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Fix issues with NaNs in tangent data from using normalize3fast on zero-length vectors and other data conditioning; also added assert to normalize3fast to make finding these problems easier in the future

master
Graham Madarasz 2013-06-12 08:09:29 -07:00
parent 7ad631e6ea
commit 48324a9383
2 changed files with 106 additions and 31 deletions
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9
indra/llmath/llvector4a.inl
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@ -331,6 +331,9 @@ inline LLSimdScalar LLVector4a::dot4(const LLVector4a& b) const
// Note that this does not consider zero length vectors!
inline void LLVector4a::normalize3()
{
// find out about bad math before it takes two man-days to track down
llassert(isFinite3() && !equals3(getZero()));
// lenSqrd = a dot a
LLVector4a lenSqrd; lenSqrd.setAllDot3( *this, *this );
// rsqrt = approximate reciprocal square (i.e., { ~1/len(a)^2, ~1/len(a)^2, ~1/len(a)^2, ~1/len(a)^2 }
@ -379,6 +382,9 @@ inline void LLVector4a::normalize4()
// Note that this does not consider zero length vectors!
inline LLSimdScalar LLVector4a::normalize3withLength()
{
// find out about bad math before it takes two man-days to track down
llassert(isFinite3() && !equals3(getZero()));
// lenSqrd = a dot a
LLVector4a lenSqrd; lenSqrd.setAllDot3( *this, *this );
// rsqrt = approximate reciprocal square (i.e., { ~1/len(a)^2, ~1/len(a)^2, ~1/len(a)^2, ~1/len(a)^2 }
@ -404,6 +410,9 @@ inline LLSimdScalar LLVector4a::normalize3withLength()
// Note that this does not consider zero length vectors!
inline void LLVector4a::normalize3fast()
{
// find out about bad math before it takes two man-days to track down
llassert(isFinite3() && !equals3(getZero()));
LLVector4a lenSqrd; lenSqrd.setAllDot3( *this, *this );
const LLQuad approxRsqrt = _mm_rsqrt_ps(lenSqrd.mQ);
mQ = _mm_mul_ps( mQ, approxRsqrt );

