quake4-sdk/source/idlib/geometry/JointTransform.cpp
2007-06-15 00:00:00 +00:00

60 lines
1.1 KiB
C++

#include "../precompiled.h"
#pragma hdrstop
/*
=============
idJointMat::ToJointQuat
=============
*/
idJointQuat idJointMat::ToJointQuat( void ) const {
idJointQuat jq;
float trace;
float s;
float t;
int i;
int j;
int k;
static int next[3] = { 1, 2, 0 };
trace = mat[0 * 4 + 0] + mat[1 * 4 + 1] + mat[2 * 4 + 2];
if ( trace > 0.0f ) {
t = trace + 1.0f;
s = idMath::InvSqrt( t ) * 0.5f;
jq.q[3] = s * t;
jq.q[0] = ( mat[1 * 4 + 2] - mat[2 * 4 + 1] ) * s;
jq.q[1] = ( mat[2 * 4 + 0] - mat[0 * 4 + 2] ) * s;
jq.q[2] = ( mat[0 * 4 + 1] - mat[1 * 4 + 0] ) * s;
} else {
i = 0;
if ( mat[1 * 4 + 1] > mat[0 * 4 + 0] ) {
i = 1;
}
if ( mat[2 * 4 + 2] > mat[i * 4 + i] ) {
i = 2;
}
j = next[i];
k = next[j];
t = ( mat[i * 4 + i] - ( mat[j * 4 + j] + mat[k * 4 + k] ) ) + 1.0f;
s = idMath::InvSqrt( t ) * 0.5f;
jq.q[i] = s * t;
jq.q[3] = ( mat[j * 4 + k] - mat[k * 4 + j] ) * s;
jq.q[j] = ( mat[i * 4 + j] + mat[j * 4 + i] ) * s;
jq.q[k] = ( mat[i * 4 + k] + mat[k * 4 + i] ) * s;
}
jq.t[0] = mat[0 * 4 + 3];
jq.t[1] = mat[1 * 4 + 3];
jq.t[2] = mat[2 * 4 + 3];
return jq;
}