_xiaofang/xiaofang/Assets/Obi/Resources/Compute/MathUtils.cginc
杨号敬 bcc74f0465 add
2024-12-18 02:18:45 +08:00

557 lines
14 KiB
HLSL

#ifndef MATHUTILS_INCLUDE
#define MATHUTILS_INCLUDE
#define PI 3.14159265359f
#define SQRT2 1.41421356237f
#define SQRT3 1.73205080757f
#define EPSILON 0.0000001f
#define FLT_MAX 3.402823466e+38
#define FLT_MIN 1.175494351e-38
#define FLOAT4_ZERO float4(0, 0, 0, 0)
#define FLOAT4_EPSILON float4(EPSILON, EPSILON, EPSILON, EPSILON)
#define zero 0
#define one 1
#define PHASE_SELFCOLLIDE (1 << 24)
#define PHASE_FLUID (1 << 25)
#define PHASE_ONESIDED (1 << 26)
#include "Quaternion.cginc"
#include "Matrix.cginc"
float4 normalizesafe(in float4 v, float4 def = float4(0,0,0,0))
{
float len = length(v);
return (len < EPSILON) ? def : v/len;
}
float3 normalizesafe(in float3 v, float3 def = float3(0,0,0))
{
float len = length(v);
return (len < EPSILON) ? def : v/len;
}
inline float cmax( in float3 v)
{
return max(max(v.x,v.y),v.z);
}
inline float3 nfmod(float3 a, float3 b)
{
return a - b * floor(a / b);
}
inline float BaryScale(float4 coords)
{
return 1.0 / dot(coords, coords);
}
float Remap01(float value, float min_, float max_)
{
return (min(value, max_) - min(value, min_)) / (max_ - min_);
}
float EllipsoidRadius(float4 normSolverDirection, quaternion orientation, float3 radii)
{
float3 localDir = rotate_vector(q_conj(orientation), normSolverDirection.xyz) / radii;
float sqrNorm = dot(localDir, localDir);
return sqrNorm > EPSILON ? sqrt(1 / sqrNorm) : radii.x;
}
float4 Project(float4 v, float4 onto)
{
float len = dot(onto,onto);
if (len < EPSILON)
return FLOAT4_ZERO;
return dot(onto, v) * onto / len;
}
float3 Project(float3 v, float3 onto)
{
float len = dot(onto,onto);
if (len < EPSILON)
return float3(0,0,0);
return dot(onto, v) * onto / len;
}
inline void OneSidedNormal(float4 forward, inout float4 normal)
{
float d = dot(normal.xyz, forward.xyz);
if (d < 0) normal -= 2 * d * forward;
}
quaternion ExtractRotation(float3x3 m, quaternion rotation, int iterations)
{
float4x4 R;
for (int i = 0; i < iterations; ++i)
{
R = q_toMatrix(rotation);
float3 omega = (cross(R._m00_m10_m20, m._m00_m10_m20) + cross(R._m01_m11_m21, m._m01_m11_m21) + cross(R._m02_m12_m22, m._m02_m12_m22)) /
(abs(dot(R._m00_m10_m20, m._m00_m10_m20) + dot(R._m01_m11_m21, m._m01_m11_m21) + dot(R._m02_m12_m22, m._m02_m12_m22)) + EPSILON);
float w = length(omega);
if (w < EPSILON)
break;
rotation = normalize(qmul(axis_angle((1.0f / w) * omega, w), rotation));
}
return rotation;
}
quaternion ExtractRotation(float4x4 m, quaternion rotation, int iterations)
