开发 VR 应用

Virtual Reality (VR) is an immersive environment that makes you feel inside a virtual or digitally reproduced real 3D world.虚拟现实（VR）是一种沉浸式环境，使你仿佛置身于一个虚拟或数字重建的三维世界中。

The main idea of VR is to create the illusion of human presence in a virtual environment. The person is immersed in it, identifies with the character, and lives in this environment.VR 的主要理念是在虚拟环境中营造出人类存在的幻觉。用户沉浸其中，代入角色，并在这个环境中生活。

To understand the basics of VR systems, let's figure out how to create a virtual world.为了了解 VR 系统的基础，让我们来看看如何创建一个虚拟世界。

The development of 3D content underlies the creation of VR. Then, you implement a program code and assign it to the rendered objects. Next, you develop a plot, work out details, and make the resulting image meet the application requirements.3D 内容的开发是创建 VR 的基础。接着，你需要实现程序代码并将其绑定到渲染的对象上。然后开发情节、完善细节，并使最终图像满足应用要求。

The 3D effect of a rendered image is achieved by tracking head and body movements by VR systems and also tracking the gaze direction (in advanced systems). All of this allows you to create a truly immersive experience. The whole principle of VR technologies is based on this. The multi-channel audio system provides the ability to navigate in VR by ear.图像的 3D 效果是通过 VR 系统对头部和身体动作的追踪（以及在高级系统中对视线方向的追踪）实现的。这一切共同营造出真正的沉浸式体验，这正是 VR 技术的核心所在。多通道音频系统还可通过听觉实现定位。

The main device for immersing in VR is VR glasses or a Head-mounted display (HMD). There are various types of VR glasses designed for different purposes — for smartphones, PCs, game consoles, and autonomous HMDs.实现 VR 沉浸的主要设备是 VR 眼镜或头戴式显示器（HMD）。有各种类型的 VR 眼镜，适用于智能手机、PC、游戏机以及独立的 HMD。

The VR headset has a special screen with a partition or two separate displays for each eye, with a combined field of view of 110 degrees (i.e., a separate image is drawn and sent to each eye). It is done so because our organs of vision see the same object from slightly different angles and with different depths. The brain can combine these two images, and we see one realistic 3D picture.VR 头显具有专用屏幕（或每只眼睛一个显示屏），视野总范围为 110 度（即每只眼睛渲染和显示一个独立图像）。这是因为我们的双眼从略微不同的角度和深度看到相同物体，大脑能将这两个图像合并，生成一个真实的三维画面。

Now, let’s see how to detect your position in the virtual world. For this purpose, there is a technology for tracking the movement of the head and body. It uses ultra-sensitive sensors: a gyroscope, a magnetometer, and an accelerometer. A user may have VR sickness, which is similar to motion sickness. So, transmitting information as quickly and accurately as possible is crucial for keeping the VR experience effective. For example, if the displayed image doesn’t change within 50 milliseconds after the user changes its head position, they can experience mild nausea. That is why modern headsets have mini-diodes that send signals to the special cameras (base stations).现在我们来看看如何检测你在虚拟世界中的位置。为此，引入了追踪头部和身体运动的技术。这些技术使用超灵敏传感器：陀螺仪、磁力计和加速度计。用户可能会产生 VR 晕动症，这类似于晕车。因此，尽可能快速、准确地传递信息对于有效的 VR 体验至关重要。例如，如果用户转动头部后图像在 50 毫秒内没有更新，就可能会感到轻微的恶心。这就是为什么现代头显中会有微型发光二极管向特殊摄像头（基站）发送信号的原因。

The headset connected to the USB and HDMI ports displays the image on the glasses screen. Smartphone glasses work even easier - the picture is displayed on the device screen, and the phone determines its own position in space.通过连接到 USB 和 HDMI 端口的头显可以将图像输出到眼镜的显示屏上。而智能手机眼镜的工作方式更为简单——图像显示在手机屏幕上，手机本身决定其在空间中的位置。

Immersion in the virtual world would be incomplete without interaction with it, and for this, you need devices to receive control signals from the user (User Input). There is a wide variety of them, ranging from all kinds of controllers and gamepads to gloves and devices that read the movement of fingers (Leap Motion). In addition, there are vibration vests on the market, entire VR suits with simulated physical sensations throughout the body, motion capture systems, climate control, and much more to maximize the depth of immersion.若无法与虚拟世界交互，沉浸体验就不完整。为此需要接收用户控制信号的设备（用户输入）。这类设备种类繁多，从各类控制器和游戏手柄，到手套和能读取手指动作的设备（如 Leap Motion）。此外，还有振动背心、提供全身模拟触感的 VR 套装、动作捕捉系统、气候控制设备等，以最大程度提升沉浸感。

Let’s talk a bit more about acronyms.我们再来聊一聊一些术语缩写。

AR or Augmented Reality is another popular technology, second in popularity after VR. The essence of AR is that the computer does not generate a new reality but only adds virtual objects to the picture of the real world. In the simplest case, a camera from a device (VR glasses or smartphone) captures an image of the current reality, and the computer on the fly processes this image and superimposes virtual objects on the picture.AR（增强现实）是仅次于 VR 的另一种流行技术。AR 的本质是：计算机不是生成一个新的现实，而是在现实世界的图像中叠加虚拟对象。在最简单的情况下，设备的摄像头（VR 眼镜或智能手机）拍摄现实画面，计算机实时处理图像并叠加虚拟对象。

MR or Mixed Reality is the most complex of the technologies under consideration. Its essence is already clear from the name — to combine virtual and ordinary reality to such an extent that a person could not distinguish one from the other. To do so, the computer must be able to draw 3D objects in the real world, recognize objects, and analyze objects in the image.MR（混合现实）是这些技术中最复杂的一种。从名字中就可以看出其本质 —— 将虚拟与现实融合到一个无法区分的程度。为实现这一点，计算机需要能够在现实世界中渲染三维对象，并识别和分析图像中的物体。

And then, there is XR (Extended Reality). Often, this term is used to refer to AR, VR, or MR.还有一个术语叫 XR（扩展现实）。通常用于统称 AR、VR 或 MR。

VR is often associated with entertainment, but it has many other uses. Nowadays, VR, AR, and MR technologies are used in manufacturing and service, construction, education, tourism, museums, medicine, and the list can go on and on. These technologies are important, necessary, and actively developing. And specialists in this field are in high demand.VR 通常与娱乐相关，但它的应用远不止如此。如今，VR、AR 和 MR 技术被广泛应用于制造与服务、建筑、教育、旅游、博物馆、医疗等多个领域。这些技术非常重要，必不可少，并且正在迅速发展。相关领域的专业人才也非常紧缺。

The development of VR applications is a fascinating process that can bring both satisfaction and benefit, but it has its own peculiarities that should be taken into account.开发 VR 应用是一个令人着迷的过程，不仅能带来满足感和成就感，也具有实际价值，但它有其独特的特点需要特别注意。