inoise8_raw() [1/3]

int8_t inoise8_raw ( uint16_t 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 623 of file noise.cpp.

{
  // Find the unit cube containing the point
  uint8_t X = x>>8;
 
  // Hash cube corner coordinates
  uint8_t A = NOISE_P(X);
  uint8_t AA = NOISE_P(A);
  uint8_t B = NOISE_P(X+1);
  uint8_t BA = NOISE_P(B);
 
  // Get the relative position of the point in the cube
  uint8_t u = x;
 
  // Get a signed version of the above for the grad function
  int8_t xx = ((uint8_t)(x)>>1) & 0x7F;
  uint8_t N = 0x80;
 
  u = EASE8( u);
  
  int8_t 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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