Driving calculations using SpriteKit

Question

I have a tilemap (Kobald Kit's KKTilemapNode) and a character in the middle, now I use joystick to move the tilemap up and down and calculate the speed, the problem I have is that if I turn the character left, it goes still just up and down as I don't know how to calculate the new position under an angle. I have tried to port some Flash examples but the ones I have found don't have tile maps :(

Edit (adding source):

rotationStep = (_velocity.x / 20); // Rotate the car by

if (fabs(_speed) > 0.3) {
    _carRotation -= (rotationStep * (_speed / maxSpeed)); // Rotation angle if speed is at least 0.3
}

CGFloat speedX = ((_carRotation * (M_PI / 180)) * _speed); // Calculation stolen from the flash game and probably changed over tooo much
CGFloat speedY = ((_carRotation * (M_PI / 180)) * _speed);

CGFloat rotationValue = (degreesToRadians(_carRotation)); // Getting radians for the rotation

if (_velocity.x != 0 || _velocity.y != 0) {
    _car.zRotation = rotationValue; // Setting correct rotation
}

NSLog(@"Speed X: %f - Y: %f", speedX, speedY); // Getting probably very incorrect values

[_track setPosition:CGPointMake(5, (_track.position.y - _speed))]; // And moving the tile map just up and down in the end based on a speed I have calculated earlier

Answer 1

One way to calculate the angle:

float angle = atan2f (touchY - joystickY, touchX - joystickX);

where touchY and touchX are the coordinates of where the player touched the joystick and joystickY and joystickX are the coordinates of the joystick. To move a node by that angle using a SKAction (you may not want to use actions but you can still use the maths to calculate the destination coordinates):

SKAction *moveWhatever = [SKAction moveByX: yourDistance*cosf(angle) y:yourDistance*sinf(angle) duration:yourDuration];
[node runAction: moveWhatever];

where you set yourDistance and yourDuration.