assimp/include/aiQuaternion.h

312 lines
10 KiB
C

/*
Open Asset Import Library (ASSIMP)
----------------------------------------------------------------------
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*/
/** @file aiQuaternion.h
* @brief Quaternion structure, including operators when compiling in C++
*/
#ifndef AI_QUATERNION_H_INC
#define AI_QUATERNION_H_INC
#include <math.h>
#include "aiTypes.h"
#ifdef __cplusplus
extern "C" {
#endif
// ---------------------------------------------------------------------------
/** Represents a quaternion in a 4D vector. */
struct aiQuaternion
{
#ifdef __cplusplus
aiQuaternion() : w(0.0f), x(0.0f), y(0.0f), z(0.0f) {}
aiQuaternion(float _w, float _x, float _y, float _z) : w(_w), x(_x), y(_y), z(_z) {}
/** Construct from rotation matrix. Result is undefined if the matrix is not orthonormal. */
aiQuaternion( const aiMatrix3x3& pRotMatrix);
/** Construct from euler angles */
aiQuaternion( float rotx, float roty, float rotz);
/** Construct from an axis-angle pair */
aiQuaternion( aiVector3D axis, float angle);
/** Construct from a normalized quaternion stored in a vec3 */
aiQuaternion( aiVector3D normalized);
/** Returns a matrix representation of the quaternion */
aiMatrix3x3 GetMatrix() const;
bool operator== (const aiQuaternion& o) const
{return x == o.x && y == o.y && z == o.z && w == o.w;}
bool operator!= (const aiQuaternion& o) const
{return !(*this == o);}
/** Normalize the quaternion */
aiQuaternion& Normalize();
/** Compute quaternion conjugate */
aiQuaternion& Conjugate ();
/** Rotate a point by this quaternion */
aiVector3D Rotate (const aiVector3D& in);
/** Multiply two quaternions */
aiQuaternion operator* (const aiQuaternion& two) const;
/** Performs a spherical interpolation between two quaternions and writes the result into the third.
* @param pOut Target object to received the interpolated rotation.
* @param pStart Start rotation of the interpolation at factor == 0.
* @param pEnd End rotation, factor == 1.
* @param pFactor Interpolation factor between 0 and 1. Values outside of this range yield undefined results.
*/
static void Interpolate( aiQuaternion& pOut, const aiQuaternion& pStart, const aiQuaternion& pEnd, float pFactor);
#endif // __cplusplus
//! w,x,y,z components of the quaternion
float w, x, y, z;
} ;
#ifdef __cplusplus
// ---------------------------------------------------------------------------
// Constructs a quaternion from a rotation matrix
inline aiQuaternion::aiQuaternion( const aiMatrix3x3 &pRotMatrix)
{
float t = 1 + pRotMatrix.a1 + pRotMatrix.b2 + pRotMatrix.c3;
// large enough
if( t > 0.001f)
{
float s = sqrt( t) * 2.0f;
x = (pRotMatrix.c2 - pRotMatrix.b3) / s;
y = (pRotMatrix.a3 - pRotMatrix.c1) / s;
z = (pRotMatrix.b1 - pRotMatrix.a2) / s;
w = 0.25f * s;
} // else we have to check several cases
else if( pRotMatrix.a1 > pRotMatrix.b2 && pRotMatrix.a1 > pRotMatrix.c3 )
{
// Column 0:
float s = sqrt( 1.0f + pRotMatrix.a1 - pRotMatrix.b2 - pRotMatrix.c3) * 2.0f;
x = 0.25f * s;
y = (pRotMatrix.b1 + pRotMatrix.a2) / s;
z = (pRotMatrix.a3 + pRotMatrix.c1) / s;
w = (pRotMatrix.c2 - pRotMatrix.b3) / s;
}
else if( pRotMatrix.b2 > pRotMatrix.c3)
{
// Column 1:
float s = sqrt( 1.0f + pRotMatrix.b2 - pRotMatrix.a1 - pRotMatrix.c3) * 2.0f;
x = (pRotMatrix.b1 + pRotMatrix.a2) / s;
y = 0.25f * s;
z = (pRotMatrix.c2 + pRotMatrix.b3) / s;
w = (pRotMatrix.a3 - pRotMatrix.c1) / s;
} else
{
// Column 2:
float s = sqrt( 1.0f + pRotMatrix.c3 - pRotMatrix.a1 - pRotMatrix.b2) * 2.0f;
x = (pRotMatrix.a3 + pRotMatrix.c1) / s;
y = (pRotMatrix.c2 + pRotMatrix.b3) / s;
z = 0.25f * s;
w = (pRotMatrix.b1 - pRotMatrix.a2) / s;
}
}
// ---------------------------------------------------------------------------
// Construction from euler angles
inline aiQuaternion::aiQuaternion( float fPitch, float fYaw, float fRoll )
{
const float fSinPitch(sin(fPitch*0.5F));
const float fCosPitch(cos(fPitch*0.5F));
const float fSinYaw(sin(fYaw*0.5F));
const float fCosYaw(cos(fYaw*0.5F));
const float fSinRoll(sin(fRoll*0.5F));
