Mixing
Parse json array to QMatrix4x4
I have such an array as json-object:
{
"id":"1",
"Matrix":
[
[1,2,3,4],
[5,6,7,8],
[9,10,11,12],
[13,14,15,16]
]
}
With QJsonDocument, QJsonObject I can already parse the array, but how can I convert it to the QMatrix4x4?
The content of array looks like:
QJsonArray jsonArray = jsonObject["Matrix"].toArray();
Matrix: QJsonArray([[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16]])
json qt
asked Aug 16 '18 at 10:49
mystic.06mystic.06
295
add a comment |
I have such an array as json-object:
{
"id":"1",
"Matrix":
[
[1,2,3,4],
[5,6,7,8],
[9,10,11,12],
[13,14,15,16]
]
}
With QJsonDocument, QJsonObject I can already parse the array, but how can I convert it to the QMatrix4x4?
The content of array looks like:
QJsonArray jsonArray = jsonObject["Matrix"].toArray();
Matrix: QJsonArray([[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16]])
json qt
asked Aug 16 '18 at 10:49
mystic.06mystic.06
295
add a comment |
I have such an array as json-object:
{
"id":"1",
"Matrix":
[
[1,2,3,4],
[5,6,7,8],
[9,10,11,12],
[13,14,15,16]
]
}
With QJsonDocument, QJsonObject I can already parse the array, but how can I convert it to the QMatrix4x4?
The content of array looks like:
QJsonArray jsonArray = jsonObject["Matrix"].toArray();
Matrix: QJsonArray([[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16]])
json qt
asked Aug 16 '18 at 10:49
mystic.06mystic.06
295
I have such an array as json-object:
{
"id":"1",
"Matrix":
[
[1,2,3,4],
[5,6,7,8],
[9,10,11,12],
[13,14,15,16]
]
}
With QJsonDocument, QJsonObject I can already parse the array, but how can I convert it to the QMatrix4x4?
The content of array looks like:
QJsonArray jsonArray = jsonObject["Matrix"].toArray();
Matrix: QJsonArray([[1,2,3,4],[5,6,7,8],[9,10,11,12],[13,14,15,16]])
json qt
json qt
asked Aug 16 '18 at 10:49
mystic.06mystic.06
295
asked Aug 16 '18 at 10:49
mystic.06mystic.06
295
asked Aug 16 '18 at 10:49
mystic.06mystic.06
295
asked Aug 16 '18 at 10:49
mystic.06mystic.06
295
asked Aug 16 '18 at 10:49
mystic.06mystic.06
295
295
add a comment |
add a comment |
1 Answer
1
active
oldest
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QMatrix4x4 has two suitable constructors:
QMatrix4x4(const float *values):
To use this constructor, you need to convert your
QJsonArrayto a data structure that provides a C-compatible floats array:
auto jsonDoc = QJsonDocument::fromJson(jsonData);
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
std::array<float, 16> myArr;
for (std::size_t i = 0; i < 16; i++)
myArr[i] =
static_cast<float>(jsonArr.at(i / 4).toArray().at(i % 4).toDouble());
QMatrix4x4 mat(myArr.data());
QMatrix4x4(float m11, float m12, ...):
To use this constructor, you need to pass elements from your
QJsonArrayas separate arguments to the constructor. You can do that manually, or you can leverage some template meta-programming tricks to make the compiler generate that for you:
template <std::size_t... indexes>
QMatrix4x4 jsonArrayToQMatrix4x4Impl(const QJsonArray &jsonArray,
std::index_sequence<indexes...>) {
return QMatrix4x4(static_cast<float>(
jsonArray.at(indexes / 4).toArray().at(indexes % 4).toDouble())...);
}
QMatrix4x4 jsonArrayToQMatrix4x4(const QJsonArray &jsonArray) {
return jsonArrayToQMatrix4x4Impl(jsonArray, std::make_index_sequence<16>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix4x4(jsonArr);
If you are dealing with different QMatrix sizes, you might want to use this generic adapter:
template <typename QMatrixType, std::size_t cols, std::size_t... indexes>
QMatrixType jsonArrayToQMatrixImpl(const QJsonArray &jsonArray,
std::index_sequence<indexes...> seq) {
const std::array<float, seq.size()> array{static_cast<float>(
jsonArray.at(indexes / cols).toArray().at(indexes % cols).toDouble())...};
return QMatrixType(array.data());
}
template <std::size_t cols, std::size_t rows,
typename QMatrixType = QGenericMatrix<cols, rows, float>>
QMatrixType jsonArrayToQMatrix(const QJsonArray &jsonArray) {
return jsonArrayToQMatrixImpl<QMatrixType, cols>(
jsonArray, std::make_index_sequence<rows * cols>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix<4, 4, QMatrix4x4>(jsonArr);
QMatrix4x3 mat2 = jsonArrayToQMatrix<4, 3>(jsonArr);
Please note that the above examples do not check that the input QJsonArray is of a valid size before the conversion. When the QJsonArray has less than the required number of elements, the result QMatrix will have 0s where the missing elements should be.
