minor optimization.

src/nvtt/squish/clusterfit.cpp

@@ -109,7 +109,7 @@ void ClusterFit::SetMetric(float r, float g, float b)
 float ClusterFit::GetBestError() const
 {
 #if SQUISH_USE_SIMD
-	return m_besterror.GetVec3().X();
+	return m_besterror.GetX();
 #else
 	return m_besterror;
 #endif

src/nvtt/squish/simd_sse.h

@@ -72,6 +72,13 @@ public:
 		_mm_store_ps( c, m_v );
 		return Vec3( c[0], c[1], c[2] );
 	}
+
+    float GetX() const 
+    {
+        SQUISH_ALIGN_16 float f;
+        _mm_store_ss(&f, m_v);
+        return f;
+    }
 	
 	Vec4 SplatX() const { return Vec4( _mm_shuffle_ps( m_v, m_v, SQUISH_SSE_SPLAT( 0 ) ) ); }
 	Vec4 SplatY() const { return Vec4( _mm_shuffle_ps( m_v, m_v, SQUISH_SSE_SPLAT( 1 ) ) ); }

src/nvtt/squish/simd_ve.h

@@ -78,7 +78,14 @@ public:
 		u.v = m_v;
 		return Vec3( u.c[0], u.c[1], u.c[2] );
 	}
-	
+
+	float GetX() const
+	{
+		union { vector float v; float c[4]; } u;
+		u.v = m_v;
+		return u.c[0];
+	}
+
 	Vec4 SplatX() const { return Vec4( vec_splat( m_v, 0 ) ); }
 	Vec4 SplatY() const { return Vec4( vec_splat( m_v, 1 ) ); }
 	Vec4 SplatZ() const { return Vec4( vec_splat( m_v, 2 ) ); }

src/nvtt/squish/weightedclusterfit.cpp

@@ -120,7 +120,7 @@ float WeightedClusterFit::GetBestError() const
 #if SQUISH_USE_SIMD
 	Vec4 x = m_xxsum * m_metricSqr;
 	Vec4 error = m_besterror + x.SplatX() + x.SplatY() + x.SplatZ();
-	return error.GetVec3().X();
+	return error.GetX();
 #else
 	return m_besterror + Dot(m_xxsum, m_metricSqr);
 #endif