{
return ExtractRotation((float3x3) m, rotation, iterations);
}
float4 GetParticleInertiaTensor(in float4 principalRadii, in float invRotationalMass)
{
float4 sqrRadii = principalRadii * principalRadii;
return 0.2f / (invRotationalMass + EPSILON) * float4(sqrRadii[1] + sqrRadii[2],
sqrRadii[0] + sqrRadii[2],
sqrRadii[0] + sqrRadii[1], 0);
}
float4x4 TransformInertiaTensor(float4 tensor, quaternion rotation)
{
float4x4 rotMatrix = q_toMatrix(rotation);
return mul(rotMatrix, mul(AsDiagonal(tensor), transpose(rotMatrix)));
}
float RotationalInvMass(float4x4 inverseInertiaTensor, float4 pos, float4 direction)
{
float4 cr = mul(inverseInertiaTensor, float4(cross(pos.xyz, direction.xyz), 0));
return dot(cross(cr.xyz, pos.xyz), direction.xyz);
}
float4 NearestPointOnEdge(float4 a, float4 b, float4 p, out float mu, bool clampToSegment = true)
{
float4 ap = p - a;
float4 ab = b - a;
ap.w = 0;
ab.w = 0;
mu = dot(ap, ab) / dot(ab, ab);
if (clampToSegment)
mu = saturate(mu);
float4 result = a + ab * mu;
result.w = 0;
return result;
}
float3 NearestPointOnEdge(float3 a, float3 b, float3 p, out float mu, bool clampToSegment = true)
{
float3 ap = p - a;
float3 ab = b - a;
mu = dot(ap, ab) / dot(ab, ab);
if (clampToSegment)
mu = saturate(mu);
float3 result = a + ab * mu;
return result;
}
float RaySphereIntersection(float3 rayOrigin, float3 rayDirection, float3 center, float radius)
{
float3 oc = rayOrigin - center;
float a = dot(rayDirection, rayDirection);
float b = 2.0 * dot(oc, rayDirection);
float c = dot(oc, oc) - radius * radius;
float discriminant = b * b - 4 * a * c;
if (discriminant < 0){
return -1.0f;
}
else{
return (-b - sqrt(discriminant)) / (2.0f * a);
}
}
struct CachedTri
{
float4 vertex;
float4 edge0;
float4 edge1;
float4 data;
void Cache(in float4 v1,
in float4 v2,
in float4 v3)
{
vertex = v1;
edge0 = v2 - v1;
edge1 = v3 - v1;
data = float4(0,0,0,0);
data[0] = dot(edge0, edge0);
data[1] = dot(edge0, edge1);
data[2] = dot(edge1, edge1);
data[3] = data[0] * data[2] - data[1] * data[1];
}
};
float4 NearestPointOnTri(in CachedTri tri,
in float4 p,
out float4 bary)
{
float4 v0 = tri.vertex - p;
float b0 = dot(tri.edge0, v0);
float b1 = dot(tri.edge1, v0);
float t0 = tri.data[1] * b1 - tri.data[2] * b0;
float t1 = tri.data[1] * b0 - tri.data[0] * b1;
if (t0 + t1 <= tri.data[3])
{
if (t0 < zero)
{
if (t1 < zero) // region 4
{
if (b0 < zero)
{
t1 = zero;
if (-b0 >= tri.data[0]) // V0
t0 = one;
else // E01
t0 = -b0 / tri.data[0];
}
else
{
t0 = zero;
if (b1 >= zero) // V0
t1 = zero;
else if (-b1 >= tri.data[2]) // V2
t1 = one;
else // E20
