/src/assimp/code/PostProcessing/ConvertToLHProcess.cpp

Source
/*
---------------------------------------------------------------------------
Open Asset Import Library (assimp)
---------------------------------------------------------------------------

Copyright (c) 2006-2025, 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  MakeLeftHandedProcess.cpp
 *  @brief Implementation of the post processing step to convert all
 *  imported data to a left-handed coordinate system.
 *
 *  Face order & UV flip are also implemented here, for the sake of a
 *  better location.
 */

#include "ConvertToLHProcess.h"
#include <assimp/postprocess.h>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>

using namespace Assimp;

#ifndef ASSIMP_BUILD_NO_MAKELEFTHANDED_PROCESS

namespace {

template <typename aiMeshType>
void flipUVs(aiMeshType *pMesh) {
    if (pMesh == nullptr) {
        return;
    }
    // mirror texture y coordinate
    for (unsigned int tcIdx = 0; tcIdx < AI_MAX_NUMBER_OF_TEXTURECOORDS; tcIdx++) {
        if (!pMesh->HasTextureCoords(tcIdx)) {
            break;
        }

        for (unsigned int vIdx = 0; vIdx < pMesh->mNumVertices; vIdx++) {
            pMesh->mTextureCoords[tcIdx][vIdx].y = 1.0f - pMesh->mTextureCoords[tcIdx][vIdx].y;
        }
    }
}

} // namespace

// ------------------------------------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool MakeLeftHandedProcess::IsActive(unsigned int pFlags) const {
    return 0 != (pFlags & aiProcess_MakeLeftHanded);
}

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void MakeLeftHandedProcess::Execute(aiScene *pScene) {
    // Check for an existent root node to proceed
    ai_assert(pScene->mRootNode != nullptr);
    ASSIMP_LOG_DEBUG("MakeLeftHandedProcess begin");

    // recursively convert all the nodes
    ProcessNode(pScene->mRootNode, aiMatrix4x4());

    // process the meshes accordingly
    for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
        ProcessMesh(pScene->mMeshes[a]);
    }

    // process the materials accordingly
    for (unsigned int a = 0; a < pScene->mNumMaterials; ++a) {
        ProcessMaterial(pScene->mMaterials[a]);
    }

    // transform all animation channels as well
    for (unsigned int a = 0; a < pScene->mNumAnimations; a++) {
        aiAnimation *anim = pScene->mAnimations[a];
        for (unsigned int b = 0; b < anim->mNumChannels; b++) {
            aiNodeAnim *nodeAnim = anim->mChannels[b];
            ProcessAnimation(nodeAnim);
        }
    }

    // process the cameras accordingly
    for( unsigned int a = 0; a < pScene->mNumCameras; ++a)
    {
        ProcessCamera(pScene->mCameras[a]);
    }
    ASSIMP_LOG_DEBUG("MakeLeftHandedProcess finished");
}

// ------------------------------------------------------------------------------------------------
// Recursively converts a node, all of its children and all of its meshes
void MakeLeftHandedProcess::ProcessNode(aiNode *pNode, const aiMatrix4x4 &pParentGlobalRotation) {
    // mirror all base vectors at the local Z axis
    pNode->mTransformation.c1 = -pNode->mTransformation.c1;
    pNode->mTransformation.c2 = -pNode->mTransformation.c2;
    pNode->mTransformation.c3 = -pNode->mTransformation.c3;
    pNode->mTransformation.c4 = -pNode->mTransformation.c4;

    // now invert the Z axis again to keep the matrix determinant positive.
    // The local meshes will be inverted accordingly so that the result should look just fine again.
    pNode->mTransformation.a3 = -pNode->mTransformation.a3;
    pNode->mTransformation.b3 = -pNode->mTransformation.b3;
    pNode->mTransformation.c3 = -pNode->mTransformation.c3;
    pNode->mTransformation.d3 = -pNode->mTransformation.d3; // useless, but anyways...

