Hardware Implementation of an Anisotropic Texture Filter

In order to decrease the texture aliasing during texture mapping,one of methods is to approximate aniso-tropic filtering by isotropic filtering in computer graphics field.In such an approximation,MIP-MAP layer could be obtained using footprint and logarithm,whose implementations cause larger size of the circuits in Cordic or quadratic approximation.In this paper,a linear approximation to calculate footprint and logarithm is presented to simplify their circuits and footprint calculation with one adder and one shifter and logarithm with one adder were implemented.The absolute value of error of MIP-MAP layers between the approximation and origin is less than 7%.The approximate anisotropic filtering proposed in this paper was validated on Xilinx ZC706 board.