Implementing random vectors on lattice points

perlin.h

@@ -6,9 +6,9 @@
 class perlin {
     public: 
         perlin() {
-            randFloat = new double[pointCount];
+            randVector = new vec3[pointCount];
             for (int i = 0; i < pointCount; i++) {
-                randFloat[i] = randomDouble();
+                randVector[i] = unitVector(vec3::random(-1, 1));
             }
 
             permX = perlinGeneratePerm();
@@ -17,7 +17,7 @@ class perlin {
         }
 
         ~perlin() {
-            delete[] randFloat;
+            delete[] randVector;
             delete[] permX;
             delete[] permY;
             delete[] permZ;
@@ -27,19 +27,16 @@ class perlin {
             auto u = p.x() - floor(p.x());
             auto v = p.y() - floor(p.y());
             auto w = p.z() - floor(p.z());
-            u = u*u*(3-2*u);
-            v = v*v*(3-2*v);
-            w = w*w*(3-2*w);
 
             auto i = int(floor(p.x()));
             auto j = int(floor(p.y()));
             auto k = int(floor(p.z()));
-            double c[2][2][2];
+            vec3 c[2][2][2];
 
             for (int di = 0; di < 2; di++) {
                 for (int dj = 0; dj < 2; dj++) {
                     for (int dk = 0; dk < 2; dk++) {
-                        c[di][dj][dk] = randFloat[
+                        c[di][dj][dk] = randVector[
                             permX[(i+di) & 255] ^
                             permY[(j+dj) & 255] ^
                             permZ[(k+dk) & 255]
@@ -47,12 +44,12 @@ class perlin {
                     }
                 }
             }
-            return trileanerInterpolation(c, u, v, w);
+            return perlinInterpolation(c, u, v, w);
         }
 
     private: 
         static const int pointCount = 256;
-        double* randFloat;
+        vec3* randVector;
         int* permX;
         int* permY;
         int* permZ;
@@ -78,19 +75,22 @@ class perlin {
             }
         }
 
-        static double trileanerInterpolation(double c[2][2][2], double u, double v, double w) {
+        static double perlinInterpolation(const vec3 c[2][2][2], double u, double v, double w) {
+            auto uu = u * u * (3 - 2 * u);
+            auto vv = v * v * (3 - 2 * v);
+            auto ww = w * w * (3 - 2 * w);
             auto accum = 0.0;
 
-            for (int i =0; i < 2; i++) {
-                for (int j = 0; j < 2; j++) {
+            for (int i = 0; i < 2; i++)
+                for (int j = 0; j < 2; j++)
                     for (int k = 0; k < 2; k++) {
-                        accum += (i*u + (1-i)*(1-u))
-                               * (j*v + (1-j)*(1-v))
-                               * (k*w + (1-k)*(1-w))
-                               * c[i][j][k];
-                    }
-                }
+                        vec3 weightV(u - i, v - j, w - k);
+                        accum += (i * uu + (1 - i)*(1 - uu))
+                            * (j * vv + (1 - j) * (1 - vv))
+                            * (k * ww + (1 - k) * (1 - ww))
+                            * dot(c[i][j][k], weightV);
                     }
+
             return accum;
         }
 };

texture.h

@@ -80,7 +80,7 @@ class noiseTexture : public texture {
     noiseTexture(double scale) : scale(scale) {}
 
     colour value(double u, double v, const point3& p) const override {
-        return colour(1,1,1) * noise.noise(scale * p);
+        return colour(1, 1, 1) * 0.5 * (1.0 + noise.noise(scale * p));
     }
 
   private: