inoise8_raw() [1/3]

fl::i8 inoise8_raw ( fl::u16 x )

extern

8-bit, fixed point implementation of Perlin's noise without scaling.

Coordinates are 8.8 fixed point values, 16-bit integers with integral coordinates in the high 8-bits and fractional in the low 8-bits.

Returns

unscaled noise value as a signed integer, roughly -70 to 70

Parameters

x	x-axis coordinate on noise map (1D)

Definition at line 628 of file noise.cpp.hpp.

{
  // Find the unit cube containing the point
  fl::u8 X = x>>8;
 
  // Hash cube corner coordinates
  fl::u8 A = NOISE_P(X);
  fl::u8 AA = NOISE_P(A);
  fl::u8 B = NOISE_P(X+1);
  fl::u8 BA = NOISE_P(B);
 
  // Get the relative position of the point in the cube
  fl::u8 u = x;
 
  // Get a signed version of the above for the grad function
  fl::i8 xx = ((fl::u8)(x)>>1) & 0x7F;
  fl::u8 N = 0x80;
 
  u = EASE8( u);
  
  fl::i8 ans = lerp7by8(grad8(NOISE_P(AA), xx), grad8(NOISE_P(BA), xx - N), u);
 
  return ans;
}

References grad8(), lerp7by8(), NOISE_P, and x.

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