    // continue for all children
    for (size_t a = 0; a < pNode->mNumChildren; ++a) {
        ProcessNode(pNode->mChildren[a], pParentGlobalRotation * pNode->mTransformation);
    }
}

// ------------------------------------------------------------------------------------------------
// Converts a single mesh to left handed coordinates.
void MakeLeftHandedProcess::ProcessMesh(aiMesh *pMesh) {
    if (nullptr == pMesh) {
        ASSIMP_LOG_ERROR("Nullptr to mesh found.");
        return;
    }
    // mirror positions, normals and stuff along the Z axis
    for (size_t a = 0; a < pMesh->mNumVertices; ++a) {
        pMesh->mVertices[a].z *= -1.0f;
        if (pMesh->HasNormals()) {
            pMesh->mNormals[a].z *= -1.0f;
        }
        if (pMesh->HasTangentsAndBitangents()) {
            pMesh->mTangents[a].z *= -1.0f;
            pMesh->mBitangents[a].z *= -1.0f;
        }
    }

    // mirror anim meshes positions, normals and stuff along the Z axis
    for (size_t m = 0; m < pMesh->mNumAnimMeshes; ++m) {
        for (size_t a = 0; a < pMesh->mAnimMeshes[m]->mNumVertices; ++a) {
            pMesh->mAnimMeshes[m]->mVertices[a].z *= -1.0f;
            if (pMesh->mAnimMeshes[m]->HasNormals()) {
                pMesh->mAnimMeshes[m]->mNormals[a].z *= -1.0f;
            }
            if (pMesh->mAnimMeshes[m]->HasTangentsAndBitangents()) {
                pMesh->mAnimMeshes[m]->mTangents[a].z *= -1.0f;
                pMesh->mAnimMeshes[m]->mBitangents[a].z *= -1.0f;
            }
        }
    }

    // mirror offset matrices of all bones
    for (size_t a = 0; a < pMesh->mNumBones; ++a) {
        aiBone *bone = pMesh->mBones[a];
        bone->mOffsetMatrix.a3 = -bone->mOffsetMatrix.a3;
        bone->mOffsetMatrix.b3 = -bone->mOffsetMatrix.b3;
        bone->mOffsetMatrix.d3 = -bone->mOffsetMatrix.d3;
        bone->mOffsetMatrix.c1 = -bone->mOffsetMatrix.c1;
        bone->mOffsetMatrix.c2 = -bone->mOffsetMatrix.c2;
        bone->mOffsetMatrix.c4 = -bone->mOffsetMatrix.c4;
    }

    // mirror bitangents as well as they're derived from the texture coords
    if (pMesh->HasTangentsAndBitangents()) {
        for (unsigned int a = 0; a < pMesh->mNumVertices; a++)
            pMesh->mBitangents[a] *= -1.0f;
    }
}

// ------------------------------------------------------------------------------------------------
// Converts a single material to left handed coordinates.
void MakeLeftHandedProcess::ProcessMaterial(aiMaterial *_mat) {
    if (nullptr == _mat) {
        ASSIMP_LOG_ERROR("Nullptr to aiMaterial found.");
        return;
    }

    aiMaterial *mat = (aiMaterial *)_mat;
    for (unsigned int a = 0; a < mat->mNumProperties; ++a) {
        aiMaterialProperty *prop = mat->mProperties[a];

        // Mapping axis for UV mappings?
        if (!::strcmp(prop->mKey.data, "$tex.mapaxis")) {
            ai_assert(prop->mDataLength >= sizeof(aiVector3D)); // something is wrong with the validation if we end up here
            aiVector3D *pff = (aiVector3D *)prop->mData;
            pff->z *= -1.f;
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Converts the given animation to LH coordinates.
void MakeLeftHandedProcess::ProcessAnimation(aiNodeAnim *pAnim) {
    // position keys
    for (unsigned int a = 0; a < pAnim->mNumPositionKeys; a++)
        pAnim->mPositionKeys[a].mValue.z *= -1.0f;

    // rotation keys
    for (unsigned int a = 0; a < pAnim->mNumRotationKeys; a++) {
        pAnim->mRotationKeys[a].mValue.x *= -1.0f;
        pAnim->mRotationKeys[a].mValue.y *= -1.0f;
    }
}

