Add: Animation support to Exporter (#64)

include/fastgltf/core.hpp

@@ -990,6 +990,7 @@ namespace fastgltf {
  std::vector<std::optional<std::filesystem::path>> imagePaths;
 
  void writeAccessors(const Asset& asset, std::string& json);
+ void writeAnimations(const Asset& asset, std::string& json);
  void writeBuffers(const Asset& asset, std::string& json);
  void writeBufferViews(const Asset& asset, std::string& json);
  void writeCameras(const Asset& asset, std::string& json);

src/fastgltf.cpp

@@ -4095,6 +4095,86 @@ void fg::Exporter::writeAccessors(const Asset& asset, std::string& json) {
  json += ']';
 }
 
+void fg::Exporter::writeAnimations(const Asset& asset, std::string& json)
+{
+ if (asset.animations.empty())
+ return;
+ if (json.back() == ']' || json.back() == '}')
+ json += ',';
+
+ json += R"("animations":[)";
+ for (auto it = asset.animations.begin(); it != asset.animations.end(); ++it) {
+ json += '{';
+
+ json += R"("channels":[)";
+ for (auto ci = it->channels.begin(); ci != it->channels.end(); ++ci) {
+ json += "{";
+ json += R"("sampler":)" + std::to_string(ci->samplerIndex) + ",";
+ json += R"("target":{)";
+ if (ci->nodeIndex.has_value()) {
+ json += R"("node":)" + std::to_string(ci->nodeIndex.value()) + ",";
+ }
+ json += R"("path":")";
+ switch (ci->path) {
+ case fg::AnimationPath::Translation:
+ json += "translation";
+ break;
+ case fg::AnimationPath::Rotation:
+ json += "rotation";
+ break;
+ case fg::AnimationPath::Scale:
+ json += "scale";
+ break;
+ case fg::AnimationPath::Weights:
+ json += "weights";
+ break;
+ }
+ json += "\"}}";
+
+ if (uabs(std::distance(it->channels.begin(), ci)) + 1 < it->channels.size())
+ json += ',';
+ }
+ json += "],";
+
+ json += R"("samplers":[)";
+ for (auto si = it->samplers.begin(); si != it->samplers.end(); ++si) {
+ json += '{';
+ json += R"("input":)" + std::to_string(si->inputAccessor) + ',';
+
+ if (si->interpolation != fg::AnimationInterpolation::Linear) {
+ json += R"("interpolation":")";
+ if (si->interpolation == fg::AnimationInterpolation::Step) {
+ json += "STEP\",";
+ } else {
+ json += "CUBICSPLINE\",";
+ }
+ }
+
+ json += R"("output":)" + std::to_string(si->outputAccessor);
+ json += '}';
+
+ if (uabs(std::distance(it->samplers.begin(), si)) + 1 < it->samplers.size())
+ json += ',';
+ }
+ json += ']';
+
+ if (extrasWriteCallback != nullptr) {
+ auto extras = extrasWriteCallback(uabs(std::distance(asset.animations.begin(), it)), fastgltf::Category::Animations, userPointer);
+ if (extras.has_value()) {
+ json += std::string(",\"extras\":") + *extras;
+ }
+ }
+
+ if (!it->name.empty())
+ json += R"(,"name":")" + fg::escapeString(it->name) + '"';
+
+ json += '}';
+ if (uabs(std::distance(asset.animations.begin(), it)) + 1 < asset.animations.size())
+ json += ',';
+ }
+ json += ']';
+}
+
 void fg::Exporter::writeBuffers(const Asset& asset, std::string& json) {
  if (asset.buffers.empty())
  return;
@@ -5254,6 +5334,7 @@ std::string fg::Exporter::writeJson(const fastgltf::Asset &asset) {
  }
 
  writeAccessors(asset, outputString);
+ writeAnimations(asset, outputString);
  writeBuffers(asset, outputString);
  writeBufferViews(asset, outputString);
  writeCameras(asset, outputString);
@@ -5322,7 +5403,7 @@ fg::Expected<fg::ExportResult<std::vector<std::byte>>> fg::Exporter::writeGltfBi
  // TODO: Add ExportOption enumeration for disabling this?
  const bool withEmbeddedBuffer = !asset.buffers.empty()
  // We only support writing Vectors and ByteViews as embedded buffers
- && (std::holds_alternative<sources::Array>(asset.buffers.front().data) || std::holds_alternative<sources::ByteView>(asset.buffers.front().data))
+ && (std::holds_alternative<sources::Array>(asset.buffers.front().data) || std::holds_alternative<sources::ByteView>(asset.buffers.front().data) || std::holds_alternative<sources::Vector>(asset.buffers.front().data))
  && asset.buffers.front().byteLength < std::numeric_limits<decltype(BinaryGltfChunk::chunkLength)>::max();
 
  std::size_t binarySize = 0;