12 replies to this topic

[Drum]

This is probably really straightforward to do, but I guess I'm just too much of a dope to figure it out on my own.

In my game there are certain types of enemies that only move when the player moves. If you've ever played Nethack or similar roguelikes, you understand the sort of system I mean.

I've tried two approaches, both in drag and drop (I'm not nearly good enough to get into coding yet):
One is to have the Step Towards action in the Any Key event, which isn't adequate - I don't want them to move when just any old key is pressed, just the direction keys.
The other is to have a Step Towards action in each of the movement key events - but then if the player is pressing, say, up and right at the same time, the monsters double their speed - so that's no good.

Any help would be appreciated, thanks.

[Katipo Games]

If you want the enemies to move the same direction as the player moves, you can just put in the same 'key' event in the enemies events

e.g:

Player:
Event keypress W:
//move up

Enemy:
Event keypress W:
//move up


Hope this helps

Edited by Katipo Games, 14 May 2012 - 06:16 AM.

[Drum]

Sorry, I guess I explained that badly. The enemies always move *towards* the player - but they only do so when the player is moving. Thanks anyway.

[FredyJabe]

Sorry, I guess I explained that badly. The enemies always move *towards* the player - but they only do so when the player is moving. Thanks anyway.

in the step event of your enemies, try using this :

// This is used to tell an object to move oward a point (position of obj_player in that case) by avoiding "solid" objects
mp_potential_step(obj_player.x,obj_player.y,speed,false);

[Drum]

Sorry, I guess I explained that badly. The enemies always move *towards* the player - but they only do so when the player is moving. Thanks anyway.

in the step event of your enemies, try using this :

// This is used to tell an object to move oward a point (position of obj_player in that case) by avoiding "solid" objects
mp_potential_step(obj_player.x,obj_player.y,speed,false);

That's a fine way of getting the enemies to move towards the player, but that hasn't been the issue - I find that the step towards action works well. It's getting them to *only* move when the player is moving that I'm having trouble with. This code doesn't address that. Thanks anyway.

EDIT: Maybe something like making the enemies active if the player speed is returned as greater than zero or something like that might work. I'll give that a try. I should know how to do this, I just did a bunch of tutorials, ugh.

Edited by Drum, 14 May 2012 - 11:21 AM.

[FredyJabe]

make a global variable something like

global.activatedEnemies = false;

In your enemy step event

// Checks if the enemies are ON or not
if (global.activatedEnemies = true)
{
      // This is used to tell an object to move oward a point (position of obj_player in that case) by avoiding "solid" objects
      mp_potential_step(obj_player.x,obj_player.y,speed,false);
}

In you character step event

// Checks if the speed is higher than 0, if so, activate the enemies
if (hspeed > 0 || vspeed > 0)
{
      global.activatedEnemies = true;
}
// Else desactivae them
else
{
      global.activatedEnemies = false;
}

That should work if I understood what you wanted

[Drum]

make a global variable something like

global.activatedEnemies = false;

In your enemy step event

// Checks if the enemies are ON or not
if (global.activatedEnemies = true)
{
      // This is used to tell an object to move oward a point (position of obj_player in that case) by avoiding "solid" objects
      mp_potential_step(obj_player.x,obj_player.y,speed,false);
}

In you character step event

// Checks if the speed is higher than 0, if so, activate the enemies
if (hspeed > 0 || vspeed > 0)
{
      global.activatedEnemies = true;
}
// Else desactivae them
else
{
      global.activatedEnemies = false;
}

That should work if I understood what you wanted

Well, I haven't got it to work correctly, but from the looks of the code it's the sort of thing I want, so I'm guessing this is a case of user error?
I put the pieces of code exactly as written into their respective enemy and player object homes. I did not know where or how to insert the initial

global.activatedEnemies = false;

bit of code - I tried putting it in various places and then not at all, but none of it worked.
Sorry, I am a bit hopeless with GML. Thanks for babysitting me anyway.

Edited by Drum, 14 May 2012 - 06:35 PM.

[adder_astros]

In the enemy's step event:

// The x and y coordinates of the spot that the enemy is moving towards.
// I'ts pased on your location.
// distance = how far away they will be from you;
// direction = what direction they will be from you;
// you.xy = your current x or y coordinates.

xx = lengthdir_x(distance,direction)+you.x; 
yy = lengthdir_y(distance,direction)+you.y;

move_towards_point(xx,yy,sp); // sp = speed that the enemy will move towards that point at

Edited by adder_astros, 14 May 2012 - 09:25 PM.

[Drum]

In the enemy's step event:

// The x and y coordinates of the spot that the enemy is moving towards.
// I'ts pased on your location.
// distance = how far away they will be from you;
// direction = what direction they will be from you;
// you.xy = your current x or y coordinates.

xx = lengthdir_x(distance,direction)+you.x; 
yy = lengthdir_y(distance,direction)+you.y;

move_towards_point(xx,yy,sp); // sp = speed that the enemy will move towards that point at

Oh bother, it looks like I've really made a hash of this thread because everybody has consistently got the wrong idea. My apologies to everybody who tried to help.
What I wanted was:
As long as the player is moving, the enemies will move towards the player. When the player stops, the enemies stop. It's basically a turn-based system where everybody only moves on the same turn.
I tried implementing FredyJabe's code but it simply didn't work - the enemies stayed rooted to the spot while I pranced about like an idiot. I guess I'll just keep hacking away at it, but I'm not confident of my ability to use GML at all and prefer a drag & drop solution. Thanks anyway adder_astros.

[Locust]

Player Create event:

global.moving = false;

Player Step event:

// Movement
x += (-keyboard_check(vk_left) + keyboard_check(vk_right))*4;
y += (-keyboard_check(vk_up) + keyboard_check(vk_down))*4;

// Check if we moved
if (x == xprevious && y == yprevious)
global.moving = false;
else 
global.moving = true;

You can use your own movement code, but at the end of the step check if the player moved and set global.moving accordingly.

In enemy Step event:

if (global.moving == true)
move_towards_point(Player.x,Player.y,2);
else
speed = 0;

[Drum]

Player Create event:

global.moving = false;

Player Step event:

// Movement
x += (-keyboard_check(vk_left) + keyboard_check(vk_right))*4;
y += (-keyboard_check(vk_up) + keyboard_check(vk_down))*4;

// Check if we moved
if (x == xprevious && y == yprevious)
global.moving = false;
else 
global.moving = true;

You can use your own movement code, but at the end of the step check if the player moved and set global.moving accordingly.

In enemy Step event:

if (global.moving == true)
move_towards_point(Player.x,Player.y,2);
else
speed = 0;

This worked perfectly, thanks a whole ton. I'll totally credit you if I somehow manage to finish this off - how do you want to be credited? Just Locust?

[Locust]

No problem.
No need to credit me but if you want to, Locust will do.

[Drum]

Cool, you bet. Thanks again.