vec Quat::WorldZ() const
{
#if defined(MATH_AUTOMATIC_SSE) && defined(MATH_SSE)
return FLOAT4_TO_DIR(quat_transform_vec4(q, float4::unitZ));
#else
return DIR_VEC(this->Transform(0.f, 0.f, 1.f));
#endif
}
vec Quat::Axis() const
{
assume2(this->IsNormalized(), *this, this->Length());
#if defined(MATH_AUTOMATIC_SSE) && defined(MATH_SSE)
// Best: 6.145 nsecs / 16.88 ticks, Avg: 6.367 nsecs, Worst: 6.529 nsecs
assume2(this->IsNormalized(), *this, this->Length());
simd4f cosAngle = _mm_shuffle_ps(q, q, _MM_SHUFFLE(3, 3, 3, 3));
simd4f rcpSinAngle = rsqrt_ps(sub_ps(set1_ps(1.f), mul_ps(cosAngle, cosAngle)));
simd4f a = mul_ps(q, rcpSinAngle);
// Set the w component to zero.
simd4f highPart = _mm_unpackhi_ps(a, zero_ps()); // [_ _ 0 z]
a = _mm_movelh_ps(a, highPart); // [0 z y x]
return FLOAT4_TO_DIR(a);
#else
// Best: 6.529 nsecs / 18.152 ticks, Avg: 6.851 nsecs, Worst: 8.065 nsecs
// Convert cos to sin via the identity sin^2 + cos^2 = 1, and fuse reciprocal and square root to the same instruction,
// since we are about to divide by it.
float rcpSinAngle = RSqrt(1.f - w*w);
return DIR_VEC(x, y, z) * rcpSinAngle;
#endif
}
ScaleOp::ScaleOp(const float4 &scale)
:scale(FLOAT4_TO_DIR(scale))
{
}
