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[arkel]

So, I have a few code templates that basically make an NPC move randomly across the screen at a constant speed and were easy to do, but is there a good way to make an NPC walk a few inches horizontally in one random direction, stop for a moment, and then walk again in another?
Think RPGMaker.

Any suggestions would be great, thanks!

[Zack Bell]

I would just use an alarm and a simple state machine.

Code:

//Create Event

walkSpeed = 2.0;

RIGHT = 1;
LEFT = -1;

facing = choose(LEFT, RIGHT);

IDLE = 10;
WALK = 11;

state = choose(IDLE, WALK);

canChangeState = true;

Code:

//Step Event

if (canChangeState) {
    if (IDLE) {
        alarm[0] = 10 + random(10);
        facing = choose(LEFT, RIGHT);
        state = WALK;
    } else {
        alarm[0] = 10 + random(10);
        state = IDLE;
    }
    canChangeState = false;
}

switch (state) {
    case IDLE: hspeed = 0; break;
    case WALK: hspeed = walkSpeed * facing; break;
}

Code:

//Alarm 0 Event

canChangeState = true;

This is one way to do it. I haven't tested it, but hopefully yo ucan see the logic behind it.              


EDIT: Had a few typos. It's better now.

[Ashkin]

Pseudocode for the update loop:

Code:

timer:int = random number
moveright:Boolean = false
if (timer > 0) timer -= 1;
else moveright = !moveright; timer = random number;
if (moveright == false) x -= 1;
else if (moveright == true) x += 1;

Basically, it creates a timer number that equals a random number, counts it down, and then when it's expired the timer resets to a new random number and the character starts moving in the opposite direction.

Edit: Ninjad. Posting anyway.

[arkel]

@Zack: I copypasted this directly into all the right events, changed the speeds and added some sprite changes, loaded up the game, and the NPC is just moving back and forth without doin' any idling. Did I miss something? Thanks for the quick help, btw!

@Ashkin: Thanks, I'll give this a try.

[Ashkin]

Oh, if you want to add idling, then do something more like this:

Code:

timer:int = random number
move:int = 0
if (timer > 0) timer -= 1;
else
{
   if (move == -1) move = 0;
   if (move == 1) move = 0;
   if (move == 0) move += (round(random)*2)-1
   timer = random number;
}
if (move == 1) x += 1;
else if (move == -1) x -= 1;

Haha I have no idea if this will work, just sorta slapped together. Good luck!

[Geeze]

@Zack: I copypasted this directly into all the right events, changed the speeds and added some sprite changes, loaded up the game, and the NPC is just moving back and forth without doin' any idling. Did I miss something? Thanks for the quick help, btw!

@Ashkin: Thanks, I'll give this a try.

Changing

Code:

if(IDLE)

to

Code:

if(state == IDLE)

should fix it.

[arkel]

Thanks Geeze, that fixed it just fine!
Surprisingly easy thing to miss.

[Zack Bell]

Sorry about that! It was really late and I never tested it 

Glad it's working for you now, though