scrTrail

 Script

/// Trail Effect
/* creates a trail effect behind the object
to use this apply values to these variables:
trail = (boolean) 
    enables/disables the script
trail_counter_inc = (double)
    the rate at which the trail object will spawn
trail_alpha_dev = (double)
    the rate at which the trail object alpha decreases
trail_scale_dev = (double)
    the rate at which the trail object scale decreases
*/
if (trail) {
    trail_counter += trail_counter_inc
    if trail_counter >= 1 {
        a=instance_create(x,y,objTrail)
        a.sprite_index = sprite_index
        a.image_angle = image_angle
        a.image_xscale = image_xscale
        a.image_yscale = image_yscale
        a.image_alpha = image_alpha
        a.image_speed = 0
        a.image_index = image_index
        a.image_blend = image_blend
        a.scale = true;
        a.scale_val = 0
        a.scale_dev = trail_scale_dev;
        a.alpha = true;
        a.alpha_val = 0;
        a.alpha_dev = trail_alpha_dev;
        trail_counter -= 1
    }
}