u32 PcgRandom::range(u32 bound)
{
+ // If the bound is 0, we cover the whole RNG's range
+ if (bound == 0)
+ return next();
/*
If the bound is not a multiple of the RNG's range, it may cause bias,
e.g. a RNG has a range from 0 to 3 and we take want a number 0 to 2.
Using rand() % 3, the number 0 would be twice as likely to appear.
With a very large RNG range, the effect becomes less prevalent but
still present. This can be solved by modifying the range of the RNG
- to become a multiple of bound by dropping values above the a threshhold.
- In our example, threshhold == 4 - 3 = 1 % 3 == 1, so reject 0, thus
+ to become a multiple of bound by dropping values above the a threshold.
+ In our example, threshold == 4 - 3 = 1 % 3 == 1, so reject 0, thus
making the range 3 with no bias.
This loop looks dangerous, but will always terminate due to the
RNG's property of uniformity.
*/
- u32 threshhold = -bound % bound;
+ u32 threshold = -bound % bound;
u32 r;
- while ((r = next()) < threshhold)
+ while ((r = next()) < threshold)
;
return r % bound;
s32 PcgRandom::range(s32 min, s32 max)
{
- assert(max >= min);
+ if (max < min)
+ throw PrngException("Invalid range (max < min)");
+
u32 bound = max - min + 1;
return range(bound) + min;
}
void PcgRandom::bytes(void *out, size_t len)
{
- u32 r;
u8 *outb = (u8 *)out;
+ int bytes_left = 0;
+ u32 r;
- size_t len_alignment = (uintptr_t)out % sizeof(u32);
- if (len_alignment) {
- len -= len_alignment;
- r = next();
- while (len_alignment--) {
- *outb = r & 0xFF;
- outb++;
- r >>= 8;
+ while (len--) {
+ if (bytes_left == 0) {
+ bytes_left = sizeof(u32);
+ r = next();
}
- }
- size_t len_dwords = len / sizeof(u32);
- while (len_dwords--) {
- r = next();
- *(u32 *)outb = next();
- outb += sizeof(u32);
- }
-
- size_t len_remaining = len % sizeof(u32);
- if (len_remaining) {
- r = next();
- while (len_remaining--) {
- *outb = r & 0xFF;
- outb++;
- r >>= 8;
- }
+ *outb = r & 0xFF;
+ outb++;
+ bytes_left--;
+ r >>= CHAR_BIT;
}
}
s32 accum = 0;
for (int i = 0; i != num_trials; i++)
accum += range(min, max);
- return ((float)accum / num_trials) + 0.5f;
+ return myround((float)accum / num_trials);
}
///////////////////////////////////////////////////////////////////////////////
float noise2d(int x, int y, int seed)
{
- int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y
+ unsigned int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y
+ NOISE_MAGIC_SEED * seed) & 0x7fffffff;
n = (n >> 13) ^ n;
n = (n * (n * n * 60493 + 19990303) + 1376312589) & 0x7fffffff;
- return 1.f - (float)n / 0x40000000;
+ return 1.f - (float)(int)n / 0x40000000;
}
float noise3d(int x, int y, int z, int seed)
{
- int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y + NOISE_MAGIC_Z * z
+ unsigned int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y + NOISE_MAGIC_Z * z
+ NOISE_MAGIC_SEED * seed) & 0x7fffffff;
n = (n >> 13) ^ n;
n = (n * (n * n * 60493 + 19990303) + 1376312589) & 0x7fffffff;
- return 1.f - (float)n / 0x40000000;
+ return 1.f - (float)(int)n / 0x40000000;
}
{
float tx = easeCurve(x);
float ty = easeCurve(y);
-#if 0
- return (
- v00 * (1 - tx) * (1 - ty) +
- v10 * tx * (1 - ty) +
- v01 * (1 - tx) * ty +
- v11 * tx * ty
- );
-#endif
float u = linearInterpolation(v00, v10, tx);
float v = linearInterpolation(v01, v11, tx);
return linearInterpolation(u, v, ty);
float tx = easeCurve(x);
float ty = easeCurve(y);
float tz = easeCurve(z);
-#if 0
- return (
- v000 * (1 - tx) * (1 - ty) * (1 - tz) +
- v100 * tx * (1 - ty) * (1 - tz) +
- v010 * (1 - tx) * ty * (1 - tz) +
- v110 * tx * ty * (1 - tz) +
- v001 * (1 - tx) * (1 - ty) * tz +
- v101 * tx * (1 - ty) * tz +
- v011 * (1 - tx) * ty * tz +
- v111 * tx * ty * tz
- );
-#endif
float u = biLinearInterpolationNoEase(v000, v100, v010, v110, tx, ty);
float v = biLinearInterpolationNoEase(v001, v101, v011, v111, tx, ty);
return linearInterpolation(u, v, tz);
return linearInterpolation(u, v, z);
}
-
-#if 0
-float noise2d_gradient(float x, float y, int seed)
-{
- // Calculate the integer coordinates
- int x0 = (x > 0.0 ? (int)x : (int)x - 1);
- int y0 = (y > 0.0 ? (int)y : (int)y - 1);
- // Calculate the remaining part of the coordinates
- float xl = x - (float)x0;
- float yl = y - (float)y0;
- // Calculate random cosine lookup table indices for the integer corners.
- // They are looked up as unit vector gradients from the lookup table.
