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

Copyright (c) 2006-2020, assimp team


All rights reserved.

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with or without modification, are permitted provided that the
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* Redistributions in binary form must reproduce the above
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* Neither the name of the assimp team, nor the names of its
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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*/
#include "ScaleProcess.h"

#include <assimp/scene.h>
#include <assimp/postprocess.h>
#include <assimp/BaseImporter.h>

namespace Assimp {

ScaleProcess::ScaleProcess()
: BaseProcess()
, mScale( AI_CONFIG_GLOBAL_SCALE_FACTOR_DEFAULT ) {
}

ScaleProcess::~ScaleProcess() {
    // empty
}

void ScaleProcess::setScale( ai_real scale ) {
    mScale = scale;
}

ai_real ScaleProcess::getScale() const {
    return mScale;
}

bool ScaleProcess::IsActive( unsigned int pFlags ) const {
    return ( pFlags & aiProcess_GlobalScale ) != 0;
}

void ScaleProcess::SetupProperties( const Importer* pImp ) {
    // User scaling
    mScale = pImp->GetPropertyFloat( AI_CONFIG_GLOBAL_SCALE_FACTOR_KEY, 1.0f );

    // File scaling * Application Scaling
    float importerScale = pImp->GetPropertyFloat( AI_CONFIG_APP_SCALE_KEY, 1.0f );

    // apply scale to the scale 
    // helps prevent bugs with backward compatibility for anyone using normal scaling.
    mScale *= importerScale;
}

void ScaleProcess::Execute( aiScene* pScene ) {
    if(mScale == 1.0f)  {
        return; // nothing to scale
    }
    
    ai_assert( mScale != 0 );
    ai_assert( nullptr != pScene );
    ai_assert( nullptr != pScene->mRootNode );

    if ( nullptr == pScene ) {
        return;
    }

    if ( nullptr == pScene->mRootNode ) {
        return;
    }
    
    // Process animations and update position transform to new unit system
    for( unsigned int animationID = 0; animationID < pScene->mNumAnimations; animationID++ )
    {
        aiAnimation* animation = pScene->mAnimations[animationID];

        for( unsigned int animationChannel = 0; animationChannel < animation->mNumChannels; animationChannel++)
        {
            aiNodeAnim* anim = animation->mChannels[animationChannel];
            
            for( unsigned int posKey = 0; posKey < anim->mNumPositionKeys; posKey++)
            {
                aiVectorKey& vectorKey = anim->mPositionKeys[posKey];
                vectorKey.mValue *= mScale;
            }
        }
    }

    for( unsigned int meshID = 0; meshID < pScene->mNumMeshes; meshID++)
    {
        aiMesh *mesh = pScene->mMeshes[meshID]; 
        
        // Reconstruct mesh vertexes to the new unit system
        for( unsigned int vertexID = 0; vertexID < mesh->mNumVertices; vertexID++)
        {
            aiVector3D& vertex = mesh->mVertices[vertexID];
            vertex *= mScale;
        }


        // bone placement / scaling
        for( unsigned int boneID = 0; boneID < mesh->mNumBones; boneID++)
        {
            // Reconstruct matrix by transform rather than by scale 
            // This prevent scale values being changed which can
            // be meaningful in some cases 
            // like when you want the modeller to see 1:1 compatibility.
            aiBone* bone = mesh->mBones[boneID];

            aiVector3D pos, scale;
            aiQuaternion rotation;

            bone->mOffsetMatrix.Decompose( scale, rotation, pos);
            
            aiMatrix4x4 translation;
            aiMatrix4x4::Translation( pos * mScale, translation );
            
            aiMatrix4x4 scaling;
            aiMatrix4x4::Scaling( aiVector3D(scale), scaling );

            aiMatrix4x4 RotMatrix = aiMatrix4x4 (rotation.GetMatrix());

            bone->mOffsetMatrix = translation * RotMatrix * scaling;
        }


        // animation mesh processing
        // convert by position rather than scale.
        for( unsigned int animMeshID = 0; animMeshID < mesh->mNumAnimMeshes; animMeshID++)
        {
            aiAnimMesh * animMesh = mesh->mAnimMeshes[animMeshID];
            
            for( unsigned int vertexID = 0; vertexID < animMesh->mNumVertices; vertexID++)
            {
                aiVector3D& vertex = animMesh->mVertices[vertexID];
                vertex *= mScale;
            }
        }
    }

    traverseNodes( pScene->mRootNode );
}

void ScaleProcess::traverseNodes( aiNode *node, unsigned int nested_node_id ) {    
    applyScaling( node );

    for( size_t i = 0; i < node->mNumChildren; i++)
    {
        // recurse into the tree until we are done!
        traverseNodes( node->mChildren[i], nested_node_id+1 ); 
    }
}

void ScaleProcess::applyScaling( aiNode *currentNode ) {
    if ( nullptr != currentNode ) {
        // Reconstruct matrix by transform rather than by scale 
        // This prevent scale values being changed which can
        // be meaningful in some cases 
        // like when you want the modeller to 
        // see 1:1 compatibility.
        
        aiVector3D pos, scale;
        aiQuaternion rotation;
        currentNode->mTransformation.Decompose( scale, rotation, pos);
        
        aiMatrix4x4 translation;
        aiMatrix4x4::Translation( pos * mScale, translation );
        
        aiMatrix4x4 scaling;

        // note: we do not use mScale here, this is on purpose.
        aiMatrix4x4::Scaling( scale, scaling );

        aiMatrix4x4 RotMatrix = aiMatrix4x4 (rotation.GetMatrix());

        currentNode->mTransformation = translation * RotMatrix * scaling;
    }
}

} // Namespace Assimp