private void NaiveUpdateCancelVerticalVelocity(Vector3 velocity, float heightFromGround, Thruster mainEngine)
{
if (heightFromGround < 0)
{
return;
}
heightFromGround += heightDetectorError;
float yVelocity = -velocity.y;
float burnDuration = yVelocity / (mainEngine.GetMaxImpulseStrength() + Physics.gravity.y);
float timeToGroundHit = heightFromGround / yVelocity;
Debug.Log($"Time to ground: {timeToGroundHit} BurnDuration: {burnDuration}");
if (timeToGroundHit < burnDuration)
{
mainEngine.SetThrottle(1);
}
else
{
mainEngine.SetThrottle(0);
}
if (heightFromGround < 1 && yVelocity < 0)
{
mainEngine.Shutdown();
}
}
private void CompleteUpdateCancelVerticalVelocity(Vector3 velocity, float heightFromGround, Thruster mainEngine)
{
if (heightFromGround < 0)
{
return;
}
// Acceleration is caused by the sum of gravity and the engine strength, so:
// h''(t) = g + e;
// h'(t) = v0 + gt + et; (Integral from h'')
// h(t) = h0 + v0*t + 0.5*g*t*t + 0.5*e*t*t (Integral from h')
// where:
// h0 = start height
// v0 = start vertical velocity
// g = gravity
// e = main engine impule strength
//To solve we need:
// Solve for h0 => At what height do we need to start burning to land perfectly?
// h(t) = 0 (We have landed)
// h'(t) = 0 (We have 0 velocity)
//Calculation:
// 0 = v0 + gt + et /-v0
// -v0 = gt + et / format
// -v0 = (g+e)*t / /(g+e)
// -v0/(g+e) = t
// so the burn duration (b) is equal to: b == t == -v0/(g+e)
//insert into h(t) = 0
// 0 = h0 + v0*b + 0.5*g*b*b + 0.5*e*t*t /-h0 /*-1
// h0 = -v0b -0.5*gbb -0.5*ebb;
float correctedHeight = heightFromGround + heightDetectorError;
float v0 = velocity.y;
float e = mainEngine.GetMaxImpulseStrength() * (1 - engineEnergyLossPercent); //engine seems to not be applying the force 100% so we use a slightly reduced engine impulse
float g = Physics.gravity.y;
float b = -v0 / (g + e);
float h0 = -v0 * b - 0.5f * g * b * b - 0.5f * e * b * b;
Debug.Log($"{Time.time} : Height: {heightFromGround} CorrectedHeight: {correctedHeight}, Height to start burn is: {h0}");
//Turn on engine if we should burn, otherwise turn off
if (correctedHeight <= h0)
{
mainEngine.SetThrottle(1);
}
else
{
mainEngine.SetThrottle(0);
}
//if we have landed, shutdown the engine (This is helpfull in case we reach v=0 slighly above the ground
if (correctedHeight < 1 && v0 > 0)
{
mainEngine.Shutdown();
}
}