Code for the inventory system. Includes drawing process.

obj_inventory: create:

globalvar showInv, invMax, inv, invScroll, ia, invFocused, invScrollAmmount, selectPos,
selectSlot, selectItem, selectNum, selectItem2, selectNum2, mouseItem, mouseNum;
showInv = true;
invMax = 92;
invScroll = 0;
invRowMax = 46;
ia = -0.5;
invFocused = 0;
invScrollAmmount = 12;
selectPos = 0;
selectItem = 0;
selectNum = 0;
mouseItem = selectItem;
mouseNum = selectNum;
selectItem2 = 0;
selectNum2 = 0;

for (i = 0; i < invMax; i += 1 ){
    inv[i,0] = 0;
    inv[i,1] = 0;
}

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///scr_drawInventory

//Scrolling
if invFocused == 1{
    if mouse_wheel_up(){
        invScroll += invScrollAmmount;
    }
    if mouse_wheel_down(){
        invScroll -= invScrollAmmount;
    }
}

//Focus on the inventory or not
if invFocused == 1{
    ia += 0.2;
    if ia >= 0 ia = 0;
}else{
    ia -= 0.2;
    if ia <= -0.5 ia = -0.5;
}

var mouseY = mouse_y;

for(i = 0; i < invMax; i++){

    var iY = view_yview[0]+(i*40)+invScroll;
    var iAlpha = 1;
    if iY-view_yview[0] >= 300 iAlpha = 0.8;
    if iY-view_yview[0] >= 350 iAlpha = 0.6;
    if iY-view_yview[0] >= 400 iAlpha = 0.4;
    if iY-view_yview[0] >= 450 iAlpha = 0.2;
    if iY-view_yview[0] >= 490 iAlpha = 0;
    if iY-view_yview[0] <= 80 iAlpha = 0.8;
    if iY-view_yview[0] <= 50 iAlpha = 0.6;
    if iY-view_yview[0] <= 20 iAlpha = 0.4;
    if iY-view_yview[0] <= 10 iAlpha = 0.2;
    if iY-view_yview[0] <= 5 iAlpha = 0.1;
    if iY-mouseY <= 8 and iY-mouseY >= 0 selectPos = iY;
    if iY-mouseY >= -8 and iY-mouseY <= 0 selectPos = iY;

    if inv[i,1] <= 0{
        inv[i,0] = 0;
    }

    if iY == selectPos{
        draw_sprite_ext(spr_invSlot,1,view_xview[0]+32,iY,1.1,1.1,0,c_white,iAlpha+ia);
        selectSlot = i;
        selectItem = inv[i,0];
        selectNum = inv[i,1];
    }else{
        draw_sprite_ext(spr_invSlot,0,view_xview[0]+32,iY,1,1,0,c_white,iAlpha+ia);
    }
    if inv[i,0] > 0{
        draw_sprite_ext(spr_items,inv[i,0],view_xview[0]+32,iY,1,1,0,c_white,iAlpha+ia);
        draw_set_alpha(iAlpha+ia)
        draw_text(view_xview[0]+32,iY,string(inv[i,1]));
        draw_set_alpha(1);
    }
}
draw_sprite_ext(spr_inventorySelect,0,view_xview[0]+16,selectPos,1,1,0,c_white,0.7+ia);

//Draw the selected item on mouse
if mouse_check_button_pressed(mb_left){
    if mouseItem == 0{
        if selectItem != 0{
            mouseItem = selectItem;
            mouseNum = 1;
            inv[selectSlot,1] -= 1;
        }
    }else{
        if invFocused == 1{
            if selectItem == mouseItem{
                inv[selectSlot,1] += mouseNum;
                mouseItem = 0;
                mouseNum = 0;
            }else{
                inv[selectSlot,0] = mouseItem;
                inv[selectSlot,1] = mouseNum;
                mouseItem = 0;
                mouseNum = 0;
            }
        }else{
            //Drop mouse item as obj_item (droppa 1 item)
            var item = instance_create(mouse_x,mouse_y,obj_item);
            obj_item.image_index = mouseItem;
            mouseNum -= 1;
        }
    }
}
if mouseNum <= 0 mouseItem = 0;

draw_sprite(spr_items,mouseItem,mouse_x,mouse_y);

draw_text(view_xview[0],view_yview[0],string(selectSlot));
draw_text(view_xview[0]+64,view_yview[0],string(selectItem));
draw_text(view_xview[0]+128,view_yview[0],string(mouseItem));
draw_text(view_xview[0]+128,view_yview[0],string(mouseNum));

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///scr_itemPickup(item,ammount)

var found = -1;

for( i = 0; i <invMax; i += 1){
    if inv[i,0] == argument0{
        found = i;
        break;
    }
}

if found == -1{
    for(i = 0; i < invMax; i += 1){
        if inv[i,0] == 0{
            found = 0;
            break;
        }
    }
}

inv[found,0] = argument0;
inv[found,1] += argument1;

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///scr_itemDrop(item,ammount)
var found = -1;

for(i = 0; i < invMax; i++){
    if inv[i,0] = argument0{
        found = i;
        break;
    }
}

if found != -1{
    inv[found,1] -= argument1;
    if inv[found,1] <= 0{
        inv[found,0] = -1;
        inv[found,1] = 0;
    }
}

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