Unity3d Quaternion Quaterion_unity3d Getting Started Tutorial Blog
Quaterion A quaternion can be understood as a rotation axis vector and a rotation angle. Note: This is not a point rotating around an axis, but a vector rotating around an axis. What you get after rotation is also a vector. Therefore, if you want to calculate the coordinates of a point P rotated by an angle around a fixed axis, you first need to fix a point S on the axis, and connect SP to form a vector. Use the quaternion to calculate the rotated vector, and add the coordinates of point S to get the rotated coordinates. Example: Calculate the coordinates of a point rotated by a certain angle around a certain axis static function RotateAroundPoint(point : Vector3, pivot : Vector3, angle : Quaternion) : Vector3 { var finalPos : Vector3 = point – pivot; //Center the point around the origin finalPos = angle * finalPos; //Rotate the point. finalPos += pivot; //Move the point back to its original offset. return finalPos; }// unity3d video tutorial var newPos = SomeClass.RotateAroundPoint(Vector3.forward, Vector3.zero, Quaternion.Euler(0, 90, 0) ); Debug. Log(newPos); //Prints (1, 0, 0) or is it (-1, 0, 0 )? Something like 2.html Quaternions Other URLs http://hi.baidu.com/czx_main/blog/item/71468e3690f438390a55a992.html http://oulehui.blog.163.com/blog/static/796146982011273184592/ http://www.cnblogs.com/softimagewht/archive/2010/11/16.html Generally…
Solve the introduction of http error in the https project_https call third-party http interface_Lccccb’s blog
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Seata Distributed Transaction Exception_seata Global Exception
1. Abnormal report: Could not register branch into global session xid =xxx.xxx.xx.xxx status = Rollbacked 2. Abnormal cause: while expecting Begin # Description: When registering a branch transaction, the global transaction state must be the first-stage state begin, and registration is not allowed unless it is begin. It belongs to the normal processing at the seata framework level, and users can solve it from their own business level. 3. Scenarios: 1. The branch transaction is asynchronous, and the global transaction cannot perceive its execution progress. The global transaction has entered the second phase, and the asynchronous branch is registered 2. Service a The rpc service b timed out (dubbo, feign, etc. default to a timeout of 1 second), a throws an exception to tm, and tm notifies tc to roll back, but b still receives the request (network delay or rpc framework retry), and then finds out when registering with tc The global transaction has been rolled back 3. tc perceives the global transaction timeout (@GlobalTransactional(timeoutMills = 60 seconds by default)), actively changes the status and notifies each branch transaction to roll back, and there is a new branch transaction to register at this time 4. The method of adding…
Importing a table in oracle says that the table does not exist, Oracle 11g plsql cannot export an empty table, exp EXP-00011: The table does not exist
Oracle 11g plsql cannot export empty tables, exp EXP-00011: The table does not exist oracle11g has a new feature, adding a new feature “deferred_segment_creation” meaning segment delay creation, the default is true, if this parameter is set to true, you create a new Table, and do not insert data into it, then this The table does not allocate extend immediately, that is, it does not occupy data space, that is, the table does not allocate segments to save space, so these tables cannot be exported. If the segment_treated field in the table is “NO” or “YES”, it indicates whether a table is allocated a segment. Check whether the table is assigned a segment SELECT TABLE_NAME,SEGMENT_CREATED FROM USER_TABLES See deferred_segment_creation show parameter deferred_segment_creation; Modify deferred_segment_creation alter system set deferred_segment_creation=false; Note: After modifying to false, the created table will allocate space immediately, but the table before adjustment will not change, you need to manually modify the allocated space 1.SELECT ‘ANALYZE TABLE ‘ || TABLE_NAME || ‘ COMPUTE STATISTICS;’ from USER_TABLES where NUM_ROWS=0; 2. Execute query results 3. SELECT ‘alter table ‘||TABLE_NAME||’ allocate extent;’ from USER_TABLES where NUM_ROWS=0; 4. Execute query results or 1.SELECT ‘ANALYZE TABLE ‘ || TABLE_NAME || ‘ COMPUTE STATISTICS;’…
The use of UITableView for iOS – processing selected cells_allowsselection_little_two_two’s blog
1. UITableView attribute allowsSelection: This attribute controls whether the form is allowed to be selected allowsMultipleSelection: This attribute controls whether the form allows multiple selection allowsSelectionDuringEditing: This attribute controls whether the form is allowed to be selected when it is in the editing state allowsMultipleSelectionDuringEditing: This attribute controls whether multiple selection is allowed when the form is in editing state. 2. UITableView method operation attribute indexPathForSelectedRow: Get the NSIndexPath corresponding to the selected table row indexPathsForSelectedRows: Get an array of NSIndexPaths corresponding to all selected table rows selectRowAtIndexPath:animated:scrollPosition:: Control the table to select the table row corresponding to the specified NSIndexPath, and the last parameter controls whether to scroll to the top, middle or bottom of the selected row deselectRowAtIndexPath:animated:: control deselects the table corresponding to the NSIndexPath specified in the tablerow 3. Respond to the selected event – UITableViewDelegate tableView: willSelectRowAtIndexPath:: This method is fired when the user is about to select a row in the table tableView:didSelectRowAtIndexPath:: This method is fired when the user finishes selecting a row in the table tableView:willDeselectRowAtIndexPath:: This method is fired when the user is about to deselect a row in the table tableView: didDeselectRowAtIndexPath:: This method is fired when the user selects…