const float fCosRoll(cos(fRoll*0.5F));
const float fCosPitchCosYaw(fCosPitch*fCosYaw);
const float fSinPitchSinYaw(fSinPitch*fSinYaw);
x = fSinRoll * fCosPitchCosYaw - fCosRoll * fSinPitchSinYaw;
y = fCosRoll * fSinPitch * fCosYaw + fSinRoll * fCosPitch * fSinYaw;
z = fCosRoll * fCosPitch * fSinYaw - fSinRoll * fSinPitch * fCosYaw;
w = fCosRoll * fCosPitchCosYaw + fSinRoll * fSinPitchSinYaw;
}
// ---------------------------------------------------------------------------
// Returns a matrix representation of the quaternion
inline aiMatrix3x3 aiQuaternion::GetMatrix() const
{
aiMatrix3x3 resMatrix;
resMatrix.a1 = 1.0f - 2.0f * (y * y + z * z);
resMatrix.a2 = 2.0f * (x * y - z * w);
resMatrix.a3 = 2.0f * (x * z + y * w);
resMatrix.b1 = 2.0f * (x * y + z * w);
resMatrix.b2 = 1.0f - 2.0f * (x * x + z * z);
resMatrix.b3 = 2.0f * (y * z - x * w);
resMatrix.c1 = 2.0f * (x * z - y * w);
resMatrix.c2 = 2.0f * (y * z + x * w);
resMatrix.c3 = 1.0f - 2.0f * (x * x + y * y);
return resMatrix;
}
// ---------------------------------------------------------------------------
// Construction from an axis-angle pair
inline aiQuaternion::aiQuaternion( aiVector3D axis, float angle)
{
axis.Normalize();
const float sin_a = sin( angle / 2 );
const float cos_a = cos( angle / 2 );
x = axis.x * sin_a;
y = axis.y * sin_a;
z = axis.z * sin_a;
w = cos_a;
}
// ---------------------------------------------------------------------------
// Construction from am existing, normalized quaternion
inline aiQuaternion::aiQuaternion( aiVector3D normalized)
{
x = normalized.x;
y = normalized.y;
z = normalized.z;
const float t = 1.0f - (x*x) - (y*y) - (z*z);
if (t < 0.0f)
w = 0.0f;
else w = sqrt (t);
}
// ---------------------------------------------------------------------------
// Performs a spherical interpolation between two quaternions
// Implementation adopted from the gmtl project. All others I found on the net fail in some cases.
// Congrats, gmtl!
inline void aiQuaternion::Interpolate( aiQuaternion& pOut, const aiQuaternion& pStart, const aiQuaternion& pEnd, float pFactor)
{
// calc cosine theta
float cosom = pStart.x * pEnd.x + pStart.y * pEnd.y + pStart.z * pEnd.z + pStart.w * pEnd.w;
// adjust signs (if necessary)
aiQuaternion end = pEnd;
if( cosom < 0.0f)
{
cosom = -cosom;
end.x = -end.x; // Reverse all signs
end.y = -end.y;
end.z = -end.z;
end.w = -end.w;
}
// Calculate coefficients
float sclp, sclq;
if( (1.0f - cosom) > 0.0001f) // 0.0001 -> some epsillon
{
// Standard case (slerp)
float omega, sinom;
omega = acos( cosom); // extract theta from dot product's cos theta
sinom = sin( omega);
sclp = sin( (1.0f - pFactor) * omega) / sinom;
sclq = sin( pFactor * omega) / sinom;
} else
{
// Very close, do linear interp (because it's faster)
sclp = 1.0f - pFactor;
sclq = pFactor;
}
pOut.x = sclp * pStart.x + sclq * end.x;
pOut.y = sclp * pStart.y + sclq * end.y;
pOut.z = sclp * pStart.z + sclq * end.z;
pOut.w = sclp * pStart.w + sclq * end.w;
}
// ---------------------------------------------------------------------------
inline aiQuaternion& aiQuaternion::Normalize()
{
// compute the magnitude and divide through it
const float mag = x*x+y*y+z*z+w*w;
if (mag)
{
x /= mag;
y /= mag;
z /= mag;
w /= mag;
}
return *this;
}
// ---------------------------------------------------------------------------
inline aiQuaternion aiQuaternion::operator* (const aiQuaternion& t) const
{
return aiQuaternion(w*t.w - x*t.x - y*t.y - z*t.z,
w*t.x + x*t.w + y*t.z - z*t.y,
w*t.y + y*t.w + z*t.x - x*t.z,
w*t.z + z*t.w + x*t.y - y*t.x);
}
// ---------------------------------------------------------------------------
inline aiQuaternion& aiQuaternion::Conjugate ()
{
x = -x;
y = -y;
z = -z;
return *this;
}
// ---------------------------------------------------------------------------
inline aiVector3D aiQuaternion::Rotate (const aiVector3D& v)
{
aiQuaternion q2(0.f,v.x,v.y,v.z), q = *this, qinv = q;
q.Conjugate();
q = q*q2*qinv;
return aiVector3D(q.x,q.y,q.z);
}
} // end extern "C"
#endif // __cplusplus
#endif // AI_QUATERNION_H_INC