Search Results

Search found 14397 results on 576 pages for 'math mode'.

Page 211/576 | < Previous Page | 207 208 209 210 211 212 213 214 215 216 217 218  | Next Page >

  • Matrix rotation of a rectangle to "face" a given point in 2d

    - by justin.m.chase
    Suppose you have a rectangle centered at point (0, 0) and now I want to rotate it such that it is facing the point (100, 100), how would I do this purely with matrix math? To give some more specifics I am using javascript and canvas and I may have something like this: var position = {x : 0, y: 0 }; var destination = { x : 100, y: 100 }; var transform = Matrix.identity(); this.update = function(state) { // update transform to rotate to face destination }; this.draw = function(ctx) { ctx.save(); ctx.transform(transform); // a helper that just calls setTransform() ctx.beginPath(); ctx.rect(-5, -5, 10, 10); ctx.fillStyle = 'Blue'; ctx.fill(); ctx.lineWidth = 2; ctx.stroke(); ctx.restore(); } Feel free to assume any matrix function you need is available.

    Read the article

  • 2D tower defense - A bullet to an enemy

    - by Tashu
    I'm trying to find a good solution for a bullet to hit the enemy. The game is 2D tower defense, the tower is supposed to shoot a bullet and hit the enemy guaranteed. I tried this solution - http://blog.wolfire.com/2009/07/linear-algebra-for-game-developers-part-1/ The link mentioned to subtract the bullet's origin and the enemy as well (vector subtraction). I tried that but a bullet just follows around the enemy. float diffX = enemy.position.x - position.x; float diffY = enemy.position.y - position.y; velocity.x = diffX; velocity.y = diffY; position.add(velocity.x * deltaTime, velocity.y * deltaTime); I'm familiar with vectors but not sure what steps (vector math operations) to be done to get this solution working.

    Read the article

  • how to use serial port in UDK using windows DLL and DLLBind directive?

