| Virtual reality technology is a kind of technology that makes use of computer to generate simulation environment and make users experience virtual simulation world.With its excellent visual and auditory perception and immersive experience,virtual reality has been widely used in teaching research,exhibition publicity,urban planning,games and entertainment and other fields.Web3 D scene roaming based on the Internet is one of the key research directions in the field of virtual reality.The difficulty of its universality lies in how to deal with the contradiction between mass data transmission and scene real-time rendering under limited hardware conditions.To this end,this paper,combined with WebGL technology,firstly elaborated the related technologies and research situation of Web3 D real-time scene roaming system.Then,the collision detection,frame number performance optimization and data transmission of 3d model scene roaming technology in Web browsers are studied.The existing problems in Web3 D application scenes are analyzed and optimization solutions are proposed to enable users to conduct smooth 3d scene roaming interaction in Web browsers.The main research contents of this paper are as follows:(1)Working principle of Web3 D scene roaming.Firstly,the technical standard of WebGL is studied,and the basic principle of WebGL and the camera and scene renderer that realize object behavior and interaction function in three.js 3d library are analyzed.Then it focuses on the basic drawing mechanism of shader in WebGL and the coordinate system used in WebGL.(2)Management strategy of data model.Before loading the scene model,the data is preprocessed.The data of three different levels of precision are divided to reduce the data volume of Web3 D scene real-time rendering.According to the file management mode of the three.js engine,the different precision models of the node are managed.In order to reduce the traversing amount of data,a graph data structure can be used to retrieve the model data from near to far according to the position of viewpoint.(3)Dynamic loading of scene model.According to WebGL data loading mode,the data is dynamically scheduled by asynchronous call.This paper proposes a way to simulate multithreading based on Web Worker,studies the process implementation of Web Worker,gives the strategy and method of dynamic loading,and explores the communication mode between Web Worker and main thread(4)Algorithm and performance optimization of 3d scene roaming.This paper introduces the 3d machining algorithm in WebGL and realizes the grid construction of circular and arc objects.Then the collision detection algorithm in roaming is introduced,and the phenomenon that Web3 D large-scale scene model is easy to cause stuck is studied and analyzed,and the performance optimization method is proposed.(5)Realization of Web3 D roaming system.After the model is built by modeling software,the system is further divided into data preprocessing,data dynamic loading and interactive subsystems.In the Web browser,Three and js libraries are combined to realize the roaming system,complete scene drawing,roaming and collision detection,and verify and analyze the feasibility of the method in this paper through system performance.Experiments show that the algorithm in this paper can make the system run smoothly. |
