Real-time GPU rendering of piecewise algebraic surfaces

摘要

Surfaces defined by Bézier tetrahedron are generated on programmable graphics hardware. Custom programmed vertex processing, performed by either the CPU or the GPU includes the computation of a symmetric tensor and the assignment of the unique elements of the computed symmetric tensor as vertex attribute data. The vertex attribute data is interpolated by the graphics hardware and output to custom programmed pixel processing. The pixel processing uses the interpolated vertex attribute data to reconstruct, at each pixel, the symmetric tensor which enables the determination of the roots of the polynomial defining the surface to be generated. If no real roots exist, the pixel processing can exit early. If the roots of the polynomial exist, the smallest root can be used as the basis for computing a normal to a point on the surface being rendered, enabling the determination of the color and depth of that pixel.