// ------------------------------------------------------------------------------------------------
// Converts a single camera to left handed coordinates.
void MakeLeftHandedProcess::ProcessCamera( aiCamera* pCam)
{
    pCam->mLookAt = ai_real(2.0f) * pCam->mPosition - pCam->mLookAt;
}

#endif // !!  ASSIMP_BUILD_NO_MAKELEFTHANDED_PROCESS
#ifndef ASSIMP_BUILD_NO_FLIPUVS_PROCESS
// # FlipUVsProcess

// ------------------------------------------------------------------------------------------------
// Constructor to be privately used by Importer
FlipUVsProcess::FlipUVsProcess() = default;

// ------------------------------------------------------------------------------------------------
// Destructor, private as well
FlipUVsProcess::~FlipUVsProcess() = default;

// ------------------------------------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool FlipUVsProcess::IsActive(unsigned int pFlags) const {
    return 0 != (pFlags & aiProcess_FlipUVs);
}

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void FlipUVsProcess::Execute(aiScene *pScene) {
    ASSIMP_LOG_DEBUG("FlipUVsProcess begin");
    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i)
        ProcessMesh(pScene->mMeshes[i]);

    for (unsigned int i = 0; i < pScene->mNumMaterials; ++i)
        ProcessMaterial(pScene->mMaterials[i]);
    ASSIMP_LOG_DEBUG("FlipUVsProcess finished");
}

// ------------------------------------------------------------------------------------------------
// Converts a single material
void FlipUVsProcess::ProcessMaterial(aiMaterial *_mat) {
    aiMaterial *mat = (aiMaterial *)_mat;
    for (unsigned int a = 0; a < mat->mNumProperties; ++a) {
        aiMaterialProperty *prop = mat->mProperties[a];
        if (!prop) {
            ASSIMP_LOG_VERBOSE_DEBUG("Property is null");
            continue;
        }

        // UV transformation key?
        if (!::strcmp(prop->mKey.data, "$tex.uvtrafo")) {
            ai_assert(prop->mDataLength >= sizeof(aiUVTransform)); // something is wrong with the validation if we end up here
            aiUVTransform *uv = (aiUVTransform *)prop->mData;

            // just flip it, that's everything
            uv->mTranslation.y *= -1.f;
            uv->mRotation *= -1.f;
        }
    }
}

// ------------------------------------------------------------------------------------------------
// Converts a single mesh
void FlipUVsProcess::ProcessMesh(aiMesh *pMesh) {
    flipUVs(pMesh);
    for (unsigned int idx = 0; idx < pMesh->mNumAnimMeshes; idx++) {
        flipUVs(pMesh->mAnimMeshes[idx]);
    }
}

#endif // !ASSIMP_BUILD_NO_FLIPUVS_PROCESS
#ifndef ASSIMP_BUILD_NO_FLIPWINDING_PROCESS
// # FlipWindingOrderProcess

// ------------------------------------------------------------------------------------------------
// Returns whether the processing step is present in the given flag field.
bool FlipWindingOrderProcess::IsActive(unsigned int pFlags) const {
    return 0 != (pFlags & aiProcess_FlipWindingOrder);
}

// ------------------------------------------------------------------------------------------------
// Executes the post processing step on the given imported data.
void FlipWindingOrderProcess::Execute(aiScene *pScene) {
    ASSIMP_LOG_DEBUG("FlipWindingOrderProcess begin");
    for (unsigned int i = 0; i < pScene->mNumMeshes; ++i)
        ProcessMesh(pScene->mMeshes[i]);
    ASSIMP_LOG_DEBUG("FlipWindingOrderProcess finished");
}

// ------------------------------------------------------------------------------------------------
// Converts a single mesh
void FlipWindingOrderProcess::ProcessMesh(aiMesh *pMesh) {
    // invert the order of all faces in this mesh
    for (unsigned int a = 0; a < pMesh->mNumFaces; a++) {
        aiFace &face = pMesh->mFaces[a];
        for (unsigned int b = 0; b < face.mNumIndices / 2; b++) {
            std::swap(face.mIndices[b], face.mIndices[face.mNumIndices - 1 - b]);
        }
    }

