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Add support for importing GLTF2 animations.

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Refactors the glTF2 internal classes to more closely reflect the structure
of the actual GLTF2 file format. Adds implementations for reading skins
and animations from GLTF2 files into those structures.

Also provides implementations for converting skins and animations from GLTF
into assimp data structures.  Special handling is required for bone weights
since assimp stores vertex-weights-per-bone whereas GLTF2 stores
bone-weights-per-vertex.  Only supports keyframed LINEAR animation data;
STEP and CUBICSPLINE is not currently supported.
This commit is contained in:
Haroon Qureshi
2018-10-26 15:36:34 -07:00
parent 19844d0cec
commit 57d3d71b6e
6 changed files with 485 additions and 197 deletions
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281
code/glTF2Importer.cpp
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@@ -54,6 +54,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#include <assimp/CreateAnimMesh.h>
#include <memory>
#include <unordered_map>
#include "MakeVerboseFormat.h"
@@ -580,7 +581,7 @@ void glTF2Importer::ImportMeshes(glTF2::Asset& r)
}
else { // no indices provided so directly generate from counts
// use the already determined count as it includes checks
// use the already determined count as it includes checks
unsigned int count = aim->mNumVertices;
switch (prim.mode) {
@@ -702,26 +703,7 @@ void glTF2Importer::ImportCameras(glTF2::Asset& r)
}
}
aiNode* ImportNode(aiScene* pScene, glTF2::Asset& r, std::vector<unsigned int>& meshOffsets, glTF2::Ref<glTF2::Node>& ptr)
{
Node& node = *ptr;
std::string nameOrId = node.name.empty() ? node.id : node.name;
aiNode* ainode = new aiNode(nameOrId);
if (!node.children.empty()) {
ainode->mNumChildren = unsigned(node.children.size());
ainode->mChildren = new aiNode*[ainode->mNumChildren];
for (unsigned int i = 0; i < ainode->mNumChildren; ++i) {
aiNode* child = ImportNode(pScene, r, meshOffsets, node.children[i]);
child->mParent = ainode;
ainode->mChildren[i] = child;
}
}
aiMatrix4x4& matrix = ainode->mTransformation;
static void GetNodeTransform(aiMatrix4x4& matrix, const glTF2::Node& node) {
if (node.matrix.isPresent) {
CopyValue(node.matrix.value, matrix);
}
@@ -748,24 +730,112 @@ aiNode* ImportNode(aiScene* pScene, glTF2::Asset& r, std::vector<unsigned int>&
matrix = matrix * s;
}
}
}
static void BuildVertexWeightMapping(Ref<Mesh>& mesh, std::vector<std::vector<aiVertexWeight>>& map)
{
Mesh::Primitive::Attributes& attr = mesh->primitives[0].attributes;
if (attr.weight.empty() || attr.joint.empty()) {
return;
}
if (attr.weight[0]->count != attr.joint[0]->count) {
return;
}
const int num_vertices = attr.weight[0]->count;
struct Weights { float values[4]; };
struct Indices { uint8_t values[4]; };
Weights* weights = nullptr;
Indices* indices = nullptr;
attr.weight[0]->ExtractData(weights);
attr.joint[0]->ExtractData(indices);
for (unsigned int i = 0; i < num_vertices; ++i) {
for (unsigned int j = 0; j < 4; ++j) {
const int bone = indices[i].values[j];
const float weight = weights[i].values[j];
if (weight > 0 && bone >= 0 && bone < map.size()) {
map[bone].reserve(8);
map[bone].emplace_back(i, weight);
}
}
}
delete[] weights;
delete[] indices;
}
aiNode* ImportNode(aiScene* pScene, glTF2::Asset& r, std::vector<unsigned int>& meshOffsets, glTF2::Ref<glTF2::Node>& ptr)
{
Node& node = *ptr;
std::string nameOrId = node.name.empty() ? node.id : node.name;
aiNode* ainode = new aiNode(nameOrId);
if (!node.children.empty()) {
ainode->mNumChildren = unsigned(node.children.size());
ainode->mChildren = new aiNode*[ainode->mNumChildren];
for (unsigned int i = 0; i < ainode->mNumChildren; ++i) {
aiNode* child = ImportNode(pScene, r, meshOffsets, node.children[i]);
child->mParent = ainode;
ainode->mChildren[i] = child;
}
}
GetNodeTransform(ainode->mTransformation, node);
if (!node.meshes.empty()) {
int count = 0;
for (size_t i = 0; i < node.meshes.size(); ++i) {
int idx = node.meshes[i].GetIndex();
count += meshOffsets[idx + 1] - meshOffsets[idx];
}
ainode->mNumMeshes = count;
int mesh_idx = node.meshes[0].GetIndex();
int count = meshOffsets[mesh_idx + 1] - meshOffsets[mesh_idx];
// GLTF files contain at most 1 mesh per node.
