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OpenSceneGraph/src/osgUtil/TangentSpaceGenerator.cpp
Robert Osfield 2cf45b50c9 From Terry Welsh, added checks to incoming Geometry for existance of normals, 
and if they are present use these to compute the tanget and binormals
vectors perpendicular to existing normals.
2004-06-04 08:24:13 +00:00

345 lines
10 KiB
C++
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#include <osgUtil/TangentSpaceGenerator>
#include <osg/Notify>
using namespace osgUtil;
TangentSpaceGenerator::TangentSpaceGenerator()
: osg::Referenced(),
T_(new osg::Vec4Array),
B_(new osg::Vec4Array),
N_(new osg::Vec4Array)
{
}
TangentSpaceGenerator::TangentSpaceGenerator(const TangentSpaceGenerator &copy, const osg::CopyOp &copyop)
: osg::Referenced(copy),
T_(static_cast<osg::Vec4Array *>(copyop(copy.T_.get()))),
B_(static_cast<osg::Vec4Array *>(copyop(copy.B_.get()))),
N_(static_cast<osg::Vec4Array *>(copyop(copy.N_.get())))
{
}
void TangentSpaceGenerator::generate(osg::Geometry *geo, int normal_map_tex_unit)
{
const osg::Array *vx = geo->getVertexArray();
const osg::Array *nx = geo->getNormalArray();
const osg::Array *tx = geo->getTexCoordArray(normal_map_tex_unit);
if (!vx || !tx) return;
unsigned int vertex_count = vx->getNumElements();
T_->assign(vertex_count, osg::Vec4());
B_->assign(vertex_count, osg::Vec4());
N_->assign(vertex_count, osg::Vec4());
unsigned i; // VC6 doesn't like for-scoped variables
for (unsigned pri=0; pri<geo->getNumPrimitiveSets(); ++pri) {
osg::PrimitiveSet *pset = geo->getPrimitiveSet(pri);
unsigned N = pset->getNumIndices();
switch (pset->getMode()) {
case osg::PrimitiveSet::TRIANGLES:
for (i=0; i<N; i+=3) {
compute_basis_vectors(pset, vx, nx, tx, i, i+1, i+2);
}
break;
case osg::PrimitiveSet::QUADS:
for (i=0; i<N; i+=4) {
compute_basis_vectors(pset, vx, nx, tx, i, i+1, i+2);
compute_basis_vectors(pset, vx, nx, tx, i+2, i+3, i);
}
break;
case osg::PrimitiveSet::TRIANGLE_STRIP:
if (pset->getType() == osg::PrimitiveSet::DrawArrayLengthsPrimitiveType) {
osg::DrawArrayLengths *dal = static_cast<osg::DrawArrayLengths *>(pset);
unsigned j = 0;
for (osg::DrawArrayLengths::const_iterator pi=dal->begin(); pi!=dal->end(); ++pi) {
unsigned iN = static_cast<unsigned>(*pi-2);
for (i=0; i<iN; ++i, ++j) {
if ((i%2) == 0) {
compute_basis_vectors(pset, vx, nx, tx, j, j+1, j+2);
} else {
compute_basis_vectors(pset, vx, nx, tx, j+1, j, j+2);
}
}
j += 2;
}
} else {
for (i=0; i<N-2; ++i) {
if ((i%2) == 0) {
compute_basis_vectors(pset, vx, nx, tx, i, i+1, i+2);
} else {
compute_basis_vectors(pset, vx, nx, tx, i+1, i, i+2);
}
}
}
break;
case osg::PrimitiveSet::TRIANGLE_FAN:
if (pset->getType() == osg::PrimitiveSet::DrawArrayLengthsPrimitiveType) {
osg::DrawArrayLengths *dal = static_cast<osg::DrawArrayLengths *>(pset);
unsigned j = 0;
for (osg::DrawArrayLengths::const_iterator pi=dal->begin(); pi!=dal->end(); ++pi) {
unsigned iN = static_cast<unsigned>(*pi-2);
for (i=0; i<iN; ++i) {
compute_basis_vectors(pset, vx, nx, tx, 0, j+1, j+2);
}
j += 2;
}
} else {
for (i=0; i<N-2; ++i) {
compute_basis_vectors(pset, vx, nx, tx, 2, i+1, i+2);
}
}
break;
case osg::PrimitiveSet::POINTS:
case osg::PrimitiveSet::LINES:
case osg::PrimitiveSet::LINE_STRIP:
case osg::PrimitiveSet::LINE_LOOP:
break;