answered Aug 17 '18 at 9:51
MikeMike
5,92511431
add a comment |
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1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
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active
oldest
votes
QMatrix4x4 has two suitable constructors:
QMatrix4x4(const float *values):
To use this constructor, you need to convert your
QJsonArrayto a data structure that provides a C-compatible floats array:
auto jsonDoc = QJsonDocument::fromJson(jsonData);
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
std::array<float, 16> myArr;
for (std::size_t i = 0; i < 16; i++)
myArr[i] =
static_cast<float>(jsonArr.at(i / 4).toArray().at(i % 4).toDouble());
QMatrix4x4 mat(myArr.data());
QMatrix4x4(float m11, float m12, ...):
To use this constructor, you need to pass elements from your
QJsonArrayas separate arguments to the constructor. You can do that manually, or you can leverage some template meta-programming tricks to make the compiler generate that for you:
template <std::size_t... indexes>
QMatrix4x4 jsonArrayToQMatrix4x4Impl(const QJsonArray &jsonArray,
std::index_sequence<indexes...>) {
return QMatrix4x4(static_cast<float>(
jsonArray.at(indexes / 4).toArray().at(indexes % 4).toDouble())...);
}
QMatrix4x4 jsonArrayToQMatrix4x4(const QJsonArray &jsonArray) {
return jsonArrayToQMatrix4x4Impl(jsonArray, std::make_index_sequence<16>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix4x4(jsonArr);
If you are dealing with different QMatrix sizes, you might want to use this generic adapter:
template <typename QMatrixType, std::size_t cols, std::size_t... indexes>
QMatrixType jsonArrayToQMatrixImpl(const QJsonArray &jsonArray,
std::index_sequence<indexes...> seq) {
const std::array<float, seq.size()> array{static_cast<float>(
jsonArray.at(indexes / cols).toArray().at(indexes % cols).toDouble())...};
return QMatrixType(array.data());
}
template <std::size_t cols, std::size_t rows,
typename QMatrixType = QGenericMatrix<cols, rows, float>>
QMatrixType jsonArrayToQMatrix(const QJsonArray &jsonArray) {
return jsonArrayToQMatrixImpl<QMatrixType, cols>(
jsonArray, std::make_index_sequence<rows * cols>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix<4, 4, QMatrix4x4>(jsonArr);
QMatrix4x3 mat2 = jsonArrayToQMatrix<4, 3>(jsonArr);
Please note that the above examples do not check that the input QJsonArray is of a valid size before the conversion. When the QJsonArray has less than the required number of elements, the result QMatrix will have 0s where the missing elements should be.
