* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
-#include <math.h>
+#include <cmath>
#include "noise.h"
#include <iostream>
-#include <string.h> // memset
+#include <cstring> // memset
#include "debug.h"
#include "util/numeric.h"
#include "util/string.h"
#define NOISE_MAGIC_X 1619
#define NOISE_MAGIC_Y 31337
#define NOISE_MAGIC_Z 52591
-#define NOISE_MAGIC_SEED 1013
-
-typedef float (*Interp2dFxn)(
- float v00, float v10, float v01, float v11,
- float x, float y);
-
-typedef float (*Interp3dFxn)(
- float v000, float v100, float v010, float v110,
- float v001, float v101, float v011, float v111,
- float x, float y, float z);
-
-float cos_lookup[16] = {
- 1.0, 0.9238, 0.7071, 0.3826, 0, -0.3826, -0.7071, -0.9238,
- 1.0, -0.9238, -0.7071, -0.3826, 0, 0.3826, 0.7071, 0.9238
-};
+// Unsigned magic seed prevents undefined behavior.
+#define NOISE_MAGIC_SEED 1013U
FlagDesc flagdesc_noiseparams[] = {
{"defaults", NOISE_FLAG_DEFAULTS},
// 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 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.
+ This is an optimization of the expression:
+ 0x100000000ull % bound
+ since 64-bit modulo operations typically much slower than 32.
*/
u32 threshold = -bound % bound;
u32 r;
+ /*
+ 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 threshold.
+
+ In our example, threshold == 4 % 3 == 1, so reject values < 1
+ (that is, 0), thus making the range == 3 with no bias.
+
+ This loop may look dangerous, but will always terminate due to the
+ RNG's property of uniformity.
+ */
while ((r = next()) < threshold)
;
if (max < min)
throw PrngException("Invalid range (max < min)");
- u32 bound = max - min + 1;
+ // We have to cast to s64 because otherwise this could overflow,
+ // and signed overflow is undefined behavior.
+ u32 bound = (s64)max - (s64)min + 1;
return range(bound) + min;
}
///////////////////////////////////////////////////////////////////////////////
-float noise2d(int x, int y, int seed)
+float noise2d(int x, int y, s32 seed)
{
unsigned int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y
+ NOISE_MAGIC_SEED * seed) & 0x7fffffff;
}
-float noise3d(int x, int y, int z, int seed)
+float noise3d(int x, int y, int z, s32 seed)
{
unsigned int n = (NOISE_MAGIC_X * x + NOISE_MAGIC_Y * y + NOISE_MAGIC_Z * z
+ NOISE_MAGIC_SEED * seed) & 0x7fffffff;
inline float biLinearInterpolation(
float v00, float v10,
float v01, float v11,
- float x, float y)
-{
- float tx = easeCurve(x);
- float ty = easeCurve(y);
- float u = linearInterpolation(v00, v10, tx);
- float v = linearInterpolation(v01, v11, tx);
- return linearInterpolation(u, v, ty);
-}
-
-
-inline float biLinearInterpolationNoEase(
- float v00, float v10,
- float v01, float v11,
- float x, float y)
+ float x, float y,
+ bool eased)
{
+ // Inlining will optimize this branch out when possible
+ if (eased) {
+ x = easeCurve(x);
+ y = easeCurve(y);
+ }
float u = linearInterpolation(v00, v10, x);
float v = linearInterpolation(v01, v11, x);
return linearInterpolation(u, v, y);
}
-float triLinearInterpolation(
+inline float triLinearInterpolation(
float v000, float v100, float v010, float v110,
float v001, float v101, float v011, float v111,
- float x, float y, float z)
+ float x, float y, float z,
+ bool eased)
{
- float tx = easeCurve(x);
- float ty = easeCurve(y);
- float tz = easeCurve(z);
- float u = biLinearInterpolationNoEase(v000, v100, v010, v110, tx, ty);
- float v = biLinearInterpolationNoEase(v001, v101, v011, v111, tx, ty);
- return linearInterpolation(u, v, tz);
-}
-
-float triLinearInterpolationNoEase(
- float v000, float v100, float v010, float v110,
- float v001, float v101, float v011, float v111,
- float x, float y, float z)
-{
- float u = biLinearInterpolationNoEase(v000, v100, v010, v110, x, y);
- float v = biLinearInterpolationNoEase(v001, v101, v011, v111, x, y);
+ // Inlining will optimize this branch out when possible
+ if (eased) {