default: osg::notify(osg::WARN) << "Warning: TangentSpaceGenerator: unknown primitive mode " << pset->getMode() << "\n";
}
}
// normalize basis vectors and force the normal vector to match
// the triangle normal's direction
for (i=0; i<vertex_count; ++i) {
osg::Vec4 &vT = (*T_)[i];
osg::Vec4 &vB = (*B_)[i];
osg::Vec4 &vN = (*N_)[i];
osg::Vec3 txN = osg::Vec3(vT.x(), vT.y(), vT.z()) ^ osg::Vec3(vB.x(), vB.y(), vB.z());
if (txN * osg::Vec3(vN.x(), vN.y(), vN.z()) >= 0) {
vN = osg::Vec4(txN, 0);
} else {
vN = osg::Vec4(-txN, 0);
}
vT.normalize();
vB.normalize();
vN.normalize();
}
}
void TangentSpaceGenerator::compute_basis_vectors(osg::PrimitiveSet *pset, const osg::Array *vx, const osg::Array *nx, const osg::Array *tx, int iA, int iB, int iC)
{
iA = pset->index(iA);
iB = pset->index(iB);
iC = pset->index(iC);
osg::Vec3 P1;
osg::Vec3 P2;
osg::Vec3 P3;
int i; // VC6 doesn't like for-scoped variables
switch (vx->getType())
{
case osg::Array::Vec2ArrayType:
for (i=0; i<2; ++i) {
P1.ptr()[i] = static_cast<const osg::Vec2Array&>(*vx)[iA].ptr()[i];
P2.ptr()[i] = static_cast<const osg::Vec2Array&>(*vx)[iB].ptr()[i];
P3.ptr()[i] = static_cast<const osg::Vec2Array&>(*vx)[iC].ptr()[i];
}
break;
case osg::Array::Vec3ArrayType:
P1 = static_cast<const osg::Vec3Array&>(*vx)[iA];
P2 = static_cast<const osg::Vec3Array&>(*vx)[iB];
P3 = static_cast<const osg::Vec3Array&>(*vx)[iC];
break;
case osg::Array::Vec4ArrayType:
for (i=0; i<3; ++i) {
P1.ptr()[i] = static_cast<const osg::Vec4Array&>(*vx)[iA].ptr()[i];
P2.ptr()[i] = static_cast<const osg::Vec4Array&>(*vx)[iB].ptr()[i];
P3.ptr()[i] = static_cast<const osg::Vec4Array&>(*vx)[iC].ptr()[i];
}
break;
default:
osg::notify(osg::WARN) << "Warning: TangentSpaceGenerator: vertex array must be Vec2Array, Vec3Array or Vec4Array" << std::endl;
}
osg::Vec3 N1;
osg::Vec3 N2;
osg::Vec3 N3;
if(nx)
{
switch (nx->getType())
{
case osg::Array::Vec2ArrayType:
for (i=0; i<2; ++i) {
N1.ptr()[i] = static_cast<const osg::Vec2Array&>(*nx)[iA].ptr()[i];
N2.ptr()[i] = static_cast<const osg::Vec2Array&>(*nx)[iB].ptr()[i];
N3.ptr()[i] = static_cast<const osg::Vec2Array&>(*nx)[iC].ptr()[i];
}
break;
case osg::Array::Vec3ArrayType:
N1 = static_cast<const osg::Vec3Array&>(*nx)[iA];
N2 = static_cast<const osg::Vec3Array&>(*nx)[iB];
N3 = static_cast<const osg::Vec3Array&>(*nx)[iC];
break;
case osg::Array::Vec4ArrayType:
for (i=0; i<3; ++i) {
N1.ptr()[i] = static_cast<const osg::Vec4Array&>(*nx)[iA].ptr()[i];
N2.ptr()[i] = static_cast<const osg::Vec4Array&>(*nx)[iB].ptr()[i];
N3.ptr()[i] = static_cast<const osg::Vec4Array&>(*nx)[iC].ptr()[i];
}
break;
default:
osg::notify(osg::WARN) << "Warning: TangentSpaceGenerator: normal array must be Vec2Array, Vec3Array or Vec4Array" << std::endl;
}
}
osg::Vec2 uv1;
osg::Vec2 uv2;
osg::Vec2 uv3;
switch (tx->getType())
{
case osg::Array::Vec2ArrayType:
uv1 = static_cast<const osg::Vec2Array&>(*tx)[iA];
uv2 = static_cast<const osg::Vec2Array&>(*tx)[iB];
uv3 = static_cast<const osg::Vec2Array&>(*tx)[iC];
break;
case osg::Array::Vec3ArrayType:
for (i=0; i<2; ++i) {
uv1.ptr()[i] = static_cast<const osg::Vec3Array&>(*tx)[iA].ptr()[i];
uv2.ptr()[i] = static_cast<const osg::Vec3Array&>(*tx)[iB].ptr()[i];
uv3.ptr()[i] = static_cast<const osg::Vec3Array&>(*tx)[iC].ptr()[i];
}
break;
