Added null pointer check and switched to a faster arctan method

By: VictorD <victor.danell@gmail.com>
This commit is contained in:
CraftBukkit/Spigot 2011-02-20 23:16:05 +01:00
parent a6afd3e020
commit 0baea2a20c

View file

@ -0,0 +1,45 @@
package org.bukkit.craftbukkit;
/**
* Got this code from a post by user aioobe on stackoverflow.com
*
*/
public class TrigMath {
static final double sq2p1 = 2.414213562373095048802e0;
static final double sq2m1 = .414213562373095048802e0;
static final double p4 = .161536412982230228262e2;
static final double p3 = .26842548195503973794141e3;
static final double p2 = .11530293515404850115428136e4;
static final double p1 = .178040631643319697105464587e4;
static final double p0 = .89678597403663861959987488e3;
static final double q4 = .5895697050844462222791e2;
static final double q3 = .536265374031215315104235e3;
static final double q2 = .16667838148816337184521798e4;
static final double q1 = .207933497444540981287275926e4;
static final double q0 = .89678597403663861962481162e3;
static final double PIO2 = 1.5707963267948966135E0;
private static double mxatan(double arg) {
double argsq = arg * arg, value;
value = ((((p4 * argsq + p3) * argsq + p2) * argsq + p1) * argsq + p0);
value = value / (((((argsq+q4)*argsq+q3)*argsq+q2)*argsq+q1)*argsq+q0);
return value * arg;
}
private static double msatan(double arg) {
return arg < sq2m1 ? mxatan(arg)
: arg > sq2p1 ? PIO2 - mxatan(1 / arg)
: PIO2 / 2 + mxatan((arg - 1) / (arg + 1));
}
public static double atan(double arg) {
return arg > 0 ? msatan(arg) : -msatan(-arg);
}
public static double atan2(double arg1, double arg2) {
if (arg1 + arg2 == arg1)
return arg1 >= 0 ? PIO2 : -PIO2;
arg1 = atan(arg1 / arg2);
return arg2 < 0 ? arg1 <= 0 ? arg1 + Math.PI : arg1 - Math.PI : arg1;
}
}