flow

//hit_player.gml
if(my_hitboxID.attack == AT_USPECIAL){
    old_hsp = -2;old_vsp = -8;
    window = 4;window_timer = 0;destroy_hitboxes();
}

//init.gml
upb_angle = 0;
upbhit = noone;
upbhit2 = noone;

//attack_update.gml REPLACE OLD USPEC CODE
else if(attack == AT_USPECIAL){
	can_move = false;
	if(window != 3){
		fall_through = true;
	}else{
		fall_through = false;
	}
	if(window == 3){
		can_wall_jump = true;
	}
    if(window == 1 && !hitpause){
    	hsp = 0;vsp = 0;
        if(window_timer == 1)move_cooldown[AT_USPECIAL] = 999;
        if (vsp > 0 && y > get_stage_data(SD_BOTTOM_BLASTZONE) - 20) vsp = 0;
    	upb_angle = 0;
		if(!joy_pad_idle){
    		upb_angle = round(joy_dir/5)*5;
    	}else{
    		upb_angle = 90;
    	}if(upb_angle < 90 && upb_angle > 0 || upb_angle > 270){
			spr_dir = 1;
		}else if(upb_angle > 90 && upb_angle < 270){
	    	spr_dir = -1;
		}
    	if(spr_dir == 1){
			set_hitbox_value(AT_USPECIAL, 1, HG_HITBOX_X, lengthdir_x(40,upb_angle));
			set_hitbox_value(AT_USPECIAL, 1, HG_HITBOX_Y, lengthdir_y(40,upb_angle));
			set_hitbox_value(AT_USPECIAL, 2, HG_HITBOX_X, lengthdir_x(40,upb_angle));
			set_hitbox_value(AT_USPECIAL, 2, HG_HITBOX_Y, lengthdir_y(40,upb_angle));
    	}else{
			set_hitbox_value(AT_USPECIAL, 1, HG_HITBOX_X, lengthdir_x(40,180-upb_angle));
			set_hitbox_value(AT_USPECIAL, 1, HG_HITBOX_Y, lengthdir_y(40,180-upb_angle));
			set_hitbox_value(AT_USPECIAL, 2, HG_HITBOX_X, lengthdir_x(40,180-upb_angle));
			set_hitbox_value(AT_USPECIAL, 2, HG_HITBOX_Y, lengthdir_y(40,180-upb_angle));
    	}
		if(window_timer < 6){
			if(hsp*spr_dir < 0 && (spr_dir == 1 && right_down || spr_dir == -1 && left_down))hsp *= 0.5;//if moving backwards and the player is holding forward, slow down the hsp
		}
    }
    if(window == 2 && !hitpause){
    	if(window_timer == 1){
    		upbhit = create_hitbox(AT_USPECIAL,2,x,y);upbhit2 = create_hitbox(AT_USPECIAL,1,x,y);
    	}
		hsp = lengthdir_x(12, upb_angle);
		vsp = lengthdir_y(12, upb_angle);
		if(spr_dir == 1){
			spr_angle = upb_angle;
		}else{
	    	spr_angle = upb_angle-180;
		}
    }
    if(window == 3){
    	hsp *= .92;vsp *= .92;
    	if(window_timer == 19)spr_angle = 0;
		if(spr_angle > 180){
			spr_angle = ease_linear(round(spr_angle), round(360), 10, 20);
		}else{
			spr_angle = ease_linear(round(spr_angle), round(0), 10, 20);
		}
    }
    if(window == 4 && !hitpause){
    	if(window_timer == 13)spr_angle = 0;
		if(spr_angle > 180){
			spr_angle = ease_linear(round(spr_angle), round(360), 10, 20);
		}else{
			spr_angle = ease_linear(round(spr_angle), round(0), 10, 20);
		}
    }
    if(window == 2 || window == 3 && window_timer <= 6){
		if(vsp > 1 && place_meeting(x,y+10,asset_get("par_block"))){
	        window = 4;
	        if(vsp < 4){
	        	vsp = -6;
	        }else {
	        	vsp = -vsp*1.1;
	        }
	        shake_camera(5, 3);sound_play(asset_get("sfx_blow_heavy1"));destroy_hitboxes();
	    }
    }
    if(instance_exists(upbhit)){
	    if(abs(hsp) > abs(vsp)){ //horizontal
	    	if(hsp > 0 && spr_dir == 1 || hsp < 0 && spr_dir == -1){
	    		upbhit.kb_angle = 45;
	    		if (instance_exists(upbhit2)){
	    			upbhit2.kb_angle = 45;
	    		}
	    	}else{
	    		upbhit.kb_angle = 135;
	    		if (instance_exists(upbhit2)){
	    			upbhit2.kb_angle = 135;
	    		}
	    	}
	    }else{ //vertical
		    if(vsp < 0){
		    	upbhit.kb_angle = 90;
		    	if (instance_exists(upbhit2)){
	    			upbhit2.kb_angle = 90;
	    		}
		    }else{
		    	upbhit.kb_angle = 270;
		    	if (instance_exists(upbhit2)){
	    			upbhit2.kb_angle = 270;
	    		}
		    }
	    }
	    if(upbhit.kb_angle == 270){ //nerf the knockback if it spikes lol
	    	upbhit.kb_value = 4;upbhit.kb_scale = .4;
	    	if (instance_exists(upbhit2)){
	    		upbhit2.kb_value = 6;upbhit2.kb_scale = .6;
	    	}
	    }else{
	    	upbhit.kb_value = get_hitbox_value(AT_USPECIAL, 2, HG_BASE_KNOCKBACK);upbhit.kb_scale = get_hitbox_value(AT_USPECIAL, 2, HG_KNOCKBACK_SCALING);
	    	if (instance_exists(upbhit2)){
	    		upbhit2.kb_value = get_hitbox_value(AT_USPECIAL, 1, HG_BASE_KNOCKBACK);upbhit2.kb_scale = get_hitbox_value(AT_USPECIAL, 1, HG_KNOCKBACK_SCALING);
	    	}
	    }
    }
    if(!snapped_to_ledge){
		snapped_to_ledge = ledge_snap();
    }
}
//Put above other atatck_update.gml defines at the bottom of the script!
#define ledge_snap
	//allows a moving attack to snap onto and over the ledge without getting caught,
	// similar to Maypul and Orcane's Forward-Specials.
	// returns 'true' when the attack successfully snaps over a ledge
	//code example by Mawral - free to use without credit.

	var step = 32; //the maximum distance to move up from the ledge. must be a power of 2. '16' or '32' is recommended.
	var xx = x + (spr_dir*4); //use 'xx = x - spr_dir' if the attack moves backwards.

	//check if there is a ledge ahead. if there is not, return 'false' and end the script.
	var par_block = asset_get("par_block");
	if (!place_meeting(xx, y, par_block) || place_meeting(xx, y - step, par_block)) return false;


	//move the player onto and above the ledge.
	X = xx;
	y -= step;
	//then, move downwards as far as possible without cutting into the stage.
	for (step /= 2; step >= 1; step /= 2) {
	    if (!place_meeting(x, y + step/4, par_block))  y += step/4;
	}
	//ledge snap successful. return 'true'.
	return true;