+// see http://www.euclideanspace.com/maths/geometry/rotations/conversions/matrixToQuaternion/index.htm
+void Matrix4x4_ToOrigin3Quat4Float(const matrix4x4_t *m, float *origin, float *quat)
+{
+#if 0
+ float s;
+ quat[3] = sqrt(1.0f + m->m[0][0] + m->m[1][1] + m->m[2][2]) * 0.5f;
+ s = 0.25f / quat[3];
+#ifdef MATRIX4x4_OPENGLORIENTATION
+ origin[0] = m->m[3][0];
+ origin[1] = m->m[3][1];
+ origin[2] = m->m[3][2];
+ quat[0] = (m->m[1][2] - m->m[2][1]) * s;
+ quat[1] = (m->m[2][0] - m->m[0][2]) * s;
+ quat[2] = (m->m[0][1] - m->m[1][0]) * s;
+#else
+ origin[0] = m->m[0][3];
+ origin[1] = m->m[1][3];
+ origin[2] = m->m[2][3];
+ quat[0] = (m->m[2][1] - m->m[1][2]) * s;
+ quat[1] = (m->m[0][2] - m->m[2][0]) * s;
+ quat[2] = (m->m[1][0] - m->m[0][1]) * s;
+#endif
+
+#else
+
+#ifdef MATRIX4x4_OPENGLORIENTATION
+ float trace = m->m[0][0] + m->m[1][1] + m->m[2][2];
+ origin[0] = m->m[3][0];
+ origin[1] = m->m[3][1];
+ origin[2] = m->m[3][2];
+ if(trace > 0)
+ {
+ float r = sqrt(1.0f + trace), inv = 0.5f / r;
+ quat[0] = (m->m[1][2] - m->m[2][1]) * inv;
+ quat[1] = (m->m[2][0] - m->m[0][2]) * inv;
+ quat[2] = (m->m[0][1] - m->m[1][0]) * inv;
+ quat[3] = 0.5f * r;
+ }
+ else if(m->m[0][0] > m->m[1][1] && m->m[0][0] > m->m[2][2])
+ {
+ float r = sqrt(1.0f + m->m[0][0] - m->m[1][1] - m->m[2][2]), inv = 0.5f / r;
+ quat[0] = 0.5f * r;
+ quat[1] = (m->m[0][1] + m->m[1][0]) * inv;
+ quat[2] = (m->m[2][0] + m->m[0][2]) * inv;
+ quat[3] = (m->m[1][2] - m->m[2][1]) * inv;
+ }
+ else if(m->m[1][1] > m->m[2][2])
+ {
+ float r = sqrt(1.0f + m->m[1][1] - m->m[0][0] - m->m[2][2]), inv = 0.5f / r;
+ quat[0] = (m->m[0][1] + m->m[1][0]) * inv;
+ quat[1] = 0.5f * r;
+ quat[2] = (m->m[1][2] + m->m[2][1]) * inv;
+ quat[3] = (m->m[2][0] - m->m[0][2]) * inv;
+ }
+ else
+ {
+ float r = sqrt(1.0f + m->m[2][2] - m->m[0][0] - m->m[1][1]), inv = 0.5f / r;
+ quat[0] = (m->m[2][0] + m->m[0][2]) * inv;
+ quat[1] = (m->m[1][2] + m->m[2][1]) * inv;
+ quat[2] = 0.5f * r;
+ quat[3] = (m->m[0][1] - m->m[1][0]) * inv;
+ }
+#else
+ float trace = m->m[0][0] + m->m[1][1] + m->m[2][2];
+ origin[0] = m->m[0][3];
+ origin[1] = m->m[1][3];
+ origin[2] = m->m[2][3];
+ if(trace > 0)
+ {
+ float r = sqrt(1.0f + trace), inv = 0.5f / r;
+ quat[0] = (m->m[2][1] - m->m[1][2]) * inv;
+ quat[1] = (m->m[0][2] - m->m[2][0]) * inv;
+ quat[2] = (m->m[1][0] - m->m[0][1]) * inv;
+ quat[3] = 0.5f * r;
+ }
+ else if(m->m[0][0] > m->m[1][1] && m->m[0][0] > m->m[2][2])
+ {
+ float r = sqrt(1.0f + m->m[0][0] - m->m[1][1] - m->m[2][2]), inv = 0.5f / r;
+ quat[0] = 0.5f * r;
+ quat[1] = (m->m[1][0] + m->m[0][1]) * inv;
+ quat[2] = (m->m[0][2] + m->m[2][0]) * inv;
+ quat[3] = (m->m[2][1] - m->m[1][2]) * inv;
+ }
+ else if(m->m[1][1] > m->m[2][2])
+ {
+ float r = sqrt(1.0f + m->m[1][1] - m->m[0][0] - m->m[2][2]), inv = 0.5f / r;
+ quat[0] = (m->m[1][0] + m->m[0][1]) * inv;
+ quat[1] = 0.5f * r;
+ quat[2] = (m->m[2][1] + m->m[1][2]) * inv;
+ quat[3] = (m->m[0][2] - m->m[2][0]) * inv;
+ }
+ else
+ {
+ float r = sqrt(1.0f + m->m[2][2] - m->m[0][0] - m->m[1][1]), inv = 0.5f / r;
+ quat[0] = (m->m[0][2] + m->m[2][0]) * inv;
+ quat[1] = (m->m[2][1] + m->m[1][2]) * inv;
+ quat[2] = 0.5f * r;
+ quat[3] = (m->m[1][0] - m->m[0][1]) * inv;
+ }
+#endif
+
+#endif
+}
+
+// LadyHavoc: I got this code from:
+//http://www.doom3world.org/phpbb2/viewtopic.php?t=2884
