| /* |
| * Copyright (c) 2007, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package sun.java2d.pisces; |
| |
| public class PiscesMath { |
| |
| private PiscesMath() {} |
| |
| private static final int SINTAB_LG_ENTRIES = 10; |
| private static final int SINTAB_ENTRIES = 1 << SINTAB_LG_ENTRIES; |
| private static int[] sintab; |
| |
| public static final int PI = (int)(Math.PI*65536.0); |
| public static final int TWO_PI = (int)(2.0*Math.PI*65536.0); |
| public static final int PI_OVER_TWO = (int)((Math.PI/2.0)*65536.0); |
| public static final int SQRT_TWO = (int)(Math.sqrt(2.0)*65536.0); |
| |
| static { |
| sintab = new int[SINTAB_ENTRIES + 1]; |
| for (int i = 0; i < SINTAB_ENTRIES + 1; i++) { |
| double theta = i*(Math.PI/2.0)/SINTAB_ENTRIES; |
| sintab[i] = (int)(Math.sin(theta)*65536.0); |
| } |
| } |
| |
| public static int sin(int theta) { |
| int sign = 1; |
| if (theta < 0) { |
| theta = -theta; |
| sign = -1; |
| } |
| // 0 <= theta |
| while (theta >= TWO_PI) { |
| theta -= TWO_PI; |
| } |
| // 0 <= theta < 2*PI |
| if (theta >= PI) { |
| theta = TWO_PI - theta; |
| sign = -sign; |
| } |
| // 0 <= theta < PI |
| if (theta > PI_OVER_TWO) { |
| theta = PI - theta; |
| } |
| // 0 <= theta <= PI/2 |
| int itheta = (int)((long)theta*SINTAB_ENTRIES/(PI_OVER_TWO)); |
| return sign*sintab[itheta]; |
| } |
| |
| public static int cos(int theta) { |
| return sin(PI_OVER_TWO - theta); |
| } |
| |
| // public static double sqrt(double x) { |
| // double dsqrt = Math.sqrt(x); |
| // int ix = (int)(x*65536.0); |
| // Int Isqrt = Isqrt(Ix); |
| |
| // Long Lx = (Long)(X*65536.0); |
| // Long Lsqrt = Lsqrt(Lx); |
| |
| // System.Out.Println(); |
| // System.Out.Println("X = " + X); |
| // System.Out.Println("Dsqrt = " + Dsqrt); |
| |
| // System.Out.Println("Ix = " + Ix); |
| // System.Out.Println("Isqrt = " + Isqrt/65536.0); |
| |
| // System.Out.Println("Lx = " + Lx); |
| // System.Out.Println("Lsqrt = " + Lsqrt/65536.0); |
| |
| // Return Dsqrt; |
| // } |
| |
| // From Ken Turkowski, _Fixed-Point Square Root_, In Graphics Gems V |
| public static int isqrt(int x) { |
| int fracbits = 16; |
| |
| int root = 0; |
| int remHi = 0; |
| int remLo = x; |
| int count = 15 + fracbits/2; |
| |
| do { |
| remHi = (remHi << 2) | (remLo >>> 30); // N.B. - unsigned shift R |
| remLo <<= 2; |
| root <<= 1; |
| int testdiv = (root << 1) + 1; |
| if (remHi >= testdiv) { |
| remHi -= testdiv; |
| root++; |
| } |
| } while (count-- != 0); |
| |
| return root; |
| } |
| |
| public static long lsqrt(long x) { |
| int fracbits = 16; |
| |
| long root = 0; |
| long remHi = 0; |
| long remLo = x; |
| int count = 31 + fracbits/2; |
| |
| do { |
| remHi = (remHi << 2) | (remLo >>> 62); // N.B. - unsigned shift R |
| remLo <<= 2; |
| root <<= 1; |
| long testDiv = (root << 1) + 1; |
| if (remHi >= testDiv) { |
| remHi -= testDiv; |
| root++; |
| } |
| } while (count-- != 0); |
| |
| return root; |
| } |
| |
| public static double hypot(double x, double y) { |
| // new RuntimeException().printStackTrace(); |
| return Math.sqrt(x*x + y*y); |
| } |
| |
| public static int hypot(int x, int y) { |
| return (int)((lsqrt((long)x*x + (long)y*y) + 128) >> 8); |
| } |
| |
| public static long hypot(long x, long y) { |
| return (lsqrt(x*x + y*y) + 128) >> 8; |
| } |
| } |