lookahead

thrusterutilsai.js

// The "optimal" velocity is the velocity needed to bring us to
// the target angle in a single physics step.
var optimalVelocity = targetAngle / dt;

// The "optimal" torque is the amount of torque needed this
// frame to achieve the "optimal" velocity.
var optimalTorque = ( optimalVelocity - angularVelocity ) / ( dt * inverseInertia );
var desiredTorqueSign = nonZeroSign( desiredTorque );

if ( desiredTorqueSign === nonZeroSign(optimalTorque) ) {
  // If the torque we desire is greater than the "optimal"
  // torque, we obviously don't need all of it.
  if ( Math.abs(desiredTorque) > Math.abs(optimalTorque) ) {
    
    // We look forward to the following physics step and predict
    // the amount of braking force required to "freeze" the
    // mouse look.          
    var requiredBrakeTorque = -optimalVelocity / ( dt * inverseInertia );

    var availableBrakeTorque;
    if ( desiredTorqueSign === nonZeroSign(requiredBrakeTorque) ) {
      availableBrakeTorque = desiredTorque;
    } else {
      availableBrakeTorque = brakeTorque;
    }
    
    // If the amount of available braking torque is enough, then
    // it will be possible to stop immediately, so we use the
    // optimal torque.

    if ( Math.abs(requiredBrakeTorque) <= Math.abs(availableBrakeTorque) ) {
      desiredTorque = optimalTorque;
    }
  }
}

result.torque = desiredTorque;
return result;