|My report has title "Portal clipping technology in 3D modelling". It belongs to computer graphics direction in programming and describes the exact way of 3D virtual worlds building. It was developed with the main goal - to reduce the calculations an evaluations connected with reflection of graphical primitives - so-called poligons on to computer screen. This technique allows to get fast screen-shots of virtual built worlds from every place of on-looker in it.
The project will be realized as the programm which emulates the movement of on-lookers camera in 3D space.The user will be able to control camera's actions by simple keyboard interface.
For better understanding this example can be shown: many programmers and ordinary users know the popular game "Quake". It illustrates the battle between players in virtually created worlds. The game was presented completely three dimensial and wonders by it's reality. From practical point of view it would be interesting to know how the authers have reached such quality of texture-mapping and the speed of frames updating in spite of sizes of virtual world where action happens.
Although there was meant "Quake", but it has another technique in modelling 3D space. It calls BSP-tree method and it wont be discussed futher, because it distinguishes from Portal Clipping. The example was given only for answer on question: "What does my work like?"
In short, Portal Clipping technology can be explained by the following way. As simple building, the virtual world consists from rooms, called sectors, and portals - passeger between rooms. The Camera can freely moves both: anythere in room and between rooms too. In last case, camera crosses the portal, which join these couple of rooms. So, any time we know the room, camera belongs to, and it allows to detect collisions of camera with only walls included in this room, excepting the whole walls retaking. The same way is lied in drawing walls on screen, it is need not to draw the virtual world completely, the algorithm clips those rooms, which can't be visible for camera's current location. It gives many advantages and saves a lot of calculations in proecting images of virtual worlds on to computer screen. Portal Clipping posesses such characteristics as: siplexity of realization, fast screen-frames updating, a few number of calculation attached to camera and other objects moving in virtual world.
Another aspect which is taken in my work is the texture-mapping. It has the particular place in this work, because it covers nearly 80% of all doing calculations. Texture-mapping or texturing in short - is the process when the wall is proected to the screen in some pattern. A pattern as it is presented like a picture of fixed sizes. It pegs on a poligon image at the screen. Thera are different ways to texturate walls. In my work I use some of them: direct texturing with high quality and interpolar texturing with reducing textures quality. As the matter of fact, the discription of these processes requires individual explainations and mathematical formulars and I avoid it because pressed for time. More detailer you will be able to see my final report.
Well, that's all that I wanted to tell you, and the rest time you can ask me some questions.
Portal clipping, трёхмерная графика, программирование 3D-движка »