answered Aug 17 '18 at 9:51
MikeMike
5,92511431
add a comment |
QMatrix4x4 has two suitable constructors:
QMatrix4x4(const float *values):
To use this constructor, you need to convert your
QJsonArrayto a data structure that provides a C-compatible floats array:
auto jsonDoc = QJsonDocument::fromJson(jsonData);
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
std::array<float, 16> myArr;
for (std::size_t i = 0; i < 16; i++)
myArr[i] =
static_cast<float>(jsonArr.at(i / 4).toArray().at(i % 4).toDouble());
QMatrix4x4 mat(myArr.data());
QMatrix4x4(float m11, float m12, ...):
To use this constructor, you need to pass elements from your
QJsonArrayas separate arguments to the constructor. You can do that manually, or you can leverage some template meta-programming tricks to make the compiler generate that for you:
template <std::size_t... indexes>
QMatrix4x4 jsonArrayToQMatrix4x4Impl(const QJsonArray &jsonArray,
std::index_sequence<indexes...>) {
return QMatrix4x4(static_cast<float>(
jsonArray.at(indexes / 4).toArray().at(indexes % 4).toDouble())...);
}
QMatrix4x4 jsonArrayToQMatrix4x4(const QJsonArray &jsonArray) {
return jsonArrayToQMatrix4x4Impl(jsonArray, std::make_index_sequence<16>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix4x4(jsonArr);
If you are dealing with different QMatrix sizes, you might want to use this generic adapter:
template <typename QMatrixType, std::size_t cols, std::size_t... indexes>
QMatrixType jsonArrayToQMatrixImpl(const QJsonArray &jsonArray,
std::index_sequence<indexes...> seq) {
const std::array<float, seq.size()> array{static_cast<float>(
jsonArray.at(indexes / cols).toArray().at(indexes % cols).toDouble())...};
return QMatrixType(array.data());
}
template <std::size_t cols, std::size_t rows,
typename QMatrixType = QGenericMatrix<cols, rows, float>>
QMatrixType jsonArrayToQMatrix(const QJsonArray &jsonArray) {
return jsonArrayToQMatrixImpl<QMatrixType, cols>(
jsonArray, std::make_index_sequence<rows * cols>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix<4, 4, QMatrix4x4>(jsonArr);
QMatrix4x3 mat2 = jsonArrayToQMatrix<4, 3>(jsonArr);
Please note that the above examples do not check that the input QJsonArray is of a valid size before the conversion. When the QJsonArray has less than the required number of elements, the result QMatrix will have 0s where the missing elements should be.
answered Aug 17 '18 at 9:51
MikeMike
5,92511431
add a comment |
QMatrix4x4 has two suitable constructors:
QMatrix4x4(const float *values):
To use this constructor, you need to convert your
QJsonArrayto a data structure that provides a C-compatible floats array:
auto jsonDoc = QJsonDocument::fromJson(jsonData);
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
std::array<float, 16> myArr;
for (std::size_t i = 0; i < 16; i++)
myArr[i] =
static_cast<float>(jsonArr.at(i / 4).toArray().at(i % 4).toDouble());
QMatrix4x4 mat(myArr.data());
QMatrix4x4(float m11, float m12, ...):
To use this constructor, you need to pass elements from your
QJsonArrayas separate arguments to the constructor. You can do that manually, or you can leverage some template meta-programming tricks to make the compiler generate that for you:
template <std::size_t... indexes>
QMatrix4x4 jsonArrayToQMatrix4x4Impl(const QJsonArray &jsonArray,
std::index_sequence<indexes...>) {
return QMatrix4x4(static_cast<float>(
jsonArray.at(indexes / 4).toArray().at(indexes % 4).toDouble())...);
}
QMatrix4x4 jsonArrayToQMatrix4x4(const QJsonArray &jsonArray) {
return jsonArrayToQMatrix4x4Impl(jsonArray, std::make_index_sequence<16>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix4x4(jsonArr);
If you are dealing with different QMatrix sizes, you might want to use this generic adapter:
template <typename QMatrixType, std::size_t cols, std::size_t... indexes>
QMatrixType jsonArrayToQMatrixImpl(const QJsonArray &jsonArray,
std::index_sequence<indexes...> seq) {
const std::array<float, seq.size()> array{static_cast<float>(
jsonArray.at(indexes / cols).toArray().at(indexes % cols).toDouble())...};
return QMatrixType(array.data());
}
template <std::size_t cols, std::size_t rows,
typename QMatrixType = QGenericMatrix<cols, rows, float>>
QMatrixType jsonArrayToQMatrix(const QJsonArray &jsonArray) {
return jsonArrayToQMatrixImpl<QMatrixType, cols>(
jsonArray, std::make_index_sequence<rows * cols>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix<4, 4, QMatrix4x4>(jsonArr);
QMatrix4x3 mat2 = jsonArrayToQMatrix<4, 3>(jsonArr);
Please note that the above examples do not check that the input QJsonArray is of a valid size before the conversion. When the QJsonArray has less than the required number of elements, the result QMatrix will have 0s where the missing elements should be.
