HelpLog.txt

2021.10.11 1:15am: search how to determine if an element is already in the vector: https://www.techiedelight.com/check-vector-contains-given-element-cpp/
2021.10.12 1:46am: search Qt GUI
2021.10.12 1:54am: how to convert in to qchar: https://stackoverflow.com/questions/9211304/qt-how-to-convert-a-number-into-qchar
2021.10.12 8:40pm: c++ destructor: https://stackoverflow.com/questions/1025313/will-an-empty-constructor-or-destructor-do-the-same-thing-as-the-generated-one#:~:text=Since%20no%20destructor%20is%20defined,defining%20an%20empty%20destructor%2C%20ie.
2021.10.12 11:30pm: c++ vector replace: https://www.cplusplus.com/reference/algorithm/replace/
Bug: 1. when select a qlistitem, the program crashed. Solution: forget to add count in my display component class.
	 2. When select a face, only three lines appears. Solution: the last element of vector idx should be 0 instead of 4.
2021.10.13 1:03am: qt set select: https://stackoverflow.com/questions/6249668/how-do-i-set-the-selected-item-in-a-qlistwidget
2021.10.13 1:17am: qt hold shift: https://stackoverflow.com/questions/22091598/qt-keypressevent-not-called-properly-when-holding-down-specific-keys-shift-key
2021.10.13 8:18pm: cross product of parallel vector: https://byjus.com/jee-questions/what-is-the-cross-product-of-two-parallel-vectors/#:~:text=The%20cross%20product%20of%20two%20parallel%20vectors%20is%20a%20zero,b%20%E2%86%92%20%3D%20c%20a%20%E2%86%92%20.

campare float with 0: https://bitbashing.io/comparing-floats.html


2021.10.20 11:30pm: c++ map: https://www.geeksforgeeks.org/map-associative-containers-the-c-standard-template-library-stl/

pass by ref or pointer: https://stackoverflow.com/questions/334856/are-there-benefits-of-passing-by-pointer-over-passing-by-reference-in-c

Pass by value when the function does not want to modify the parameter and the value is easy to copy (ints, doubles, char, bool, etc... simple types. std::string, std::vector, and all other STL containers are NOT simple types.)

Pass by const pointer when the value is expensive to copy AND the function does not want to modify the value pointed to AND NULL is a valid, expected value that the function handles.

Pass by non-const pointer when the value is expensive to copy AND the function wants to modify the value pointed to AND NULL is a valid, expected value that the function handles.

Pass by const reference when the value is expensive to copy AND the function does not want to modify the value referred to AND NULL would not be a valid value if a pointer was used instead.

Pass by non-cont reference when the value is expensive to copy AND the function wants to modify the value referred to AND NULL would not be a valid value if a pointer was used instead.


2021.10.21 7:05pm: unique pointer: move ， watch lecture video

2021.10.21 11:27pm: bool std::map::contains( const Key& key ) const;

2021.10.23 21:54pm: qt readline: https://stackoverflow.com/questions/5444959/read-a-text-file-line-by-line-in-qt

2021.10.23 22:45pm: qstring to float: https://www.qtcentre.org/threads/53074-How-to-convert-QString-to-float-and-compare-values

2021 10.24 1:45am: c++ unordered_ map hash: https://stackoverflow.com/questions/17016175/c-unordered-map-using-a-custom-class-type-as-the-key

2021.11.1 0:43am: QJsonarray element to float: https://stackoverflow.com/questions/51875248/parse-json-array-to-qmatrix4x4

2021.11.1 1:11am: build glm quaternion: https://glm.g-truc.net/0.9.0/api/a00184.html

2021.11.3 1:56am: bug: QTreewidgetitem signal not exist. Solution: need to pass an int as well.

2021.11.3 2:04am: glm convert vec4 to vec3: https://stackoverflow.com/questions/14657303/convert-glmvec4-to-glmvec3