float Noise(float x, float y, float z) {
// Compute noise cell coordinates and offsets
int ix = Floor2Int(x), iy = Floor2Int(y), iz = Floor2Int(z);
float dx = x - ix, dy = y - iy, dz = z - iz;
// Compute gradient weights
ix &= (NOISE_PERM_SIZE-1);
iy &= (NOISE_PERM_SIZE-1);
iz &= (NOISE_PERM_SIZE-1);
float w000 = Grad(ix, iy, iz, dx, dy, dz);
float w100 = Grad(ix+1, iy, iz, dx-1, dy, dz);
float w010 = Grad(ix, iy+1, iz, dx, dy-1, dz);
float w110 = Grad(ix+1, iy+1, iz, dx-1, dy-1, dz);
float w001 = Grad(ix, iy, iz+1, dx, dy, dz-1);
float w101 = Grad(ix+1, iy, iz+1, dx-1, dy, dz-1);
float w011 = Grad(ix, iy+1, iz+1, dx, dy-1, dz-1);
float w111 = Grad(ix+1, iy+1, iz+1, dx-1, dy-1, dz-1);
// Compute trilinear interpolation of weights
float wx = NoiseWeight(dx), wy = NoiseWeight(dy), wz = NoiseWeight(dz);
float x00 = Lerp(wx, w000, w100);
float x10 = Lerp(wx, w010, w110);
float x01 = Lerp(wx, w001, w101);
float x11 = Lerp(wx, w011, w111);
float y0 = Lerp(wy, x00, x10);
float y1 = Lerp(wy, x01, x11);
return Lerp(wz, y0, y1);
}
Float Noise(Float x, Float y, Float z) {
// Compute noise cell coordinates and offsets
int ix = std::floor(x), iy = std::floor(y), iz = std::floor(z);
Float dx = x - ix, dy = y - iy, dz = z - iz;
// Compute gradient weights
ix &= NoisePermSize - 1;
iy &= NoisePermSize - 1;
iz &= NoisePermSize - 1;
Float w000 = Grad(ix, iy, iz, dx, dy, dz);
Float w100 = Grad(ix + 1, iy, iz, dx - 1, dy, dz);
Float w010 = Grad(ix, iy + 1, iz, dx, dy - 1, dz);
Float w110 = Grad(ix + 1, iy + 1, iz, dx - 1, dy - 1, dz);
Float w001 = Grad(ix, iy, iz + 1, dx, dy, dz - 1);
Float w101 = Grad(ix + 1, iy, iz + 1, dx - 1, dy, dz - 1);
Float w011 = Grad(ix, iy + 1, iz + 1, dx, dy - 1, dz - 1);
Float w111 = Grad(ix + 1, iy + 1, iz + 1, dx - 1, dy - 1, dz - 1);
// Compute trilinear interpolation of weights
Float wx = NoiseWeight(dx), wy = NoiseWeight(dy), wz = NoiseWeight(dz);
Float x00 = Lerp(wx, w000, w100);
Float x10 = Lerp(wx, w010, w110);
Float x01 = Lerp(wx, w001, w101);
Float x11 = Lerp(wx, w011, w111);
Float y0 = Lerp(wy, x00, x10);
Float y1 = Lerp(wy, x01, x11);
return Lerp(wz, y0, y1);
}
float perlin::noise(float x, float y, float z, float n) {
// Transform to voxel space
float vx = 0.5f + x;
float vy = 0.5f + y;
float vz = 0.5f + z;
// Compute noise cell cooridinates and offsets
// obtain voxel cooridinates
// This is to index into the Noise_Perm Array
int ix = (int) floor(vx * n) % NOISE_PERM_SIZE;
int iy = (int) floor(vy * n) % NOISE_PERM_SIZE;
int iz = (int) floor(vz * n) % NOISE_PERM_SIZE;
// Offset
float dx = vx * n - ix;
float dy = vy * n - iy;
float dz = vz * n - iz;
// Compute gradient weights
float w000 = Grad(ix, iy, iz, dx, dy, dz);
float w100 = Grad(ix+1, iy, iz, dx-1, dy, dz);
float w010 = Grad(ix, iy+1, iz, dx, dy-1, dz);
float w110 = Grad(ix+1, iy+1, iz, dx-1, dy-1, dz);
float w001 = Grad(ix, iy, iz+1, dx, dy, dz-1);
float w101 = Grad(ix+1, iy, iz+1, dx-1, dy, dz-1);
float w011 = Grad(ix, iy+1, iz+1, dx, dy-1, dz-1);
float w111 = Grad(ix+1, iy+1, iz+1, dx-1, dy-1, dz-1);
// Compute interpolation of weights
float wx = NoiseWeight(dx);
float wy = NoiseWeight(dy);
float wz = NoiseWeight(dz);
// Compute trilinear interpolation of weights
float x00 = pbrt_lerp(wx, w000, w100);
float x10 = pbrt_lerp(wx, w010, w110);
float x01 = pbrt_lerp(wx, w001, w101);
float x11 = pbrt_lerp(wx, w011, w111);
float y0 = pbrt_lerp(wy, x00, x10);
float y1 = pbrt_lerp(wy, x01, x11);
float result = pbrt_lerp(wz, y0, y1);
return glm::abs(result);
}
//*****************************************************************************
//
//
// *
//=============================================================================
float SJCNoise::
Eval(const float x, const float y, const float z)
//=============================================================================
{
int ix = (int)floor(x);
float dx = x - ix;
int iy = (int)floor(y);
float dy = y - iy;
int iz = (int)floor(z);
float dz = z - iz;
ix &= ( PERM_SIZE - 1 );
iy &= ( PERM_SIZE - 1 );
iz &= ( PERM_SIZE - 1 );
float w000 = Grad(ix, iy, iz, dx, dy, dz);
float w010 = Grad(ix, iy+1, iz, dx, dy-1.0f, dz);
float w100 = Grad(ix+1, iy, iz, dx-1.0f, dy, dz);
float w110 = Grad(ix+1, iy+1, iz, dx-1.0f, dy-1.0f, dz);
float w001 = Grad(ix, iy, iz+1, dx, dy, dz-1.0f);
float w011 = Grad(ix, iy+1, iz+1, dx, dy-1.0f, dz-1.0f);
float w101 = Grad(ix+1, iy, iz+1, dx-1.0f, dy, dz-1.0f);
float w111 = Grad(ix+1, iy+1, iz+1, dx-1.0f, dy-1.0f, dz-1.0f);
float ux = NoiseWeight(dx);
float uy = NoiseWeight(dy);
float uz = NoiseWeight(dz);
float x00 = ( 1 - ux ) * w000 + ux * w100;
float x10 = ( 1 - ux ) * w010 + ux * w110;
float x01 = ( 1 - ux ) * w001 + ux * w101;
float x11 = ( 1 - ux ) * w011 + ux * w111;
float y0 = ( 1 - uy ) * x00 + uy * x10;
float y1 = ( 1 - uy ) * x01 + uy * x11;
return ( 1 - uz ) * y0 + uz * y1;
}
