libgdx: rotate a rectangle shape (manual math calculation).

rotate-libgdx-trig.txt

Rectangle rectangle = (Rectangle)shape;

Vector2 center = new Vector2();
rectangle.getCenter(center);

float centerX = center.x - rectangle.x;
float centerY = center.y - rectangle.y - rectangle.height;
float cos = MathUtils.cosDeg(rotation);
float sin = MathUtils.sinDeg(rotation);
float x = centerX * cos + centerY * sin;
float y = -centerX * sin + centerY * cos;
center.x = x + rectangle.x;
center.y = y + rectangle.y + rectangle.height;