+ x = easeCurve(x);
+ y = easeCurve(y);
+ z = easeCurve(z);
+ }
+ float u = biLinearInterpolation(v000, v100, v010, v110, x, y, false);
+ float v = biLinearInterpolation(v001, v101, v011, v111, x, y, false);
return linearInterpolation(u, v, z);
}
-float noise2d_gradient(float x, float y, int seed, bool eased)
+float noise2d_gradient(float x, float y, s32 seed, bool eased)
{
// Calculate the integer coordinates
int x0 = myfloor(x);
float v01 = noise2d(x0, y0+1, seed);
float v11 = noise2d(x0+1, y0+1, seed);
// Interpolate
- if (eased)
- return biLinearInterpolation(v00, v10, v01, v11, xl, yl);
- else
- return biLinearInterpolationNoEase(v00, v10, v01, v11, xl, yl);
+ return biLinearInterpolation(v00, v10, v01, v11, xl, yl, eased);
}
-float noise3d_gradient(float x, float y, float z, int seed, bool eased)
+float noise3d_gradient(float x, float y, float z, s32 seed, bool eased)
{
// Calculate the integer coordinates
int x0 = myfloor(x);
float v011 = noise3d(x0, y0 + 1, z0 + 1, seed);
float v111 = noise3d(x0 + 1, y0 + 1, z0 + 1, seed);
// Interpolate
- if (eased) {
- return triLinearInterpolation(
- v000, v100, v010, v110,
- v001, v101, v011, v111,
- xl, yl, zl);
- } else {
- return triLinearInterpolationNoEase(
- v000, v100, v010, v110,
- v001, v101, v011, v111,
- xl, yl, zl);
- }
+ return triLinearInterpolation(
+ v000, v100, v010, v110,
+ v001, v101, v011, v111,
+ xl, yl, zl,
+ eased);
}
-float noise2d_perlin(float x, float y, int seed,
+float noise2d_perlin(float x, float y, s32 seed,
int octaves, float persistence, bool eased)
{
float a = 0;
}
-float noise2d_perlin_abs(float x, float y, int seed,
- int octaves, float persistence, bool eased)
-{
- float a = 0;
- float f = 1.0;
- float g = 1.0;
- for (int i = 0; i < octaves; i++) {
- a += g * fabs(noise2d_gradient(x * f, y * f, seed + i, eased));
- f *= 2.0;
- g *= persistence;
- }
- return a;
-}
-
-
-float noise3d_perlin(float x, float y, float z, int seed,
- int octaves, float persistence, bool eased)
-{
- float a = 0;
- float f = 1.0;
- float g = 1.0;
- for (int i = 0; i < octaves; i++) {
- a += g * noise3d_gradient(x * f, y * f, z * f, seed + i, eased);
- f *= 2.0;
- g *= persistence;
- }
- return a;
-}
-
-
-float noise3d_perlin_abs(float x, float y, float z, int seed,
- int octaves, float persistence, bool eased)
-{
- float a = 0;
- float f = 1.0;
- float g = 1.0;
- for (int i = 0; i < octaves; i++) {
- a += g * fabs(noise3d_gradient(x * f, y * f, z * f, seed + i, eased));
- f *= 2.0;
- g *= persistence;
- }
- return a;
-}
-
-
float contour(float v)
{
- v = fabs(v);
+ v = std::fabs(v);
if (v >= 1.0)
return 0.0;
return (1.0 - v);
///////////////////////// [ New noise ] ////////////////////////////
-float NoisePerlin2D(NoiseParams *np, float x, float y, int seed)
+float NoisePerlin2D(const NoiseParams *np, float x, float y, s32 seed)
{
float a = 0;
float f = 1.0;
np->flags & (NOISE_FLAG_DEFAULTS | NOISE_FLAG_EASED));
if (np->flags & NOISE_FLAG_ABSVALUE)
- noiseval = fabs(noiseval);
+ noiseval = std::fabs(noiseval);
a += g * noiseval;
f *= np->lacunarity;
}
-float NoisePerlin3D(NoiseParams *np, float x, float y, float z, int seed)
+float NoisePerlin3D(const NoiseParams *np, float x, float y, float z, s32 seed)
{
float a = 0;
float f = 1.0;
np->flags & NOISE_FLAG_EASED);
if (np->flags & NOISE_FLAG_ABSVALUE)
- noiseval = fabs(noiseval);
+ noiseval = std::fabs(noiseval);
a += g * noiseval;
f *= np->lacunarity;
}
-Noise::Noise(NoiseParams *np_, int seed, u32 sx, u32 sy, u32 sz)
+Noise::Noise(const NoiseParams *np_, s32 seed, u32 sx, u32 sy, u32 sz)
{
- memcpy(&np, np_, sizeof(np));
+ np = *np_;
this->seed = seed;
this->sx = sx;
this->sy = sy;
this->sz = sz;
- this->persist_buf = NULL;
- this->gradient_buf = NULL;
- this->result = NULL;
-
allocBuffers();
}
void Noise::resizeNoiseBuf(bool is3d)
{
- //maximum possible spread value factor
+ // Maximum possible spread value factor
float ofactor = (np.lacunarity > 1.0) ?
