GameMaker Studio 2 Demos and Tutorials. Space Rocks - DnD. Space Rocks - GML. When starting your first GameMaker Studio 2 project, you’ll be presented with one of two choices: To make a Drag And Drop project or to make a GameMaker Language project. There are pros and cons to each, but you’ll find users will typically lean more to one than the other, at least in the beginning.
This section explains the various uses for 'with' in GameMaker: Studio.
As indicated in the section Addressing Variables in Other Instances, it is possible to read and change the value of variables in other instances. But in a number of cases you want to do a lot more than just change a single variable with those other instances. For example, imagine that you want to move all the ball objects in your game 8 pixels. You may think that this is achieved simply by the following piece of code:
obj_ball.y = obj_ball.y + 8;
But this is not correct, as the right side of the assignment gets the value of the y-coordinate of the first ball and adds 8 to it. Next this new value is set as y-coordinate of all balls, so the result is that all balls get the same y-coordinate, and even if you use the following:
obj_ball.y += 8;
it will have exactly the same effect because it is simply an abbreviation of the first statement. So how do we achieve this? For this purpose there exists the with statement in GML. Its global form is:
with (<expression>) <statement>
<Expression> indicates one or more instances, and for this you can use an instance id, the name of an object (which indicates all instances of this object are to run the code block) or one of the special keywords (all, self, other). <Statement> is now executed for each of the indicated instances, as if that instance is the current (self) instance. So, to move all instances of the ball object 8 pixels down, you can type:
with (obj_ball) y += 8;
If you want to execute multiple statements, put curly brackets around them, the same as you would around any other program. So for example, to move all balls to a random position, you can use:
with (obj_ball)
{
x = random(room_width);
y = random(room_height);
}
Note that, within the statement(s), the indicated instance has become the target (self) instance that runs the code block, which means that the statements the original instance (that contains the 'with' and the code block) has become the other instance. So for example, to move all balls to the position of the current instance, you can type this:
with (obj_ball) { x = other.x; y = other.y; }
The with statement is an extremely powerful tool and is useful in many, many circumstances so it is important that you understand fully how it can be used. To help there are a few more examples of use below:
with (instance_create(x, y, obj_Ball))
{
speed = other.speed;
direction = other.direction;
}
The above code will create an instance of obj_Ball and assign it the speed and direction of the instance that runs the whole code block.
with (instance_nearest(x, y, obj_Ball))
{
instance_destroy();
}
The above code will destroy the instance of obj_Ball nearest to the instance running the code.
var inst;
inst = noone;
with (obj_ball)
{
if str > other.str inst = id;
}
if inst != noone target = inst;
The above code is slightly more complex than previous ones due to it using a local variable. This variable is local to the script and not to the instance and so can be used and accessed by all instances that are referenced within the code block. So, in the code we have set it to the special keywordnoone and then use the 'with' construction to have every instance of obj_Ball check their 'str' variable against that of the instance running the code block. If the value of the variable is larger, then they store their unique id in the 'inst' local variable, meaning that at the end of the code, only the instance with a value greater than the calling instance (or the keywordnoone if none are larger) will be stored in the local variable inst. For more information on local variables see the section Variables And variable Scope.
© Copyright YoYo Games Ltd. 2018 All Rights Reserved
Written in May 2018 by Nathan Ranney, the founder of game development studio Gutter Arcade.
A timer is a mechanism that allows you to count up, or down, to a certain value and then trigger something once that value is reached.
So for example, let's say you have a character who has been poisoned. Poison damage is generally a damage over time status effect, that deals a small amount of damage every so often. Imagine your game runs at 60 frames per second, and you decided that poison damage should be one damage. Your character has 100 hp and your code looks like this.
Example poison code
This does not have a timer, or any sort of limitation on it, so it ticks down your hp by one every frame at 60 frames per second. Which means, your character with 100 hp dies in 1.6 seconds. What you would really want to do is tick down your poison damage every couple of frames. Maybe even every second. That code looks something like this.
Example poison timer code
In this example, I am using a new variable, poisonTick, to determine when to apply poison damage. So now, what took 1.6 seconds previously, takes 100 seconds. poisonTick counts down by one every frame. Once poisonTick reaches 0, the player hp is reduced by the poisonDamage value, and poisonTick is reset back to its maximum of 60. This requires slightly more management than using alarms, but is much more versatile.
To use timers in this way, you need at least one variable, which is the variable that stores whatever you are counting. In the above example that is poisonTick. I would highly recommend a second variable to use when you reset your counted variable. This makes it much easier to manage. I'll go over this in an example below.
More Examples
Another benefit to using manual timers is you can use the same timer variable in multiple cases. I often use a variable called actionDur (action duration) in my games to determine how long any one character action can be performed. Let's say a character has two actions, attack and dash, both of which are timer dependent. The character is locked into either action for the duration of the timer. You could use two timers to manage this, like attackDur and dashDur. Or you can use a single timer, and use it in both places. See the example below.
Multi-use timer
As you can see, both actions are able to use the same timer variables. Be aware that if you are using the same timer variable in multiple places, each use of the timer has to be completely independent of the other uses. So, using the above example again, I have to make sure that attack and dash cannot be true at the same time. If both variables were ever true at the same time, actionDur would countdown twice as fast. I highly recommend setting up a state machine for your character which will help you manage what code is running when.
You can also count up with your timers, which changes the structure slightly. It is somewhat personal preference whether you choose to count up or down. You may run into some cases where counting up or down is more beneficial than the alternative.
Timer counting up
Gamemaker Studio 2
There are some slight differences here. Our timer starts at 0, rather than the max, and counts up towards the max.
So what happens if you want to use a single timer for multiple actions, but have those action durations differ? The easiest way to do this, if you are using the same kind of setup that I've been talking about, is to define the starting point of your timer when the action happens. Using the attack action again, let's see how that might work.
Different timer duration with a single timer variable
In this example, we had to make use of a new block of code. We've added the attack_button variable, which you can imagine is a player pushing the attack button in a game. When that button is pressed, attack becomes true, and actionDur is set to 30. By default, actionDur is set to 0, and we are overriding that when pressing our imaginary attack button. However, actionDur is still counting up to the actionDurMax when attack is set to true. Only this time, instead of starting from 0, it starts from 30. This effectively halves the duration of our attack action. Here is another example using a second action.
Game Maker 8.1
Multiple actions with different timer durations
Gamemaker Studio 2 Sdk
Mirroring app for mac. Though it requires a bit more management than using alarms, using timers is a much more flexible and transparent setup.