Added perlin noise generator

src/main.cpp

@@ -84,11 +84,24 @@ void earth() {
     camera.render(scene, "image.ppm");
 }
 
+void twoPerlinSpheres() {
+    shared_ptr<Scene> scene = make_shared<Scene>();
+
+    auto perlinTexture = make_shared<NoiseTexture>();
+    scene->add(make_shared<Sphere>(Point(0.0, -1000.0, 0.0), 1000, make_shared<Lambertian>(perlinTexture)));
+    scene->add(make_shared<Sphere>(Point(0.0, 2.0, 0.0), 2.0, make_shared<Lambertian>(perlinTexture)));
+
+    Camera camera(16.0 / 9.0, 100, 50, 400, 20.0, Vector(13.0, 2.0, 3.0), Vector(0.0, 0.0, 0.0), Vector(0.0, 1.0, 0.0), 0.0, 10.0);
+
+    camera.render(scene, "image.ppm");
+}
+
 int main() {
-    switch (3) {
+    switch (4) {
         case 1: randomSpheres(); break;
         case 2: twoSpheres(); break;
         case 3: earth(); break;
+        case 4: twoPerlinSpheres(); break;
     }
     return 0;
 }

src/perlin.cpp

@@ -0,0 +1,46 @@
+#include "perlin.h"
+
+void permute(int* p, int n) {
+    for (int i = n-1; i > 0; i--) {
+        int target = randomInt(0, i);
+        int tmp = p[i];
+        p[i] = p[target];
+        p[target] = tmp;
+    }
+}
+
+int* generatePerm() {
+    auto p = new int[Perlin::POINT_COUNT];
+
+    for (int i = 0; i < Perlin::POINT_COUNT; i++) {
+        p[i] = i;
+    }
+    permute(p, Perlin::POINT_COUNT);
+    return p;
+}
+
+Perlin::Perlin() {
+    _randomData = new double[Perlin::POINT_COUNT];
+    for (int i = 0; i < Perlin::POINT_COUNT; ++i) {
+        _randomData[i] = randomDouble();
+    }
+
+    _permuteX = generatePerm();
+    _permuteY = generatePerm();
+    _permuteZ = generatePerm();
+}
+
+Perlin::~Perlin() {
+    delete [] _randomData;
+    delete [] _permuteX;
+    delete [] _permuteY;
+    delete [] _permuteZ;
+}
+
+double Perlin::noise(const Point& point) const {
+    auto i = int(4.0 * point.x()) & 255;
+    auto j = int(4.0 * point.y()) & 255;
+    auto k = int(4.0 * point.z()) & 255;
+
+    return _randomData[_permuteX[i] ^ _permuteY[j] ^ _permuteZ[k]];
+}

src/perlin.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include "vector.h"
+
+class Perlin {
+
+private:
+
+    double* _randomData;
+    int* _permuteX;
+    int* _permuteY;
+    int* _permuteZ;
+
+public:
+
+    static const int POINT_COUNT = 256;
+
+    Perlin();
+    ~Perlin();
+
+    double noise(const Point& point) const;
+};

src/texture.h

@@ -2,6 +2,7 @@
 
 #include "vector.h"
 #include "image.h"
+#include "perlin.h"
 
 #include <memory>
 #include <string>
@@ -89,3 +90,19 @@ class ImageTexture : public Texture {
     }
 
 };
+
+class NoiseTexture : public Texture {
+
+private:
+
+    Perlin _noise;
+
+public:
+
+    NoiseTexture() {}
+
+    Color color(double u, double v, const Point &point) override {
+        return Color(1.0, 1.0, 1.0) * _noise.noise(point);
+    }
+
+};