t1 = -b1 / tri.data[2];
}
}
else // region 3
{
t0 = zero;
if (b1 >= zero) // V0
t1 = zero;
else if (-b1 >= tri.data[2]) // V2
t1 = one;
else // E20
t1 = -b1 / tri.data[2];
}
}
else if (t1 < zero) // region 5
{
t1 = zero;
if (b0 >= zero) // V0
t0 = zero;
else if (-b0 >= tri.data[0]) // V1
t0 = one;
else // E01
t0 = -b0 / tri.data[0];
}
else // region 0, interior
{
float invDet = one / tri.data[3];
t0 *= invDet;
t1 *= invDet;
}
}
else
{
float tmp0, tmp1, numer, denom;
if (t0 < zero) // region 2
{
tmp0 = tri.data[1] + b0;
tmp1 = tri.data[2] + b1;
if (tmp1 > tmp0)
{
numer = tmp1 - tmp0;
denom = tri.data[0] - 2 * tri.data[1] + tri.data[2];
if (numer >= denom) // V1
{
t0 = one;
t1 = zero;
}
else // E12
{
t0 = numer / denom;
t1 = one - t0;
}
}
else
{
t0 = zero;
if (tmp1 <= zero) // V2
t1 = one;
else if (b1 >= zero) // V0
t1 = zero;
else // E20
t1 = -b1 / tri.data[2];
}
}
else if (t1 < zero) // region 6
{
tmp0 = tri.data[1] + b1;
tmp1 = tri.data[0] + b0;
if (tmp1 > tmp0)
{
numer = tmp1 - tmp0;
denom = tri.data[0] - 2 * tri.data[1] + tri.data[2];
if (numer >= denom) // V2
{
t1 = one;
t0 = zero;
}
else // E12
{
t1 = numer / denom;
t0 = one - t1;
}
}
else
{
t1 = zero;
if (tmp1 <= zero) // V1
t0 = one;
else if (b0 >= zero) // V0
t0 = zero;
else // E01
t0 = -b0 / tri.data[0];
}
}
else // region 1
{
numer = tri.data[2] + b1 - tri.data[1] - b0;
if (numer <= zero) // V2
{
t0 = zero;
t1 = one;
}
else
{
denom = tri.data[0] - 2 * tri.data[1] + tri.data[2];
if (numer >= denom) // V1
{
t0 = one;
t1 = zero;
}
else // 12
{
t0 = numer / denom;
t1 = one - t0;
}
}
}
}
bary = float4(1 - (t0 + t1), t0, t1,0);
return tri.vertex + t0 * tri.edge0 + t1 * tri.edge1;
}
float3 unitOrthogonal(float3 input)
{
// Find a vector to cross() the input with.
if (!(input.x < input.z * EPSILON)
|| !(input.y < input.z * EPSILON))
{
float invnm = 1 / length(input.xy);
return float3(-input.y * invnm, input.x * invnm, 0);
}
else
{
float invnm = 1 / length(input.yz);
return float3(0, -input.z * invnm, input.y * invnm);
}
}
// D is symmetric, S is an eigen value
float3 EigenVector(float3x3 D, float S)
{
// Compute a cofactor matrix of D - sI.
float3 c0 = D._m00_m10_m20; c0[0] -= S;
float3 c1 = D._m01_m11_m21; c1[1] -= S;
float3 c2 = D._m02_m12_m22; c2[2] -= S;
// Upper triangular matrix
float3 c0p = float3(c1[1] * c2[2] - c2[1] * c2[1], 0, 0);
float3 c1p = float3(c2[1] * c2[0] - c1[0] * c2[2], c0[0] * c2[2] - c2[0] * c2[0], 0);
float3 c2p = float3(c1[0] * c2[1] - c1[1] * c2[0], c1[0] * c2[0] - c0[0] * c2[1], c0[0] * c1[1] - c1[0] * c1[0]);
// Get a column vector with a largest norm (non-zero).
