <  0;
   keyRight = GetKeyState(VK_RIGHT) <  0;
}

// Process the input
void processInput()
{
   int newX = player.x;
   int newY = player.y;

   // Check every key needed
   if(keyLeft){
      if(spotWalkable(newX-2,newY))
         newX-=2;
   }

   if(keyRight){
      if(spotWalkable(newX+2,newY))
         newX+=2;
   }
   if(keyUp){
      if(spotWalkable(newX,newY-2))
         newY-=2;
   }

   if(keyDown){
      if(spotWalkable(newX,newY+2))
         newY+=2;
   }
   // All done, set the new position
   player.x = newX;
   player.y = newY;
} 

Something like that.

[NoteMe]

As Shell said using bools is the fastest way. Strings are very very time consuming to use.

It is not DInput but I wrote a tutorial I think on the technique in the FAQ....

ØØ

[Electroman]

The method I use is a Byte Array with 255 elements. Then I use the value 0 if the button isn't pressed, 1 if its just been pressed (occours for one frame just to show its inital press), 2 for while its being held down And finally -1 when it is released (similar to 1 apart from the other edge ).

Not all the elements need to be processed each frame mind cos not all keys will be assigned during gameplay but the InGame Input process will just loop though the used keys and process them and ignore the other elements. But in the Options menu when you are redifining keys you will need to loop though all and keep checking for the value 1 so that you know which key the user is trying to redefine a key to .

I'll post some code to go with this if you want it?


P.S. For this method things like movement keys are done like: if (Keys[MoveUpKey] > 0). And for say typing words: if (Keys[SomeLetterKey] == 1).

This also allows for special stuff like sounds to be activated and deactivated, for example:

if (Keys[MoveUpKey] > 0)
{
    if (Keys[MoveUpKey] == 1)
    {
        // Play Looping Sound...
    }
    // Do Movement Code...
}
else if (Keys[MoveUpKey] == -1)
{
    // Stop Sound Playing...
} 

[Halsafar]

I enjoy that method, but I do understand what you mean when you say using a ByteArray.

Like I know what a ByteArray is, so that would mean then
Keys() is a function, with a parameter
Keys(DIK_KEY)
which returns a value given its state? 0,1,2,-1??

I don't get how you are getting those value's..I get everything else.

[Electroman]

Posted by Halsafar
I enjoy that method, but I do understand what you mean when you say using a ByteArray.

Like I know what a ByteArray is, so that would mean then
Keys() is a function, with a parameter
Keys(DIK_KEY)
which returns a value given its state? 0,1,2,-1??

I don't get how you are getting those value's..I get everything else.

Not a function but an array .

So to define Keys I would do:

char Keys[255]; 

Or for VB:

Dim Keys(255) As Byte

That should clear up how I am getting the values too? They are just the value of that element