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Diffstat (limited to 'src/libnoiseforjava/Interp.java')
| -rw-r--r-- | src/libnoiseforjava/Interp.java | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/src/libnoiseforjava/Interp.java b/src/libnoiseforjava/Interp.java new file mode 100644 index 0000000..53ed56d --- /dev/null +++ b/src/libnoiseforjava/Interp.java @@ -0,0 +1,107 @@ +/*
+ * Copyright (C) 2003, 2004 Jason Bevins (original libnoise code)
+ * Copyright 2010 Thomas J. Hodge (java port of libnoise)
+ *
+ * This file is part of libnoiseforjava.
+ *
+ * libnoiseforjava is a Java port of the C++ library libnoise, which may be found at
+ * http://libnoise.sourceforge.net/. libnoise was developed by Jason Bevins, who may be
+ * contacted at [email protected] (for great email, take off every 'zig').
+ * Porting to Java was done by Thomas Hodge, who may be contacted at
+ * [email protected] (remove every 'zag').
+ *
+ * libnoiseforjava is free software: you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * libnoiseforjava 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 for more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * libnoiseforjava. If not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+package libnoiseforjava;
+
+public class Interp
+{
+
+ /// Performs cubic interpolation between two values bound between two other
+ /// values.
+ ///
+ /// @param n0 The value before the first value.
+ /// @param n1 The first value.
+ /// @param n2 The second value.
+ /// @param n3 The value after the second value.
+ /// @param a The alpha value.
+ ///
+ /// @returns The interpolated value.
+ ///
+ /// The alpha value should range from 0.0 to 1.0. If the alpha value is
+ /// 0.0, this function returns @a n1. If the alpha value is 1.0, this
+ /// function returns @a n2.
+ public static double cubicInterp (double n0, double n1, double n2, double n3,
+ double a)
+ {
+ double p = (n3 - n2) - (n0 - n1);
+ double q = (n0 - n1) - p;
+ double r = n2 - n0;
+ double s = n1;
+ return p * a * a * a + q * a * a + r * a + s;
+ }
+
+ /// Performs linear interpolation between two values.
+ ///
+ /// @param n0 The first value.
+ /// @param n1 The second value.
+ /// @param a The alpha value.
+ ///
+ /// @returns The interpolated value.
+ ///
+ /// The alpha value should range from 0.0 to 1.0. If the alpha value is
+ /// 0.0, this function returns @a n0. If the alpha value is 1.0, this
+ /// function returns @a n1.
+ public static double linearInterp (double n0, double n1, double a)
+ {
+ return ((1.0 - a) * n0) + (a * n1);
+ }
+
+ /// Maps a value onto a cubic S-curve.
+ ///
+ /// @param a The value to map onto a cubic S-curve.
+ ///
+ /// @returns The mapped value.
+ ///
+ /// @a a should range from 0.0 to 1.0.
+ ///
+ /// The derivative of a cubic S-curve is zero at @a a = 0.0 and @a a =
+ /// 1.0
+ public static double SCurve3 (double a)
+ {
+ return (a * a * (3.0 - 2.0 * a));
+ }
+
+ /// Maps a value onto a quintic S-curve.
+ ///
+ /// @param a The value to map onto a quintic S-curve.
+ ///
+ /// @returns The mapped value.
+ ///
+ /// @a a should range from 0.0 to 1.0.
+ ///
+ /// The first derivative of a quintic S-curve is zero at @a a = 0.0 and
+ /// @a a = 1.0
+ ///
+ /// The second derivative of a quintic S-curve is zero at @a a = 0.0 and
+ /// @a a = 1.0
+ static double SCurve5 (double a)
+ {
+ double a3 = a * a * a;
+ double a4 = a3 * a;
+ double a5 = a4 * a;
+ return (6.0 * a5) - (15.0 * a4) + (10.0 * a3);
+ }
+
+}
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