Question: How do you detect keyboard keys in GameMaker?

Answer

In GameMaker, detecting keyboard input is a common task necessary for player control and other interactions. To check whether a specific key is pressed, released, or held down, you use GameMaker's built-in keyboard functions.

Here's an example of how to detect if a player is pressing the arrow keys:

// Inside the Step event of an object:

// Check for left arrow key press
if (keyboard_check(vk_left)) {
    // Move player or object to the left
}

// Check for right arrow key press
if (keyboard_check(vk_right)) {
    // Move player or object to the right
}

// Check for up arrow key press
if (keyboard_check(vk_up)) {
    // Move player or object upward
}

// Check for down arrow key press
if (keyboard_check(vk_down)) {
    // Move player or object downward
}

The keyboard_check function returns true if the key is currently being pressed. You can also use keyboard_check_pressed to detect if a key has been pressed in the current step or keyboard_check_released to detect if a key was just released.

For alphanumeric keys, you would use the ord() function with double quotes to get the keycode:

// Check for 'A' key press
if (keyboard_check(ord("A"))) {
    // Execute action when "A" is pressed
}

It's important to note that these checks are typically done within the Step event of an object, as it allows you to continuously monitor the keyboard state each frame of the game.

For more complex input handling, you might want to create input maps or use arrays to manage multiple keys and their states.