The Final Drone Grid Game - Beginning Android 3D Game Development - page 387

The FrameMove() function does the following:

The UpdateScene() and ProcessCameraMove() functions are called only if the
elapsed time since the last update is greater than k_SecondsPerTick , which is
the time for one update to occur.

1.

After UpdateScene() is called, m_UpdateTimeCount is changed to reflect that
an update has happened, by subtracting k_SecondsPerTick , which is the time
for a single frame update or “tick.”

2.

3. If more frame updates have to occur in order to meet the goal of one game

update every k_SecondsPerTick , which means that m_UpdateTimeCount ➤
k_SecondsPerTick , UpdateScene() is called repeatedly, until the elapsed time
since the last game update is equal to or less than k_SecondsPerTick .

Listing 10-51. Updating the Game

void FrameMove()
{
m_UpdateTimeCount += m_ElapsedTime;
if (m_UpdateTimeCount > k_SecondsPerTick)
{
while(m_UpdateTimeCount > k_SecondsPerTick)
{
// Update Camera Position
if (m_CameraMoved)
{
ProcessCameraMove();
}
// update the scene
UpdateScene();
m_UpdateTimeCount -= k_SecondsPerTick;
}
}
}

The onDrawFrame() function modifications (see Listing 10-52) involve the following:

New code for sound control is added. If m_SFXOn is true, the sound
effects are turned on for the arena objects, tanks, and pyramid by calling
TurnSFXOnOff() . Otherwise, the sound effects are turned off for these game
elements.

1.

2. The time that has elapsed since the last game update is calculated by calling

the CalculateFrameUpdateElapsedTime() function.

The game is updated by calling FrameMove() .

3.

The game objects are rendered to the screen by calling RenderScene() .

4.