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Codechange: Improve performance of perlin noise function. (#14991)

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Avoid pow() and reduce computations.
This commit is contained in:
Peter Nelson
2025-12-26 22:01:23 +00:00
committed by GitHub
parent b2fd405e55
commit 5c96a2c19a
1 changed files with 9 additions and 7 deletions
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16
src/tgp.cpp
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@@ -944,15 +944,17 @@ static double interpolated_noise(const double x, const double y, const int prime
*/
static double perlin_coast_noise_2D(const double x, const double y, const double p, const int prime)
{
constexpr int OCTAVES = 6;
constexpr double INITIAL_FREQUENCY = 1 << OCTAVES;
double total = 0.0;
for (int i = 0; i < 6; i++) {
const double frequency = (double)(1 << i);
const double amplitude = pow(p, (double)i);
total += interpolated_noise((x * frequency) / 64.0, (y * frequency) / 64.0, prime) * amplitude;
double frequency = 1.0 / INITIAL_FREQUENCY;
double amplitude = 1.0;
for (int i = 0; i < OCTAVES; i++) {
total += interpolated_noise(x * frequency, y * frequency, prime) * amplitude;
frequency *= 2.0;
amplitude *= p;
}
return total;
}