assert(node.meshes.size() == 1);
assert(count == 1);
ainode->mNumMeshes = count;
ainode->mMeshes = new unsigned int[count];
int k = 0;
for (size_t i = 0; i < node.meshes.size(); ++i) {
int idx = node.meshes[i].GetIndex();
for (unsigned int j = meshOffsets[idx]; j < meshOffsets[idx + 1]; ++j, ++k) {
ainode->mMeshes[k] = j;
if (node.skin) {
aiMesh* mesh = pScene->mMeshes[meshOffsets[mesh_idx]];
mesh->mNumBones = node.skin->jointNames.size();
mesh->mBones = new aiBone*[mesh->mNumBones];
// GLTF and Assimp choose to store bone weights differently.
// GLTF has each vertex specify which bones influence the vertex.
// Assimp has each bone specify which vertices it has influence over.
// To convert this data, we first read over the vertex data and pull
// out the bone-to-vertex mapping. Then, when creating the aiBones,
// we copy the bone-to-vertex mapping into the bone. This is unfortunate
// both because it's somewhat slow and because, for many applications,
// we then need to reconvert the data back into the vertex-to-bone
// mapping which makes things doubly-slow.
std::vector<std::vector<aiVertexWeight>> weighting(mesh->mNumBones);
BuildVertexWeightMapping(node.meshes[0], weighting);
for (size_t i = 0; i < mesh->mNumBones; ++i) {
aiBone* bone = new aiBone();
Ref<Node> joint = node.skin->jointNames[i];
bone->mName = joint->name;
GetNodeTransform(bone->mOffsetMatrix, *joint);
std::vector<aiVertexWeight>& weights = weighting[i];
bone->mNumWeights = weights.size();
if (bone->mNumWeights > 0) {
bone->mWeights = new aiVertexWeight[bone->mNumWeights];
memcpy(bone->mWeights, weights.data(), bone->mNumWeights * sizeof(aiVertexWeight));
}
mesh->mBones[i] = bone;
}
}
int k = 0;
for (unsigned int j = meshOffsets[mesh_idx]; j < meshOffsets[mesh_idx + 1]; ++j, ++k) {
ainode->mMeshes[k] = j;
}
}
if (node.camera) {
@@ -802,6 +872,151 @@ void glTF2Importer::ImportNodes(glTF2::Asset& r)
//}
}
struct AnimationSamplers {
AnimationSamplers() : translation(nullptr), rotation(nullptr), scale(nullptr) {}
Animation::Sampler* translation;
Animation::Sampler* rotation;
Animation::Sampler* scale;
};
aiNodeAnim* CreateNodeAnim(glTF2::Asset& r, Node& node, AnimationSamplers& samplers)
{
aiNodeAnim* anim = new aiNodeAnim();
anim->mNodeName = node.name;
static const float kMillisecondsFromSeconds = 1000.f;
if (samplers.translation) {
float* times = nullptr;
samplers.translation->input->ExtractData(times);
aiVector3D* values = nullptr;
samplers.translation->output->ExtractData(values);
anim->mNumPositionKeys = samplers.translation->input->count;
anim->mPositionKeys = new aiVectorKey[anim->mNumPositionKeys];
for (int i = 0; i < anim->mNumPositionKeys; ++i) {
anim->mPositionKeys[i].mTime = times[i] * kMillisecondsFromSeconds;
anim->mPositionKeys[i].mValue = values[i];
}
delete[] times;
delete[] values;
} else if (node.translation.isPresent) {
anim->mNumPositionKeys = 1;
anim->mPositionKeys = new aiVectorKey();
anim->mPositionKeys->mTime = 0.f;
anim->mPositionKeys->mValue.x = node.translation.value[0];
anim->mPositionKeys->mValue.y = node.translation.value[1];
anim->mPositionKeys->mValue.z = node.translation.value[2];
}
if (samplers.rotation) {
float* times = nullptr;
samplers.rotation->input->ExtractData(times);
aiQuaternion* values = nullptr;
samplers.rotation->output->ExtractData(values);
anim->mNumRotationKeys = samplers.rotation->input->count;
anim->mRotationKeys = new aiQuatKey[anim->mNumRotationKeys];
