Advanced sprite settings

First of all there are options related to collision checking. Whenever two instances meet a collision event is generated. Collisions are checked in the following way. Each sprite has a bounding box. This box is such that it contains the non-transparent part of all the subimages. When the bounding boxes do overlap, it is checked whether two pixels in the current subimages of the two sprites overlap. This second operation is expensive and requires extra memory and preprocessing. So if you are not interested in precise collision checking for a certain sprite, you should uncheck the box labeled Precise collision checking. In this case only bounding box checking is performed. You can also change the bounding box. This is hardly ever required but sometimes you might want to make the bounding box smaller, so that collisions with some extending parts of the sprite are not taken into account.

The edges of sprites can look a bit blocky. To avoid this you can check the box labelled Smooth edges. In this case pixel at the edges of the sprite (that is, pixels that are neighbors to transparent pixels) are drawn partially transparent. This can make them look a lot nicer. (Don't use this when the sprites need to match up to form larger shapes because in that case a partially transparent line will appear between the parts.) The effect of this setting is only visible in the game, not in the editor!

During gameplay, sprites are turned into textures. Textures must be moved to video memory (on the graphics card) before they can be used. When the box Preload texture is checked this happens immediately when the game loads such that there will be no delay during the game. If you have lots of large sprites though that are not used in the beginning you might want to uncheck this option. Game Maker will then swap textures to video memory and back when required.

Finally, you can indicate the origin of the sprite. This is the point in the sprite that corresponds with its position. When you set an instance at a particular position, the origin of the sprite is placed there. Default it is the top left corner of the sprite but it is sometimes more convenient to use the center or some other important point. You can even choose an origin outside the sprite. You can also set the origin by clicking in the sprite image (when the origin is shown in the image).