mirror of
https://github.com/MonsterDruide1/OdysseyDecomp
synced 2026-04-26 18:44:33 +00:00
123 lines
4 KiB
C++
123 lines
4 KiB
C++
#include "Library/Math/FractalGenerator.h"
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#include "Library/Math/MathUtil.h"
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namespace al {
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FractalGenerator::FractalGenerator(u32 permutations, f32 amplitude, f32 scale,
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f32 nextOrderAmplitude)
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: mPermutations(permutations), mAmplitude(amplitude), mScale(scale),
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mNextOrderAmplitude(nextOrderAmplitude) {}
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void FractalGenerator::setParam(u32 permutations, f32 amplitude, f32 scale,
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f32 nextOrderAmplitude) {
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mPermutations = permutations;
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mAmplitude = amplitude;
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mScale = scale;
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mNextOrderAmplitude = nextOrderAmplitude;
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}
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f32 FractalGenerator::calcFractal(f32 x, f32 y, bool useSmoothPerlingNoise) {
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f32 value = 0.0f;
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f32 amplitude = mAmplitude;
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f32 scale = mScale;
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for (s32 i = 0; i < (s32)(mPermutations - 1); i++) {
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if (useSmoothPerlingNoise)
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value += makeSmoothPerlinNoise(scale * x, scale * y) * amplitude;
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else
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value += makePerlinNoise(scale * x, scale * y) * amplitude;
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scale *= 2;
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amplitude *= mNextOrderAmplitude;
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}
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return value;
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}
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f32 FractalGenerator::makeSmoothPerlinNoise(f32 x, f32 y) {
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s32 gridX = (s32)x;
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s32 gridY = (s32)y;
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f32 fracX = x - gridX;
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f32 fracY = y - gridY;
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// NOTE: ASM is using an undef call for subsequent calls. This is not a bug since
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// makeSmoothRandom doesn't make use of any class members. This is probably a compiler
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// optimization error
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FractalGenerator* gen;
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f32 r00 = makeSmoothRandom(gridX, gridY);
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f32 r10 = gen->makeSmoothRandom(gridX + 1, gridY);
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f32 r01 = gen->makeSmoothRandom(gridX, gridY + 1);
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f32 r11 = gen->makeSmoothRandom(gridX + 1, gridY + 1);
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return lerpValue(lerpValue(r00, r10, easeInOut(fracX)), lerpValue(r01, r11, easeInOut(fracX)),
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easeInOut(fracY));
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}
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f32 FractalGenerator::makePerlinNoise(f32 x, f32 y) {
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s32 gridX = (s32)x;
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s32 gridY = (s32)y;
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f32 fracX = x - gridX;
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f32 fracY = y - gridY;
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f32 r00 = makeRandom(gridX, gridY);
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f32 r10 = makeRandom(gridX + 1, gridY);
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f32 r01 = makeRandom(gridX, gridY + 1);
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f32 r11 = makeRandom(gridX + 1, gridY + 1);
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return lerpValue(lerpValue(r00, r10, easeInOut(fracX)), lerpValue(r01, r11, easeInOut(fracX)),
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easeInOut(fracY));
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}
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f32 FractalGenerator::calcMultiFractal(f32 x, f32 y, f32 baseAmplitude,
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bool useSmoothPerlingNoise) {
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f32 value = 1.0f;
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f32 amplitude = mAmplitude;
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f32 scale = mScale;
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for (s32 i = 0; i < (s32)(mPermutations - 1); i++) {
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if (useSmoothPerlingNoise)
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value *= baseAmplitude * makeSmoothPerlinNoise(scale * x, scale * y) * amplitude;
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else
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value *= baseAmplitude * makePerlinNoise(scale * x, scale * y) * amplitude;
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scale *= 2;
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amplitude *= mNextOrderAmplitude;
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}
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return value;
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}
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inline s32 makeSeed(s32 x, s32 y) {
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s32 seed = x + y * 57;
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seed ^= seed << 13;
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return seed;
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}
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inline f32 makeNoise(s32 seed) {
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// NOTE: The only true random are all these magic values
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s32 hash = (seed * seed * 0x4bd9 + 0x2e59b) * seed + 0x4bcb4b;
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return static_cast<f32>(hash & 0x4b746f) / -3354521.0f;
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}
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f32 FractalGenerator::makeRandom(s32 x, s32 y) {
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return makeNoise(makeSeed(x, y)) + 1.0f;
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}
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f32 FractalGenerator::makeSmoothRandom(s32 x, s32 y) {
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constexpr f32 weight_corners = 0.25f;
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constexpr f32 weight_sides = 0.5f;
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constexpr f32 weight_center = 0.25f;
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f32 corners = (makeRandom(x - 1, y - 1) + makeRandom(x + 1, y - 1) + makeRandom(x - 1, y + 1) +
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makeRandom(x + 1, y + 1)) *
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((1.0f / 4.0f) * weight_corners);
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f32 sides = (makeRandom(x - 1, y) + makeRandom(x + 1, y) + makeRandom(x, y - 1) +
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makeRandom(x, y + 1)) *
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((1.0f / 4.0f) * weight_sides);
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;
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f32 center = makeRandom(x, y) * weight_center;
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return corners + sides + center;
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}
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} // namespace al
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