128
indra/llmath/llvolume.cpp
View File

@ -7209,46 +7209,53 @@ BOOL LLVolumeFace::createSide(LLVolume* volume, BOOL partial_build)
return TRUE;
}
#define TANGENTIAL_PARANOIA_ASSERTS 1
#if TANGENTIAL_PARANOIA_ASSERTS
#define tangential_paranoia(a) llassert(a)
#else
#define tangential_paranoia(a)
#endif
//adapted from Lengyel, Eric. “Computing Tangent Space Basis Vectors for an Arbitrary Mesh”. Terathon Software 3D Graphics Library, 2001. http://www.terathon.com/code/tangent.html
void CalculateTangentArray(U32 vertexCount, const LLVector4a *vertex, const LLVector4a *normal,
const LLVector2 *texcoord, U32 triangleCount, const U16* index_array, LLVector4a *tangent)
{
//LLVector4a *tan1 = new LLVector4a[vertexCount * 2];
LLVector4a* tan1 = (LLVector4a*) ll_aligned_malloc_16(vertexCount*2*sizeof(LLVector4a));
LLVector4a* tan2 = tan1 + vertexCount;
LLVector4a* tan2 = tan1 + vertexCount;
memset(tan1, 0, vertexCount*2*sizeof(LLVector4a));
for (U32 a = 0; a < triangleCount; a++)
{
U32 i1 = *index_array++;
U32 i2 = *index_array++;
U32 i3 = *index_array++;
for (U32 a = 0; a < triangleCount; a++)
{
U32 i1 = *index_array++;
U32 i2 = *index_array++;
U32 i3 = *index_array++;
const LLVector4a& v1 = vertex[i1];
const LLVector4a& v2 = vertex[i2];
const LLVector4a& v3 = vertex[i3];
const LLVector4a& v1 = vertex[i1];
const LLVector4a& v2 = vertex[i2];
const LLVector4a& v3 = vertex[i3];
const LLVector2& w1 = texcoord[i1];
const LLVector2& w2 = texcoord[i2];
const LLVector2& w3 = texcoord[i3];
const LLVector2& w1 = texcoord[i1];
const LLVector2& w2 = texcoord[i2];
const LLVector2& w3 = texcoord[i3];
const F32* v1ptr = v1.getF32ptr();
const F32* v2ptr = v2.getF32ptr();
const F32* v3ptr = v3.getF32ptr();
float x1 = v2ptr[0] - v1ptr[0];
float x2 = v3ptr[0] - v1ptr[0];
float y1 = v2ptr[1] - v1ptr[1];
float y2 = v3ptr[1] - v1ptr[1];
float z1 = v2ptr[2] - v1ptr[2];
float z2 = v3ptr[2] - v1ptr[2];
float x1 = v2ptr[0] - v1ptr[0];
float x2 = v3ptr[0] - v1ptr[0];
float y1 = v2ptr[1] - v1ptr[1];
float y2 = v3ptr[1] - v1ptr[1];
float z1 = v2ptr[2] - v1ptr[2];
float z2 = v3ptr[2] - v1ptr[2];
float s1 = w2.mV[0] - w1.mV[0];
float s2 = w3.mV[0] - w1.mV[0];
float t1 = w2.mV[1] - w1.mV[1];
float t2 = w3.mV[1] - w1.mV[1];
float s1 = w2.mV[0] - w1.mV[0];
float s2 = w3.mV[0] - w1.mV[0];
float t1 = w2.mV[1] - w1.mV[1];
float t2 = w3.mV[1] - w1.mV[1];
F32 rd = s1*t2-s2*t1;
@ -7262,18 +7269,67 @@ void CalculateTangentArray(U32 vertexCount, const LLVector4a *vertex, const LLVe
LLVector4a tdir((s1 * x2 - s2 * x1) * r, (s1 * y2 - s2 * y1) * r,
(s1 * z2 - s2 * z1) * r);
tan1[i1].add(sdir);
tan1[i2].add(sdir);
tan1[i3].add(sdir);
tangential_paranoia(tan1[i1].isFinite3());
tangential_paranoia(tan1[i2].isFinite3());
tangential_paranoia(tan1[i3].isFinite3());
tan2[i1].add(tdir);
tan2[i2].add(tdir);
tan2[i3].add(tdir);
}
for (U32 a = 0; a < vertexCount; a++)
{
LLVector4a n = normal[a];
tangential_paranoia(tan2[i1].isFinite3());
tangential_paranoia(tan2[i2].isFinite3());
tangential_paranoia(tan2[i3].isFinite3());
}
// These appear to come out of the summing above distinctly non-unit-length
//
for (U32 a = 0; a < vertexCount; a++)
{
// Conditioning required by assets which don't necessarily reference every vert index
// (i.e. some of the tangents can end up uninitialized and therefore indeterminate/INF)
// and protection against zero length vectors which are not handled by normalize3fast.
//
if (!tan1[a].isFinite3() || tan1[a].equals3(LLVector4a::getZero()))
{
tan1[a].set(0,0,1,1);
}
else
{
tan1[a].normalize3fast();
}
if (!tan2[a].isFinite3() || tan2[a].equals3(LLVector4a::getZero()))
{
tan2[a].set(0,0,1,1);
}
else
{
tan2[a].normalize3fast();
}
const F32 cefgw = 0.03f;
tangential_paranoia(tan1[a].isFinite3());
tangential_paranoia(tan2[a].isFinite3());
tangential_paranoia(tan1[a].isNormalized3(cefgw));
tangential_paranoia(tan2[a].isNormalized3(cefgw));
}
for (U32 a = 0; a < vertexCount; a++)
{
LLVector4a n = normal[a];
if (!n.isFinite3() || n.equals3(LLVector4a::getZero()))
{
n.set(0,1,0,1);
}
n.normalize3fast();
const LLVector4a& t = tan1[a];
@ -7283,12 +7339,20 @@ void CalculateTangentArray(U32 vertexCount, const LLVector4a *vertex, const LLVe
LLVector4a ncrosst;
ncrosst.setCross3(n,t);
// Gram-Schmidt orthogonalize
n.mul(n.dot3(t).getF32());
F32 n_dot_t = n.dot3(t).getF32();
tangential_paranoia(llfinite(n_dot_t) && !llisnan(n_dot_t));
// Gram-Schmidt orthogonalize
n.mul(n_dot_t);
tangential_paranoia(n.isFinite3());
LLVector4a tsubn;
tsubn.setSub(t,n);
tangential_paranoia(tsubn.isFinite3());
if (tsubn.dot3(tsubn).getF32() > F_APPROXIMATELY_ZERO)
{
tsubn.normalize3fast();
@ -7300,6 +7364,8 @@ void CalculateTangentArray(U32 vertexCount, const LLVector4a *vertex, const LLVe
tangent[a] = tsubn;
tangential_paranoia(tangent[a].isNormalized3(0.1f));
llassert(llfinite(tangent[a].getF32ptr()[0]));
llassert(llfinite(tangent[a].getF32ptr()[1]));
llassert(llfinite(tangent[a].getF32ptr()[2]));