Merge pull request #23837 from fire/asset_import

Add Open Asset Importer to Godot.

1 files changed, 342 insertions, 0 deletions

diff --git a/thirdparty/assimp/code/SpatialSort.cpp b/thirdparty/assimp/code/SpatialSort.cpp
new file mode 100644
index 0000000000..a4f3a4e4b8
--- /dev/null
+++ b/thirdparty/assimp/code/SpatialSort.cpp
@@ -0,0 +1,342 @@
+/*
+---------------------------------------------------------------------------
+Open Asset Import Library (assimp)
+---------------------------------------------------------------------------
+
+Copyright (c) 2006-2019, assimp team
+
+
+
+All rights reserved.
+
+Redistribution and use of this software in source and binary forms,
+with or without modification, are permitted provided that the following
+conditions are met:
+
+* Redistributions of source code must retain the above
+  copyright notice, this list of conditions and the
+  following disclaimer.
+
+* Redistributions in binary form must reproduce the above
+  copyright notice, this list of conditions and the
+  following disclaimer in the documentation and/or other
+  materials provided with the distribution.
+
+* Neither the name of the assimp team, nor the names of its
+  contributors may be used to endorse or promote products
+  derived from this software without specific prior
+  written permission of the assimp team.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+---------------------------------------------------------------------------
+*/
+
+/** @file Implementation of the helper class to quickly find vertices close to a given position */
+
+#include <assimp/SpatialSort.h>
+#include <assimp/ai_assert.h>
+
+using namespace Assimp;
+
+// CHAR_BIT seems to be defined under MVSC, but not under GCC. Pray that the correct value is 8.
+#ifndef CHAR_BIT
+#   define CHAR_BIT 8
+#endif
+
+// ------------------------------------------------------------------------------------------------
+// Constructs a spatially sorted representation from the given position array.
+SpatialSort::SpatialSort( const aiVector3D* pPositions, unsigned int pNumPositions,
+    unsigned int pElementOffset)
+
+    // define the reference plane. We choose some arbitrary vector away from all basic axises
+    // in the hope that no model spreads all its vertices along this plane.
+    : mPlaneNormal(0.8523f, 0.34321f, 0.5736f)
+{
+    mPlaneNormal.Normalize();
+    Fill(pPositions,pNumPositions,pElementOffset);
+}
+
+// ------------------------------------------------------------------------------------------------
+SpatialSort :: SpatialSort()
+: mPlaneNormal(0.8523f, 0.34321f, 0.5736f)
+{
+    mPlaneNormal.Normalize();
+}
+
+// ------------------------------------------------------------------------------------------------
+// Destructor
+SpatialSort::~SpatialSort()
+{
+    // nothing to do here, everything destructs automatically
+}
+
+// ------------------------------------------------------------------------------------------------
+void SpatialSort::Fill( const aiVector3D* pPositions, unsigned int pNumPositions,
+    unsigned int pElementOffset,
+    bool pFinalize /*= true */)
+{
+    mPositions.clear();
+    Append(pPositions,pNumPositions,pElementOffset,pFinalize);
+}
+
+// ------------------------------------------------------------------------------------------------
+void SpatialSort :: Finalize()
+{
+    std::sort( mPositions.begin(), mPositions.end());
+}
+
+// ------------------------------------------------------------------------------------------------
+void SpatialSort::Append( const aiVector3D* pPositions, unsigned int pNumPositions,
+    unsigned int pElementOffset,
+    bool pFinalize /*= true */)
+{
+    // store references to all given positions along with their distance to the reference plane
+    const size_t initial = mPositions.size();
+    mPositions.reserve(initial + (pFinalize?pNumPositions:pNumPositions*2));
+    for( unsigned int a = 0; a < pNumPositions; a++)
+    {
+        const char* tempPointer = reinterpret_cast<const char*> (pPositions);
+        const aiVector3D* vec   = reinterpret_cast<const aiVector3D*> (tempPointer + a * pElementOffset);
+
+        // store position by index and distance
+        ai_real distance = *vec * mPlaneNormal;
+        mPositions.push_back( Entry( static_cast<unsigned int>(a+initial), *vec, distance));
+    }
+
+    if (pFinalize) {
+        // now sort the array ascending by distance.
+        Finalize();
+    }
+}
+
+// ------------------------------------------------------------------------------------------------
+// Returns an iterator for all positions close to the given position.
