Data commit

Task/Perlin-noise/C/perlin-noise.c

@@ -0,0 +1,61 @@
+#include<stdlib.h>
+#include<stdio.h>
+#include<math.h>
+
+int p[512];
+
+double fade(double t) { return t * t * t * (t * (t * 6 - 15) + 10); }
+double lerp(double t, double a, double b) { return a + t * (b - a); }
+double grad(int hash, double x, double y, double z) {
+      int h = hash & 15;
+      double u = h<8 ? x : y,
+             v = h<4 ? y : h==12||h==14 ? x : z;
+      return ((h&1) == 0 ? u : -u) + ((h&2) == 0 ? v : -v);
+   }
+
+double noise(double x, double y, double z) {
+      int X = (int)floor(x) & 255,
+          Y = (int)floor(y) & 255,
+          Z = (int)floor(z) & 255;
+      x -= floor(x);
+      y -= floor(y);
+      z -= floor(z);
+      double u = fade(x),
+             v = fade(y),
+             w = fade(z);
+      int A = p[X  ]+Y, AA = p[A]+Z, AB = p[A+1]+Z,
+          B = p[X+1]+Y, BA = p[B]+Z, BB = p[B+1]+Z;
+
+      return lerp(w, lerp(v, lerp(u, grad(p[AA  ], x  , y  , z   ),
+                                     grad(p[BA  ], x-1, y  , z   )),
+                             lerp(u, grad(p[AB  ], x  , y-1, z   ),
+                                     grad(p[BB  ], x-1, y-1, z   ))),
+                     lerp(v, lerp(u, grad(p[AA+1], x  , y  , z-1 ),
+                                     grad(p[BA+1], x-1, y  , z-1 )),
+                             lerp(u, grad(p[AB+1], x  , y-1, z-1 ),
+                                     grad(p[BB+1], x-1, y-1, z-1 ))));
+   }
+
+void loadPermutation(char* fileName){
+	FILE* fp = fopen(fileName,"r");
+	int permutation[256],i;
+	
+	for(i=0;i<256;i++)
+		fscanf(fp,"%d",&permutation[i]);
+	
+	fclose(fp);
+	
+	for (int i=0; i < 256 ; i++) p[256+i] = p[i] = permutation[i];
+}
+
+int main(int argC,char* argV[])
+{
+	if(argC!=5)
+		printf("Usage : %s <permutation data file> <x,y,z co-ordinates separated by space>");
+	else{
+		loadPermutation(argV[1]);
+		printf("Perlin Noise for (%s,%s,%s) is %.17lf",argV[2],argV[3],argV[4],noise(strtod(argV[2],NULL),strtod(argV[3],NULL),strtod(argV[4],NULL)));
+	}
+	
+	return 0;
+}