for (int i = 0; i < anim->mNumRotationKeys; ++i) {
anim->mRotationKeys[i].mTime = times[i] * kMillisecondsFromSeconds;
anim->mRotationKeys[i].mValue.x = values[i].w;
anim->mRotationKeys[i].mValue.y = values[i].x;
anim->mRotationKeys[i].mValue.z = values[i].y;
anim->mRotationKeys[i].mValue.w = values[i].z;
}
delete[] times;
delete[] values;
} else if (node.rotation.isPresent) {
anim->mNumRotationKeys = 1;
anim->mRotationKeys = new aiQuatKey();
anim->mRotationKeys->mTime = 0.f;
anim->mRotationKeys->mValue.x = node.rotation.value[0];
anim->mRotationKeys->mValue.y = node.rotation.value[1];
anim->mRotationKeys->mValue.z = node.rotation.value[2];
anim->mRotationKeys->mValue.w = node.rotation.value[3];
}
if (samplers.scale) {
float* times = nullptr;
samplers.scale->input->ExtractData(times);
aiVector3D* values = nullptr;
samplers.scale->output->ExtractData(values);
anim->mNumScalingKeys = samplers.scale->input->count;
anim->mScalingKeys = new aiVectorKey[anim->mNumScalingKeys];
for (int i = 0; i < anim->mNumScalingKeys; ++i) {
anim->mScalingKeys[i].mTime = times[i] * kMillisecondsFromSeconds;
anim->mScalingKeys[i].mValue = values[i];
}
delete[] times;
delete[] values;
} else if (node.scale.isPresent) {
anim->mNumScalingKeys = 1;
anim->mScalingKeys = new aiVectorKey();
anim->mScalingKeys->mTime = 0.f;
anim->mScalingKeys->mValue.x = node.scale.value[0];
anim->mScalingKeys->mValue.y = node.scale.value[1];
anim->mScalingKeys->mValue.z = node.scale.value[2];
}
return anim;
}
std::unordered_map<unsigned int, AnimationSamplers> GatherSamplers(Animation& anim)
{
std::unordered_map<unsigned int, AnimationSamplers> samplers;
for (unsigned int c = 0; c < anim.channels.size(); ++c) {
Animation::Channel& channel = anim.channels[c];
if (channel.sampler >= anim.samplers.size()) {
continue;
}
const unsigned int node_index = channel.target.node.GetIndex();
AnimationSamplers& sampler = samplers[node_index];
if (channel.target.path == AnimationPath_TRANSLATION) {
sampler.translation = &anim.samplers[channel.sampler];
} else if (channel.target.path == AnimationPath_ROTATION) {
sampler.rotation = &anim.samplers[channel.sampler];
} else if (channel.target.path == AnimationPath_SCALE) {
sampler.scale = &anim.samplers[channel.sampler];
}
}
return samplers;
}
void glTF2Importer::ImportAnimations(glTF2::Asset& r)
{
if (!r.scene) return;
mScene->mNumAnimations = r.animations.Size();
if (mScene->mNumAnimations == 0) {
return;
}
mScene->mAnimations = new aiAnimation*[mScene->mNumAnimations];
for (unsigned int i = 0; i < r.animations.Size(); ++i) {
Animation& anim = r.animations[i];
aiAnimation* ai_anim = new aiAnimation();
ai_anim->mName = anim.name;
ai_anim->mDuration = 0;
ai_anim->mTicksPerSecond = 0;
std::unordered_map<unsigned int, AnimationSamplers> samplers = GatherSamplers(anim);
ai_anim->mNumChannels = r.skins[0].jointNames.size();
if (ai_anim->mNumChannels > 0) {
ai_anim->mChannels = new aiNodeAnim*[ai_anim->mNumChannels];
int j = 0;
for (auto& iter : r.skins[0].jointNames) {
ai_anim->mChannels[j] = CreateNodeAnim(r, *iter, samplers[iter.GetIndex()]);
++j;
}
}
mScene->mAnimations[i] = ai_anim;
}
}
void glTF2Importer::ImportEmbeddedTextures(glTF2::Asset& r)
{
embeddedTexIdxs.resize(r.images.Size(), -1);
@@ -869,6 +1084,8 @@ void glTF2Importer::InternReadFile(const std::string& pFile, aiScene* pScene, IO
ImportNodes(asset);
ImportAnimations(asset);
if (pScene->mNumMeshes == 0) {
pScene->mFlags |= AI_SCENE_FLAGS_INCOMPLETE;
}