assimp/code/Common/ScenePreprocessor.cpp

/*
Open Asset Import Library (assimp)
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  copyright notice, this list of conditions and the
  following disclaimer.

* Redistributions in binary form must reproduce the above
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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*/

#include "ScenePreprocessor.h"
#include <assimp/ai_assert.h>
#include <assimp/scene.h>
#include <assimp/DefaultLogger.hpp>


using namespace Assimp;

// ---------------------------------------------------------------------------------------------
void ScenePreprocessor::ProcessScene ()
{
    ai_assert(scene != NULL);

    // Process all meshes
    for (unsigned int i = 0; i < scene->mNumMeshes;++i)
        ProcessMesh(scene->mMeshes[i]);

    // - nothing to do for nodes for the moment
    // - nothing to do for textures for the moment
    // - nothing to do for lights for the moment
    // - nothing to do for cameras for the moment

    // Process all animations
    for (unsigned int i = 0; i < scene->mNumAnimations;++i)
        ProcessAnimation(scene->mAnimations[i]);

    // Generate a default material if none was specified
    if (!scene->mNumMaterials && scene->mNumMeshes) {
        scene->mMaterials      = new aiMaterial*[2];
        aiMaterial* helper;

        aiString name;

        scene->mMaterials[scene->mNumMaterials] = helper = new aiMaterial();
        aiColor3D clr(0.6f,0.6f,0.6f);
        helper->AddProperty(&clr,1,AI_MATKEY_COLOR_DIFFUSE);

        // setup the default name to make this material identifiable
        name.Set(AI_DEFAULT_MATERIAL_NAME);
        helper->AddProperty(&name,AI_MATKEY_NAME);

        ASSIMP_LOG_DEBUG("ScenePreprocessor: Adding default material \'" AI_DEFAULT_MATERIAL_NAME  "\'");

        for (unsigned int i = 0; i < scene->mNumMeshes;++i) {
            scene->mMeshes[i]->mMaterialIndex = scene->mNumMaterials;
        }

        scene->mNumMaterials++;
    }
}

// ---------------------------------------------------------------------------------------------
void ScenePreprocessor::ProcessMesh (aiMesh* mesh)
{
    // If aiMesh::mNumUVComponents is *not* set assign the default value of 2
    for (unsigned int i = 0; i < AI_MAX_NUMBER_OF_TEXTURECOORDS; ++i)   {
        if (!mesh->mTextureCoords[i]) {
            mesh->mNumUVComponents[i] = 0;
        } else {
            if (!mesh->mNumUVComponents[i])
                mesh->mNumUVComponents[i] = 2;

            aiVector3D* p = mesh->mTextureCoords[i], *end = p+mesh->mNumVertices;

            // Ensure unused components are zeroed. This will make 1D texture channels work
            // as if they were 2D channels .. just in case an application doesn't handle
            // this case
            if (2 == mesh->mNumUVComponents[i]) {
                for (; p != end; ++p)
                    p->z = 0.f;
            }
            else if (1 == mesh->mNumUVComponents[i]) {
                for (; p != end; ++p)
                    p->z = p->y = 0.f;
            }
            else if (3 == mesh->mNumUVComponents[i]) {
                // Really 3D coordinates? Check whether the third coordinate is != 0 for at least one element
                for (; p != end; ++p) {
                    if (p->z != 0)
                        break;
                }
                if (p == end) {
                    ASSIMP_LOG_WARN("ScenePreprocessor: UVs are declared to be 3D but they're obviously not. Reverting to 2D.");
                    mesh->mNumUVComponents[i] = 2;
                }
            }
        }
    }

    // If the information which primitive types are there in the
    // mesh is currently not available, compute it.
    if (!mesh->mPrimitiveTypes) {
        for (unsigned int a = 0; a < mesh->mNumFaces; ++a)  {
            aiFace& face = mesh->mFaces[a];
            switch (face.mNumIndices)
            {
            case 3u:
                mesh->mPrimitiveTypes |= aiPrimitiveType_TRIANGLE;
                break;

            case 2u:
                mesh->mPrimitiveTypes |= aiPrimitiveType_LINE;
                break;

            case 1u:
                mesh->mPrimitiveTypes |= aiPrimitiveType_POINT;
                break;

            default:
                mesh->mPrimitiveTypes |= aiPrimitiveType_POLYGON;
                break;
            }
        }
    }

