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Add SIMD implementation of power method. Fixes issue 94.

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This commit is contained in:
castano 2009-06-14 08:18:23 +00:00
parent 341c393dde
commit 7629e396b8
1 changed files with 31 additions and 1 deletions
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32
src/nvtt/squish/maths.cpp
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@ -24,6 +24,7 @@
-------------------------------------------------------------------------- */
#include "maths.h"
#include "simd.h"
#include <cfloat>
namespace squish {
@ -60,12 +61,40 @@ Sym3x3 ComputeWeightedCovariance( int n, Vec3 const* points, float const* weight
}
#define POWER_ITERATION_COUNT 8
#if SQUISH_USE_SIMD
Vec3 ComputePrincipleComponent( Sym3x3 const& matrix )
{
Vec4 const row0( matrix[0], matrix[1], matrix[2], 0.0f );
Vec4 const row1( matrix[1], matrix[3], matrix[4], 0.0f );
Vec4 const row2( matrix[2], matrix[4], matrix[5], 0.0f );
Vec4 v = VEC4_CONST( 1.0f );
for( int i = 0; i < POWER_ITERATION_COUNT; ++i )
{
// matrix multiply
Vec4 w = row0*v.SplatX();
w = MultiplyAdd(row1, v.SplatY(), w);
w = MultiplyAdd(row2, v.SplatZ(), w);
// get max component from xyz in all channels
Vec4 a = Max(w.SplatX(), Max(w.SplatY(), w.SplatZ()));
// divide through and advance
v = w*Reciprocal(a);
}
return v.GetVec3();
}
#else
Vec3 ComputePrincipleComponent( Sym3x3 const& matrix )
{
const int NUM = 8;
Vec3 v(1, 1, 1);
for(int i = 0; i < NUM; i++) {
for (int i = 0; i < POWER_ITERATION_COUNT; i++) {
float x = v.X() * matrix[0] + v.Y() * matrix[1] + v.Z() * matrix[2];
float y = v.X() * matrix[1] + v.Y() * matrix[3] + v.Z() * matrix[4];
float z = v.X() * matrix[2] + v.Y() * matrix[4] + v.Z() * matrix[5];
@ -82,5 +111,6 @@ Vec3 ComputePrincipleComponent( Sym3x3 const& matrix )
return v;
}
#endif
} // namespace squish