closes https://github.com/assimp/assimp/issues/2598: introduce getEpsilon

code/Collada/ColladaExporter.cpp

@@ -45,6 +45,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "ColladaExporter.h"
 #include <assimp/Bitmap.h>
+#include <assimp/MathFunctions.h>
 #include <assimp/fast_atof.h>
 #include <assimp/SceneCombiner.h>
 #include <assimp/StringUtils.h>
@@ -155,7 +156,7 @@ void ColladaExporter::WriteFile() {
 // ------------------------------------------------------------------------------------------------
 // Writes the asset header
 void ColladaExporter::WriteHeader() {
-    static const ai_real epsilon = ai_real( 0.00001 );
+    static const ai_real epsilon = Math::getEpsilon<ai_real>();
     static const aiQuaternion x_rot(aiMatrix3x3(
         0, -1,  0,
         1,  0,  0,
@@ -1671,4 +1672,4 @@ void ColladaExporter::WriteNode( const aiScene* pScene, aiNode* pNode)
 }
 
 #endif
-#endif
+#endif

code/FBX/FBXConverter.cpp

@@ -55,6 +55,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "FBXImporter.h"
 
 #include <assimp/StringComparison.h>
+#include <assimp/MathFunctions.h>
 
 #include <assimp/scene.h>
 
@@ -553,7 +554,7 @@ namespace Assimp {
                 return;
             }
 
-            const float angle_epsilon = 1e-6f;
+            const float angle_epsilon = Math::getEpsilon<float>();
 
             out = aiMatrix4x4();
 

include/assimp/MathFunctions.h

@@ -39,22 +39,24 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 ---------------------------------------------------------------------------
 */
 
+#pragma once
+
 /** @file  MathFunctions.h
- *  @brief Implementation of the math functions (gcd and lcm)
+*  @brief Implementation of math utility functions.
  *
- *  Copied from BoostWorkaround/math
- */
+*/
+
+#include <limits>
 
 namespace Assimp {
 namespace Math {
 
 // TODO: use binary GCD for unsigned integers ....
 template < typename IntegerType >
-IntegerType  gcd( IntegerType a, IntegerType b )
-{
+inline
+IntegerType gcd( IntegerType a, IntegerType b ) {
 	const IntegerType zero = (IntegerType)0;
-	while ( true )
-	{
+	while ( true ) {
 		if ( a == zero )
 			return b;
 		b %= a;
@@ -66,12 +68,19 @@ IntegerType  gcd( IntegerType a, IntegerType b )
 }
 
 template < typename IntegerType >
-IntegerType  lcm( IntegerType a, IntegerType b )
-{
+inline
+IntegerType lcm( IntegerType a, IntegerType b ) {
 	const IntegerType t = gcd (a,b);
-	if (!t)return t;
+	if (!t)
+        return t;
 	return a / t * b;
 }
 
+template<class T>
+inline
+T getEpsilon() {
+    return std::numeric_limits<T>::epsilon();
+}
+
 }
 }

include/assimp/matrix4x4.inl

@@ -5,8 +5,6 @@ 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,
@@ -53,6 +51,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #include "matrix4x4.h"
 #include "matrix3x3.h"
 #include "quaternion.h"
+#include "MathFunctions.h"
 
 #include <algorithm>
 #include <limits>
@@ -420,8 +419,8 @@ inline void aiMatrix4x4t<TReal>::Decompose (aiVector3t<TReal>& pScaling, aiQuate
 }
 
 template <typename TReal>
-inline void aiMatrix4x4t<TReal>::Decompose(aiVector3t<TReal>& pScaling, aiVector3t<TReal>& pRotation, aiVector3t<TReal>& pPosition) const
-{
+inline
+void aiMatrix4x4t<TReal>::Decompose(aiVector3t<TReal>& pScaling, aiVector3t<TReal>& pRotation, aiVector3t<TReal>& pPosition) const {
 	ASSIMP_MATRIX4_4_DECOMPOSE_PART;
 
     /*
@@ -442,7 +441,7 @@ inline void aiMatrix4x4t<TReal>::Decompose(aiVector3t<TReal>& pScaling, aiVector
 	*/
 
 	// Use a small epsilon to solve floating-point inaccuracies
-    const TReal epsilon = 10e-3f;
+    const TReal epsilon = Math::getEpsilon<TReal>();
 
 	pRotation.y  = std::asin(-vCols[0].z);// D. Angle around oY.