@spongehammer i wasnt able to fully undestand your capx, but i was able to reproduce it, but its far too heavy . nice but heavy.
the @bluephaze solution is working well and allow 60fps .
but it doesnt take count of the walls.
@Joannesalfa 's example , i cant make it work. impossible to spawn object on tiled background, and i will not make all my walls with single sprite. it will cause many toomuch sprite animated on every tick. not usable exept for very small layout i think....
it left me with maybe trying the C7 version of bluephaze example.
but i need to find a solution to tell : set invisible to the sprite who are between the player and the point where the detection sprite overlap the wall, and let the other, after the wall visible. dont know how to do that.
i hope there will be a behavior like that in the future :)
someone know where we can consult the TO-DO list ?
anyway thanks all for your help.