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 != nullptr);

    // Process all meshes
    for (unsigned int i = 0; i < scene->mNumMeshes; ++i) {
        if (nullptr == scene->mMeshes[i]) {
            continue;
        }
        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) {
        if (nullptr == scene->mAnimations[i]) {
            continue;
        }
        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) {
            if (nullptr == scene->mMeshes[i]) {
                continue;
            }
            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;
            continue;
        } 

        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 nullptr
            {
                // 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) {
                    if (channel->mRotationKeys) {
                        delete[] channel->mRotationKeys;
                        channel->mRotationKeys = nullptr;
                    }
                    ai_assert(!channel->mRotationKeys);
                    channel->mNumRotationKeys = 1;
                    channel->mRotationKeys = new aiQuatKey[1];
                    aiQuatKey &q = channel->mRotationKeys[0];

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

                    ASSIMP_LOG_VERBOSE_DEBUG("ScenePreprocessor: Dummy rotation track has been generated");
                } else {
                    ai_assert(channel->mRotationKeys);
                }

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

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

                    ASSIMP_LOG_VERBOSE_DEBUG("ScenePreprocessor: Dummy scaling track has been generated");
                } else {
                    ai_assert(channel->mScalingKeys);
                }

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

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

                    ASSIMP_LOG_VERBOSE_DEBUG("ScenePreprocessor: Dummy position track has been generated");
                } else {
                    ai_assert(channel->mPositionKeys);
                }
            }
        }
    }

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