    - by Shayan Abbas
    I want to use serial port in UDK, For that purpose i use a windows DLL and DLLBind directive. I have a thread in windows DLL for serial port data recieve event. My problem is: this thread doesn't work properly. Please Help me. below is my code SerialPortDLL Code: // SerialPortDLL.cpp : Defines the exported functions for the DLL application. // #include "stdafx.h" #include "Cport.h" extern "C" { // This is an example of an exported variable //SERIALPORTDLL_API int nSerialPortDLL=0; // This is an example of an exported function. //SERIALPORTDLL_API int fnSerialPortDLL(void) //{ // return 42; //} CPort *sp; __declspec(dllexport) void Open(wchar_t* portName) { sp = new CPort(portName); //MessageBox(0,L"ha ha!!!",L"ha ha",0); //MessageBox(0,portName,L"ha ha",0); } __declspec(dllexport) void Close() { sp->Close(); MessageBox(0,L"ha ha!!!",L"ha ha",0); } __declspec(dllexport) wchar_t *GetData() { return sp->GetData(); } __declspec(dllexport) unsigned int GetDSR() { return sp->getDSR(); } __declspec(dllexport) unsigned int GetCTS() { return sp->getCTS(); } __declspec(dllexport) unsigned int GetRing() { return sp->getRing(); } } CPort class code: #include "stdafx.h" #include "CPort.h" #include "Serial.h" CSerial serial; HANDLE HandleOfThread; LONG lLastError = ERROR_SUCCESS; bool fContinue = true; HANDLE hevtOverlapped; HANDLE hevtStop; OVERLAPPED ov = {0}; //char szBuffer[101] = ""; wchar_t *szBuffer = L""; wchar_t *data = L""; DWORD WINAPI ThreadHandler( LPVOID lpParam ) { // Keep reading data, until an EOF (CTRL-Z) has been received do { MessageBox(0,L"ga ga!!!",L"ga ga",0); //Sleep(10); // Wait for an event lLastError = serial.WaitEvent(&ov); if (lLastError != ERROR_SUCCESS) { //LOG( " Unable to wait for a COM-port event" ); } // Setup array of handles in which we are interested HANDLE ahWait[2]; ahWait[0] = hevtOverlapped; ahWait[1] = hevtStop; // Wait until something happens switch (::WaitForMultipleObjects(sizeof(ahWait)/sizeof(*ahWait),ahWait,FALSE,INFINITE)) { case WAIT_OBJECT_0: { // Save event const CSerial::EEvent eEvent = serial.GetEventType(); // Handle break event if (eEvent & CSerial::EEventBreak) { //LOG( " ### BREAK received ###" ); } // Handle CTS event if (eEvent & CSerial::EEventCTS) { //LOG( " ### Clear to send %s ###", serial.GetCTS() ? "on":"off" ); } // Handle DSR event if (eEvent & CSerial::EEventDSR) { //LOG( " ### Data set ready %s ###", serial.GetDSR() ? "on":"off" ); } // Handle error event if (eEvent & CSerial::EEventError) { switch (serial.GetError()) { case CSerial::EErrorBreak: /*LOG( " Break condition" );*/ break; case CSerial::EErrorFrame: /*LOG( " Framing error" );*/ break; case CSerial::EErrorIOE: /*LOG( " IO device error" );*/ break; case CSerial::EErrorMode: /*LOG( " Unsupported mode" );*/ break; case CSerial::EErrorOverrun: /*LOG( " Buffer overrun" );*/ break; case CSerial::EErrorRxOver: /*LOG( " Input buffer overflow" );*/ break; case CSerial::EErrorParity: /*LOG( " Input parity error" );*/ break; case CSerial::EErrorTxFull: /*LOG( " Output buffer full" );*/ break; default: /*LOG( " Unknown" );*/ break; } } // Handle ring event if (eEvent & CSerial::EEventRing) { //LOG( " ### RING ###" ); } // Handle RLSD/CD event if (eEvent & CSerial::EEventRLSD) { //LOG( " ### RLSD/CD %s ###", serial.GetRLSD() ? "on" : "off" ); } // Handle data receive event if (eEvent & CSerial::EEventRecv) { // Read data, until there is nothing left DWORD dwBytesRead = 0; do { // Read data from the COM-port lLastError = serial.Read(szBuffer,33,&dwBytesRead); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to read from COM-port" ); } if( dwBytesRead == 33 && szBuffer[0]=='$' ) { // Finalize the data, so it is a valid string szBuffer[dwBytesRead] = '\0'; ////LOG( "\n%s\n", szBuffer ); data = szBuffer; } } while (dwBytesRead > 0); } } break; case WAIT_OBJECT_0+1: { // Set the continue bit to false, so we'll exit fContinue = false; } break; default: { // Something went wrong //LOG( "Error while calling WaitForMultipleObjects" ); } break; } } while (fContinue); MessageBox(0,L"kka kk!!!",L"kka ga",0); return 0; } CPort::CPort(wchar_t *portName) { // Attempt to open the serial port (COM2) //lLastError = serial.Open(_T(portName),0,0,true); lLastError = serial.Open(portName,0,0,true); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to open COM-port" ); } // Setup the serial port (115200,8N1, which is the default setting) lLastError = serial.Setup(CSerial::EBaud115200,CSerial::EData8,CSerial::EParNone,CSerial::EStop1); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to set COM-port setting" ); } // Register only for the receive event lLastError = serial.SetMask(CSerial::EEventBreak | CSerial::EEventCTS | CSerial::EEventDSR | CSerial::EEventError | CSerial::EEventRing | CSerial::EEventRLSD | CSerial::EEventRecv); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to set COM-port event mask" ); } // Use 'non-blocking' reads, because we don't know how many bytes // will be received. This is normally the most convenient mode // (and also the default mode for reading data). lLastError = serial.SetupReadTimeouts(CSerial::EReadTimeoutNonblocking); if (lLastError != ERROR_SUCCESS) { //LOG( "Unable to set COM-port read timeout" ); } // Create a handle for the overlapped operations hevtOverlapped = ::CreateEvent(0,TRUE,FALSE,0);; if (hevtOverlapped == 0) { //LOG( "Unable to create manual-reset event for overlapped I/O" ); } // Setup the overlapped structure ov.hEvent = hevtOverlapped; // Open the "STOP" handle hevtStop = ::CreateEvent(0,TRUE,FALSE,_T("Overlapped_Stop_Event")); if (hevtStop == 0) { //LOG( "Unable to create manual-reset event for stop event" ); } HandleOfThread = CreateThread( NULL, 0, ThreadHandler, 0, 0, NULL); } CPort::~CPort() { //fContinue = false; //CloseHandle( HandleOfThread ); //serial.Close(); } void CPort::Close() { fContinue = false; CloseHandle( HandleOfThread ); serial.Close(); } wchar_t *CPort::GetData() { return data; } bool CPort::getCTS() { return serial.GetCTS(); } bool CPort::getDSR() { return serial.GetDSR(); } bool CPort::getRing() { return serial.GetRing(); } Unreal Script Code: class MyPlayerController extends GamePlayerController DLLBind(SerialPortDLL); dllimport final function Open(string portName); dllimport final function Close(); dllimport final function string GetData();

