added a 4D noise function for use by shaders

git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@7367 d7cf8633-e32d-0410-b094-e92efae38249

diff --git a/fractalnoise.c b/fractalnoise.c
index c161f12b7c4eaf87387272beea954ee3ff2233e9..40beb8af3cc2315451627ead0816164fecda78be 100644 (file)
--- a/fractalnoise.c
+++ b/fractalnoise.c
@@ -123,3 +123,103 @@ void fractalnoisequick(unsigned char *noise, int size, int startgrid)
 #undef n
 }
 
+#define NOISE_SIZE 256
+#define NOISE_MASK 255
+float noise4f(float x, float y, float z, float w)
+{
+       int i;
+       int index[4][2];
+       float frac[4][2];
+       float v[4];
+       static float noisetable[NOISE_SIZE];
+       static int r[NOISE_SIZE];
+       // LordHavoc: this is inspired by code I saw in Quake3, however I think my
+       // version is much cleaner and substantially faster as well
+       //
+       // the following changes were made:
+       // 1. for the permutation indexing (r[] array in this code) I substituted
+       //    the ^ operator (which never overflows) for the original addition and
+       //    masking code, this should not have any effect on quality.
+       // 2. removed the outermost randomization array lookup.
+       //    (it really wasn't necessary, it's fine if X indexes the array
+       //     directly without permutation indexing)
+       // 3. reimplemented the blending using frac[] arrays rather than a macro.
+       //    (the original macro read one parameter twice - not good)
+       // 4. cleaned up the code by using 4 nested loops to make it read nicer
+       //    (but then I unrolled it completely for speed, it still looks nicer).
+       if (!noisetable[0])
+       {
+               // noisetable is a random-ish series of float values in +/- 1 range
+               for (i = 0;i < NOISE_SIZE;i++)
+                       noisetable[i] = (rand() / (double)RAND_MAX) * 2 - 1;
+               // r is a remapping table to make each dimension of the index have different indexing behavior
+               for (i = 0;i < NOISE_SIZE;i++)
+                       r[i] = (int)(rand() * (double)NOISE_MASK / (double)RAND_MAX);
+       }
+       frac[1][0] = x - floor(x);index[0][0] = (int)floor(x);
+       frac[1][1] = y - floor(y);index[1][0] = (int)floor(y);
+       frac[1][2] = z - floor(z);index[2][0] = (int)floor(z);
+       frac[1][3] = w - floor(w);index[3][0] = (int)floor(w);
+       for (i = 0;i < 4;i++)
+               frac[i][0] = 1 - frac[i][1];
+       for (i = 0;i < 4;i++)
+               index[i][1] = (index[i][0] < NOISE_SIZE - 1) ? (index[i][0] + 1) : 0;
+#if 1
+       // short version
+       v[0] = frac[1][0] * (frac[0][0] * noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][0]] ^ index[0][0]] + frac[0][1] * noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][0]] ^ index[0][1]]) + frac[1][1] * (frac[0][0] * noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][1]] ^ index[0][0]] + frac[0][1] * noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][1]] ^ index[0][1]]);
+       v[1] = frac[1][0] * (frac[0][0] * noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][0]] ^ index[0][0]] + frac[0][1] * noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][0]] ^ index[0][1]]) + frac[1][1] * (frac[0][0] * noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][1]] ^ index[0][0]] + frac[0][1] * noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][1]] ^ index[0][1]]);
+       v[2] = frac[1][0] * (frac[0][0] * noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][0]] ^ index[0][0]] + frac[0][1] * noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][0]] ^ index[0][1]]) + frac[1][1] * (frac[0][0] * noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][1]] ^ index[0][0]] + frac[0][1] * noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][1]] ^ index[0][1]]);
