Moving your player

There are many different types of games with different visuals and play styles. Some games are devoid of a visible player character but most, especially 2D games, have the player controlling a sprite or 3D model onscreen. We're going to take a quick look at putting a character in front of the player that he/she can control.

Getting ready

You've animated some sprites, but animated sprites won't do you any good without a character to which they can be applied. Create a new object and call it obj_player. Under Sprite, click the menu icon and select spr_player_idle.

How to do it...

In obj_player's Object Properties window, click Add Event, then click Keyboard and select <Right> from the menu. This event will allow you to make things happen while you're pressing the right arrow key on your keyboard. What we want to have happen is for our player character to move to the right and to have his right facing walk cycle play while he is doing it, so let's do it.
Under the Main1 tab on the right side of the Object Properties window, drag Change Sprite (it looks like a green Pac-Man) and drop it in the Actions box.
The actions we want apply to obj_player, so select Applies to Self.
Since we want to use spr_player_walk in this case, select the sprite from the drop-down menu.
Subimage defaults to 0, but this tells GameMaker that we only want to show the first frame of the animation. Since we want to have the entire animation play, you'll need to set this value to -1, which tells GameMaker to ignore the subimage count.
The sprite's play speed can be altered by setting the Speed option to a value between 0 and 1. Set the value to 0.8 so that the walk cycle will play at 80 percent of the room's frame rate and close this box.
We want the player character to move right when the right arrow key is pressed but we don't want him to simply walk right off the screen. How mad would you be if the character you were controlling simply gave up, said That's it, I'm out of here! and disappeared off screen? Sounds like an entirely frustrating experience. Since we don't want this to happen, let's make sure it can't. For that, you'll need to add a variable check before your character goes anywhere.
Under the Control tab, drag and drop Test Variable to the Actions box.
We want to test the variable x, which is the player's x coordinate or horizontal position. Since we want to the player to stay on-screen, we'll set the value to room_width-16 and the operation will be less than.
Close the Test Variable box and under the Move tab, drag and drop Jump to Position to the Actions box.
Set x to 4, leave y as 0, and make sure Relative is checked. If you were to test this out now, your player will begin moving to the right as his walk cycle animation played. The problem is that now it doesn't stop.
Add another event but this time choose Key Release <Right>. Add Change Sprite to the Actions box but this time select spr_player_idle from the menu. This time, if you were to run a test, your player would walk right when holding the right arrow key and go back to his idle pose when it is released.
These same steps can be repeated for all directions using corresponding keyboard events but you need to take into consideration whether or not you need to mirror the sprites. If you've created separate sprites for each direction you'll simply choose which sprite you'll need at the time. If, however, you've opted to mirror the sprites, you'll need to add one more thing to each key event.
Under the Main1 tab, drag and drop Transform Sprite into the Actions box for each key event (key release events included) and modify the xscale (for horizontal mirroring) or the yscale (for vertical flipping). Setting the value to -1 would flip the image and setting it to 1 would revert it to its original facing. If the image is already facing that way, no change is made. Avoid using the options in the Mirror menu, as these selections alter the image from its present state instead of assigning a value. This would mean that if you hit the left arrow key, and the character was already facing left, he would flip and face right. That would be confusing!

Tip

This and any other drag and drop function in GameMaker can also be used in code and scripts. In fact, coding them yourself often allows for greater control over how they work.

How it works...

The movement discussed in this section is quite simple. In this case, you've instructed GameMaker to make your character move left or right and play the walk animation (facing the proper direction) as he goes. Using jump to position allows you to move a character to any point in the screen or, as you did here, move the character relative to its current position, adding the entered values to existing coordinates. Using a negative value would subtract from the current coordinates, causing the character to move in the opposite direction. If you want your character to move up or down you would change the value of y and leave x as 0. I encourage you to play around with the values entered, as this will change the player's speed.

There's more...

It might seem like this section had a lot of text to set up very simple movement, but I can assure you it is all necessary. This section and the rest of the chapter set up some core ideas that will recur throughout your GameMaker experience and will be explored much further later on.

GameMaker Cookbook

By : Gardiner

GameMaker Cookbook

By: Gardiner

Overview of this book

Moving your player

Getting ready

How to do it...

Tip

How it works...

There's more...

See also

GameMaker Cookbook

By : Gardiner

GameMaker Cookbook

By: Gardiner

Overview of this book

Moving your player

Getting ready

How to do it...

Tip

How it works...

There's more...

See also

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