    // invert the order of all components in this mesh anim meshes
    for (unsigned int m = 0; m < pMesh->mNumAnimMeshes; m++) {
        aiAnimMesh *animMesh = pMesh->mAnimMeshes[m];
        unsigned int numVertices = animMesh->mNumVertices;
        if (animMesh->HasPositions()) {
            for (unsigned int a = 0; a < numVertices; a++) {
                std::swap(animMesh->mVertices[a], animMesh->mVertices[numVertices - 1 - a]);
            }
        }
        if (animMesh->HasNormals()) {
            for (unsigned int a = 0; a < numVertices; a++) {
                std::swap(animMesh->mNormals[a], animMesh->mNormals[numVertices - 1 - a]);
            }
        }
        for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; i++) {
            if (animMesh->HasTextureCoords(i)) {
                for (unsigned int a = 0; a < numVertices; a++) {
                    std::swap(animMesh->mTextureCoords[i][a], animMesh->mTextureCoords[i][numVertices - 1 - a]);
                }
            }
        }
        if (animMesh->HasTangentsAndBitangents()) {
            for (unsigned int a = 0; a < numVertices; a++) {
                std::swap(animMesh->mTangents[a], animMesh->mTangents[numVertices - 1 - a]);
                std::swap(animMesh->mBitangents[a], animMesh->mBitangents[numVertices - 1 - a]);
            }
        }
        for (unsigned int v = 0; v < AI_MAX_NUMBER_OF_COLOR_SETS; v++) {
            if (animMesh->HasVertexColors(v)) {
                for (unsigned int a = 0; a < numVertices; a++) {
                    std::swap(animMesh->mColors[v][a], animMesh->mColors[v][numVertices - 1 - a]);
                }
            }
        }
    }
}

