this should work(not tested):

Code:
function mouse_trace()
{
	vec_set(mouse_from.x,mouse_cursor.x); 
	vec_set(mouse_to.x,mouse_from.x); 
	mouse_to.z = 4000;
	
	vec_for_screen(mouse_from.x,camera); 
	vec_for_screen(mouse_to.x,camera); 

	editor_raster_scale(mouse_to.x,32);
	c_trace(mouse_from.x,mouse_to.x,IGNORE_ME | IGNORE_PASSABLE);
}


Everything is possible, just Do it!