CS计算机代考程序代写 ///////////////////////////////////////////////////////////////////////////////////

///////////////////////////////////////////////////////////////////////////////////
/// OpenGL Mathematics (glm.g-truc.net)
///
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/// @ref core
/// @file glm/detail/func_noise.inl
/// @date 2008-08-01 / 2011-09-27
/// @author Christophe Riccio
///////////////////////////////////////////////////////////////////////////////////

#include “../detail/_noise.hpp”
#include “./func_common.hpp”

namespace glm{
namespace detail
{
template
GLM_FUNC_QUALIFIER tvec4 grad4(T const & j, tvec4 const & ip)
{
tvec3 pXYZ = floor(fract(tvec3(j) * tvec3(ip)) * T(7)) * ip[2] – T(1);
T pW = static_cast(1.5) – dot(abs(pXYZ), tvec3(1));
tvec4 s = tvec4(lessThan(tvec4(pXYZ, pW), tvec4(0.0)));
pXYZ = pXYZ + (tvec3(s) * T(2) – T(1)) * s.w;
return tvec4(pXYZ, pW);
}
}//namespace detail

template
GLM_FUNC_QUALIFIER T noise1(T const & x)
{
return noise1(tvec2(x, T(0)));
}

template
GLM_FUNC_QUALIFIER tvec2 noise2(T const & x)
{
return tvec2(
noise1(x + T(0.0)),
noise1(x + T(1.0)));
}

template
GLM_FUNC_QUALIFIER tvec3 noise3(T const & x)
{
return tvec3(
noise1(x – T(1.0)),
noise1(x + T(0.0)),
noise1(x + T(1.0)));
}

template
GLM_FUNC_QUALIFIER tvec4 noise4(T const & x)
{
return tvec4(
noise1(x – T(1.0)),
noise1(x + T(0.0)),
noise1(x + T(1.0)),
noise1(x + T(2.0)));
}

template
GLM_FUNC_QUALIFIER T noise1(tvec2 const & v)
{
tvec4 const C = tvec4(
T( 0.211324865405187), // (3.0 – sqrt(3.0)) / 6.0
T( 0.366025403784439), // 0.5 * (sqrt(3.0) – 1.0)
T(-0.577350269189626), // -1.0 + 2.0 * C.x
T( 0.024390243902439)); // 1.0 / 41.0

// First corner
tvec2 i = floor(v + dot(v, tvec2(C[1])));
tvec2 x0 = v – i + dot(i, tvec2(C[0]));

// Other corners
//i1.x = step( x0.y, x0.x ); // x0.x > x0.y ? 1.0 : 0.0
//i1.y = 1.0 – i1.x;
tvec2 i1 = (x0.x > x0.y) ? tvec2(1, 0) : tvec2(0, 1);

// x0 = x0 – 0.0 + 0.0 * C.xx ;
// x1 = x0 – i1 + 1.0 * C.xx ;
// x2 = x0 – 1.0 + 2.0 * C.xx ;
tvec4 x12 = tvec4(x0.x, x0.y, x0.x, x0.y) + tvec4(C.x, C.x, C.z, C.z);
x12 = tvec4(tvec2(x12) – i1, x12.z, x12.w);

// Permutations
i = mod(i, T(289)); // Avoid truncation effects in permutation
tvec3 p = detail::permute(
detail::permute(i.y + tvec3(T(0), i1.y, T(1))) + i.x + tvec3(T(0), i1.x, T(1)));

tvec3 m = max(T(0.5) – tvec3(
dot(x0, x0),
dot(tvec2(x12.x, x12.y), tvec2(x12.x, x12.y)),
dot(tvec2(x12.z, x12.w), tvec2(x12.z, x12.w))), T(0));

m = m * m;
m = m * m;

// Gradients: 41 points uniformly over a line, mapped onto a diamond.
// The ring size 17*17 = 289 is close to a multiple of 41 (41*7 = 287)

tvec3 x = static_cast(2) * fract(p * C.w) – T(1);
tvec3 h = abs(x) – T(0.5);
tvec3 ox = floor(x + T(0.5));
tvec3 a0 = x – ox;

// Normalise gradients implicitly by scaling m
// Inlined for speed: m *= taylorInvSqrt( a0*a0 + h*h );
m *= static_cast(1.79284291400159) – T(0.85373472095314) * (a0 * a0 + h * h);

// Compute final noise value at P
tvec3 g;
g.x = a0.x * x0.x + h.x * x0.y;
//g.yz = a0.yz * x12.xz + h.yz * x12.yw;
g.y = a0.y * x12.x + h.y * x12.y;
g.z = a0.z * x12.z + h.z * x12.w;
return T(130) * dot(m, g);
}

template
GLM_FUNC_QUALIFIER T noise1(tvec3 const & v)
{
tvec2 const C(1.0 / 6.0, 1.0 / 3.0);
tvec4 const D(0.0, 0.5, 1.0, 2.0);

// First corner
tvec3 i(floor(v + dot(v, tvec3(C.y))));
tvec3 x0(v – i + dot(i, tvec3(C.x)));