#endif // !! ASSIMP_BUILD_NO_FLIPWINDING_PROCESS

Coverage Report

Created: 2026-01-07 06:50

Line	Count	Source
1		/*
2		---------------------------------------------------------------------------
3		Open Asset Import Library (assimp)
4		---------------------------------------------------------------------------
5
6		Copyright (c) 2006-2025, assimp team
7
8		All rights reserved.
9
10		Redistribution and use of this software in source and binary forms,
11		with or without modification, are permitted provided that the following
12		conditions are met:
13
14		* Redistributions of source code must retain the above
15		copyright notice, this list of conditions and the
16		following disclaimer.
17
18		* Redistributions in binary form must reproduce the above
19		copyright notice, this list of conditions and the
20		following disclaimer in the documentation and/or other
21		materials provided with the distribution.
22
23		* Neither the name of the assimp team, nor the names of its
24		contributors may be used to endorse or promote products
25		derived from this software without specific prior
26		written permission of the assimp team.
27
28		THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29		"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30		LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31		A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32		OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33		SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34		LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35		DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36		THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37		(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38		OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39		---------------------------------------------------------------------------
40		*/
41
42		/** @file MakeLeftHandedProcess.cpp
43		* @brief Implementation of the post processing step to convert all
44		* imported data to a left-handed coordinate system.
45		*
46		* Face order & UV flip are also implemented here, for the sake of a
47		* better location.
48		*/
49
50		#include "ConvertToLHProcess.h"
51		#include <assimp/postprocess.h>
52		#include <assimp/scene.h>
53		#include <assimp/DefaultLogger.hpp>
54
55		using namespace Assimp;
56
57		#ifndef ASSIMP_BUILD_NO_MAKELEFTHANDED_PROCESS
58
59		namespace {
60
61		template <typename aiMeshType>
62	0	void flipUVs(aiMeshType *pMesh) {
63	0	if (pMesh == nullptr) {
64	0	return;
65	0	}
66		// mirror texture y coordinate
67	0	for (unsigned int tcIdx = 0; tcIdx < AI_MAX_NUMBER_OF_TEXTURECOORDS; tcIdx++) {
68	0	if (!pMesh->HasTextureCoords(tcIdx)) {
69	0	break;
70	0	}
71
72	0	for (unsigned int vIdx = 0; vIdx < pMesh->mNumVertices; vIdx++) {
73	0	pMesh->mTextureCoords[tcIdx][vIdx].y = 1.0f - pMesh->mTextureCoords[tcIdx][vIdx].y;
74	0	}
75	0	}
76	0	} Unexecuted instantiation: ConvertToLHProcess.cpp:void (anonymous namespace)::flipUVs<aiMesh>(aiMesh) Unexecuted instantiation: ConvertToLHProcess.cpp:void (anonymous namespace)::flipUVs<aiAnimMesh>(aiAnimMesh)
77
78		} // namespace
79
80		// ------------------------------------------------------------------------------------------------
81		// Returns whether the processing step is present in the given flag field.
82	106	bool MakeLeftHandedProcess::IsActive(unsigned int pFlags) const {
83	106	return 0 != (pFlags & aiProcess_MakeLeftHanded);
84	106	}
85
86		// ------------------------------------------------------------------------------------------------
87		// Executes the post processing step on the given imported data.
88	28	void MakeLeftHandedProcess::Execute(aiScene *pScene) {
89		// Check for an existent root node to proceed
90	28	ai_assert(pScene->mRootNode != nullptr);
91	28	ASSIMP_LOG_DEBUG("MakeLeftHandedProcess begin");
92
93		// recursively convert all the nodes
