| 1 | /* |
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| 2 | Copyright 2018 Google Inc. All Rights Reserved. |
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| 3 | |
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| 4 | Licensed under the Apache License, Version 2.0 (the "License"); |
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| 5 | you may not use this file except in compliance with the License. |
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| 6 | You may obtain a copy of the License at |
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| 7 | |
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| 8 | http://www.apache.org/licenses/LICENSE-2.0 |
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| 9 | |
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| 10 | Unless required by applicable law or agreed to in writing, software |
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| 11 | distributed under the License is distributed on an "AS-IS" BASIS, |
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| 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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| 13 | See the License for the specific language governing permissions and |
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| 14 | limitations under the License. |
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| 15 | */ |
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| 16 | |
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| 17 | #include "platforms/common/utils.h" |
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| 18 | |
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| 19 | namespace vraudio { |
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| 20 | |
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| 21 | void FlipZAxis(Eigen::Matrix4f* matrix) { |
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| 22 | // This operation is equivalent to: |
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| 23 | // matrix = flipZ * matrix * flipZ |
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| 24 | // where flipZ is the scale(1, 1, -1) matrix. |
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| 25 | (*matrix)(0, 2) *= -1.0f; |
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| 26 | (*matrix)(1, 2) *= -1.0f; |
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| 27 | (*matrix)(2, 0) *= -1.0f; |
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| 28 | (*matrix)(2, 1) *= -1.0f; |
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| 29 | (*matrix)(2, 3) *= -1.0f; |
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| 30 | (*matrix)(3, 2) *= -1.0f; |
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| 31 | } |
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| 32 | |
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| 33 | Eigen::Quaternionf GetQuaternion(const Eigen::Matrix4f& matrix) { |
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| 34 | const Eigen::Matrix3f rotation_matrix = matrix.block(startRow: 0, startCol: 0, blockRows: 3, blockCols: 3); |
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| 35 | Eigen::Quaternionf quaternion(rotation_matrix); |
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| 36 | return quaternion.normalized(); |
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| 37 | } |
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| 38 | |
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| 39 | Eigen::Vector3f GetPosition(const Eigen::Matrix4f& matrix) { |
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| 40 | return Eigen::Vector3f(matrix.col(i: 3).head<3>()); |
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| 41 | } |
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| 42 | |
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| 43 | Eigen::Matrix4f GetTransformMatrix(const Eigen::Vector3f& position, |
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| 44 | const Eigen::Vector3f& forward, |
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| 45 | const Eigen::Vector3f& up) { |
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| 46 | Eigen::Matrix4f transform_matrix; |
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| 47 | // Compose the homogeneous vectors for the transformation matrix. |
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| 48 | const Eigen::Vector3f right = up.cross(other: forward); |
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| 49 | const Eigen::Vector4f position_4(position.x(), position.y(), position.z(), |
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| 50 | 1.0f); |
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| 51 | const Eigen::Vector4f forward_4(forward.x(), forward.y(), forward.z(), 0.0f); |
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| 52 | const Eigen::Vector4f up_4(up.x(), up.y(), up.z(), 0.0f); |
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| 53 | const Eigen::Vector4f right_4(right.x(), right.y(), right.z(), 0.0f); |
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| 54 | // Fill in the transformation matrix. |
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| 55 | transform_matrix << right_4, up_4, forward_4, position_4; |
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| 56 | return transform_matrix; |
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| 57 | } |
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| 58 | |
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| 59 | } // namespace vraudio |
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| 60 | |
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