    // If tangents and normals are given but no bitangents compute them
    if (mesh->mTangents && mesh->mNormals && !mesh->mBitangents)    {

        mesh->mBitangents = new aiVector3D[mesh->mNumVertices];
        for (unsigned int i = 0; i < mesh->mNumVertices;++i)    {
            mesh->mBitangents[i] = mesh->mNormals[i] ^ mesh->mTangents[i];
        }
    }
}

// ---------------------------------------------------------------------------------------------
void ScenePreprocessor::ProcessAnimation (aiAnimation* anim)
{
    double first = 10e10, last = -10e10;
    for (unsigned int i = 0; i < anim->mNumChannels;++i)    {
        aiNodeAnim* channel = anim->mChannels[i];

        /*  If the exact duration of the animation is not given
         *  compute it now.
         */
        if (anim->mDuration == -1.) {

            // Position keys
            for (unsigned int j = 0; j < channel->mNumPositionKeys;++j) {
                aiVectorKey& key = channel->mPositionKeys[j];
                first = std::min (first, key.mTime);
                last  = std::max (last,  key.mTime);
            }

            // Scaling keys
            for (unsigned int j = 0; j < channel->mNumScalingKeys;++j )  {
                aiVectorKey& key = channel->mScalingKeys[j];
                first = std::min (first, key.mTime);
                last  = std::max (last,  key.mTime);
            }

            // Rotation keys
            for (unsigned int j = 0; j < channel->mNumRotationKeys;++j ) {
                aiQuatKey& key = channel->mRotationKeys[ j ];
                first = std::min (first, key.mTime);
                last  = std::max (last,  key.mTime);
            }
        }

        /*  Check whether the animation channel has no rotation
         *  or position tracks. In this case we generate a dummy
         *  track from the information we have in the transformation
         *  matrix of the corresponding node.
         */
        if (!channel->mNumRotationKeys || !channel->mNumPositionKeys || !channel->mNumScalingKeys)  {
            // Find the node that belongs to this animation
            aiNode* node = scene->mRootNode->FindNode(channel->mNodeName);
            if (node) // ValidateDS will complain later if 'node' is NULL
            {
                // Decompose the transformation matrix of the node
                aiVector3D scaling, position;
                aiQuaternion rotation;

                node->mTransformation.Decompose(scaling, rotation,position);

                // No rotation keys? Generate a dummy track
                if (!channel->mNumRotationKeys) {
                    channel->mNumRotationKeys = 1;
                    channel->mRotationKeys = new aiQuatKey[1];
                    aiQuatKey& q = channel->mRotationKeys[0];

                    q.mTime  = 0.;
                    q.mValue = rotation;

                    ASSIMP_LOG_DEBUG("ScenePreprocessor: Dummy rotation track has been generated");
                }

                // No scaling keys? Generate a dummy track
                if (!channel->mNumScalingKeys)  {
                    channel->mNumScalingKeys = 1;
                    channel->mScalingKeys = new aiVectorKey[1];
                    aiVectorKey& q = channel->mScalingKeys[0];

                    q.mTime  = 0.;
                    q.mValue = scaling;

                    ASSIMP_LOG_DEBUG("ScenePreprocessor: Dummy scaling track has been generated");
                }

                // No position keys? Generate a dummy track
                if (!channel->mNumPositionKeys) {
                    channel->mNumPositionKeys = 1;
                    channel->mPositionKeys = new aiVectorKey[1];
                    aiVectorKey& q = channel->mPositionKeys[0];

                    q.mTime  = 0.;
                    q.mValue = position;

                    ASSIMP_LOG_DEBUG("ScenePreprocessor: Dummy position track has been generated");
                }
            }
        }
    }

    if (anim->mDuration == -1.)     {
        ASSIMP_LOG_DEBUG("ScenePreprocessor: Setting animation duration");
        anim->mDuration = last - std::min( first, 0. );
    }
}