c++实现横版游戏角色大跳小跳的一种思路

void HelloWorld::update(float ft)
{
	if (_isJumping)
		_JumpingTime += ft;
		
	if (_isJumping)
	{
		if (_JumpingTime < __PressTimeMax && _isPressedW)
			_accelY = __JumpAccelerate;
		else
			_accelY = __JumpGravity;
		_speedY += _accelY;
		newPosY = max(__floorH, oldPos.y + _speedY * ft);
		
		_spritePos.y = newPosY;
		if (newPosY == __floorH)
			_JumpingTime = 0,
			_isJumping = 0;
	}
}