Added FBM 3D & 4D and HybridMultiFractal 2D + cleaned code

this commit will change the scale of values produced by fbm2d. This will
probably not happen again. As a consequence, fbm values will always be
constrained between -1 and 1, but do not perfectly stick to that scale.
There is no easy solution, if the user wants the best dynamic between -1
and 1, he should adjust manually the value by multiplying by a gain slightly superior to 1.


Former-commit-id: ebdba9e9f4bbb972abe355c07ec9f8bce42329b9

src/Nazara/Noise/HybridMultifractal2D.cpp

@@ -0,0 +1,65 @@
+// Copyright (C) 2012 Rémi Bèges
+// This file is part of the "Nazara Engine".
+// For conditions of distribution and use, see copyright notice in Config.hpp
+
+#include <Nazara/Core/Error.hpp>
+#include <Nazara/Noise/Config.hpp>
+#include <Nazara/Noise/HybridMultiFractal2D.hpp>
+#include <Nazara/Noise/Perlin2D.hpp>
+#include <Nazara/Noise/Simplex2D.hpp>
+#include <Nazara/Noise/Debug.hpp>
+
+NzHybridMultiFractal2D::NzHybridMultiFractal2D(nzNoises source, int seed)
+{
+    switch(source)
+    {
+        case PERLIN:
+            m_source = new NzPerlin2D();
+        break;
+
+        default:
+            m_source = new NzSimplex2D();
+        break;
+    }
+    m_source->SetNewSeed(seed);
+    m_source->ShufflePermutationTable();
+    m_noiseType = source;
+}
+
+float NzHybridMultiFractal2D::GetValue(float x, float y, float resolution)
+{
+    this->RecomputeExponentArray();
+
+    float offset = 1.0f;
+
+    m_value = (m_source->GetValue(x,y,resolution) + offset) * m_exponent_array[0];
+    float weight = m_value;
+    float signal;
+
+    resolution *= m_lacunarity;
+
+    for(int i(1) ; i < m_octaves; ++i)
+    {
+        if(weight > 1.0)
+            weight = 1.0;
+
+        signal = (m_source->GetValue(x,y,resolution) + offset) * m_exponent_array[i];
+        m_value += weight * signal;
+
+        weight *= signal;
+
+        resolution *= m_lacunarity;
+    }
+
+    m_remainder = m_octaves - static_cast<int>(m_octaves);
+
+    if(remainder != 0)
+        m_value += m_remainder * m_source->GetValue(x,y,resolution) * m_exponent_array[static_cast<int>(m_octaves-1)];
+
+    return m_value/this->m_sum;
+}
+
+NzHybridMultiFractal2D::~NzHybridMultiFractal2D()
+{
+    delete m_source;
+}