+       v[3] = frac[1][0] * (frac[0][0] * noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][0]] ^ index[0][0]] + frac[0][1] * noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][0]] ^ index[0][1]]) + frac[1][1] * (frac[0][0] * noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][1]] ^ index[0][0]] + frac[0][1] * noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][1]] ^ index[0][1]]);
+       return frac[3][0] * (frac[2][0] * v[0] + frac[2][1] * v[1]) + frac[3][1] * (frac[2][0] * v[2] + frac[2][1] * v[3]);
+#elif 1
+       // longer version
+       v[ 0] = noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][0]] ^ index[0][0]];
+       v[ 1] = noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][0]] ^ index[0][1]];
+       v[ 2] = noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][1]] ^ index[0][0]];
+       v[ 3] = noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][1]] ^ index[0][1]];
+       v[ 4] = noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][0]] ^ index[0][0]];
+       v[ 5] = noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][0]] ^ index[0][1]];
+       v[ 6] = noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][1]] ^ index[0][0]];
+       v[ 7] = noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][1]] ^ index[0][1]];
+       v[ 8] = noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][0]] ^ index[0][0]];
+       v[ 9] = noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][0]] ^ index[0][1]];
+       v[10] = noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][1]] ^ index[0][0]];
+       v[11] = noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][1]] ^ index[0][1]];
+       v[12] = noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][0]] ^ index[0][0]];
+       v[13] = noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][0]] ^ index[0][1]];
+       v[14] = noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][1]] ^ index[0][0]];
+       v[15] = noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][1]] ^ index[0][1]];
+       v[16] = frac[0][0] * v[ 0] + frac[0][1] * v[ 1];
+       v[17] = frac[0][0] * v[ 2] + frac[0][1] * v[ 3];
+       v[18] = frac[0][0] * v[ 4] + frac[0][1] * v[ 5];
+       v[19] = frac[0][0] * v[ 6] + frac[0][1] * v[ 7];
+       v[20] = frac[0][0] * v[ 8] + frac[0][1] * v[ 9];
+       v[21] = frac[0][0] * v[10] + frac[0][1] * v[11];
+       v[22] = frac[0][0] * v[12] + frac[0][1] * v[13];
+       v[23] = frac[0][0] * v[14] + frac[0][1] * v[15];
+       v[24] = frac[1][0] * v[16] + frac[1][1] * v[17];
+       v[25] = frac[1][0] * v[18] + frac[1][1] * v[19];
+       v[26] = frac[1][0] * v[20] + frac[1][1] * v[21];
+       v[27] = frac[1][0] * v[22] + frac[1][1] * v[23];
+       v[28] = frac[2][0] * v[24] + frac[2][1] * v[25];
+       v[29] = frac[2][0] * v[26] + frac[2][1] * v[27];
+       return frac[3][0] * v[28] + frac[3][1] * v[29];
+#else
+       // the algorithm...
+       for (l = 0;l < 2;l++)
+       {
+               for (k = 0;k < 2;k++)
+               {
+                       for (j = 0;j < 2;j++)
+                       {
+                               for (i = 0;i < 2;i++)
+                                       v[l][k][j][i] = noisetable[r[r[r[index[l][3]] ^ index[k][2]] ^ index[j][1]] ^ index[i][0]];
+                               v[l][k][j][2] = frac[0][0] * v[l][k][j][0] + frac[0][1] * v[l][k][j][1];
+                       }
+                       v[l][k][2][2] = frac[1][0] * v[l][k][0][2] + frac[1][1] * v[l][k][1][2];
+               }
+               v[l][2][2][2] = frac[2][0] * v[l][0][2][2] + frac[2][1] * v[l][1][2][2];
+       }
+       v[2][2][2][2] = frac[3][0] * v[0][2][2][2] + frac[3][1] * v[1][2][2][2];
+#endif
+}

diff --git a/quakedef.h b/quakedef.h
index 65a442549dd560816446c5a8210054f927da35d8..ade02aee250e51d032c1e67dfcbbce534591ffff 100644 (file)
--- a/quakedef.h
+++ b/quakedef.h
@@ -285,6 +285,7 @@ void Chase_Update (void);
 
 void fractalnoise(unsigned char *noise, int size, int startgrid);
 void fractalnoisequick(unsigned char *noise, int size, int startgrid);
+float noise4f(float x, float y, float z, float w);
 
 void Sys_Shared_Init(void);