+void SpatialSort::FindPositions( const aiVector3D& pPosition,
+    ai_real pRadius, std::vector<unsigned int>& poResults) const
+{
+    const ai_real dist = pPosition * mPlaneNormal;
+    const ai_real minDist = dist - pRadius, maxDist = dist + pRadius;
+
+    // clear the array
+    poResults.clear();
+
+    // quick check for positions outside the range
+    if( mPositions.size() == 0)
+        return;
+    if( maxDist < mPositions.front().mDistance)
+        return;
+    if( minDist > mPositions.back().mDistance)
+        return;
+
+    // do a binary search for the minimal distance to start the iteration there
+    unsigned int index = (unsigned int)mPositions.size() / 2;
+    unsigned int binaryStepSize = (unsigned int)mPositions.size() / 4;
+    while( binaryStepSize > 1)
+    {
+        if( mPositions[index].mDistance < minDist)
+            index += binaryStepSize;
+        else
+            index -= binaryStepSize;
+
+        binaryStepSize /= 2;
+    }
+
+    // depending on the direction of the last step we need to single step a bit back or forth
+    // to find the actual beginning element of the range
+    while( index > 0 && mPositions[index].mDistance > minDist)
+        index--;
+    while( index < (mPositions.size() - 1) && mPositions[index].mDistance < minDist)
+        index++;
+
+    // Mow start iterating from there until the first position lays outside of the distance range.
+    // Add all positions inside the distance range within the given radius to the result aray
+    std::vector<Entry>::const_iterator it = mPositions.begin() + index;
+    const ai_real pSquared = pRadius*pRadius;
+    while( it->mDistance < maxDist)
+    {
+        if( (it->mPosition - pPosition).SquareLength() < pSquared)
+            poResults.push_back( it->mIndex);
+        ++it;
+        if( it == mPositions.end())
+            break;
+    }
+
+    // that's it
+}
+
+namespace {
+
+    // Binary, signed-integer representation of a single-precision floating-point value.
+    // IEEE 754 says: "If two floating-point numbers in the same format are ordered then they are
+    //  ordered the same way when their bits are reinterpreted as sign-magnitude integers."
+    // This allows us to convert all floating-point numbers to signed integers of arbitrary size
+    //  and then use them to work with ULPs (Units in the Last Place, for high-precision
+    //  computations) or to compare them (integer comparisons are faster than floating-point
+    //  comparisons on many platforms).
+    typedef ai_int BinFloat;
+
+    // --------------------------------------------------------------------------------------------
+    // Converts the bit pattern of a floating-point number to its signed integer representation.
+    BinFloat ToBinary( const ai_real & pValue) {
+
+        // If this assertion fails, signed int is not big enough to store a float on your platform.
+        //  Please correct the declaration of BinFloat a few lines above - but do it in a portable,
+        //  #ifdef'd manner!
+        static_assert( sizeof(BinFloat) >= sizeof(ai_real), "sizeof(BinFloat) >= sizeof(ai_real)");
+
+        #if defined( _MSC_VER)
+            // If this assertion fails, Visual C++ has finally moved to ILP64. This means that this
+            //  code has just become legacy code! Find out the current value of _MSC_VER and modify
+            //  the #if above so it evaluates false on the current and all upcoming VC versions (or
+            //  on the current platform, if LP64 or LLP64 are still used on other platforms).
+            static_assert( sizeof(BinFloat) == sizeof(ai_real), "sizeof(BinFloat) == sizeof(ai_real)");
+
+            // This works best on Visual C++, but other compilers have their problems with it.
+            const BinFloat binValue = reinterpret_cast<BinFloat const &>(pValue);
+        #else
+            // On many compilers, reinterpreting a float address as an integer causes aliasing
+            // problems. This is an ugly but more or less safe way of doing it.
+            union {
+                ai_real     asFloat;
+                BinFloat    asBin;
+            } conversion;
+            conversion.asBin    = 0; // zero empty space in case sizeof(BinFloat) > sizeof(float)
+            conversion.asFloat  = pValue;
+            const BinFloat binValue = conversion.asBin;
+        #endif
+
+        // floating-point numbers are of sign-magnitude format, so find out what signed number
+        //  representation we must convert negative values to.
+        // See http://en.wikipedia.org/wiki/Signed_number_representations.
+
+        // Two's complement?
+        if( (-42 == (~42 + 1)) && (binValue & 0x80000000))
+            return BinFloat(1 << (CHAR_BIT * sizeof(BinFloat) - 1)) - binValue;
+        // One's complement?
+        else if ( (-42 == ~42) && (binValue & 0x80000000))
+            return BinFloat(-0) - binValue;
+        // Sign-magnitude?
+        else if( (-42 == (42 | (-0))) && (binValue & 0x80000000)) // -0 = 1000... binary
+            return binValue;
+        else
+            return binValue;
+    }
+
+} // namespace
+
+// ------------------------------------------------------------------------------------------------
+// Fills an array with indices of all positions identical to the given position. In opposite to
+// FindPositions(), not an epsilon is used but a (very low) tolerance of four floating-point units.