94	28	ProcessNode(pScene->mRootNode, aiMatrix4x4());
95
96		// process the meshes accordingly
97	28	for (unsigned int a = 0; a < pScene->mNumMeshes; ++a) {
98	0	ProcessMesh(pScene->mMeshes[a]);
99	0	}
100
101		// process the materials accordingly
102	28	for (unsigned int a = 0; a < pScene->mNumMaterials; ++a) {
103	0	ProcessMaterial(pScene->mMaterials[a]);
104	0	}
105
106		// transform all animation channels as well
107	39	for (unsigned int a = 0; a < pScene->mNumAnimations; a++) {
108	11	aiAnimation *anim = pScene->mAnimations[a];
109	48	for (unsigned int b = 0; b < anim->mNumChannels; b++) {
110	37	aiNodeAnim *nodeAnim = anim->mChannels[b];
111	37	ProcessAnimation(nodeAnim);
112	37	}
113	11	}
114
115		// process the cameras accordingly
116	87	for( unsigned int a = 0; a < pScene->mNumCameras; ++a)
117	59	{
118	59	ProcessCamera(pScene->mCameras[a]);
119	59	}
120	28	ASSIMP_LOG_DEBUG("MakeLeftHandedProcess finished");
121	28	}
122
123		// ------------------------------------------------------------------------------------------------
124		// Recursively converts a node, all of its children and all of its meshes
125	7.51k	void MakeLeftHandedProcess::ProcessNode(aiNode *pNode, const aiMatrix4x4 &pParentGlobalRotation) {
126		// mirror all base vectors at the local Z axis
127	7.51k	pNode->mTransformation.c1 = -pNode->mTransformation.c1;
128	7.51k	pNode->mTransformation.c2 = -pNode->mTransformation.c2;
129	7.51k	pNode->mTransformation.c3 = -pNode->mTransformation.c3;
130	7.51k	pNode->mTransformation.c4 = -pNode->mTransformation.c4;
131
132		// now invert the Z axis again to keep the matrix determinant positive.
133		// The local meshes will be inverted accordingly so that the result should look just fine again.
134	7.51k	pNode->mTransformation.a3 = -pNode->mTransformation.a3;
135	7.51k	pNode->mTransformation.b3 = -pNode->mTransformation.b3;
136	7.51k	pNode->mTransformation.c3 = -pNode->mTransformation.c3;
137	7.51k	pNode->mTransformation.d3 = -pNode->mTransformation.d3; // useless, but anyways...
138
139		// continue for all children
140	14.9k	for (size_t a = 0; a < pNode->mNumChildren; ++a) {
141	7.48k	ProcessNode(pNode->mChildren[a], pParentGlobalRotation * pNode->mTransformation);
142	7.48k	}
143	7.51k	}
144
145		// ------------------------------------------------------------------------------------------------
146		// Converts a single mesh to left handed coordinates.
147	0	void MakeLeftHandedProcess::ProcessMesh(aiMesh *pMesh) {
148	0	if (nullptr == pMesh) {
149	0	ASSIMP_LOG_ERROR("Nullptr to mesh found.");
150	0	return;
151	0	}
152		// mirror positions, normals and stuff along the Z axis
153	0	for (size_t a = 0; a < pMesh->mNumVertices; ++a) {
154	0	pMesh->mVertices[a].z *= -1.0f;
155	0	if (pMesh->HasNormals()) {
156	0	pMesh->mNormals[a].z *= -1.0f;
157	0	}
158	0	if (pMesh->HasTangentsAndBitangents()) {
159	0	pMesh->mTangents[a].z *= -1.0f;
160	0	pMesh->mBitangents[a].z *= -1.0f;
161	0	}
162	0	}
163
164		// mirror anim meshes positions, normals and stuff along the Z axis
165	0	for (size_t m = 0; m < pMesh->mNumAnimMeshes; ++m) {
166	0	for (size_t a = 0; a < pMesh->mAnimMeshes[m]->mNumVertices; ++a) {
167	0	pMesh->mAnimMeshes[m]->mVertices[a].z *= -1.0f;
168	0	if (pMesh->mAnimMeshes[m]->HasNormals()) {
169	0	pMesh->mAnimMeshes[m]->mNormals[a].z *= -1.0f;
170	0	}
171	0	if (pMesh->mAnimMeshes[m]->HasTangentsAndBitangents()) {
172	0	pMesh->mAnimMeshes[m]->mTangents[a].z *= -1.0f;
173	0	pMesh->mAnimMeshes[m]->mBitangents[a].z *= -1.0f;
174	0	}
175	0	}
176	0	}
177
178		// mirror offset matrices of all bones
179	0	for (size_t a = 0; a < pMesh->mNumBones; ++a) {
180	0	aiBone *bone = pMesh->mBones[a];
181	0	bone->mOffsetMatrix.a3 = -bone->mOffsetMatrix.a3;
182	0	bone->mOffsetMatrix.b3 = -bone->mOffsetMatrix.b3;
183	0	bone->mOffsetMatrix.d3 = -bone->mOffsetMatrix.d3;
184	0	bone->mOffsetMatrix.c1 = -bone->mOffsetMatrix.c1;
