图形处理器中几何流水线的设计与实现

Design and implementation of geometric pipeline in GPU

几何流水线可以完成图元装配、图元裁剪与剔除、Tile切割与链表的建立等功能,是图形处理器GPU管线中重要的组成部分。对几何流水线涉及到的算法进行研究和改进,通过将三维图元正投影到二维平面的方式优化视见体剔除算法,使用查找表结构降低背面剔除算法的运算量,选用包围盒裁剪算法对特殊位置小三角形进行处理,加入分层概念,优化Tile切割。利用Xilinx公司的Virtex UltraScale VU440开发板进行系统测试,实验结果表明,几何流水线可以稳定而正确的工作。

Geometric pipeline is an important part of graphics processing unit(GPU) pipeline of graphics processor and it has graph assembly,graph cutting and culling,Tile cutting and linked list establishment and other functions.The improved algorithm involved in geometrical line is investigated.In the improved algorithm,Figure yuan see body culling algorithm is optimised by using a three-dimensional orthogonal projection to the optimization of two-dimensional plane.The back-culling algorithm computational complexity is reduced by adding a lookup table structure.In the meantime,bounding box cut algorithm is chosen to deal with special place small triangle,the Tile cutting is optimised,and the layered concept is used.System testing is carried out with the Virtex UltraScale VU440 development board of Xilinx company.Experimental results show that the geometric pipeline can work stably and correctly.