+void SpatialSort::FindIdenticalPositions( const aiVector3D& pPosition,
+    std::vector<unsigned int>& poResults) const
+{
+    // Epsilons have a huge disadvantage: they are of constant precision, while floating-point
+    //  values are of log2 precision. If you apply e=0.01 to 100, the epsilon is rather small, but
+    //  if you apply it to 0.001, it is enormous.
+
+    // The best way to overcome this is the unit in the last place (ULP). A precision of 2 ULPs
+    //  tells us that a float does not differ more than 2 bits from the "real" value. ULPs are of
+    //  logarithmic precision - around 1, they are 1*(2^24) and around 10000, they are 0.00125.
+
+    // For standard C math, we can assume a precision of 0.5 ULPs according to IEEE 754. The
+    //  incoming vertex positions might have already been transformed, probably using rather
+    //  inaccurate SSE instructions, so we assume a tolerance of 4 ULPs to safely identify
+    //  identical vertex positions.
+    static const int toleranceInULPs = 4;
+    // An interesting point is that the inaccuracy grows linear with the number of operations:
+    //  multiplying to numbers, each inaccurate to four ULPs, results in an inaccuracy of four ULPs
+    //  plus 0.5 ULPs for the multiplication.
+    // To compute the distance to the plane, a dot product is needed - that is a multiplication and
+    //  an addition on each number.
+    static const int distanceToleranceInULPs = toleranceInULPs + 1;
+    // The squared distance between two 3D vectors is computed the same way, but with an additional
+    //  subtraction.
+    static const int distance3DToleranceInULPs = distanceToleranceInULPs + 1;
+
+    // Convert the plane distance to its signed integer representation so the ULPs tolerance can be
+    //  applied. For some reason, VC won't optimize two calls of the bit pattern conversion.
+    const BinFloat minDistBinary = ToBinary( pPosition * mPlaneNormal) - distanceToleranceInULPs;
+    const BinFloat maxDistBinary = minDistBinary + 2 * distanceToleranceInULPs;
+
+    // clear the array in this strange fashion because a simple clear() would also deallocate
+    // the array which we want to avoid
+    poResults.resize( 0 );
+
+    // do a binary search for the minimal distance to start the iteration there
+    unsigned int index = (unsigned int)mPositions.size() / 2;
+    unsigned int binaryStepSize = (unsigned int)mPositions.size() / 4;
+    while( binaryStepSize > 1)
+    {
+        // Ugly, but conditional jumps are faster with integers than with floats
+        if( minDistBinary > ToBinary(mPositions[index].mDistance))
+            index += binaryStepSize;
+        else
+            index -= binaryStepSize;
+
+        binaryStepSize /= 2;
+    }
+
+    // depending on the direction of the last step we need to single step a bit back or forth
+    // to find the actual beginning element of the range
+    while( index > 0 && minDistBinary < ToBinary(mPositions[index].mDistance) )
+        index--;
+    while( index < (mPositions.size() - 1) && minDistBinary > ToBinary(mPositions[index].mDistance))
+        index++;
+
+    // Now start iterating from there until the first position lays outside of the distance range.
+    // Add all positions inside the distance range within the tolerance to the result array
+    std::vector<Entry>::const_iterator it = mPositions.begin() + index;
+    while( ToBinary(it->mDistance) < maxDistBinary)
+    {
+        if( distance3DToleranceInULPs >= ToBinary((it->mPosition - pPosition).SquareLength()))
+            poResults.push_back(it->mIndex);
+        ++it;
+        if( it == mPositions.end())
+            break;
+    }
+
+    // that's it
+}
+
+// ------------------------------------------------------------------------------------------------
+unsigned int SpatialSort::GenerateMappingTable(std::vector<unsigned int>& fill, ai_real pRadius) const
+{
+    fill.resize(mPositions.size(),UINT_MAX);
+    ai_real dist, maxDist;
+
+    unsigned int t=0;
+    const ai_real pSquared = pRadius*pRadius;
+    for (size_t i = 0; i < mPositions.size();) {
+        dist = mPositions[i].mPosition * mPlaneNormal;
+        maxDist = dist + pRadius;
+
+        fill[mPositions[i].mIndex] = t;
+        const aiVector3D& oldpos = mPositions[i].mPosition;
+        for (++i; i < fill.size() && mPositions[i].mDistance < maxDist
+            && (mPositions[i].mPosition - oldpos).SquareLength() < pSquared; ++i)
+        {
+            fill[mPositions[i].mIndex] = t;
+        }
+        ++t;
+    }
+
+#ifdef ASSIMP_BUILD_DEBUG
+
+    // debug invariant: mPositions[i].mIndex values must range from 0 to mPositions.size()-1
+    for (size_t i = 0; i < fill.size(); ++i) {
+        ai_assert(fill[i]<mPositions.size());
+    }
+
+#endif
+    return t;
+}