185	0	bone->mOffsetMatrix.c2 = -bone->mOffsetMatrix.c2;
186	0	bone->mOffsetMatrix.c4 = -bone->mOffsetMatrix.c4;
187	0	}
188
189		// mirror bitangents as well as they're derived from the texture coords
190	0	if (pMesh->HasTangentsAndBitangents()) {
191	0	for (unsigned int a = 0; a < pMesh->mNumVertices; a++)
192	0	pMesh->mBitangents[a] *= -1.0f;
193	0	}
194	0	}
195
196		// ------------------------------------------------------------------------------------------------
197		// Converts a single material to left handed coordinates.
198	0	void MakeLeftHandedProcess::ProcessMaterial(aiMaterial *_mat) {
199	0	if (nullptr == _mat) {
200	0	ASSIMP_LOG_ERROR("Nullptr to aiMaterial found.");
201	0	return;
202	0	}
203
204	0	aiMaterial mat = (aiMaterial )_mat;
205	0	for (unsigned int a = 0; a < mat->mNumProperties; ++a) {
206	0	aiMaterialProperty *prop = mat->mProperties[a];
207
208		// Mapping axis for UV mappings?
209	0	if (!::strcmp(prop->mKey.data, "$tex.mapaxis")) {
210	0	ai_assert(prop->mDataLength >= sizeof(aiVector3D)); // something is wrong with the validation if we end up here
211	0	aiVector3D pff = (aiVector3D )prop->mData;
212	0	pff->z *= -1.f;
213	0	}
214	0	}
215	0	}
216
217		// ------------------------------------------------------------------------------------------------
218		// Converts the given animation to LH coordinates.
219	37	void MakeLeftHandedProcess::ProcessAnimation(aiNodeAnim *pAnim) {
220		// position keys
221	120	for (unsigned int a = 0; a < pAnim->mNumPositionKeys; a++)
222	83	pAnim->mPositionKeys[a].mValue.z *= -1.0f;
223
224		// rotation keys
225	82	for (unsigned int a = 0; a < pAnim->mNumRotationKeys; a++) {
226	45	pAnim->mRotationKeys[a].mValue.x *= -1.0f;
227	45	pAnim->mRotationKeys[a].mValue.y *= -1.0f;
228	45	}
229	37	}
230
231		// ------------------------------------------------------------------------------------------------
232		// Converts a single camera to left handed coordinates.
233		void MakeLeftHandedProcess::ProcessCamera( aiCamera* pCam)
234	59	{
235	59	pCam->mLookAt = ai_real(2.0f) * pCam->mPosition - pCam->mLookAt;
236	59	}
237
238		#endif // !! ASSIMP_BUILD_NO_MAKELEFTHANDED_PROCESS
239		#ifndef ASSIMP_BUILD_NO_FLIPUVS_PROCESS
240		// # FlipUVsProcess
241
242		// ------------------------------------------------------------------------------------------------
243		// Constructor to be privately used by Importer
244	383	FlipUVsProcess::FlipUVsProcess() = default;
245
246		// ------------------------------------------------------------------------------------------------
247		// Destructor, private as well
248	383	FlipUVsProcess::~FlipUVsProcess() = default;
249
250		// ------------------------------------------------------------------------------------------------
251		// Returns whether the processing step is present in the given flag field.
252	106	bool FlipUVsProcess::IsActive(unsigned int pFlags) const {
253	106	return 0 != (pFlags & aiProcess_FlipUVs);
254	106	}
255
256		// ------------------------------------------------------------------------------------------------
257		// Executes the post processing step on the given imported data.
258	0	void FlipUVsProcess::Execute(aiScene *pScene) {
259	0	ASSIMP_LOG_DEBUG("FlipUVsProcess begin");
260	0	for (unsigned int i = 0; i < pScene->mNumMeshes; ++i)
261	0	ProcessMesh(pScene->mMeshes[i]);
262
263	0	for (unsigned int i = 0; i < pScene->mNumMaterials; ++i)
264	0	ProcessMaterial(pScene->mMaterials[i]);
265	0	ASSIMP_LOG_DEBUG("FlipUVsProcess finished");
266	0	}
267
268		// ------------------------------------------------------------------------------------------------
269		// Converts a single material
270	0	void FlipUVsProcess::ProcessMaterial(aiMaterial *_mat) {
271	0	aiMaterial mat = (aiMaterial )_mat;
272	0	for (unsigned int a = 0; a < mat->mNumProperties; ++a) {
273	0	aiMaterialProperty *prop = mat->mProperties[a];
