Ch 10. View Scrolling Compensation and Aircraft Scrolling Compensation

[kyuhyunp]

The code tries to compensate client and server's different scrolling time by multiplying a compensation ratio defined by currentViewPosition / currentWorldPosition. Then it multiplies the ratio by speed to get a more appropriate speed.

There are a problem with this approach:

The farther away from the goal, the less impact the compensation ratio makes (4010/4000 vs 20/10 even though both have 10 units difference)

Compensation=1.0+(Error×Constant) should be used for equal impact throughout where Error is (Server - Client)

This compensation should also be multipled to each aircraft's velocity to prevent it from continuously drifting.

void World::adaptPlayerVelocity()
{
	for (Aircraft* aircraft : mPlayerAircrafts)
	{
		sf::Vector2f velocity = aircraft->getVelocity();
		if (velocity.x != 0.f && velocity.y != 0.f)
		{
			aircraft->setVelocity(velocity / sqrtf(2.f));
		}

		aircraft->accelerate({ 0.f, mScrollSpeed * mScrollSpeedCompensation });
	}
}

[eXpl0it3r]

Note that there likely won't be any code changes, otherwise it would cause confusion with readers of the book. Though we can leave the issue open, so others may potentially see it as well.