The hue of the surface colors are computed by the following fragment program. The conversion from hsv to rgb is done in a separate pass.

!!ARBfp1.0

TEMP R0;

PARAM U0 = program.local[0];

PARAM C0 = {
38.000000000000000000000000000000,
0.500000000000000000000000000000,
1.000000000000000000000000000000,
0.000000000000000000000000000000
};

MUL R0.x, fragment.texcoord[0].x, fragment.texcoord[0].x;
MAD R0.y, fragment.texcoord[0].y, fragment.texcoord[0].y, R0.x;
MAD R0.x, fragment.texcoord[0].z, fragment.texcoord[0].z, R0.y;
RSQ R0.y, R0.x;
RCP R0.x, R0.y;
MUL R0.y, C0.x, R0.x;
ADD R0.x, R0.y, U0.x;
SIN R0.y, R0.x;
MOV_SAT R0.x, C0.z;
FRC result.color.x, R0.y;
MOV result.color.y, C0.y;
MUL result.color.z, C0.z, fragment.color.primary.z;
MOV result.color.w, C0.z;

END