+void Matrix4x4_FromDoom3Joint(matrix4x4_t *m, double ox, double oy, double oz, double x, double y, double z)
+{
+ double w = 1.0f - (x*x+y*y+z*z);
+ w = w > 0.0f ? -sqrt(w) : 0.0f;
+#ifdef MATRIX4x4_OPENGLORIENTATION
+ m->m[0][0]=1-2*(y*y+z*z);m->m[1][0]= 2*(x*y-z*w);m->m[2][0]= 2*(x*z+y*w);m->m[3][0]=ox;
+ m->m[0][1]= 2*(x*y+z*w);m->m[1][1]=1-2*(x*x+z*z);m->m[2][1]= 2*(y*z-x*w);m->m[3][1]=oy;
+ m->m[0][2]= 2*(x*z-y*w);m->m[1][2]= 2*(y*z+x*w);m->m[2][2]=1-2*(x*x+y*y);m->m[3][2]=oz;
+ m->m[0][3]= 0 ;m->m[1][3]= 0 ;m->m[2][3]= 0 ;m->m[3][3]=1;
+#else
+ m->m[0][0]=1-2*(y*y+z*z);m->m[0][1]= 2*(x*y-z*w);m->m[0][2]= 2*(x*z+y*w);m->m[0][3]=ox;
+ m->m[1][0]= 2*(x*y+z*w);m->m[1][1]=1-2*(x*x+z*z);m->m[1][2]= 2*(y*z-x*w);m->m[1][3]=oy;
+ m->m[2][0]= 2*(x*z-y*w);m->m[2][1]= 2*(y*z+x*w);m->m[2][2]=1-2*(x*x+y*y);m->m[2][3]=oz;
+ m->m[3][0]= 0 ;m->m[3][1]= 0 ;m->m[3][2]= 0 ;m->m[3][3]=1;
+#endif
+}
+
+void Matrix4x4_FromBonePose7s(matrix4x4_t *m, float originscale, const short *pose7s)
+{
+ float origin[3];
+ float quat[4];
+ float quatscale = pose7s[6] > 0 ? -1.0f / 32767.0f : 1.0f / 32767.0f;
+ origin[0] = pose7s[0] * originscale;
+ origin[1] = pose7s[1] * originscale;
+ origin[2] = pose7s[2] * originscale;
+ quat[0] = pose7s[3] * quatscale;
+ quat[1] = pose7s[4] * quatscale;
+ quat[2] = pose7s[5] * quatscale;
+ quat[3] = pose7s[6] * quatscale;
+ Matrix4x4_FromOriginQuat(m, origin[0], origin[1], origin[2], quat[0], quat[1], quat[2], quat[3]);
+}
+
+void Matrix4x4_ToBonePose7s(const matrix4x4_t *m, float origininvscale, short *pose7s)
+{
+ float origin[3];
+ float quat[4];
+ float quatscale;
+ Matrix4x4_ToOrigin3Quat4Float(m, origin, quat);
+ // normalize quaternion so that it is unit length
+ quatscale = quat[0]*quat[0]+quat[1]*quat[1]+quat[2]*quat[2]+quat[3]*quat[3];
+ if (quatscale)
+ quatscale = (quat[3] >= 0 ? -32767.0f : 32767.0f) / sqrt(quatscale);
+ // use a negative scale on the quat because the above function produces a
+ // positive quat[3] and canonical quaternions have negative quat[3]
+ pose7s[0] = origin[0] * origininvscale;
+ pose7s[1] = origin[1] * origininvscale;
+ pose7s[2] = origin[2] * origininvscale;
+ pose7s[3] = quat[0] * quatscale;
+ pose7s[4] = quat[1] * quatscale;
+ pose7s[5] = quat[2] * quatscale;
+ pose7s[6] = quat[3] * quatscale;
+}
+
+void Matrix4x4_Blend (matrix4x4_t *out, const matrix4x4_t *in1, const matrix4x4_t *in2, double blend)
+{
+ double iblend = 1 - blend;
+ out->m[0][0] = in1->m[0][0] * iblend + in2->m[0][0] * blend;
+ out->m[0][1] = in1->m[0][1] * iblend + in2->m[0][1] * blend;
+ out->m[0][2] = in1->m[0][2] * iblend + in2->m[0][2] * blend;
+ out->m[0][3] = in1->m[0][3] * iblend + in2->m[0][3] * blend;
+ out->m[1][0] = in1->m[1][0] * iblend + in2->m[1][0] * blend;
+ out->m[1][1] = in1->m[1][1] * iblend + in2->m[1][1] * blend;
+ out->m[1][2] = in1->m[1][2] * iblend + in2->m[1][2] * blend;
+ out->m[1][3] = in1->m[1][3] * iblend + in2->m[1][3] * blend;
+ out->m[2][0] = in1->m[2][0] * iblend + in2->m[2][0] * blend;
+ out->m[2][1] = in1->m[2][1] * iblend + in2->m[2][1] * blend;
+ out->m[2][2] = in1->m[2][2] * iblend + in2->m[2][2] * blend;
+ out->m[2][3] = in1->m[2][3] * iblend + in2->m[2][3] * blend;
+ out->m[3][0] = in1->m[3][0] * iblend + in2->m[3][0] * blend;
+ out->m[3][1] = in1->m[3][1] * iblend + in2->m[3][1] * blend;
+ out->m[3][2] = in1->m[3][2] * iblend + in2->m[3][2] * blend;
+ out->m[3][3] = in1->m[3][3] * iblend + in2->m[3][3] * blend;
+}
+
+