魔兽mdx文件导出为Ogre Mesh的小进展

     最近一直在试图把魔兽3的mdx文件转为Ogre Mesh，学习一下基础的3D编程。Ogre Mesh的导出在很久之前也曾试图做过，并且还把WOW的m2模型以及WMO模型导入到了Max中，但是只做到了骨架的导入，动画数据始终出不来，于是放弃。

 

    这次依然是碰到这里的问题，导出静态的Mesh很快就完成，包括模型与材质，代码也比较简单。

 

// 模型数据
bool ModelLoaderMdx::loadGeosets(Ogre::MeshPtr model, MdxDataStreamPtr dataStream, int size)
{
    unsigned int index = 0;
    while(size > 0)
    {
        int geosetSize = dataStream->read<int>();
        size -= geosetSize;

        Ogre::String meshName = m_modelName + Ogre::String("_sub_") + Ogre::StringConverter::toString(index++);
        Ogre::SubMesh* subMesh = model->createSubMesh(meshName);
    
        // 硬件缓冲编号
        // 分别为顶点坐标 法线 贴图坐标
#define HARDWARE_BUFFER_SOURCE_VERTEX 0
#define HARDWARE_BUFFER_SOURCE_NORMAL 1
#define HARDWARE_BUFFER_SOURCE_TEXPOS 2


        //
        // 顶点数据
        //
        if(!expectTag(dataStream, 'VRTX')) 
        {
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, "Expect VRTX data for geoset",
                "ModelLoaderMdx::loadGeosets");
        }

        unsigned int vertexCount = dataStream->read<unsigned int>();

        // 不使用共享顶点数据
        // 每个SubMesh都创建自己的VertexData
        subMesh->useSharedVertices = false;
        subMesh->vertexData = OGRE_NEW Ogre::VertexData();

        subMesh->vertexData->vertexStart = 0;
        subMesh->vertexData->vertexCount = vertexCount;

        subMesh->vertexData->vertexDeclaration->addElement(
            HARDWARE_BUFFER_SOURCE_VERTEX, 0, Ogre::VET_FLOAT3, Ogre::VES_POSITION);

        size_t vertexSize = sizeof(float) * 3;
        assert(subMesh->vertexData->vertexDeclaration->getVertexSize(HARDWARE_BUFFER_SOURCE_VERTEX) == vertexSize);
        if (subMesh->vertexData->vertexDeclaration->getVertexSize(HARDWARE_BUFFER_SOURCE_VERTEX) != vertexSize)
        {
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, "VertexSize error", 
                "ModelLoaderMdx::loadGeoset");
        }

        Ogre::HardwareVertexBufferSharedPtr vertexBuffer;
        vertexBuffer = Ogre::HardwareBufferManager::getSingleton().createVertexBuffer(
            vertexSize,
            vertexCount,
            Ogre::HardwareBuffer::HBU_STATIC_WRITE_ONLY);
        void* vertexBufferData = vertexBuffer->lock(Ogre::HardwareBuffer::HBL_DISCARD);

        unsigned int vertexBufferDataPos = 0;
        for (unsigned int i = 0; i < vertexCount; ++i)
        {
            Ogre::Vector3 data(
                dataStream->read<float>(),
                dataStream->read<float>(),
                dataStream->read<float>()
                );
            transformCoord(data);
            memcpy((char*)vertexBufferData + vertexBufferDataPos, &data, sizeof(Ogre::Vector3));
            vertexBufferDataPos += sizeof(Ogre::Vector3);
        }

        vertexBuffer->unlock();
        subMesh->vertexData->vertexBufferBinding->setBinding(HARDWARE_BUFFER_SOURCE_VERTEX, vertexBuffer);


        //
        // 法线数据
        //
        if(!expectTag(dataStream, 'NRMS'))
        {
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, "Expect NRMS data for material",
                "ModelLoaderMdx::loadGeosets");
        }

        unsigned int normalCount = dataStream->read<unsigned int>();
        if(normalCount != vertexCount)
        {
            std::stringstream stream;
            stream << "Normal count mismatch, " << normalCount << " normals for " << vertexCount << " vertices)!";
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, stream.str(), 
                "ModelLoaderMdx::loadGeoset");
        }

        subMesh->vertexData->vertexDeclaration->addElement(
            HARDWARE_BUFFER_SOURCE_NORMAL, 0, Ogre::VET_FLOAT3, Ogre::VES_NORMAL);

        size_t normalSize = sizeof(float) * 3;
        assert(subMesh->vertexData->vertexDeclaration->getVertexSize(HARDWARE_BUFFER_SOURCE_NORMAL) == normalSize);
        if (subMesh->vertexData->vertexDeclaration->getVertexSize(HARDWARE_BUFFER_SOURCE_NORMAL) != normalSize)
        {
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, "NormalSize error", 
                "ModelLoaderMdx::loadGeoset");
        }

        Ogre::HardwareVertexBufferSharedPtr normalBuffer;
        normalBuffer = Ogre::HardwareBufferManager::getSingleton().createVertexBuffer(
            normalSize,
            normalCount,
            Ogre::HardwareBuffer::HBU_STATIC_WRITE_ONLY);
        void* normalBufferData = normalBuffer->lock(Ogre::HardwareBuffer::HBL_DISCARD);

        unsigned int normalBufferDataPos = 0;
        for (unsigned int i = 0; i < normalCount; ++i)
        {
            Ogre::Vector3 data(
                dataStream->read<float>(),
                dataStream->read<float>(),
                dataStream->read<float>()
                );
            transformCoord(data);
            memcpy((char*)normalBufferData + normalBufferDataPos, &data, sizeof(Ogre::Vector3));
            normalBufferDataPos += sizeof(Ogre::Vector3);
        }

        normalBuffer->unlock();
        subMesh->vertexData->vertexBufferBinding->setBinding(HARDWARE_BUFFER_SOURCE_NORMAL, normalBuffer);


