Displacement mapping using scan conversion hardware architectures

This paper presents a novel algorithm and architectures for perspective con ect displacement of the surface geometry of a polygonal model using a disp lacement map. This new displaced surface geometry is passed onto a traditio nal rendering pipeline. The algorithm uses a multiple pass approach in whic h the geometry is displaced in the first pass and then the displaced geomet ry is rendered. The significant features of the algorithm are that the surf ace is displaced after its triangle mesh is transformed into screen space a nd that it uses only bi-linear interpolation for calculating the displaced geometry allowing a cheap incremental scan-line implementation. A hardware architecture based on this algorithm is presented along with possible alter native implementations. The technique presented here allows greater photore alism by using increased detail without an increase in bandwidth for geomet ry or calculation time for transformation.