    Read the article

  • Multi database link and mix and match email alert

    - by menardmam
    I have a site which is a large database of people that have different knowledge in different domains, such as teaching (maths, french, science etc...) On the site there is a page where you can search people base on different request, such as distance from home, grade, sex. Now, I would like to add a page where people that are looking for mentor will fill a request, and when a tutor in his area of search will match request, a email will be send to this researcher. Because I know for sure, that when in January you look for a math teacher for your 10 year old son, and you find none, you won't go again in February, March... and on and on just to see. Maybe there is one now, you want to be informed when the tutor will get into database automatically (more or less like www.jobboom.com) So the question is, what CMS do I need to be able to do that ? Wordpress, drupal or something custom made?

    Read the article

  • Unable to boot Ubuntu 13.10 (nVidia GTX 770m and Intel HD 4600)

    - by Raziel Gonzalez
    Ever since I bought this laptop I've been trying to install Ubuntu on it. It came with W8 preinstalled. Up to this point, I've been able to boot in UEFI mode with a black screen. I can tell it's trying to use the nVidia card (there's a led on the computer, depending on the color you can tell which GPU is using) and if I press crtl+alt+F1 I can go to console mode. Taking this advantage I tried to install bumblebee and after a successful install the led that indicates which GPU is being used change, indicating that it switched to the Intel HD 4600 graphics. After the installation I tried to initiate the graphic interface (startx) with no success. Xorg.0.log shows the error: [ 3706.779] X.Org X Server 1.14.3 Release Date: 2013-09-12 [ 3706.782] X Protocol Version 11, Revision 0 [ 3706.783] Build Operating System: Linux 3.2.0-37-generic x86_64 Ubuntu [ 3706.783] Current Operating System: Linux ubuntu 3.11.0-12-generic #19-Ubuntu SMP Wed Oct 9 16:20:46 UTC 2013 x86_64 [ 3706.783] Kernel command line: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/ubuntu.seed boot=casper nomodeset -- [ 3706.785] Build Date: 15 October 2013 09:23:37AM [ 3706.786] xorg-server 2:1.14.3-3ubuntu2 (For technical support please see http://www.ubuntu.com/support) [ 3706.786] Current version of pixman: 0.30.2 [ 3706.788] Before reporting problems, check http://wiki.x.org to make sure that you have the latest version. [ 3706.788] Markers: (--) probed, (**) from config file, (==) default setting, (++) from command line, (!!) notice, (II) informational, (WW) warning, (EE) error, (NI) not implemented, (??) unknown. [ 3706.791] (==) Log file: "/var/log/Xorg.0.log", Time: Sat Nov 2 12:28:52 2013 [ 3706.792] (==) Using system config directory "/usr/share/X11/xorg.conf.d" [ 3706.792] (==) No Layout section. Using the first Screen section. [ 3706.792] (==) No screen section available. Using defaults. [ 3706.792] (**) |-->Screen "Default Screen Section" (0) [ 3706.792] (**) | |-->Monitor "<default monitor>" [ 3706.792] (==) No monitor specified for screen "Default Screen Section". Using a default monitor configuration. [ 3706.792] (==) Automatically adding devices [ 3706.792] (==) Automatically enabling devices [ 3706.792] (==) Automatically adding GPU devices [ 3706.792] (WW) The directory "/usr/share/fonts/X11/cyrillic" does not exist. [ 3706.792] Entry deleted from font path. [ 3706.792] (WW) The directory "/usr/share/fonts/X11/100dpi/" does not exist. [ 3706.792] Entry deleted from font path. [ 3706.792] (WW) The directory "/usr/share/fonts/X11/75dpi/" does not exist. [ 3706.792] Entry deleted from font path. [ 3706.792] (WW) The directory "/usr/share/fonts/X11/100dpi" does not exist. [ 3706.792] Entry deleted from font path. [ 3706.792] (WW) The directory "/usr/share/fonts/X11/75dpi" does