float C01s = c1p[0] * c1p[0];
float C02s = c2p[0] * c2p[0];
float C12s = c2p[1] * c2p[1];
float3 norm = float3(c0p[0] * c0p[0] + C01s + C02s,
C01s + c1p[1] * c1p[1] + C12s,
C02s + C12s + c2p[2] * c2p[2]);
// index of largest:
int index = 0;
if (norm[0] > norm[1] && norm[0] > norm[2])
index = 0;
else if (norm[1] > norm[0] && norm[1] > norm[2])
index = 1;
else
index = 2;
float3 V = float3(0,0,0);
// special case
if (norm[index] < EPSILON)
{
V[0] = 1; return V;
}
else if (index == 0)
{
V[0] = c0p[0]; V[1] = c1p[0]; V[2] = c2p[0];
return normalize(V);
}
else if (index == 1)
{
V[0] = c1p[0]; V[1] = c1p[1]; V[2] = c2p[1];
return normalize(V);
}
else
{
V = c2p;
return normalize(V);
}
}
static float3 EigenValues(float3x3 D)
{
float one_third = 1 / 3.0f;
float one_sixth = 1 / 6.0f;
float three_sqrt = sqrt(3.0f);
float3 c0 = D._m00_m10_m20;
float3 c1 = D._m01_m11_m21;
float3 c2 = D._m02_m12_m22;
float m = one_third * (c0[0] + c1[1] + c2[2]);
// K is D - I*diag(S)
float K00 = c0[0] - m;
float K11 = c1[1] - m;
float K22 = c2[2] - m;
float K01s = c1[0] * c1[0];
float K02s = c2[0] * c2[0];
float K12s = c2[1] * c2[1];
float q = 0.5f * (K00 * (K11 * K22 - K12s) - K22 * K01s - K11 * K02s) + c1[0] * c2[1] * c0[2];
float p = one_sixth * (K00 * K00 + K11 * K11 + K22 * K22 + 2 * (K01s + K02s + K12s));
float p_sqrt = sqrt(p);
float tmp = p * p * p - q * q;
float phi = one_third * atan2(sqrt(max(0, tmp)), q);
float phi_c = cos(phi);
float phi_s = sin(phi);
float sqrt_p_c_phi = p_sqrt * phi_c;
float sqrt_p_3_s_phi = p_sqrt * three_sqrt * phi_s;
float e0 = m + 2 * sqrt_p_c_phi;
float e1 = m - sqrt_p_c_phi - sqrt_p_3_s_phi;
float e2 = m - sqrt_p_c_phi + sqrt_p_3_s_phi;
float aux;
if (e0 > e1)
{
aux = e0;
e0 = e1;
e1 = aux;
}
if (e0 > e2)
{
aux = e0;
e0 = e2;
e2 = aux;
}
if (e1 > e2)
{
aux = e1;
e1 = e2;
e2 = aux;
}
return float3(e2, e1, e0);
}
void EigenSolve(float3x3 D, out float3 S, out float3x3 V)
{
// D is symmetric
// S is a vector whose elements are eigenvalues
// V is a matrix whose columns are eigenvectors
S = EigenValues(D);
float3 V0, V1, V2;
if (S[0] - S[1] > S[1] - S[2])
{
V0 = EigenVector(D, S[0]);
if (S[1] - S[2] < EPSILON)
{
V2 = unitOrthogonal(V0);
}
else
{
V2 = EigenVector(D, S[2]); V2 -= V0 * dot(V0, V2); V2 = normalize(V2);
}
V1 = cross(V2, V0);
}
else
{
V2 = EigenVector(D, S[2]);
if (S[0] - S[1] < EPSILON)
{
V1 = unitOrthogonal(V2);
}
else
{
V1 = EigenVector(D, S[1]); V1 -= V2 * dot(V2, V1); V1 = normalize(V1);
}
V0 = cross(V1, V2);
}
V._m00_m10_m20 = V0;
V._m01_m11_m21 = V1;
V._m02_m12_m22 = V2;
}
float4 UnpackFloatRGBA(float v)
{
uint rgba = asuint(v);
float r = ((rgba & 0xff000000) >> 24) / 255.0;
float g = ((rgba & 0x00ff0000) >> 16) / 255.0;
float b = ((rgba & 0x0000ff00) >> 8) / 255.0;
float a = (rgba & 0x000000ff) / 255.0;
return float4(r, g, b, a);
}
float PackFloatRGBA(float4 enc)
{
uint rgba = ((uint)(enc.x * 255.0) << 24) +
((uint)(enc.y * 255.0) << 16) +
((uint)(enc.z * 255.0) << 8) +
(uint)(enc.w * 255.0);
return asfloat(rgba);
}
float2 UnpackFloatRG(float v)
{
uint rgba = asuint(v);
float r = ((rgba & 0xffff0000) >> 16) / 65535.0;
float g = (rgba & 0x0000ffff) / 65535.0;
return float2(r, g);
}
float PackFloatRG(float2 enc)
{
uint rgba = ((uint)(enc.x * 65535.0) << 16) +
(uint)(enc.y * 65535.0);
return asfloat(rgba);
}
#endif