227 lines
9.7 KiB
C
227 lines
9.7 KiB
C
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#include "quakedef.h"
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void fractalnoise(unsigned char *noise, int size, int startgrid)
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{
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int x, y, g, g2, amplitude, min, max, size1 = size - 1, sizepower, gridpower;
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int *noisebuf;
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#define n(x,y) noisebuf[((y)&size1)*size+((x)&size1)]
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for (sizepower = 0;(1 << sizepower) < size;sizepower++);
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if (size != (1 << sizepower))
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{
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Con_Printf("fractalnoise: size must be power of 2\n");
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return;
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}
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for (gridpower = 0;(1 << gridpower) < startgrid;gridpower++);
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if (startgrid != (1 << gridpower))
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{
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Con_Printf("fractalnoise: grid must be power of 2\n");
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return;
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}
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startgrid = bound(0, startgrid, size);
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amplitude = 0xFFFF; // this gets halved before use
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noisebuf = (int *)Mem_Alloc(tempmempool, size*size*sizeof(int));
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memset(noisebuf, 0, size*size*sizeof(int));
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for (g2 = startgrid;g2;g2 >>= 1)
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{
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// brownian motion (at every smaller level there is random behavior)
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amplitude >>= 1;
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for (y = 0;y < size;y += g2)
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for (x = 0;x < size;x += g2)
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n(x,y) += (rand()&litude);
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g = g2 >> 1;
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if (g)
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{
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// subdivide, diamond-square algorithm (really this has little to do with squares)
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// diamond
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for (y = 0;y < size;y += g2)
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for (x = 0;x < size;x += g2)
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n(x+g,y+g) = (n(x,y) + n(x+g2,y) + n(x,y+g2) + n(x+g2,y+g2)) >> 2;
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// square
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for (y = 0;y < size;y += g2)
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for (x = 0;x < size;x += g2)
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{
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n(x+g,y) = (n(x,y) + n(x+g2,y) + n(x+g,y-g) + n(x+g,y+g)) >> 2;
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n(x,y+g) = (n(x,y) + n(x,y+g2) + n(x-g,y+g) + n(x+g,y+g)) >> 2;
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}
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}
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}
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// find range of noise values
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min = max = 0;
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for (y = 0;y < size;y++)
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for (x = 0;x < size;x++)
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{
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if (n(x,y) < min) min = n(x,y);
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if (n(x,y) > max) max = n(x,y);
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}
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max -= min;
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max++;
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// normalize noise and copy to output
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for (y = 0;y < size;y++)
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for (x = 0;x < size;x++)
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*noise++ = (unsigned char) (((n(x,y) - min) * 256) / max);
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Mem_Free(noisebuf);
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#undef n
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}
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// unnormalized, used for explosions mainly, does not allocate/free memory (hence the name quick)
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void fractalnoisequick(unsigned char *noise, int size, int startgrid)
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{
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int x, y, g, g2, amplitude, size1 = size - 1, sizepower, gridpower;
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#define n(x,y) noise[((y)&size1)*size+((x)&size1)]
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for (sizepower = 0;(1 << sizepower) < size;sizepower++);
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if (size != (1 << sizepower))
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{
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Con_Printf("fractalnoise: size must be power of 2\n");
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return;
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}
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for (gridpower = 0;(1 << gridpower) < startgrid;gridpower++);
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if (startgrid != (1 << gridpower))
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{
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Con_Printf("fractalnoise: grid must be power of 2\n");
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return;
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}
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startgrid = bound(0, startgrid, size);
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amplitude = 255; // this gets halved before use
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memset(noise, 0, size*size);
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for (g2 = startgrid;g2;g2 >>= 1)
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{
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// brownian motion (at every smaller level there is random behavior)
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amplitude >>= 1;
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for (y = 0;y < size;y += g2)
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for (x = 0;x < size;x += g2)
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n(x,y) += (rand()&litude);
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g = g2 >> 1;
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if (g)
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{
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// subdivide, diamond-square algorithm (really this has little to do with squares)
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// diamond
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for (y = 0;y < size;y += g2)
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for (x = 0;x < size;x += g2)
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n(x+g,y+g) = (unsigned char) (((int) n(x,y) + (int) n(x+g2,y) + (int) n(x,y+g2) + (int) n(x+g2,y+g2)) >> 2);
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// square
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for (y = 0;y < size;y += g2)
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for (x = 0;x < size;x += g2)
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{
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n(x+g,y) = (unsigned char) (((int) n(x,y) + (int) n(x+g2,y) + (int) n(x+g,y-g) + (int) n(x+g,y+g)) >> 2);
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n(x,y+g) = (unsigned char) (((int) n(x,y) + (int) n(x,y+g2) + (int) n(x-g,y+g) + (int) n(x+g,y+g)) >> 2);
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}
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}
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}
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#undef n
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}
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#define NOISE_SIZE 256
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#define NOISE_MASK 255
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float noise4f(float x, float y, float z, float w)
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{
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int i;
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int index[4][2];
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float frac[4][2];
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float v[4];
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static float noisetable[NOISE_SIZE];
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static int r[NOISE_SIZE];
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// LordHavoc: this is inspired by code I saw in Quake3, however I think my
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// version is much cleaner and substantially faster as well
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//
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// the following changes were made:
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// 1. for the permutation indexing (r[] array in this code) I substituted
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// the ^ operator (which never overflows) for the original addition and
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// masking code, this should not have any effect on quality.