not exist. [ 3706.792] Entry deleted from font path. [ 3706.792] (==) FontPath set to: /usr/share/fonts/X11/misc, /usr/share/fonts/X11/Type1, built-ins [ 3706.792] (==) ModulePath set to "/usr/lib/x86_64-linux-gnu/xorg/extra-modules,/usr/lib/xorg/extra-modules,/usr/lib/xorg/modules" [ 3706.792] (II) The server relies on udev to provide the list of input devices. If no devices become available, reconfigure udev or disable AutoAddDevices. [ 3706.792] (II) Loader magic: 0x7ff680918d20 [ 3706.792] (II) Module ABI versions: [ 3706.792] X.Org ANSI C Emulation: 0.4 [ 3706.792] X.Org Video Driver: 14.1 [ 3706.792] X.Org XInput driver : 19.1 [ 3706.792] X.Org Server Extension : 7.0 [ 3706.793] (--) PCI:*(0:0:2:0) 8086:0416:1462:10e8 rev 6, Mem @ 0xf7400000/4194304, 0xb0000000/268435456, I/O @ 0x0000f000/64 [ 3706.793] (II) Open ACPI successful (/var/run/acpid.socket) [ 3706.794] Initializing built-in extension Generic Event Extension [ 3706.795] Initializing built-in extension SHAPE [ 3706.796] Initializing built-in extension MIT-SHM [ 3706.797] Initializing built-in extension XInputExtension [ 3706.797] Initializing built-in extension XTEST [ 3706.798] Initializing built-in extension BIG-REQUESTS [ 3706.799] Initializing built-in extension SYNC [ 3706.799] Initializing built-in extension XKEYBOARD [ 3706.800] Initializing built-in extension XC-MISC [ 3706.801] Initializing built-in extension SECURITY [ 3706.802] Initializing built-in extension XINERAMA [ 3706.802] Initializing built-in extension XFIXES [ 3706.803] Initializing built-in extension RENDER [ 3706.804] Initializing built-in extension RANDR [ 3706.804] Initializing built-in extension COMPOSITE [ 3706.805] Initializing built-in extension DAMAGE [ 3706.806] Initializing built-in extension MIT-SCREEN-SAVER [ 3706.806] Initializing built-in extension DOUBLE-BUFFER [ 3706.807] Initializing built-in extension RECORD [ 3706.807] Initializing built-in extension DPMS [ 3706.808] Initializing built-in extension X-Resource [ 3706.809] Initializing built-in extension XVideo [ 3706.809] Initializing built-in extension XVideo-MotionCompensation [ 3706.810] Initializing built-in extension SELinux [ 3706.811] Initializing built-in extension XFree86-VidModeExtension [ 3706.811] Initializing built-in extension XFree86-DGA [ 3706.812] Initializing built-in extension XFree86-DRI [ 3706.812] Initializing built-in extension DRI2 [ 3706.812] (II) "glx" will be loaded by default. [ 3706.812] (WW) "xmir" is not to be loaded by default. Skipping. [ 3706.812] (II) LoadModule: "dri2" [ 3706.812] (II) Module "dri2" already built-in [ 3706.812] (II) LoadModule: "glamoregl" [ 3706.813] (II) Loading /usr/lib/xorg/modules/libglamoregl.so [ 3706.813] (II) Module glamoregl: vendor="X.Org Foundation" [ 3706.813] compiled for 1.14.2.901, module version = 0.5.1 [ 3706.813] ABI class: X.Org ANSI C Emulation, version 0.4 [ 3706.813] (II) LoadModule: "glx" [ 3706.813] (II) Loading /usr/lib/xorg/modules/extensions/libglx.so [ 3706.813] (II) Module glx: vendor="X.Org Foundation" [ 3706.813] compiled for 1.14.3, module version = 1.0.0 [ 3706.813] ABI class: X.Org Server Extension, version 7.0 [ 3706.813] (==) AIGLX enabled [ 3706.814] Loading extension GLX [ 3706.814] (==) Matched intel as autoconfigured driver 0 [ 3706.814] (==) Matched vesa as autoconfigured driver 1 [ 3706.814] (==) Matched modesetting as autoconfigured driver 2 [ 3706.814] (==) Matched fbdev as autoconfigured driver 3 [ 3706.814] (==) Assigned the driver to the xf86ConfigLayout [ 3706.814] (II) LoadModule: "intel" [ 3706.814] (II) Loading /usr/lib/xorg/modules/drivers/intel_drv.so [ 3706.814] (II) Module intel: vendor="X.Org Foundation" [ 3706.814] compiled for 1.14.3, module version = 2.99.904 [ 3706.814] Module class: X.Org Video Driver [ 3706.814] ABI class: X.Org Video Driver, version 14.1 [ 3706.814] (II) LoadModule: "vesa" [ 3706.814] (II) Loading /usr/lib/xorg/modules/drivers/vesa_drv.so [ 3706.814] (II) Module vesa: vendor="X.Org Foundation" [ 3706.814] compiled for 1.14.1, module version = 2.3.2 [ 3706.814] Module class: X.Org Video Driver [ 3706.814] ABI class: X.Org Video Driver, version 14.1 [ 3706.814] (II) LoadModule: "modesetting" [ 3706.814] (II) Loading /usr/lib/xorg/modules/drivers/modesetting_drv.so [ 3706.814] (II) Module modesetting: vendor="X.Org Foundation" [ 3706.814] compiled for 1.14.1, module version = 0.8.0 [ 3706.814] Module class: X.Org Video Driver [ 3706.814] ABI class: X.Org Video Driver, version 14.1 [ 3706.814] (II) LoadModule: "fbdev" [ 3706.814] (II) Loading /usr/lib/xorg/modules/drivers/fbdev_drv.so [ 3706.815] (II) Module fbdev: vendor="X.Org Foundation" [ 3706.815] compiled for 1.14.1, module version = 0.4.3 [ 3706.815] Module class: X.Org Video Driver [ 3706.815] ABI class: X.Org Video Driver, version 14.1 [ 3706.815] (II) intel: Driver for Intel(R) Integrated Graphics Chipsets: i810, i810-dc100, i810e, i815, i830M, 845G, 854, 852GM/855GM, 865G, 915G, E7221 (i915), 915GM, 945G, 945GM, 945GME, Pineview GM, Pineview G, 965G, G35, 965Q, 946GZ, 965GM, 965GME/GLE, G33, Q35, Q33, GM45, 4 Series, G45/G43, Q45/Q43, G41, B43, HD Graphics, HD Graphics 2000, HD Graphics 3000, HD Graphics 2500, HD Graphics 4000, HD Graphics P4000, HD Graphics 4600, HD Graphics 5000, HD Graphics P4600/P4700, Iris(TM) Graphics 5100, HD Graphics 4400, HD Graphics 4200, Iris(TM) Pro Graphics 5200 [ 3706.815] (II) VESA: driver for VESA chipsets: vesa [ 3706.815] (II) modesetting: Driver for Modesetting Kernel Drivers: kms [ 3706.815] (II) FBDEV: driver for framebuffer: fbdev [ 3706.815] (--) using VT number 7 [ 3706.819] (WW) Falling back to old probe method for modesetting [ 3706.819] (EE) open /dev/dri/card0: No such file or directory [ 3706.819] (WW) Falling back to old probe method for fbdev [ 3706.819] (II) Loading sub module "fbdevhw" [ 3706.819] (II) LoadModule: "fbdevhw" [ 3706.819] (II) Loading /usr/lib/xorg/modules/libfbdevhw.so [ 3706.819] (II) Module fbdevhw: vendor="X.Org Foundation" [ 3706.819] compiled for 1.14.3, module version = 0.0.2 [ 3706.819] ABI class: X.Org Video Driver, version 14.1 [ 3706.819] (II) Loading sub module "vbe" [ 3706.819] (II) LoadModule: "vbe" [ 3706.819] (II) Loading /usr/lib/xorg/modules/libvbe.so [ 3706.819] (II) Module vbe: vendor="X.Org Foundation" [ 3706.819] compiled for 1.14.3, module version = 1.1.0 [ 3706.819] ABI class: X.Org Video Driver, version 14.1 [ 3706.819] (II) Loading sub module "int10" [ 3706.819] (II) LoadModule: "int10" [ 3706.819] (II) Loading /usr/lib/xorg/modules/libint10.so [ 3706.819] (II) Module int10: vendor="X.Org Foundation" [ 3706.819] compiled for 1.14.3, module version = 1.0.0 [ 3706.819] ABI class: X.Org Video Driver, version 14.1 [ 3706.819] (II) VESA(0): initializing int10 [ 3706.820] (EE) VESA(0): V_BIOS address 0x0 out of range [ 3706.820] (II) UnloadModule: "vesa" [ 3706.820] (II) UnloadSubModule: "int10" [ 3706.820] (II) Unloading int10 [ 3706.820] (II) UnloadSubModule: "vbe" [ 3706.820] (II) Unloading vbe [ 3706.820] (EE) Screen(s) found, but none have a usable configuration. [ 3706.820] (EE) Fatal server error: [ 3706.820] (EE) no screens found(EE) [ 3706.820] (EE) Please consult the The X.Org Foundation support at http://wiki.x.org for help. [ 3706.820] (EE) Please also check the log file at "/var/log/Xorg.0.log" for additional information. [ 3706.820] (EE) [ 3706.827] (EE) Server terminated with error (1). Closing log file. I also saved the dsmeg output to see if it can be of any help. In order to be able to get to this stage I had to boot with nomodeset option and removed quiet and splash. Anyone got this same error? Any guidance? I've tried other linux distros and so far the only one that is able to boot is Opensuse 12.3 without any issues (but only when I switch to legacy mode instead of UEFI).

