There is not just one kind of VR experience. In fact, there are many. Consider the following types of VR experiences:
- Diorama: In the simplest case, webuilda 3D scene. You're observing from a third-person perspective. Your eye is the camera. Actually, each eye is a separate camera that gives you a stereoscopic view. You can look around.
- First-person experience: This time, you'reimmersedin the scene as a freely moving agent. Using an input controller (a hand controller or some other technique), you can "walk" around and explore the virtual scene.
- Room scale: The first-person experience with physical space. Given positional tracking, you can physically walk around a predefined area. A guardian system will show when you've reached unsafe boundaries.
- Interactive virtual environment: This islikethe first-person experience, but you're more than an observer. While you are in the scene, you can interact with the objects in it. Physics is at play. Objects may respond to you. You may be given specific goals to achieve and challenges to face using the game mechanics. You might even earn points and keep score.
- 3D content creation: In VR, you can create content that can be experienced in VR.Google Tilt Brushis one of the first blockbuster experiences, as isOculus MediumandGoogle Blocks, among others. Unity is working onEditorXRfor Unity developers to work on their projects directly in the VR scene.
- Riding on rails: In thiskindof experience, you're seated and being transported through the environment (or the environment changes around you). For example, you can ride a rollercoaster using this VR experience. However, it may not necessarily be an extreme thrill ride; it could be a simple real estate walk-through or even a slow, easy, and meditative experience.
- 360-degree media: Thinkpanoramicimages that are projected on the inside of a sphere. You're positioned at the center of the sphere and can look all around. Some purists don't consider thisreal VR, because you're seeing a projection and not a model rendering. However, it can provide an effective sense of presence.
- Social VR: When multipleplayersenter the same VR space and can see and speak with each other's avatars, it becomes a remarkable social experience.
In this book, we will implement a number of projects that demonstrate how to build each of these types of VR experience. For brevity, we'll need to keep it pure and simple, with suggestions for areas for further investigation. Our focus will be on consumer-grade devices, described in the next section.