274	0	if (!prop) {
275	0	ASSIMP_LOG_VERBOSE_DEBUG("Property is null");
276	0	continue;
277	0	}
278
279		// UV transformation key?
280	0	if (!::strcmp(prop->mKey.data, "$tex.uvtrafo")) {
281	0	ai_assert(prop->mDataLength >= sizeof(aiUVTransform)); // something is wrong with the validation if we end up here
282	0	aiUVTransform uv = (aiUVTransform )prop->mData;
283
284		// just flip it, that's everything
285	0	uv->mTranslation.y *= -1.f;
286	0	uv->mRotation *= -1.f;
287	0	}
288	0	}
289	0	}
290
291		// ------------------------------------------------------------------------------------------------
292		// Converts a single mesh
293	0	void FlipUVsProcess::ProcessMesh(aiMesh *pMesh) {
294	0	flipUVs(pMesh);
295	0	for (unsigned int idx = 0; idx < pMesh->mNumAnimMeshes; idx++) {
296	0	flipUVs(pMesh->mAnimMeshes[idx]);
297	0	}
298	0	}
299
300		#endif // !ASSIMP_BUILD_NO_FLIPUVS_PROCESS
301		#ifndef ASSIMP_BUILD_NO_FLIPWINDING_PROCESS
302		// # FlipWindingOrderProcess
303
304		// ------------------------------------------------------------------------------------------------
305		// Returns whether the processing step is present in the given flag field.
306	106	bool FlipWindingOrderProcess::IsActive(unsigned int pFlags) const {
307	106	return 0 != (pFlags & aiProcess_FlipWindingOrder);
308	106	}
309
310		// ------------------------------------------------------------------------------------------------
311		// Executes the post processing step on the given imported data.
312	28	void FlipWindingOrderProcess::Execute(aiScene *pScene) {
313	28	ASSIMP_LOG_DEBUG("FlipWindingOrderProcess begin");
314	28	for (unsigned int i = 0; i < pScene->mNumMeshes; ++i)
315	0	ProcessMesh(pScene->mMeshes[i]);
316	28	ASSIMP_LOG_DEBUG("FlipWindingOrderProcess finished");
317	28	}
318
319		// ------------------------------------------------------------------------------------------------
320		// Converts a single mesh
321	0	void FlipWindingOrderProcess::ProcessMesh(aiMesh *pMesh) {
322		// invert the order of all faces in this mesh
323	0	for (unsigned int a = 0; a < pMesh->mNumFaces; a++) {
324	0	aiFace &face = pMesh->mFaces[a];
325	0	for (unsigned int b = 0; b < face.mNumIndices / 2; b++) {
326	0	std::swap(face.mIndices[b], face.mIndices[face.mNumIndices - 1 - b]);
327	0	}
328	0	}
329
330		// invert the order of all components in this mesh anim meshes
331	0	for (unsigned int m = 0; m < pMesh->mNumAnimMeshes; m++) {
332	0	aiAnimMesh *animMesh = pMesh->mAnimMeshes[m];
333	0	unsigned int numVertices = animMesh->mNumVertices;
334	0	if (animMesh->HasPositions()) {
335	0	for (unsigned int a = 0; a < numVertices; a++) {
336	0	std::swap(animMesh->mVertices[a], animMesh->mVertices[numVertices - 1 - a]);
337	0	}
338	0	}
339	0	if (animMesh->HasNormals()) {
340	0	for (unsigned int a = 0; a < numVertices; a++) {
341	0	std::swap(animMesh->mNormals[a], animMesh->mNormals[numVertices - 1 - a]);
342	0	}
343	0	}
344	0	for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; i++) {
345	0	if (animMesh->HasTextureCoords(i)) {
346	0	for (unsigned int a = 0; a < numVertices; a++) {
347	0	std::swap(animMesh->mTextureCoords[i][a], animMesh->mTextureCoords[i][numVertices - 1 - a]);
348	0	}
349	0	}
350	0	}
351	0	if (animMesh->HasTangentsAndBitangents()) {
352	0	for (unsigned int a = 0; a < numVertices; a++) {
353	0	std::swap(animMesh->mTangents[a], animMesh->mTangents[numVertices - 1 - a]);
354	0	std::swap(animMesh->mBitangents[a], animMesh->mBitangents[numVertices - 1 - a]);
355	0	}
356	0	}
357	0	for (unsigned int v = 0; v < AI_MAX_NUMBER_OF_COLOR_SETS; v++) {
358	0	if (animMesh->HasVertexColors(v)) {
359	0	for (unsigned int a = 0; a < numVertices; a++) {
360	0	std::swap(animMesh->mColors[v][a], animMesh->mColors[v][numVertices - 1 - a]);
361	0	}
362	0	}
363	0	}
364	0	}
365	0	}
366
367		#endif // !! ASSIMP_BUILD_NO_FLIPWINDING_PROCESS