3D Tutorial - Step 17 - Head Bobbing
by Monstrous Software
Step 17 - Head Bobbing
Somewhere along the way we lost the head bobbing effect that we added in step 2 of this tutorial.
Let us reintroduce this. We add a method to the GameView class that calculates a bob height value which gets
added to the camera height in the render method. The bob height value is calculated with a sine function.
If the player speed is close to zero the effect is disabled to avoid head bobbing when the player is standing
still. The render() method now needs a new parameter to know the player speed.
GameView:
public void render(float delta, float speed ) {
if(!isOverlay)
camController.update(world.getPlayer().getPosition(), world.getPlayerController().getViewingDirection());
addHeadBob(delta, speed);
cam.update();
...
}
private void addHeadBob(float deltaTime, float speed ) {
if( speed > 0.1f ) {
bobAngle += speed * deltaTime * Math.PI / Settings.headBobDuration;
// move the head up and down in a sine wave
cam.position.y += bobScale * Settings.headBobHeight * (float)Math.sin(bobAngle);
}
}
In the GameScreen class we now have to calculate the player speed to pass it to the game view render() method.
The gun view will also apply a camera bobbing motion to simulate the player’s hand going up and down while running.
GameScreen:
@Override
public void render(float delta) {
...
world.update(delta);
float moveSpeed = world.getPlayer().body.getVelocity().len();
gameView.render(delta, moveSpeed);
if(debugRender) {
gridView.render(gameView.getCamera());
physicsView.render(gameView.getCamera());
}
if(!thirdPersonView && world.weaponState.currentWeaponType == WeaponType.GUN && !lookThroughScope) {
gunView.render(delta, moveSpeed);
}
...
}
To calculate the player’s velocity we add a new method to the PhysicsBody class which converts the linear velocity of the rigid body to a Vector3.
PhysicsBody:
public Vector3 getVelocity() {
DVector3C v = geom.getBody().getLinearVel();
linearVelocity.set((float)v.get0(), (float)v.get1(), (float)v.get2());
return linearVelocity;
}
This concludes step 17.