GameMaker [SOLVED] Finding a specific item in a ds_grid and subtracting it.

[PlayerOne]

Right now I'm creating an upgrade system akin to the Fallout 4 / New Vegas workbench system. Everything is set up but I need to find the first item id of an item that I'm specifically looking for. In this case the item id is a sprite that is used to identify items in my players inventory.

Now I have found a function that identifies if an item exists in the grid.

ds_grid_value_exists(global.player_inv, 0, 0, ds_grid_width(global.player_inv), ds_grid_height(global.player_inv), item);

The problem is that I need the x and y position in that grid for the very first item that I'm looking for. Then I can subtract it when an upgrade meets the requirements for my players equipment.

There is a function that seems to do what I'm looking for:

//word for word directly from the doc's
if ds_grid_value_disk_exists(grid, 5, 5, 5, val)
   {
   xpos = ds_grid_value_disk_x(grid, 5, 5, 5, val);
   ypos = ds_grid_value_disk_y(grid, 5, 5, 5, val);
   }

I tried using it (modified to fit my game of course) but I'm not sure if I'm using it correctly.

 

[MirthCastle]

I don't have access to the help file right now. But I don't think you need to use the disc version of that function...

I think the basic one for value exists, and DS grid get value X or Y.

Another way to would be to use a nested for-loop. You would just scan the grid, and when it finds the item you're looking for... You use the 2 for-loop variables like I and J, to do what you need with it (that's all those functions are doing anyway).

I'm on my phone right now but I can write up an example when I get home if you dont know how.

 

[PlayerOne]

I appreciate that. Although I was trying to access data within a ds_grid and not on the disc. After a few hours of tinkering this is what I needed:

if ds_grid_value_exists(global.player_inv, 0, 0, ds_grid_width(global.player_inv), ds_grid_height(global.player_inv), item); // <<< Does the item exist?
{
xpos = ds_grid_value_disk_x(grid, 5, 5, 5, val); // <<< Write [X,0]
ypos = ds_grid_value_disk_y(grid, 5, 5, 5, val); // <<<  write [0,Y]
}

The answer was staring at me in the face I didn't notice the answer.

My goal is to check if there is anything in [0,X], [1,X], etc. It was tricky especially taking into account other factors.

 

[MirthCastle]

I was referring to:

1. ds_grid_value_x
   
2. ds_grid_value_y

you don't need the disk_x and disk_y - though it uses less parameters and seems easier then ds_grid_value_x.

the for loop would\could look like this in a script:
itemtofind = argument[0];
var griditem
for (var i = 0; i < ds_grid_width(global.player_inv), i++ ) {

for (var j = 0; j < ds_grid_height(global.player_inv), j++ ) {

griditem = global.player_inv[# i , j]

if ( griditem = itemtofind ) {

//do stuff with item at that spot​

break;
}​

}​

}

in the above - the i and j are the same as xpos and ypos.

I believe this is far more efficient because you aren't doing three separate full grid lookups for the one item like you are in the grid functions.

​