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 /* * Copyright 2012 Google Inc. * * Use of this source code is governed by a BSD-style license that can be * found in the LICENSE file. */ // inline utilities /* Returns 0 if negative, 1 if zero, 2 if positive */ inline int side(double x) { return (x > 0) + (x >= 0); } /* Returns 1 if negative, 2 if zero, 4 if positive */ inline int sideBit(double x) { return 1 << side(x); } /* Given the set [0, 1, 2, 3], and two of the four members, compute an XOR mask that computes the other two. Note that: one ^ two == 3 for (0, 3), (1, 2) one ^ two < 3 for (0, 1), (0, 2), (1, 3), (2, 3) 3 - (one ^ two) is either 0, 1, or 2 1 >> 3 - (one ^ two) is either 0 or 1 thus: returned == 2 for (0, 3), (1, 2) returned == 3 for (0, 1), (0, 2), (1, 3), (2, 3) given that: (0, 3) ^ 2 -> (2, 1) (1, 2) ^ 2 -> (3, 0) (0, 1) ^ 3 -> (3, 2) (0, 2) ^ 3 -> (3, 1) (1, 3) ^ 3 -> (2, 0) (2, 3) ^ 3 -> (1, 0) */ inline int other_two(int one, int two) { return 1 >> 3 - (one ^ two) ^ 3; } /* Returns -1 if negative, 0 if zero, 1 if positive */ inline int sign(double x) { return (x > 0) - (x < 0); } inline double interp(double A, double B, double t) { return A + (B - A) * t; }