Study On Optimized Algorithms For 3D Model Transmission And 3D Graphics Pipeline Over Wireless Environment

With both the mature of the mobile network infrastructure and wide use of mobile handheld devices, 3D applications based on mobile devices connected wireless network have got rapid development. However, the shortcomings of high packet-loss-ratio and error-ratio among wireless network and the limitations of low power consumption and low computing performance for mobile devices hinder the further developing of the 3D graphics application on mobile devices. To overcome above shortcomings, this dissertation mainly discusses the transmission mechanism for progressive model among wireless network and the optimized tactics for texture operation of 3D pipeline on mobile devices. The main contribution of this dissertation includes:A new packetization algorithm for progressive model transmission over unreliable wireless network. In order to achieve better rendering result at client, we firstly construct a non-redundant Directed Acyclic Graph encoding the dependencies among the entire vertex split operations of the Progressive Mesh in this packetization algorithm. Then, a special global graph equal partition algorithm that partitions the dependency graph with special local-circular features into several equal size sub-graphs, which is packed as packets, is presented. Briefly, the global partition algorithm consists of two main phases including initial partition phase and global refinement phase. Experimental results demonstrate that the proposed algorithm can maximizes the number of rendering nodes at any time so as to achieve better progressive rendering quality.A transmission mechanism for colored progressive model based on predictive reconstruction methods over unreliable wireless network. Firstly, to resolve the adverse visual effects brought by the lost packets, this transmission mechanism first makes use of a packetization method proposed in the paper to minimize the dependencies among packets holding the model information. Secondly, the scheme adopts a hybrid transmission technique to send model information efficiently. Finally, a predictive reconstruction method is developed to help a 3D model render in a desired visual quality even if some model information is lost. In particularly, the method consists mechanisms to handle geometry, color, normal and texture coordinate information. The experimental results show that the proposed transmission enables the clients achieve good model visual quality with less transmission time.A hybrid adaptive normal map texture compression algorithm for mobile devices: Normal mapping can reveal the details of complex geometry object and improve the photorealistic rendering. However, GPU may compress these normal map textures to save the valuable video memory and limited bandwidth just as the common texture compression technology does. The texture compression algorithm proposed in this paper utilizes three useful tactics, which are TSSA, BlockIndexTable and I3DC, to compress the normal map texture according to its different features such as a great many of, few or fewer zero texels existed in the normal map texture. The experimental results and comparisons show that it can reach higher compression rate and achieve better image result than other methods' do. What's more, it will be a good candidate for hardware implementation because of its low cost.An Anisotropic texture mapping algorithm for mobile devices: Anisotropic texture mapping, which needs extra ROM memory and abundant computation, is not suitable for the mobile devices because of its limited power supply and low performance. To solve this problem, this paper proposes a triangle-based subtexel precision anisotropic filter called TSPAF firstly. On the basic of the TSPAF, this paper also presents a hybrid anisotropic filter called HTSPAF, which combines the bilinear filtering and TSPAF filtering with the MIPMap layer chosen method. The high quality results, together with the low computational and storage requirements obtained with HTSPAF, make it be feasible for mobile GPU implementation.As the basic of 3D rendering, mobile graphics library plays an important role for the 3D application real-time rendering on mobile devices. One mobile graphics library for mobile devices and several optimizing methods are proposed in this thesis. Mainly, we analyze the JIT-based optimizing method, which can improve the efficiency of this library greatly. Besides, we also discuss the game construction based on mobile devices. One mobile billiards game is implemented based on the integrated mobile game platform, and the collision detection optimization algorithm is introduced.