    Read the article

  • C#/.NET Little Wonders: The Generic Func Delegates

    - by James Michael Hare
    Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Back in one of my three original “Little Wonders” Trilogy of posts, I had listed generic delegates as one of the Little Wonders of .NET.  Later, someone posted a comment saying said that they would love more detail on the generic delegates and their uses, since my original entry just scratched the surface of them. Last week, I began our look at some of the handy generic delegates built into .NET with a description of delegates in general, and the Action family of delegates.  For this week, I’ll launch into a look at the Func family of generic delegates and how they can be used to support generic, reusable algorithms and classes. Quick Delegate Recap Delegates are similar to function pointers in C++ in that they allow you to store a reference to a method.  They can store references to either static or instance methods, and can actually be used to chain several methods together in one delegate. Delegates are very type-safe and can be satisfied with any standard method, anonymous method, or a lambda expression.  They can also be null as well (refers to no method), so care should be taken to make sure that the delegate is not null before you invoke it. Delegates are defined using the keyword delegate, where the delegate’s type name is placed where you would typically place the method name: 1: // This delegate matches any method that takes string, returns nothing 2: public delegate void Log(string message); This delegate defines a delegate type named Log that can be used to store references to any method(s) that satisfies its signature (whether instance, static, lambda expression, etc.). Delegate instances then can be assigned zero (null) or more methods using the operator = which replaces the existing delegate chain, or by using the operator += which adds a method to the end of a delegate chain: 1: // creates a delegate instance named currentLogger defaulted to Console.WriteLine (static method) 2: Log currentLogger = Console.Out.WriteLine; 3:  4: // invokes the delegate, which writes to the console out 5: currentLogger("Hi Standard Out!"); 6:  7: // append a delegate to Console.Error.WriteLine to go to std error 8: currentLogger += Console.Error.WriteLine; 9:  10: // invokes the delegate chain and writes message to std out and std err 11: currentLogger("Hi Standard Out and Error!"); While delegates give us a lot of power, it can be cumbersome to re-create fairly standard delegate definitions repeatedly, for this purpose the generic delegates were introduced in various stages in .NET.  These support various method types with particular signatures. Note: a caveat with generic delegates is that while they can support multiple parameters, they do not match methods that contains ref or out parameters. If you want to a delegate to represent methods that takes ref or out parameters, you will need to create a custom delegate. We’ve got the Func… delegates Just like it’s cousin, the Action delegate family, the Func delegate family gives us a lot of power to use generic delegates to make classes and algorithms more generic.  Using them keeps us from having to define a new delegate type when need to make a class or algorithm generic. Remember that the point of the Action delegate family was to be able to perform an “action” on an item, with no return results.  Thus Action delegates can be used to represent most methods that take 0 to 16 arguments but return void.  You can assign a method The Func delegate family was introduced in .NET 3.5 with the advent of LINQ, and gives us the power to define a function that can be called on 0 to 16 arguments and returns a result.  Thus, the main difference between Action and Func, from a delegate perspective, is that Actions return nothing, but Funcs return a result. The Func family of delegates have signatures as follows: Func<TResult> – matches a method that takes no arguments, and returns value of type TResult. Func<T, TResult> – matches a method that takes an argument of type T, and returns value of type TResult. Func<T1, T2, TResult> – matches a method that takes arguments of type T1 and T2, and returns value of type TResult. Func<T1, T2, …, TResult> – and so on up to 16 arguments, and returns value of type TResult. These are handy because they quickly allow you to be able to specify that a method or class you design will perform a function to produce a result as long as the method you specify meets the signature. For example, let’s say you were designing a generic aggregator, and you wanted to allow the user to define how the values will be aggregated into the result (i.e. Sum, Min, Max, etc…).  To do this, we would ask the user of our class to pass in a method that would take the current total, the next value, and produce a new total.  