a7bb9496ae
Vanilla-faithful overworld generator (final_density + multi-noise biomes), full connection lifecycle (status/login/configuration/play), chunk streaming, creative block editing, and the protocol/nbt/registry infrastructure.
49 lines
1.6 KiB
Go
49 lines
1.6 KiB
Go
package worldgen
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// normalInputFactor is NormalNoise.INPUT_FACTOR, the frequency offset applied
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// to the second Perlin field so the two octave stacks don't align.
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const normalInputFactor = 1.0181268882175227
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// NormalNoise combines two PerlinNoise fields, scaled so the result has a
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// normalized deviation. This is the noise type referenced by density functions.
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type NormalNoise struct {
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first *PerlinNoise
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second *PerlinNoise
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valueFactor float64
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maxValue float64
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}
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// NewNormalNoise builds a NormalNoise from the same parameters vanilla uses:
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// two PerlinNoise stacks drawn sequentially from r, plus a value factor derived
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// from the span of non-zero amplitudes.
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func NewNormalNoise(r RandomSource, firstOctave int, amplitudes []float64) *NormalNoise {
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n := &NormalNoise{
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first: NewPerlinNoise(r, firstOctave, amplitudes),
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second: NewPerlinNoise(r, firstOctave, amplitudes),
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}
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min, max := len(amplitudes), 0
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for i, a := range amplitudes {
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if a != 0 {
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if i < min {
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min = i
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}
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if i > max {
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max = i
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}
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}
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}
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expectedDeviation := 0.1 * (1.0 + 1.0/float64(max-min+1))
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n.valueFactor = (1.0 / 6.0) / expectedDeviation
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n.maxValue = (n.first.MaxValue() + n.second.MaxValue()) * n.valueFactor
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return n
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}
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// GetValue samples the combined noise at (x, y, z).
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func (n *NormalNoise) GetValue(x, y, z float64) float64 {
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return (n.first.GetValue(x, y, z) +
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n.second.GetValue(x*normalInputFactor, y*normalInputFactor, z*normalInputFactor)) * n.valueFactor
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}
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// MaxValue returns the theoretical maximum magnitude.
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func (n *NormalNoise) MaxValue() float64 { return n.maxValue }
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