ray-casting method that enable pre-fetching in order to have a smooth navigation in

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CHAPTER 5 CONCLUSIONS AND FUTURE WORKS

5.1 A summary

We have described an overlapped file I/O mechanism, cache management, and

ray-casting method that enable pre-fetching in order to have a smooth navigation in

massive interactive 3D environment, which players can traverse in from section to

section without waiting for loading. First of all, we loaded the original section files to

recovery the 3D scene. Secondly, we have proposed a ray-casting approach as well as

auxiliary plane meshes to detect which sections we can see in each section.

Furthermore, we recorded the information in order to append directives to each

original section files. During runtime, these directives guide the pre-fetching without

other heavy computation and players experience that a whole massive 3D scene has

been loaded into memory. Finally, we take advantage of overlapped I/O and cache

management to accelerate loading rate of section files.

5.2 Future works 5.2.1 3D scene tools

In our implementation, we make an assumption that all section files are created

by 3D scene tools. In other words, we have not implemented the 3D scene tools and

the current format of section files is temporary. For automation, we shall develop the

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3D scene tool with following features: to partition a massive 3D virtual environment

in accordance with given parameters such as polygon density, texture density, position

of lights, and overall scene shape; to generate a master scene description file of the

original 3D scene; to generate files of each section. Accordingly, we can acquire more

efficiency by this tool rather than man-made.

5.2.2 Memory allocation management

Recall our earlier description in which we load sections into memory without

flushing them out. Eventually this will result in a waste of system memory, especially

when a player’s character is traversing a more complex 3D environment. Therefore,

we would like to develop a memory allocation management module which monitors

memory usage. In addition, the module can flush some resources which have not been

used for a specified interval by several strategies such as least recently used(LRU)

strategy, longest relative distance region(LRDR) strategy, and Reference counting(RC)

strategy. With these flushing strategies, end-user machines can run streaming 3D

virtual environments without more physical memory space.

5.2.3 Various resource types

For the time being, our section files merely include mesh data. Actually, the

resources of a 3D virtual environment are various. For instance, there may be textures,

sound, lighting, and character animations. In order to enrich our 3D scene, supporting

more resource types rather than mesh is desirable.