pow(np.lacunarity, np.octaves - 1) :
np.lacunarity;
- // noise lattice point count
+ // 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
+ // Protect against obviously invalid parameters
if (num_noise_points_x > 1000000000.f ||
- num_noise_points_y > 1000000000.f ||
- num_noise_points_z > 1000000000.f)
+ num_noise_points_y > 1000000000.f ||
+ num_noise_points_z > 1000000000.f)
throw InvalidNoiseParamsException();
+ // Protect against an octave having a spread < 1, causing broken noise values
+ if (np.spread.X / ofactor < 1.0f ||
+ np.spread.Y / ofactor < 1.0f ||
+ np.spread.Z / ofactor < 1.0f) {
+ errorstream << "A noise parameter has too many octaves: "
+ << np.octaves << " octaves" << std::endl;
+ throw InvalidNoiseParamsException("A noise parameter has too many octaves");
+ }
+
// + 2 for the two initial endpoints
// + 1 for potentially crossing a boundary due to offset
- 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;
+ size_t nlx = (size_t)std::ceil(num_noise_points_x) + 3;
+ size_t nly = (size_t)std::ceil(num_noise_points_y) + 3;
+ size_t nlz = is3d ? (size_t)std::ceil(num_noise_points_z) + 3 : 1;
delete[] noise_buf;
try {
void Noise::gradientMap2D(
float x, float y,
float step_x, float step_y,
- int seed)
+ s32 seed)
{
float v00, v01, v10, v11, u, v, orig_u;
u32 index, i, j, noisex, noisey;
s32 x0, y0;
bool eased = np.flags & (NOISE_FLAG_DEFAULTS | NOISE_FLAG_EASED);
- Interp2dFxn interpolate = eased ?
- biLinearInterpolation : biLinearInterpolationNoEase;
-
- x0 = floor(x);
- y0 = floor(y);
+ x0 = std::floor(x);
+ y0 = std::floor(y);
u = x - (float)x0;
v = y - (float)y0;
orig_u = u;
u = orig_u;
noisex = 0;
for (i = 0; i != sx; i++) {
- gradient_buf[index++] = interpolate(v00, v10, v01, v11, u, v);
+ gradient_buf[index++] =
+ biLinearInterpolation(v00, v10, v01, v11, u, v, eased);
u += step_x;
if (u >= 1.0) {
void Noise::gradientMap3D(
float x, float y, float z,
float step_x, float step_y, float step_z,
- int seed)
+ s32 seed)
{
float v000, v010, v100, v110;
float v001, v011, v101, v111;
u32 nlx, nly, nlz;
s32 x0, y0, z0;
- Interp3dFxn interpolate = (np.flags & NOISE_FLAG_EASED) ?
- triLinearInterpolation : triLinearInterpolationNoEase;
+ bool eased = np.flags & NOISE_FLAG_EASED;
- x0 = floor(x);
- y0 = floor(y);
- z0 = floor(z);
+ x0 = std::floor(x);
+ y0 = std::floor(y);
+ z0 = std::floor(z);
u = x - (float)x0;
v = y - (float)y0;
w = z - (float)z0;
u = orig_u;
noisex = 0;
for (i = 0; i != sx; i++) {
- gradient_buf[index++] = interpolate(
+ gradient_buf[index++] = triLinearInterpolation(
v000, v100, v010, v110,
v001, v101, v011, v111,
- u, v, w);
+ u, v, w,
+ eased);
u += step_x;
if (u >= 1.0) {
g *= np.persist;
}
- if (fabs(np.offset - 0.f) > 0.00001 || fabs(np.scale - 1.f) > 0.00001) {
+ if (std::fabs(np.offset - 0.f) > 0.00001 || std::fabs(np.scale - 1.f) > 0.00001) {
for (size_t i = 0; i != bufsize; i++)
result[i] = result[i] * np.scale + np.offset;
}
g *= np.persist;
}
- if (fabs(np.offset - 0.f) > 0.00001 || fabs(np.scale - 1.f) > 0.00001) {
+ if (std::fabs(np.offset - 0.f) > 0.00001 || std::fabs(np.scale - 1.f) > 0.00001) {
for (size_t i = 0; i != bufsize; i++)
result[i] = result[i] * np.scale + np.offset;
}
void Noise::updateResults(float g, float *gmap,
- float *persistence_map, size_t bufsize)
+ const float *persistence_map, size_t bufsize)
{
// This looks very ugly, but it is 50-70% faster than having
// conditional statements inside the loop
if (np.flags & NOISE_FLAG_ABSVALUE) {
if (persistence_map) {
for (size_t i = 0; i != bufsize; i++) {
- result[i] += gmap[i] * fabs(gradient_buf[i]);
+ result[i] += gmap[i] * std::fabs(gradient_buf[i]);
gmap[i] *= persistence_map[i];
}
} else {
for (size_t i = 0; i != bufsize; i++)
- result[i] += g * fabs(gradient_buf[i]);
+ result[i] += g * std::fabs(gradient_buf[i]);
}
} else {
if (persistence_map) {
projects / minetest.git / blobdiff