First Commit

For Azeroth!

dep/g3dlite/source/g3dmath.cpp

@@ -0,0 +1,109 @@
+/**
+ @file g3dmath.cpp
+ 
+ @author Morgan McGuire, graphics3d.com
+  
+ @created 2001-06-02
+ @edited  2004-02-24
+ */
+
+#include "G3D/g3dmath.h"
+#include <cstdlib>
+#include <cstring>
+
+
+namespace G3D {
+
+float gaussRandom(float mean, float stdev) {
+
+    // Using Box-Mueller method from http://www.taygeta.com/random/gaussian.html
+    // Modified to specify standard deviation and mean of distribution
+    float w, x1, x2;
+
+    // Loop until w is less than 1 so that log(w) is negative
+    do {
+        x1 = uniformRandom(-1.0, 1.0);
+        x2 = uniformRandom(-1.0, 1.0);
+
+        w = float(square(x1) + square(x2));
+    } while (w > 1.0f);
+
+    // Transform to gassian distribution
+    // Multiply by sigma (stdev ^ 2) and add mean.
+    return x2 * (float)square(stdev) * sqrtf((-2.0f * logf(w) ) / w) + mean; 
+}
+
+/** 
+    This value should not be tested against directly, instead
+    G3D::isNan() and G3D::isFinite() will return reliable results. */
+double inf() {
+    return std::numeric_limits<double>::infinity();
+}
+
+bool isNaN(float x) {
+    static const float n = fnan();
+    return memcmp(&x, &n, sizeof(float)) == 0;
+}
+
+bool isNaN(double x) {
+    static const double n = nan();
+    return memcmp(&x, &n, sizeof(double)) == 0;
+}
+
+
+/** 
+    This value should not be tested against directly, instead
+    G3D::isNan() and G3D::isFinite() will return reliable results. */
+float finf() {
+    return std::numeric_limits<float>::infinity();
+}
+
+/** This value should not be tested against directly, instead
+    G3D::isNan() and G3D::isFinite() will return reliable results. */
+double nan() {
+    // double is a standard type and should have quiet NaN
+    return std::numeric_limits<double>::quiet_NaN();
+}
+
+float fnan() {
+    // double is a standard type and should have quiet NaN
+    return std::numeric_limits<float>::quiet_NaN();
+}
+
+
+int highestBit(uint32 x) {
+    // Binary search.
+    int base = 0;
+
+    if (x & 0xffff0000)	{
+        base = 16;
+        x >>= 16;
+    }
+    if (x & 0x0000ff00) {
+        base += 8;
+        x >>= 8;
+    }
+    if (x & 0x000000f0) {
+        base += 4;
+        x >>= 4;
+    }
+    
+    static const int lut[] = {-1,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3};
+    return base + lut[x];
+}
+
+
+int iRandom(int low, int high) {
+    int r = iFloor(low + (high - low + 1) * (double)rand() / RAND_MAX);
+    
+    // There is a *very small* chance of generating
+    // a number larger than high.
+    if (r > high) {
+        return high;
+    } else {
+        return r;
+    }
+}
+
+
+}