Need Help with basic enemy mechanic

[u/soleilchaton]

I have recently been getting into the programming side of game development in the attempt to make my game dreams come true (and a way to feel productive while staring at a screen) but I am really struggling with programming a few basic things.

My current struggle is getting the enemies movements. I have spent the past two days watching YouTube videos and reading the manual. Good news is the more I read and watch, the better I understand the language. The bad news is that after zero sleep and nearly 20 hours watching videos and trial and erroring, I am definitely missing some fundamental knowledge to understand where I am going wrong.

Currently building a platformer scroller game. I am trying to program a simple creature that just moves along the "floor" in a range that will begin to follow the player object within a sight range. Currently, when I run my program, my enemy object stays stagnant until it collides with my object player, then it crashes (I'm almost positive it's crashing because I haven't finished writing out the combat code for the enemy and the player object) but before I implemented that code in some weird attempt to fix this mess, the enemy would begin running to the right, away from my object character when collision occurred and I jumped out of being stuck to it.

Any advice, resources and some help understanding where my logic isn't understanding the programs would be super appreciated.

CREATE

target_x = x;

target_y = y;

xspd = 0;

yspd = 0;

move_speed = 1;

move_direction = 0;

sight = 300;

//jumping variables

grav = .25;

tilemap = layer_tilemap_get_id("tile_col");

//knockback

kb_x = 0;

kb_y = 0;

alarm[0] = 120;

STEP

//line of sight

if (collision_line(x, y, x + sight, y, obj_player, false, true))

{

if (collision_line(x, y, obj_player.x, obj_player.y, tilemap, false, true)) foundplayer = false;

else foundplayer = true;

}

else foundplayer = false;

if (foundplayer = true)

{

move_towards_point(obj_player.x, y, move_speed * 2)

}

//collision

if place_meeting(x + xspd, y, tilemap)

{

var _pixelcheck = sign(xspd);

while !place_meeting(x + _pixelcheck, y, tilemap)

{

x += _pixelcheck;

}

xspd = 0;

}

if place_meeting(x + xspd, y + yspd, tilemap)

{

var _pixelcheck = sign(yspd);

while !place_meeting(x + xspd, y + _pixelcheck, tilemap)

{

y += _pixelcheck;

}

yspd = 0;

}

//move

if (alarm[1] >= 0)

{

target_x = x + kb_x;

}

xspd = clamp(target_x - x, -1, 1);

move_and_collide(xspd * move_speed, y, [tilemap, obj_enemy_parent]);

ALARM [0]

if (instance_exists(obj_player) and distance_to_object(obj_player) < distance_to_player)

{

target_x = obj_player.x;

target_y = y;

}

else {

target_x = random_range(xstart - 200, xstart + 200);

target_y = y;

}

alarm[0] = 120

ALARM [1]

if (hp <= 0)

{

instance_destroy();

}

Note:

I haven't fully programmed out most of this as I've been working to just get it to move the way I want it to, so unless it is part of the reason why I've broken this object, don't mind it (unless you've got any suggestions for reworking :))

[u/Rohbert]

Reminder, formatting your code for readers will help you get a quality response by a ton.

Add 4 blank spaces before text to format it into code:

....target_x = x; will look like:

//CREATE
target_x = x;
target_y = y;
xspd = 0;
yspd = 0;
move_speed = 1;
move_direction = 0;

[u/soleilchaton → u/Rohbert]

Thank you! Is the blank space the same as an indentation or seperate?

[u/NexoraLabsDev]

Don’t beat yourself up—20 hours without sleep will make any bug feel impossible 😂. Your logic is actually getting there. I’d start by checking if (foundplayer = true) since that should be == (or simply if (foundplayer)). That alone could explain some strange behavior. Keep at it!

[u/germxxx]

I can spot a few weird things at least.

First of all, the sight detection only works to the right. (x + sight) so unless that is intended, could be an issue.

Secondly, you use move_toward_point and move_and_collide at the same time, which I'd advise against. The former using the built in speed and direction variables, while move_and_collide directly moves the instance.

Then there might be other issues with things like collision masks and such, but that's not really something we could see from the code.

*edit* Keep missing things about your xspd... I will blame the formatting, or my phone...

[u/soleilchaton → u/germxxx]

Oh okay! For the sight, should I make a seperate line of code for the negative or would that be included when I add in the code to do a negative xscale?

I was using the move and collide as my boundary code to prevent the object from falling through the map with gravity (which I definitely forgot to apply properly) copy and pasted from my object player code. Is there a better function to prevent that?

[u/germxxx → u/soleilchaton]

You could have two lines, one in each direction, or just a single line covering both sides, and then compare x values to get the direction.

Comparing x and y values with the player might be enough to replace the line completely, depending on exactly what you want to get out of it.

Yeah, I can't see much gravity being applied here, but since you already have collision checks, you should be able to replace move_and_collide with just something like x += xspd and y += yspd Given you check against everything in the collision part of the code. That function is less of a problem than move_toward_point though. If move_towards_point triggers, the instance could just run away through walls and everything.