// Other corners
tvec3 g(step(tvec3(x0.y, x0.z, x0.x), x0));
tvec3 l(T(1) – g);
tvec3 i1(min(g, tvec3(l.z, l.x, l.y)));
tvec3 i2(max(g, tvec3(l.z, l.x, l.y)));

// x0 = x0 – 0.0 + 0.0 * C.xxx;
// x1 = x0 – i1 + 1.0 * C.xxx;
// x2 = x0 – i2 + 2.0 * C.xxx;
// x3 = x0 – 1.0 + 3.0 * C.xxx;
tvec3 x1(x0 – i1 + C.x);
tvec3 x2(x0 – i2 + C.y); // 2.0*C.x = 1/3 = C.y
tvec3 x3(x0 – D.y); // -1.0+3.0*C.x = -0.5 = -D.y

// Permutations
i = mod289(i);
tvec4 p(detail::permute(detail::permute(detail::permute(
i.z + tvec4(T(0), i1.z, i2.z, T(1))) +
i.y + tvec4(T(0), i1.y, i2.y, T(1))) +
i.x + tvec4(T(0), i1.x, i2.x, T(1))));

// Gradients: 7×7 points over a square, mapped onto an octahedron.
// The ring size 17*17 = 289 is close to a multiple of 49 (49*6 = 294)
T n_ = static_cast(0.142857142857); // 1.0/7.0
tvec3 ns(n_ * tvec3(D.w, D.y, D.z) – tvec3(D.x, D.z, D.x));

tvec4 j(p – T(49) * floor(p * ns.z * ns.z)); // mod(p,7*7)

tvec4 x_(floor(j * ns.z));
tvec4 y_(floor(j – T(7) * x_)); // mod(j,N)

tvec4 x(x_ * ns.x + ns.y);
tvec4 y(y_ * ns.x + ns.y);
tvec4 h(T(1) – abs(x) – abs(y));

tvec4 b0(x.x, x.y, y.x, y.y);
tvec4 b1(x.z, x.w, y.z, y.w);

// vec4 s0 = vec4(lessThan(b0,0.0))*2.0 – 1.0;
// vec4 s1 = vec4(lessThan(b1,0.0))*2.0 – 1.0;
tvec4 s0(floor(b0) * T(2) + T(1));
tvec4 s1(floor(b1) * T(2) + T(1));
tvec4 sh(-step(h, tvec4(0.0)));

tvec4 a0 = tvec4(b0.x, b0.z, b0.y, b0.w) + tvec4(s0.x, s0.z, s0.y, s0.w) * tvec4(sh.x, sh.x, sh.y, sh.y);
tvec4 a1 = tvec4(b1.x, b1.z, b1.y, b1.w) + tvec4(s1.x, s1.z, s1.y, s1.w) * tvec4(sh.z, sh.z, sh.w, sh.w);

tvec3 p0(a0.x, a0.y, h.x);
tvec3 p1(a0.z, a0.w, h.y);
tvec3 p2(a1.x, a1.y, h.z);
tvec3 p3(a1.z, a1.w, h.w);

// Normalise gradients
tvec4 norm = taylorInvSqrt(tvec4(dot(p0, p0), dot(p1, p1), dot(p2, p2), dot(p3, p3)));
p0 *= norm.x;
p1 *= norm.y;
p2 *= norm.z;
p3 *= norm.w;

// Mix final noise value
tvec4 m = max(T(0.6) – tvec4(dot(x0, x0), dot(x1, x1), dot(x2, x2), dot(x3, x3)), T(0));
m = m * m;
return T(42) * dot(m * m, tvec4(dot(p0, x0), dot(p1, x1), dot(p2, x2), dot(p3, x3)));
}

template
GLM_FUNC_QUALIFIER T noise1(tvec4 const & v)
{
tvec4 const C(
0.138196601125011, // (5 – sqrt(5))/20 G4
0.276393202250021, // 2 * G4
0.414589803375032, // 3 * G4
-0.447213595499958); // -1 + 4 * G4

// (sqrt(5) – 1)/4 = F4, used once below
T const F4 = static_cast(0.309016994374947451);

// First corner
tvec4 i = floor(v + dot(v, tvec4(F4)));
tvec4 x0 = v – i + dot(i, tvec4(C.x));

// Other corners

// Rank sorting originally contributed by Bill Licea-Kane, AMD (formerly ATI)
tvec4 i0;
tvec3 isX = step(tvec3(x0.y, x0.z, x0.w), tvec3(x0.x));
tvec3 isYZ = step(tvec3(x0.z, x0.w, x0.w), tvec3(x0.y, x0.y, x0.z));

// i0.x = dot(isX, vec3(1.0));
//i0.x = isX.x + isX.y + isX.z;
//i0.yzw = static_cast(1) – isX;
i0 = tvec4(isX.x + isX.y + isX.z, T(1) – isX);

// i0.y += dot(isYZ.xy, vec2(1.0));
i0.y += isYZ.x + isYZ.y;

//i0.zw += 1.0 – tvec2(isYZ.x, isYZ.y);
i0.z += static_cast(1) – isYZ.x;
i0.w += static_cast(1) – isYZ.y;
i0.z += isYZ.z;
i0.w += static_cast(1) – isYZ.z;