answered Aug 17 '18 at 9:51
MikeMike
5,92511431
QMatrix4x4 has two suitable constructors:
QMatrix4x4(const float *values):
To use this constructor, you need to convert your
QJsonArrayto a data structure that provides a C-compatible floats array:
auto jsonDoc = QJsonDocument::fromJson(jsonData);
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
std::array<float, 16> myArr;
for (std::size_t i = 0; i < 16; i++)
myArr[i] =
static_cast<float>(jsonArr.at(i / 4).toArray().at(i % 4).toDouble());
QMatrix4x4 mat(myArr.data());
QMatrix4x4(float m11, float m12, ...):
To use this constructor, you need to pass elements from your
QJsonArrayas separate arguments to the constructor. You can do that manually, or you can leverage some template meta-programming tricks to make the compiler generate that for you:
template <std::size_t... indexes>
QMatrix4x4 jsonArrayToQMatrix4x4Impl(const QJsonArray &jsonArray,
std::index_sequence<indexes...>) {
return QMatrix4x4(static_cast<float>(
jsonArray.at(indexes / 4).toArray().at(indexes % 4).toDouble())...);
}
QMatrix4x4 jsonArrayToQMatrix4x4(const QJsonArray &jsonArray) {
return jsonArrayToQMatrix4x4Impl(jsonArray, std::make_index_sequence<16>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix4x4(jsonArr);
If you are dealing with different QMatrix sizes, you might want to use this generic adapter:
template <typename QMatrixType, std::size_t cols, std::size_t... indexes>
QMatrixType jsonArrayToQMatrixImpl(const QJsonArray &jsonArray,
std::index_sequence<indexes...> seq) {
const std::array<float, seq.size()> array{static_cast<float>(
jsonArray.at(indexes / cols).toArray().at(indexes % cols).toDouble())...};
return QMatrixType(array.data());
}
template <std::size_t cols, std::size_t rows,
typename QMatrixType = QGenericMatrix<cols, rows, float>>
QMatrixType jsonArrayToQMatrix(const QJsonArray &jsonArray) {
return jsonArrayToQMatrixImpl<QMatrixType, cols>(
jsonArray, std::make_index_sequence<rows * cols>{});
}
//usage:
QJsonArray jsonArr = jsonDoc.object()["Matrix"].toArray();
QMatrix4x4 mat = jsonArrayToQMatrix<4, 4, QMatrix4x4>(jsonArr);
QMatrix4x3 mat2 = jsonArrayToQMatrix<4, 3>(jsonArr);
Please note that the above examples do not check that the input QJsonArray is of a valid size before the conversion. When the QJsonArray has less than the required number of elements, the result QMatrix will have 0s where the missing elements should be.
answered Aug 17 '18 at 9:51
MikeMike
5,92511431
edited Nov 20 '18 at 12:30
answered Aug 17 '18 at 9:51
MikeMike
5,92511431
answered Aug 17 '18 at 9:51
MikeMike
5,92511431
answered Aug 17 '18 at 9:51
MikeMike
5,92511431
5,92511431
add a comment |
add a comment |
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