Add get lane functions for vec4

src/tenvex/expressions/core.h

@@ -4,9 +4,10 @@
 #include "defines.h"
 
 #if defined(HAS_SSE42)
-#include <smmintrin.h>
-using vf4 = __m128;
+	#include <smmintrin.h>
+	using vf4 = __m128;
 #else
+	#error "tenvex requires an SSE4.1 backend (define HAS_SSE42 and build with -msse4.1 on GCC/Clang)"
 #endif
 
 namespace tnvx::detail
@@ -31,6 +32,13 @@ vf4 scalar(float value) noexcept
 	return _mm_set_ps1(value);
 }
 
+template<int lane>
+[[nodiscard]] TNVX_INLINE
+float get_lane(vf4 v) noexcept
+{
+	return _mm_cvtss_f32(_mm_shuffle_ps(v, v, _MM_SHUFFLE(0, 0, 0, lane)));
+}
+
 [[nodiscard]] TNVX_INLINE
 vf4 add(vf4 l, vf4 r) noexcept
 {

src/tenvex/expressions/vec4.h

@@ -20,10 +20,23 @@ struct alignas(16) vec4 : Expr<vec4>
 	TNVX_INLINE
 	vec4(const E& e) noexcept;
 
+	[[nodiscard]] TNVX_INLINE
+	float x() const noexcept;
+
+	[[nodiscard]] TNVX_INLINE
+	float y() const noexcept;
+
+	[[nodiscard]] TNVX_INLINE
+	float z() const noexcept;
+
+	[[nodiscard]] TNVX_INLINE
+	float w() const noexcept;
+
 	[[nodiscard]] TNVX_INLINE
 	vf4 eval() const noexcept;
 
 private:
+
 	vf4 _data;
 };
 

src/tenvex/expressions/vec4_impl.hpp

@@ -31,9 +31,33 @@ bool approx_eq(const vec4& lhs, const vec4& rhs, float eps) noexcept
 }
 
 TNVX_INLINE
-bool tnvx::operator==(const vec4& lhs, const vec4& rhs) noexcept
+bool operator==(const vec4& lhs, const vec4& rhs) noexcept
 {
 	return detail::eq(lhs.eval(), rhs.eval());
 }
 
+TNVX_INLINE
+float vec4::x() const noexcept
+{
+	return detail::get_lane<0>(_data);
+}
+
+TNVX_INLINE
+float vec4::y() const noexcept
+{
+	return detail::get_lane<1>(_data);
+}
+
+TNVX_INLINE
+float vec4::z() const noexcept
+{
+	return detail::get_lane<2>(_data);
+}
+
+TNVX_INLINE
+float vec4::w() const noexcept
+{
+	return detail::get_lane<3>(_data);
+}
+
 }