-/*
- * Compute mipmap level of detail.
- */
-static INLINE GLfloat
-compute_lambda(const GLfloat sPlane[4], const GLfloat tPlane[4],
- GLfloat invQ, GLfloat width, GLfloat height)
-{
- GLfloat dudx = sPlane[0] / sPlane[2] * invQ * width;
- GLfloat dudy = sPlane[1] / sPlane[2] * invQ * width;
- GLfloat dvdx = tPlane[0] / tPlane[2] * invQ * height;
- GLfloat dvdy = tPlane[1] / tPlane[2] * invQ * height;
- GLfloat r1 = dudx * dudx + dudy * dudy;
- GLfloat r2 = dvdx * dvdx + dvdy * dvdy;
- GLfloat rho2 = r1 + r2;
- /* return log base 2 of rho */
- if (rho2 == 0.0F)
- return 0.0;
- else
- return (GLfloat) (log(rho2) * 1.442695 * 0.5); /* 1.442695 = 1/log(2) */
-}
-
-