create PositiveWhiteNoiseSampler

common/addons/config-noise-function/src/main/java/com/dfsek/terra/addons/noise/samplers/noise/random/PositiveWhiteNoiseSampler.java

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) 2020-2021 Polyhedral Development
+ *
+ * The Terra Core Addons are licensed under the terms of the MIT License. For more details,
+ * reference the LICENSE file in this module's root directory.
+ */
+
+package com.dfsek.terra.addons.noise.samplers.noise.random;
+
+import com.dfsek.terra.addons.noise.samplers.noise.NoiseFunction;
+
+
+/**
+ * NoiseSampler implementation to produce random, uniformly distributed (white) noise.
+ */
+public class PositiveWhiteNoiseSampler extends WhiteNoiseSampler {
+    private static final long POSITIVE_POW1 = 0b01111111111L << 52;
+    // Bits that when applied to the exponent/sign section of a double, produce a positive number with a power of 1.
+    
+    public double getNoiseRaw(long seed) {
+        return (Double.longBitsToDouble((murmur64(seed) & 0x000fffffffffffffL) | POSITIVE_POW1) - 1.5) * 2;
+    }
+    
+    @Override
+    public double getNoiseRaw(long seed, double x, double y) {
+        return (getNoiseUnmapped(seed, x, y) - 1);
+    }
+    
+    @Override
+    public double getNoiseRaw(long seed, double x, double y, double z) {
+        return (getNoiseUnmapped(seed, x, y, z) - 1);
+    }
+}