Rotation based on x coordinate and x velocity?

-(void) accelerometer:(UIAccelerometer *)accelerometer didAccelerate:(UIAcceleration *)acceleration
{

float deceleration = 0.3f, sensitivity = 8.0f, maxVelocity = 150;

// adjust velocity based on current accelerometer acceleration
playerVelocity.x = playerVelocity.x * deceleration + acceleration.x * sensitivity;

// we must limit the maximum velocity of the player sprite, in both directions (positive & negative values)
playerVelocity.x = fmaxf(fminf(playerVelocity.x, maxVelocity), -maxVelocity);

}


Hi, I want to rotate my sprite based on the velocity and accelerometer input. My sprite can move along the X axis like so:

<--------- sprite ----------->

But it always faces forwards, if it is moving left I want it to point slightly to the left, the degree of how far it is pointing to be judged from the velocity. This should also work for the right.

I tried using atan but as the y velocity and position is always the same the function returns 0, which doesn't rotate it at all.

Any ideas?

Regards,

Lewis.

float Proportion = 0.25f; // adjust value to your needs