// i0 now contains the unique values 0,1,2,3 in each channel
tvec4 i3 = clamp(i0, T(0), T(1));
tvec4 i2 = clamp(i0 – T(1), T(0), T(1));
tvec4 i1 = clamp(i0 – T(2), T(0), T(1));

// x0 = x0 – 0.0 + 0.0 * C.xxxx
// x1 = x0 – i1 + 0.0 * C.xxxx
// x2 = x0 – i2 + 0.0 * C.xxxx
// x3 = x0 – i3 + 0.0 * C.xxxx
// x4 = x0 – 1.0 + 4.0 * C.xxxx
tvec4 x1 = x0 – i1 + C.x;
tvec4 x2 = x0 – i2 + C.y;
tvec4 x3 = x0 – i3 + C.z;
tvec4 x4 = x0 + C.w;

// Permutations
i = mod(i, T(289));
T j0 = detail::permute(detail::permute(detail::permute(detail::permute(i.w) + i.z) + i.y) + i.x);
tvec4 j1 = detail::permute(detail::permute(detail::permute(detail::permute(
i.w + tvec4(i1.w, i2.w, i3.w, T(1))) +
i.z + tvec4(i1.z, i2.z, i3.z, T(1))) +
i.y + tvec4(i1.y, i2.y, i3.y, T(1))) +
i.x + tvec4(i1.x, i2.x, i3.x, T(1)));

// Gradients: 7x7x6 points over a cube, mapped onto a 4-cross polytope
// 7*7*6 = 294, which is close to the ring size 17*17 = 289.
tvec4 ip = tvec4(T(1) / T(294), T(1) / T(49), T(1) / T(7), T(0));

tvec4 p0 = detail::grad4(j0, ip);
tvec4 p1 = detail::grad4(j1.x, ip);
tvec4 p2 = detail::grad4(j1.y, ip);
tvec4 p3 = detail::grad4(j1.z, ip);
tvec4 p4 = detail::grad4(j1.w, ip);

// Normalise gradients
tvec4 norm = detail::taylorInvSqrt(tvec4(dot(p0, p0), dot(p1, p1), dot(p2, p2), dot(p3, p3)));
p0 *= norm.x;
p1 *= norm.y;
p2 *= norm.z;
p3 *= norm.w;
p4 *= taylorInvSqrt(dot(p4, p4));

// Mix contributions from the five corners
tvec3 m0 = max(T(0.6) – tvec3(dot(x0, x0), dot(x1, x1), dot(x2, x2)), T(0));
tvec2 m1 = max(T(0.6) – tvec2(dot(x3, x3), dot(x4, x4) ), T(0));
m0 = m0 * m0;
m1 = m1 * m1;

return T(49) * (
dot(m0 * m0, tvec3(dot(p0, x0), dot(p1, x1), dot(p2, x2))) +
dot(m1 * m1, tvec2(dot(p3, x3), dot(p4, x4))));
}

template
GLM_FUNC_QUALIFIER tvec2 noise2(tvec2 const & x)
{
return tvec2(
noise1(x + tvec2(0.0)),
noise1(tvec2(0.0) – x));
}

template
GLM_FUNC_QUALIFIER tvec2 noise2(tvec3 const & x)
{
return tvec2(
noise1(x + tvec3(0.0)),
noise1(tvec3(0.0) – x));
}

template
GLM_FUNC_QUALIFIER tvec2 noise2(tvec4 const & x)
{
return tvec2(
noise1(x + tvec4(0)),
noise1(tvec4(0) – x));
}

template
GLM_FUNC_QUALIFIER tvec3 noise3(tvec2 const & x)
{
return tvec3(
noise1(x – tvec2(1.0)),
noise1(x + tvec2(0.0)),
noise1(x + tvec2(1.0)));
}

template
GLM_FUNC_QUALIFIER tvec3 noise3(tvec3 const & x)
{
return tvec3(
noise1(x – tvec3(1.0)),
noise1(x + tvec3(0.0)),
noise1(x + tvec3(1.0)));
}

template
GLM_FUNC_QUALIFIER tvec3 noise3(tvec4 const & x)
{
return tvec3(
noise1(x – tvec4(1)),
noise1(x + tvec4(0)),
noise1(x + tvec4(1)));
}

template
GLM_FUNC_QUALIFIER tvec4 noise4(tvec2 const & x)
{
return tvec4(
noise1(x – tvec2(1)),
noise1(x + tvec2(0)),
noise1(x + tvec2(1)),
noise1(x + tvec2(2)));
}

template
GLM_FUNC_QUALIFIER tvec4 noise4(tvec3 const & x)
{
return tvec4(
noise1(x – tvec3(1)),
noise1(x + tvec3(0)),
noise1(x + tvec3(1)),
noise1(x + tvec3(2)));
}

template
GLM_FUNC_QUALIFIER tvec4 noise4(tvec4 const & x)
{
return tvec4(
noise1(x – tvec4(1)),
noise1(x + tvec4(0)),
noise1(x + tvec4(1)),
noise1(x + tvec4(2)));
}

}//namespace glm