Using this function you can change the angle for the given sprite element on a layer. You give the sprite element ID (which you get when you create a sprite element using layer_sprite_create() or when you use the function layer_sprite_get_id()), and then set the angle value, from 0 to 359 anti-clockwise, where 0 is to the right, 90 is to the top, 180 is to the left and 270 is to the bottom. If you set a value greater than 360 this will be looped to bring it within the 0 - 359 range.
Argument Description sprite_element_id The unique ID value of the sprite element to change angle The angle of the sprite (default is 0)
var asset_sprite = layer_sprite_get_id(layer,
if layer_sprite_get_angle(asset_sprite) != 0
The above code will check the sprite element assigned to the layer the instance running the code is on and if its angle is not 0 it will set it to 0.