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/*
Copyright 2018 Google Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS-IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#include "platforms/common/utils.h"
namespace vraudio {
void FlipZAxis(Eigen::Matrix4f* matrix) {
// This operation is equivalent to:
// matrix = flipZ * matrix * flipZ
// where flipZ is the scale(1, 1, -1) matrix.
(*matrix)(0, 2) *= -1.0f;
(*matrix)(1, 2) *= -1.0f;
(*matrix)(2, 0) *= -1.0f;
(*matrix)(2, 1) *= -1.0f;
(*matrix)(2, 3) *= -1.0f;
(*matrix)(3, 2) *= -1.0f;
}
Eigen::Quaternionf GetQuaternion(const Eigen::Matrix4f& matrix) {
const Eigen::Matrix3f rotation_matrix = matrix.block(0, 0, 3, 3);
Eigen::Quaternionf quaternion(rotation_matrix);
return quaternion.normalized();
}
Eigen::Vector3f GetPosition(const Eigen::Matrix4f& matrix) {
return Eigen::Vector3f(matrix.col(3).head<3>());
}
Eigen::Matrix4f GetTransformMatrix(const Eigen::Vector3f& position,
const Eigen::Vector3f& forward,
const Eigen::Vector3f& up) {
Eigen::Matrix4f transform_matrix;
// Compose the homogeneous vectors for the transformation matrix.
const Eigen::Vector3f right = up.cross(forward);
const Eigen::Vector4f position_4(position.x(), position.y(), position.z(),
1.0f);
const Eigen::Vector4f forward_4(forward.x(), forward.y(), forward.z(), 0.0f);
const Eigen::Vector4f up_4(up.x(), up.y(), up.z(), 0.0f);
const Eigen::Vector4f right_4(right.x(), right.y(), right.z(), 0.0f);
// Fill in the transformation matrix.
transform_matrix << right_4, up_4, forward_4, position_4;
return transform_matrix;
}
} // namespace vraudio