Function UpdateFrame

demo/main.cpp:1904–2180

}

void UpdateFrame()
{
	static double lastTime;

	// real elapsed frame time
	double frameBeginTime = GetSeconds();

	g_realdt = float(frameBeginTime - lastTime);
	lastTime = frameBeginTime;

	// do gamepad input polling
	double currentTime = frameBeginTime;
	static double lastJoyTime = currentTime;

	if (g_gamecontroller && currentTime - lastJoyTime > g_dt)
	{
		lastJoyTime = currentTime;

		int leftStickX = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_LEFTX);
		int leftStickY = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_LEFTY);
		int rightStickX = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_RIGHTX);
		int rightStickY = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_RIGHTY);
		int leftTrigger = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_TRIGGERLEFT);
		int rightTrigger = SDL_GameControllerGetAxis(g_gamecontroller, SDL_CONTROLLER_AXIS_TRIGGERRIGHT);

		Vec2 leftStick(joyAxisFilter(leftStickX, 0), joyAxisFilter(leftStickY, 0));
		Vec2 rightStick(joyAxisFilter(rightStickX, 1), joyAxisFilter(rightStickY, 1));
		Vec2 trigger(leftTrigger / 32768.0f, rightTrigger / 32768.0f);

		if (leftStick.x != 0.0f || leftStick.y != 0.0f ||
			rightStick.x != 0.0f || rightStick.y != 0.0f)
		{
			// note constant factor to speed up analog control compared to digital because it is more controllable.
			g_camVel.z = -4 * g_camSpeed * leftStick.y;
			g_camVel.x = 4 * g_camSpeed * leftStick.x;

			// cam orientation
			g_camAngle.x -= rightStick.x * 0.05f;
			g_camAngle.y -= rightStick.y * 0.05f;
		}

		// Handle left stick motion
		static bool bLeftStick = false;

		if ((leftStick.x != 0.0f || leftStick.y != 0.0f) && !bLeftStick)
		{
			bLeftStick = true;
		}
		else if ((leftStick.x == 0.0f && leftStick.y == 0.0f) && bLeftStick)
		{
			bLeftStick = false;
			g_camVel.z = -4 * g_camSpeed * leftStick.y;
			g_camVel.x = 4 * g_camSpeed * leftStick.x;
		}

		// Handle triggers as controller button events
		void ControllerButtonEvent(SDL_ControllerButtonEvent event);