//parses a rotation
M4Err Q_DecRotation(BifsDecoder *codec, BitStream *bs, u32 NbBits, void *field_ptr)
{
u32 i;
SFFloat angle, epsil, sin2, comp[4];
M4Err e;
e = Q_DecCoordOnUnitSphere(codec, bs, NbBits, 3, comp);
if (e) return e;
angle = (SFFloat) ( 2 * acos(comp[0]) );
epsil = M4_EPSILON_FLOAT;
sin2 = (SFFloat) sin(angle / 2);
if (fabs(sin2) <= epsil) {
for(i=1; i<4; i++) comp[i] = 0;
comp[3] = 1;
} else {
for(i=1; i<4; i++) comp[i] /= sin2;
}
((SFRotation *)field_ptr)->xAxis = comp[1];
((SFRotation *)field_ptr)->yAxis = comp[2];
((SFRotation *)field_ptr)->zAxis = comp[3];
((SFRotation *)field_ptr)->angle = angle;
return M4OK;
}
//parses a Normal vec
GF_Err Q_DecNormal(GF_BifsDecoder *codec, GF_BitStream *bs, u32 NbBits, void *field_ptr)
{
Fixed comp[3];
SFVec3f v;
GF_Err e;
e = Q_DecCoordOnUnitSphere(codec, bs, NbBits, 2, comp);
if (e) return e;
v.x = comp[0];
v.y = comp[1];
v.z = comp[2];
gf_vec_norm(&v);
*((SFVec3f *)field_ptr) = v;
return GF_OK;
}
//parses a Normal vec
M4Err Q_DecNormal(BifsDecoder *codec, BitStream *bs, u32 NbBits, void *field_ptr)
{
SFFloat comp[3];
SFFloat delta;
u32 i;
M4Err e;
e = Q_DecCoordOnUnitSphere(codec, bs, NbBits, 2, comp);
if (e) return e;
// normalize to avoid round-off problems
delta=0;
for (i=0; i<3; i++) delta += comp[i]*comp[i];
delta = (SFFloat) sqrt(delta);
if(delta > 0) {
for (i=0; i<3; i++) comp[i] /= delta;
}
((SFVec3f *)field_ptr)->x = comp[0];
((SFVec3f *)field_ptr)->y = comp[1];
((SFVec3f *)field_ptr)->z = comp[2];
return M4OK;
}
//parses a rotation
GF_Err Q_DecRotation(GF_BifsDecoder *codec, GF_BitStream *bs, u32 NbBits, void *field_ptr)
{
u32 i;
Fixed q, sin2, comp[4];
GF_Err e;
e = Q_DecCoordOnUnitSphere(codec, bs, NbBits, 3, comp);
if (e) return e;
q = 2 * gf_acos(comp[0]);
sin2 = gf_sin(q / 2);
if (ABS(sin2) <= FIX_EPSILON) {
for (i=1; i<4; i++) comp[i] = 0;
comp[3] = FIX_ONE;
} else {
for (i=1; i<4; i++) comp[i] = gf_divfix(comp[i], sin2);
}
((SFRotation *)field_ptr)->x = comp[1];
((SFRotation *)field_ptr)->y = comp[2];
((SFRotation *)field_ptr)->z = comp[3];
((SFRotation *)field_ptr)->q = q;
return GF_OK;
}