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// 2. removed the outermost randomization array lookup.
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// (it really wasn't necessary, it's fine if X indexes the array
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// directly without permutation indexing)
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// 3. reimplemented the blending using frac[] arrays rather than a macro.
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// (the original macro read one parameter twice - not good)
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// 4. cleaned up the code by using 4 nested loops to make it read nicer
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// (but then I unrolled it completely for speed, it still looks nicer).
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if (!noisetable[0])
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{
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// noisetable is a random-ish series of float values in +/- 1 range
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for (i = 0;i < NOISE_SIZE;i++)
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noisetable[i] = (rand() / (double)RAND_MAX) * 2 - 1;
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// r is a remapping table to make each dimension of the index have different indexing behavior
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for (i = 0;i < NOISE_SIZE;i++)
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r[i] = (int)(rand() * (double)NOISE_SIZE / ((double)RAND_MAX + 1)) & NOISE_MASK;
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// that & is only needed if RAND_MAX is > the range of double, which isn't the case on most platforms
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}
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frac[0][1] = x - floor(x);index[0][0] = ((int)floor(x)) & NOISE_MASK;
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frac[1][1] = y - floor(y);index[1][0] = ((int)floor(y)) & NOISE_MASK;
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frac[2][1] = z - floor(z);index[2][0] = ((int)floor(z)) & NOISE_MASK;
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frac[3][1] = w - floor(w);index[3][0] = ((int)floor(w)) & NOISE_MASK;
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for (i = 0;i < 4;i++)
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frac[i][0] = 1 - frac[i][1];
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for (i = 0;i < 4;i++)
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index[i][1] = (index[i][0] < NOISE_SIZE - 1) ? (index[i][0] + 1) : 0;
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#if 1
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// short version
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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]]);
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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]]);
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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]]);
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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]]);
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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]);
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#elif 1
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// longer version
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v[ 0] = noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][0]] ^ index[0][0]];
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v[ 1] = noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][0]] ^ index[0][1]];
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v[ 2] = noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][1]] ^ index[0][0]];
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v[ 3] = noisetable[r[r[r[index[3][0]] ^ index[2][0]] ^ index[1][1]] ^ index[0][1]];
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v[ 4] = noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][0]] ^ index[0][0]];
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v[ 5] = noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][0]] ^ index[0][1]];
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v[ 6] = noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][1]] ^ index[0][0]];
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v[ 7] = noisetable[r[r[r[index[3][0]] ^ index[2][1]] ^ index[1][1]] ^ index[0][1]];
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v[ 8] = noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][0]] ^ index[0][0]];
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v[ 9] = noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][0]] ^ index[0][1]];
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v[10] = noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][1]] ^ index[0][0]];
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v[11] = noisetable[r[r[r[index[3][1]] ^ index[2][0]] ^ index[1][1]] ^ index[0][1]];
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v[12] = noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][0]] ^ index[0][0]];
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v[13] = noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][0]] ^ index[0][1]];
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v[14] = noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][1]] ^ index[0][0]];
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v[15] = noisetable[r[r[r[index[3][1]] ^ index[2][1]] ^ index[1][1]] ^ index[0][1]];
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v[16] = frac[0][0] * v[ 0] + frac[0][1] * v[ 1];
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v[17] = frac[0][0] * v[ 2] + frac[0][1] * v[ 3];
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v[18] = frac[0][0] * v[ 4] + frac[0][1] * v[ 5];
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v[19] = frac[0][0] * v[ 6] + frac[0][1] * v[ 7];
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v[20] = frac[0][0] * v[ 8] + frac[0][1] * v[ 9];
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v[21] = frac[0][0] * v[10] + frac[0][1] * v[11];
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v[22] = frac[0][0] * v[12] + frac[0][1] * v[13];
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v[23] = frac[0][0] * v[14] + frac[0][1] * v[15];
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v[24] = frac[1][0] * v[16] + frac[1][1] * v[17];
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v[25] = frac[1][0] * v[18] + frac[1][1] * v[19];
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v[26] = frac[1][0] * v[20] + frac[1][1] * v[21];
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v[27] = frac[1][0] * v[22] + frac[1][1] * v[23];
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v[28] = frac[2][0] * v[24] + frac[2][1] * v[25];
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v[29] = frac[2][0] * v[26] + frac[2][1] * v[27];
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return frac[3][0] * v[28] + frac[3][1] * v[29];
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#else
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// the algorithm...
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for (l = 0;l < 2;l++)
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{
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for (k = 0;k < 2;k++)
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{
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for (j = 0;j < 2;j++)
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{
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for (i = 0;i < 2;i++)
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v[l][k][j][i] = noisetable[r[r[r[index[l][3]] ^ index[k][2]] ^ index[j][1]] ^ index[i][0]];
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v[l][k][j][2] = frac[0][0] * v[l][k][j][0] + frac[0][1] * v[l][k][j][1];
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}
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v[l][k][2][2] = frac[1][0] * v[l][k][0][2] + frac[1][1] * v[l][k][1][2];
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}
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v[l][2][2][2] = frac[2][0] * v[l][0][2][2] + frac[2][1] * v[l][1][2][2];
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}
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v[2][2][2][2] = frac[3][0] * v[0][2][2][2] + frac[3][1] * v[1][2][2][2];
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#endif
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}
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