…………

        //
        // 顶点索引
        //
        if(!expectTag(dataStream, 'PVTX')) 
        {
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, "Expect PVTX data for geoset",
                "ModelLoaderMdx::loadGeosets");
        }

        unsigned int indexCount = dataStream->read<unsigned int>();
        assert(totalIndexCount == indexCount);
        if (totalIndexCount != indexCount)
        {
            std::stringstream stream;
            stream << "indexCount is " << indexCount << ", but totalIndexCount for all faces is " << totalIndexCount;
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, stream.str(), 
                "ModelLoaderMdx::loadGeoset");
        }

        subMesh->indexData->indexStart = 0;
        subMesh->indexData->indexCount = indexCount;

        Ogre::HardwareIndexBufferSharedPtr indexBuffer;
        indexBuffer = Ogre::HardwareBufferManager::getSingleton().createIndexBuffer(
            Ogre::HardwareIndexBuffer::IT_16BIT,
            indexCount,
            Ogre::HardwareBuffer::HBU_STATIC_WRITE_ONLY);

        void* indexBufferData = indexBuffer->lock(Ogre::HardwareBuffer::HBL_DISCARD);
        dataStream->read(indexBufferData, indexCount * sizeof(unsigned short));

        // 三角形反转, 将原来的反面朝外
        unsigned short* tmpData = (unsigned short*)indexBufferData;
        for (unsigned int i = 0; i < indexCount; i += 3)
        {
            unsigned short tmp = tmpData[i + 1];
            tmpData[i + 1] = tmpData[i + 2];
            tmpData[i + 2] = tmp;
        }

        indexBuffer->unlock();


        subMesh->indexData->indexBuffer = indexBuffer;
        subMesh->operationType = Ogre::RenderOperation::OT_TRIANGLE_LIST;


…………

        // 材质ID
        unsigned int materialID = dataStream->read<unsigned int>();
        Ogre::String materialName = m_modelName + Ogre::String("_") + boost::lexical_cast<Ogre::String>(materialID);
        subMesh->setMaterialName(materialName);

…………

        //
        // 贴图坐标
        //
        if(!expectTag(dataStream, 'UVBS')) 
        {
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, "Expect UVBS data for geoset",
                "ModelLoaderMdx::loadGeosets");
        }

        unsigned int texturePositionCount = dataStream->read<unsigned int>();
        if(texturePositionCount != vertexCount)
        {
            std::stringstream stream;
            stream << "Texture position count mismatch, " << texturePositionCount << " texture positions for " << vertexCount << " vertices)!";
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, stream.str(), 
                "ModelLoaderMdx::loadGeoset");
        }

        // TextureCoord Data
        subMesh->vertexData->vertexDeclaration->addElement(
            HARDWARE_BUFFER_SOURCE_TEXPOS, 0, Ogre::VET_FLOAT2, Ogre::VES_TEXTURE_COORDINATES);

        size_t texPosSize = sizeof(float) * 2;
        assert(subMesh->vertexData->vertexDeclaration->getVertexSize(HARDWARE_BUFFER_SOURCE_TEXPOS) == texPosSize);
        if (subMesh->vertexData->vertexDeclaration->getVertexSize(HARDWARE_BUFFER_SOURCE_TEXPOS) != texPosSize)
        {
            OGRE_EXCEPT(Ogre::Exception::ERR_INTERNAL_ERROR, "TexturePositionSize error", 
                "ModelLoaderMdx::loadGeoset");
        }

        Ogre::HardwareVertexBufferSharedPtr texPosBuffer;
        texPosBuffer = Ogre::HardwareBufferManager::getSingleton().createVertexBuffer(
            texPosSize,
            texturePositionCount,
            Ogre::HardwareBuffer::HBU_STATIC_WRITE_ONLY);
        void* texPosBufferData = texPosBuffer->lock(Ogre::HardwareBuffer::HBL_DISCARD);
        dataStream->read(texPosBufferData, texPosSize * texturePositionCount);
        texPosBuffer->unlock();
        subMesh->vertexData->vertexBufferBinding->setBinding(HARDWARE_BUFFER_SOURCE_TEXPOS, texPosBuffer);
    }

    return true;
}

 

    但是到了动画数据这里问题又出来了，而且mdx模型与m2模型还有些差别，mdx模型中没有骨骼数据，只有max中最简单的三种变换数据，Ogre中只有MorphAnimation能够实现此种动画。

 

    Ogre的MorphAnimation的第一个KeyFrame必须带有完整的顶点信息，而mdx模型中旋转、缩放与位移是分开的，也就是一个KeyFrame上可能只有一种变换，或者多种。而实际上在max中制作动画的时候这三种变换也是独立开的，Ogre的论坛上找到一篇讨论有人提到了这个问题，可惜制作者的回复是MorphAnimation只实现到这样……

 

    也确实，现在除了一些小物件的动画外，主角，怪物的动画都用skeleton了，也许MorphAnimation就快退出历史的舞台，在Ogre中看不到了，也不能指望会有什么改进。

 

    继续实现之，那就只能在有KeyFrame的地方把三种变换都计算一次，然后取得最终变换后的位置数据，也就是做人工的动画帧采样。在War3EditorSource的基础上做了些修改，终于，一帧帧的动画计算出来了。

 

 

    不过问题依然还有很多，比如mdx模型，尤其是怪物和角色模型中大量用到了ReplacableTexture，这些需要通过读配置文件来获取可用的贴图，另外模型上附带的粒子特效、纹理动画等都还没有导出，看看这个没有贴图的攻击中的蝎子，前面的路仍然很远。