1 files changed, 75 insertions, 0 deletions
diff --git a/perlin.c b/perlin.c
new file mode 100644
index 0000000..0a08147
--- /dev/null
+++ b/perlin.c
@@ -0,0 +1,75 @@
+#include "include/perlin.h"
+
+static float       noise(int x, int y) //seed this??
+{
+    int n;
+
+        n = x + y * 57 * 2749;
+        n = (n << 13) ^ n * 1087;
+        return (1.0 - ( (n * ((n * n * 15731) + 789221) +  1376312589) & 0x7fffffff) / 1073741824.0)*3433;
+}
+
+static float       interpolate(float a, float b, float x)
+{
+  float     pi_mod;
+  float     f_unk;
+
+  pi_mod = x * 3.1415927;
+  f_unk = (1 - cos(pi_mod)) * 0.5;
+  return (a * (1 - f_unk) + b * x);
+}
+
+static float       smooth_noise(int x, int y)
+{
+  float     corners;
+  float     center;
+  float     sides;
+
+  corners = (noise(x - 1, y - 1) + noise(x + 1, y - 1) +
+         noise(x - 1, x + 1) + noise(x + 1, y + 1)) / 16;
+  sides = (noise(x - 1, y) + noise(x + 1, y) + noise(x, y - 1) +
+       noise(x, y + 1)) / 8;
+  center = noise(x, y) / 4;
+  return (corners + sides + center);
+}
+
+static float       noise_handler(float x, float y)
+{
+  int       int_val[2];
+  float     frac_val[2];
+  float     value[4];
+  float     res[2];
+
+  int_val[0] = (int)x;
+  int_val[1] = (int)y;
+  frac_val[0] = x - int_val[0];
+  frac_val[1] = y - int_val[1];
+  value[0] = smooth_noise(int_val[0], int_val[1]);
+  value[1] = smooth_noise(int_val[0] + 1, int_val[1]);
+  value[2] = smooth_noise(int_val[0], int_val[1] + 1);
+  value[3] = smooth_noise(int_val[0] + 1, int_val[1] + 1);
+  res[0] = interpolate(value[0], value[1], frac_val[0]);
+  res[1] = interpolate(value[2], value[3], frac_val[0]);
+  return (interpolate(res[0], res[1], frac_val[1]));
+}
+
+float perlin_noise(float x, float y) //implement Fractal Brownian Motion?
+{
+    srand(time(NULL));
+  float     total;
+  float     per;
+  float     amp;
+  int       hz;
+  int       octave;
+
+  total = 0.0;
+  per = 0.5;
+  octave = 10;
+  for(int i = 0; i < octave; i++)
+    {
+      hz = pow(2, i);
+      amp = pow(per, (float)i);
+      total += noise_handler(x * (float)hz, y * (float)hz) * amp;
+    }
+  return (total);
+}