//vars to define outside of this script:
//angle_index = the angle we want to use
//angle_subimg = our internal image_index;
//img_speed = our internal image_speed (don't use image_speed)

var angle_count=argument[0];//the number of angles contained wihin the sprite
var imgdex_real=((image_number)/angle_count);//how many subimages per loop there really is


//going through the actual subimg loop, angle_subimg defines the actual frame of animation in the loop
angle_subimg+=img_speed*delta_realtime;
while angle_subimg>=imgdex_real{angle_subimg-=imgdex_real};//going back to start when looped
while angle_subimg<0{angle_subimg+=imgdex_real};

//finally setting image_index based on angle index + subimg
image_index=(angle_index*imgdex_real)+angle_subimg