Because Im not a professional developer and my game it's just only for me and for fun I did this the simplest way:
poly_set = nonConvexPoly.getVertices(nonConvexBody.getPosition(), nonConvexBody.getRotation());
this function, I guess is a bit faster than this:
public float rotateX(float angle, float x, float y)
Now a have another problem..
I want to rotate my texture together with my polygon, but this don't work:
The texture is still at 90 degrees
It is possible to rotate texture image ?
I load my texture image with this:
SlickMyGame.my_texture = new Image("data/square.png", false, Image.FILTER_NEAREST);