From e8b5598ebc14182bb5c2582d7b7708004ae51393 Mon Sep 17 00:00:00 2001 From: havoc Date: Fri, 25 May 2007 07:57:11 +0000 Subject: [PATCH] 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 --- fractalnoise.c | 100 +++++++++++++++++++++++++++++++++++++++++++++++++ quakedef.h | 1 + 2 files changed, 101 insertions(+) diff --git a/fractalnoise.c b/fractalnoise.c index c161f12b..40beb8af 100644 --- 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 65a44254..ade02aee 100644 --- 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); -- 2.39.2