case osg::Array::Vec4ArrayType:
for (i=0; i<2; ++i) {
uv1.ptr()[i] = static_cast<const osg::Vec4Array&>(*tx)[iA].ptr()[i];
uv2.ptr()[i] = static_cast<const osg::Vec4Array&>(*tx)[iB].ptr()[i];
uv3.ptr()[i] = static_cast<const osg::Vec4Array&>(*tx)[iC].ptr()[i];
}
break;
default:
osg::notify(osg::WARN) << "Warning: TangentSpaceGenerator: texture coord array must be Vec2Array, Vec3Array or Vec4Array" << std::endl;
}
if(nx){
osg::Vec3 V, T1, T2, T3, B1, B2, B3;
V = osg::Vec3(P2.x() - P1.x(), uv2.x() - uv1.x(), uv2.y() - uv1.y()) ^
osg::Vec3(P3.x() - P1.x(), uv3.x() - uv1.x(), uv3.y() - uv1.y());
if (V.x() != 0) {
V.normalize();
T1.x() += -V.y() / V.x();
B1.x() += -V.z() / V.x();
T2.x() += -V.y() / V.x();
B2.x() += -V.z() / V.x();
T3.x() += -V.y() / V.x();
B3.x() += -V.z() / V.x();
}
V = osg::Vec3(P2.y() - P1.y(), uv2.x() - uv1.x(), uv2.y() - uv1.y()) ^
osg::Vec3(P3.y() - P1.y(), uv3.x() - uv1.x(), uv3.y() - uv1.y());
if (V.x() != 0) {
V.normalize();
T1.y() += -V.y() / V.x();
B1.y() += -V.z() / V.x();
T2.y() += -V.y() / V.x();
B2.y() += -V.z() / V.x();
T3.y() += -V.y() / V.x();
B3.y() += -V.z() / V.x();
}
V = osg::Vec3(P2.z() - P1.z(), uv2.x() - uv1.x(), uv2.y() - uv1.y()) ^
osg::Vec3(P3.z() - P1.z(), uv3.x() - uv1.x(), uv3.y() - uv1.y());
if (V.x() != 0) {
V.normalize();
T1.z() += -V.y() / V.x();
B1.z() += -V.z() / V.x();
T2.z() += -V.y() / V.x();
B2.z() += -V.z() / V.x();
T3.z() += -V.y() / V.x();
B3.z() += -V.z() / V.x();
}
osg::Vec3 tempvec;
tempvec = N1 ^ T1;
(*T_)[iA] = osg::Vec4(tempvec ^ N1, 0);
tempvec = B1 ^ N1;
(*B_)[iA] = osg::Vec4(N1 ^ tempvec, 0);
tempvec = N2 ^ T2;
(*T_)[iB] = osg::Vec4(tempvec ^ N2, 0);
tempvec = B2 ^ N2;
(*B_)[iB] = osg::Vec4(N2 ^ tempvec, 0);
tempvec = N3 ^ T3;
(*T_)[iC] = osg::Vec4(tempvec ^ N3, 0);
tempvec = B3 ^ N3;
(*B_)[iC] = osg::Vec4(N3 ^ tempvec, 0);
(*N_)[iA] += osg::Vec4(N1, 0);
(*N_)[iB] += osg::Vec4(N2, 0);
(*N_)[iC] += osg::Vec4(N3, 0);
}
else{
osg::Vec3 face_normal = (P2 - P1) ^ (P3 - P1);
osg::Vec3 V;
V = osg::Vec3(P2.x() - P1.x(), uv2.x() - uv1.x(), uv2.y() - uv1.y()) ^
osg::Vec3(P3.x() - P1.x(), uv3.x() - uv1.x(), uv3.y() - uv1.y());
if (V.x() != 0) {
V.normalize();
(*T_)[iA].x() += -V.y() / V.x();
(*B_)[iA].x() += -V.z() / V.x();
(*T_)[iB].x() += -V.y() / V.x();
(*B_)[iB].x() += -V.z() / V.x();
(*T_)[iC].x() += -V.y() / V.x();
(*B_)[iC].x() += -V.z() / V.x();
}
V = osg::Vec3(P2.y() - P1.y(), uv2.x() - uv1.x(), uv2.y() - uv1.y()) ^
osg::Vec3(P3.y() - P1.y(), uv3.x() - uv1.x(), uv3.y() - uv1.y());
if (V.x() != 0) {
V.normalize();
(*T_)[iA].y() += -V.y() / V.x();
(*B_)[iA].y() += -V.z() / V.x();
(*T_)[iB].y() += -V.y() / V.x();
(*B_)[iB].y() += -V.z() / V.x();
(*T_)[iC].y() += -V.y() / V.x();
(*B_)[iC].y() += -V.z() / V.x();
}
V = osg::Vec3(P2.z() - P1.z(), uv2.x() - uv1.x(), uv2.y() - uv1.y()) ^
osg::Vec3(P3.z() - P1.z(), uv3.x() - uv1.x(), uv3.y() - uv1.y());
if (V.x() != 0) {
V.normalize();
(*T_)[iA].z() += -V.y() / V.x();
(*B_)[iA].z() += -V.z() / V.x();
(*T_)[iB].z() += -V.y() / V.x();
(*B_)[iB].z() += -V.z() / V.x();
(*T_)[iC].z() += -V.y() / V.x();
(*B_)[iC].z() += -V.z() / V.x();
}
(*N_)[iA] += osg::Vec4(face_normal, 0);
(*N_)[iB] += osg::Vec4(face_normal, 0);
(*N_)[iC] += osg::Vec4(face_normal, 0);
}
}
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