- int n00 = (int)((noise2d(x0, y0, seed)+1)*8);
- int n10 = (int)((noise2d(x0+1, y0, seed)+1)*8);
- int n01 = (int)((noise2d(x0, y0+1, seed)+1)*8);
- int n11 = (int)((noise2d(x0+1, y0+1, seed)+1)*8);
- // Make a dot product for the gradients and the positions, to get the values
- float s = dotProduct(cos_lookup[n00], cos_lookup[(n00+12)%16], xl, yl);
- float u = dotProduct(-cos_lookup[n10], cos_lookup[(n10+12)%16], 1.-xl, yl);
- float v = dotProduct(cos_lookup[n01], -cos_lookup[(n01+12)%16], xl, 1.-yl);
- float w = dotProduct(-cos_lookup[n11], -cos_lookup[(n11+12)%16], 1.-xl, 1.-yl);
- // Interpolate between the values
- return biLinearInterpolation(s,u,v,w,xl,yl);
-}
-#endif
-
-
float noise2d_gradient(float x, float y, int seed, bool eased)
{
// Calculate the integer coordinates
}
-Noise::Noise(NoiseParams *np_, int seed, int sx, int sy, int sz)
+Noise::Noise(NoiseParams *np_, int seed, u32 sx, u32 sy, u32 sz)
{
memcpy(&np, np_, sizeof(np));
this->seed = seed;
void Noise::allocBuffers()
{
+ if (sx < 1)
+ sx = 1;
+ if (sy < 1)
+ sy = 1;
+ if (sz < 1)
+ sz = 1;
+
this->noise_buf = NULL;
resizeNoiseBuf(sz > 1);
}
-void Noise::setSize(int sx, int sy, int sz)
+void Noise::setSize(u32 sx, u32 sy, u32 sz)
{
this->sx = sx;
this->sy = sy;
void Noise::resizeNoiseBuf(bool is3d)
{
- int nlx, nly, nlz;
- float ofactor;
-
//maximum possible spread value factor
- ofactor = pow(np.lacunarity, np.octaves - 1);
+ float ofactor = (np.lacunarity > 1.0) ?
+ pow(np.lacunarity, np.octaves - 1) :
+ np.lacunarity;
+
+ // noise lattice point count
+ // (int)(sz * spread * ofactor) is # of lattice points crossed due to length
+ float num_noise_points_x = sx * ofactor / np.spread.X;
+ float num_noise_points_y = sy * ofactor / np.spread.Y;
+ float num_noise_points_z = sz * ofactor / np.spread.Z;
+
+ // protect against obviously invalid parameters
+ if (num_noise_points_x > 1000000000.f ||
+ num_noise_points_y > 1000000000.f ||
+ num_noise_points_z > 1000000000.f)
+ throw InvalidNoiseParamsException();
- //noise lattice point count
- //(int)(sz * spread * ofactor) is # of lattice points crossed due to length
// + 2 for the two initial endpoints
// + 1 for potentially crossing a boundary due to offset
- nlx = (int)ceil(sx * ofactor / np.spread.X) + 3;
- nly = (int)ceil(sy * ofactor / np.spread.Y) + 3;
- nlz = is3d ? (int)ceil(sz * ofactor / np.spread.Z) + 3 : 1;
+ size_t nlx = (size_t)ceil(num_noise_points_x) + 3;
+ size_t nly = (size_t)ceil(num_noise_points_y) + 3;
+ size_t nlz = is3d ? (size_t)ceil(num_noise_points_z) + 3 : 1;
delete[] noise_buf;
try {
int seed)
{
float v00, v01, v10, v11, u, v, orig_u;
- int index, i, j, x0, y0, noisex, noisey;
- int nlx, nly;
+ u32 index, i, j, noisex, noisey;
+ u32 nlx, nly;
+ s32 x0, y0;
bool eased = np.flags & (NOISE_FLAG_DEFAULTS | NOISE_FLAG_EASED);
Interp2dFxn interpolate = eased ?
orig_u = u;
//calculate noise point lattice
- nlx = (int)(u + sx * step_x) + 2;
- nly = (int)(v + sy * step_y) + 2;
+ nlx = (u32)(u + sx * step_x) + 2;
+ nly = (u32)(v + sy * step_y) + 2;
index = 0;
for (j = 0; j != nly; j++)
for (i = 0; i != nlx; i++)
float v000, v010, v100, v110;
float v001, v011, v101, v111;
float u, v, w, orig_u, orig_v;
- int index, i, j, k, x0, y0, z0, noisex, noisey, noisez;
- int nlx, nly, nlz;
+ u32 index, i, j, k, noisex, noisey, noisez;
+ u32 nlx, nly, nlz;
+ s32 x0, y0, z0;
Interp3dFxn interpolate = (np.flags & NOISE_FLAG_EASED) ?
triLinearInterpolation : triLinearInterpolationNoEase;
orig_v = v;
//calculate noise point lattice
- nlx = (int)(u + sx * step_x) + 2;
- nly = (int)(v + sy * step_y) + 2;
- nlz = (int)(w + sz * step_z) + 2;
+ nlx = (u32)(u + sx * step_x) + 2;
+ nly = (u32)(v + sy * step_y) + 2;
+ nlz = (u32)(w + sz * step_z) + 2;
index = 0;
for (k = 0; k != nlz; k++)
for (j = 0; j != nly; j++)
projects / minetest.git / blobdiff