MIP-map level selection for texture mapping

Texture mapping is a fundamental feature of computer graphics image generation. In current PC-based acceleration hardware, MIP-mapping with bilinear and trilinear filtering is a commonly used filtering technique for reducing spatial aliasing artifacts. The effectiveness of this technique in reducing image aliasing at the expense of blurring is dependent upon the MIP-map level selection and the associated calculation of screen-space to texture-space pixel scaling. This paper describes an investigation of practical methods for per-pixel and per-primitive level of detail calculation. This investigation was carried out as part of the design work for a screen-space rasterization ASIC. The implementations of several algorithms of comparable visual quality are discussed and a comparison is provided in terms of per-primitive and per-pixel computational costs.