Hart, John C.Kurt Akeley and Ulrich Neumann2013-10-282013-10-282001158113407X1727-3471https://doi.org/10.2312/EGGH/EGGH01/087-094While working on a method for supporting real-time procedural solid texturing, we developed a general purpose multipass pixel shader to generate the Perlin noise function. We implemented this algorithm on SGI workstations using accelerated OpenGL PixelMap and PixelTransfer operations, achieving a rate of 2.5 Hz for a 256x256 image. We also implemented the noise algorithm on the NVidia GeForce2 using register combiners. Our register combiner implementation required 375 passes, but ran at 1.3 Hz. This exercise illustrated a variety of abilities and shortcomings of current graphics hardware. The paper concludes with an exploration of directions for expanding pixel shading hardware to further support iterative multipass pixel-shader applications.I.3.3 [Computer Graphics]Picture/Image GenerationBitmap and framebuffer operations.I.3.7 [Computer Graphics]Three Dimensional Graphics and RealismColorshadingshadowing and texture.