Trigonometry in libGDX - velocity and angle - libgdx

Question

For my game i wanted to use trigonometry. As i have initialy searched everything was the same as it was in Actionscript3. But i was wrong. Nothing worked as it should. So after searching the libGDX forum and stachoverflow posts i have "played" with numbers and find solution. Hope it helps someone

Answer 1

How to calculate an angle in libgdx and how to set x and y velocity with trigonometry (code omitted for clarity):
//variables
private Object object;
private float touchX, touchY, angle, xSpeed, ySpeed;
private final int power = 5;
//touch up event
#Override
public boolean touchUp(int screenX, int screenY, int pointer, int button) {
touchX = screenX;
touchY = h - screenY; // screenX gives an inverted y position (y == 0 is at the top)
setPosition(touchX, touchY);
}
//set angle and velocity method
public void setPosition(int x, int y){
//example 1 (velocity is calculated without angle):
angle = (float) (Math.atan2(y - object.y, x - object.x) * tdg) - 90.0f;
//at the end there is not always -90.0f. It depends of how the texture (or sth else we
//want to rotate) is rotated in .png file. Play with nuber if -90.0f is not good. Use
//the scale from -360 to 360
xSpeed = (x - bx) / 30;
ySpeed = (y - by) / 30;
//example 2 (velocity with angle):
angle = (float) Math.atan2(y - object.y, x - object.x);
xSpeed = (float) (Math.cos(angle)*power);
ySpeed = (float) (Math.sin(angle)*power);
angle = (angle*180/Math.PI) - 90.0f;
}