Designing Games with Game Maker - YoYo Games

• Make sure you delete resources you no longer need. Otherwise the system soon runs
out of memory.
In general, you should not change any resources during game play. Better create and change
the resources at the beginning of the game or maybe at the beginning of a room.
Sprites
The following routines are available for changing sprite properties:
sprite_set_offset(ind,xoff,yoff) Sets the offset of the sprite with the
given index.
sprite_set_bbox_mode(ind,mode) Sets the bounding box mode of the
sprite (0=automatic, 1=full image, 2=manual).
sprite_set_bbox(ind,left,top,right,bottom) Sets the bounding box
of the sprite with the given index. Works only when the bounding box mode is
manual.
sprite_set_precise(ind,mode) Sets whether the sprite with the given
index uses precise collision checking (true or false).
The following routines can be used to create new sprites and to remove them.
sprite_duplicate(ind) Creates a duplicate of the sprite with the given
index. It returns the index of the new sprite. When an error occurs -1 is
returned.
sprite_assign(ind,spr) Assigns the indicated sprite to sprite ind. So this
makes a copy of the sprite. In this way you can easily set an existing sprite to
a different, e.g. new sprite.
sprite_merge(ind1,ind2) Merges the images from sprite ind2 into sprite
ind1, adding them at the end. If the sizes don't match the sprites are
stretched to fit. Sprite ind2 is not deleted!
sprite_add(fname,imgnumb,precise,transparent,smooth,preload
,xorig,yorig) Adds the image stored in the file fname to the set of sprite
resources. Many different image file types can be dealt with. When the image
is not a gif image it can be a strip containing a number of subimages for the
sprite next to each other. Use imgnumb to indicate their number (1 for a
single image). For (animated) gif images, this argument is not used; the