Graphics Rendering Technologies On Mobile Devices

Mobile graphics is a newly emerged research field as inter-discipline of embedded system, computer graphics and mobile communication. It is increasingly urgent to render realistic 2D/3D graphics on mobile devices with limited resources. This dissertation studies the technologies of graphics rendering on mobile devices. Main contents and contributions are expressed as follows:(1) Studies on rendering framework of mobile graphics. Currently researches of mobile graphics focus on concrete applications. One complete rendering framework for mobile graphics is presented, which comprised both local and remote rendering. In local rendering, graphics standard is implemented following the rules of hierarchy and modularity. Then, optimizations are applied on rendering pipeline. Remote rendering includes efficient network transmission scheme on isomeric platforms and rendering optimizations. Efficient optimizations technologies are summarized from aspects of graphics and transmission. Methods to balance the rendering workload among the client, hardware accelerator and server are presented. This framework integrates the clients, wireless network and remote server together. With some generality character, it can be used to guide the development of mobile applications.(2) Vector graphics rendering on mobile devices. Researches for the vector graphics standard, OpenVG, are ongoing. Rendering pipeline of OpenVG is analyzed, and the algorithm of path drawing is presented. To solve computation bottlenecks of path rendering, non-uniform tessellate algorithm of Bezier curves based on local curvature is presented. The suggested algorithm not only takes the features of curves into account, but also avoids the resource-hungry iterative operations and high-computation flattening test. When applied to vector graphics samples, this algorithm results in fast and more visual quality graphics.(3) Texture synthesis based on multiple samples on mobile device. Currently, researches related to realistic texture synthesis on mobile devices are few. Texture synthesis based on Wang Tiles is suitable for mobile device because of the simplicity and relative low memory requirement. An improved bi-direction texture synthesis algorithm is presented after deep analyzing Cohen's stochastic tilling algorithm. Mechanism of selecting sample sub-images from source texture based on Hammersley points set is characterized by even distribution and low discrepancy. Improved method of filling texture into tile enlarges the region for searching the best cut path, which is benefit to reduce the artifact of seam in the result. And bi-direction tilling enhanced the aperiodic appearance. The suggested algorithm gives better visual quality than stochastic tilling. The constraints of both computation capability and memory space on mobile device are considered in the process of algorithm design.(4) Synthesized synchronicity mechanism for network games. Synchronicity greatly affects the game playability. Factors that impact synchronicity are summarized and current algorithms can be divided into two categories, conservative and optimistic. Adaptive synchronicity algorithm is presented through altering the speed of objects, and human visual perception ability is utilized as well. Techniques of area-of-interest and dynamic user-list have been implemented on the side of server and client to compensate network latency and reduce bandwidth requirements respectively. Such synthesized synchronicity algorithm improves both synchronicity and response. Experimental evaluation of prototype validates the feasibility of this mechanism.Based on this scheme, one prototype of fitness-oriented Virtual Network Marathon is implemented. This system supports many users to exercise, train or compete with others in one virtual environment. Users enjoy both the entertainment and fitness at the same time.