A class like this could look like: 1: public sealed class Aggregator<TValue, TResult> 2: { 3: // holds method that takes previous result, combines with next value, creates new result 4: private Func<TResult, TValue, TResult> _aggregationMethod; 5:  6: // gets or sets the current result of aggregation 7: public TResult Result { get; private set; } 8:  9: // construct the aggregator given the method to use to aggregate values 10: public Aggregator(Func<TResult, TValue, TResult> aggregationMethod = null) 11: { 12: if (aggregationMethod == null) throw new ArgumentNullException("aggregationMethod"); 13:  14: _aggregationMethod = aggregationMethod; 15: } 16:  17: // method to add next value 18: public void Aggregate(TValue nextValue) 19: { 20: // performs the aggregation method function on the current result and next and sets to current result 21: Result = _aggregationMethod(Result, nextValue); 22: } 23: } Of course, LINQ already has an Aggregate extension method, but that works on a sequence of IEnumerable<T>, whereas this is designed to work more with aggregating single results over time (such as keeping track of a max response time for a service). We could then use this generic aggregator to find the sum of a series of values over time, or the max of a series of values over time (among other things): 1: // creates an aggregator that adds the next to the total to sum the values 2: var sumAggregator = new Aggregator<int, int>((total, next) => total + next); 3:  4: // creates an aggregator (using static method) that returns the max of previous result and next 5: var maxAggregator = new Aggregator<int, int>(Math.Max); So, if we were timing the response time of a web method every time it was called, we could pass that response time to both of these aggregators to get an idea of the total time spent in that web method, and the max time spent in any one call to the web method: 1: // total will be 13 and max 13 2: int responseTime = 13; 3: sumAggregator.Aggregate(responseTime); 4: maxAggregator.Aggregate(responseTime); 5:  6: // total will be 20 and max still 13 7: responseTime = 7; 8: sumAggregator.Aggregate(responseTime); 9: maxAggregator.Aggregate(responseTime); 10:  11: // total will be 40 and max now 20 12: responseTime = 20; 13: sumAggregator.Aggregate(responseTime); 14: maxAggregator.Aggregate(responseTime); The Func delegate family is useful for making generic algorithms and classes, and in particular allows the caller of the method or user of the class to specify a function to be performed in order to generate a result. What is the result of a Func delegate chain? If you remember, we said earlier that you can assign multiple methods to a delegate by using the += operator to chain them.  So how does this affect delegates such as Func that return a value, when applied to something like the code below? 1: Func<int, int, int> combo = null; 2:  3: // What if we wanted to aggregate the sum and max together? 4: combo += (total, next) => total + next; 5: combo += Math.Max; 6:  7: // what is the result? 8: var comboAggregator = new Aggregator<int, int>(combo); Well, in .NET if you chain multiple methods in a delegate, they will all get invoked, but the result of the delegate is the result of the last method invoked in the chain.  Thus, this aggregator would always result in the Math.Max() result.  The other chained method (the sum) gets executed first, but it’s result is thrown away: 1: // result is 13 2: int responseTime = 13; 3: comboAggregator.Aggregate(responseTime); 4:  5: // result is still 13 6: responseTime = 7; 7: comboAggregator.Aggregate(responseTime); 8:  9: // result is now 20 10: responseTime = 20; 11: comboAggregator.Aggregate(responseTime); So remember, you can chain multiple Func (or other delegates that return values) together, but if you do so you will only get the last executed result. Func delegates and co-variance/contra-variance in .NET 4.0 Just like the Action delegate, as of .NET 4.0, the Func delegate family is contra-variant on its arguments.  In addition, it is co-variant on its return type.  To support this, in .NET 4.0 the signatures of the Func delegates changed to: Func<out TResult> – matches a method that takes no arguments, and returns value of type TResult (or a more derived type). Func<in T, out TResult> – matches a method that takes an argument of type T (or a less derived type), and returns value of type TResult(or a more derived type). Func<in T1, in T2, out TResult> – matches a method that takes arguments of type T1 and T2 (or less derived types), and returns value of type TResult (or a more derived type). Func<in T1, in T2, …, out TResult> – and so on up to 16 arguments, and returns value of type TResult (or a more derived type). Notice the addition of the in and out keywords before each of the generic type placeholders.  As we saw last week, the in keyword is used to specify that a generic type can be contra-variant -- it can match the given type or a type that is less derived.  However, the out keyword, is used to specify that a generic type can be co-variant -- it can match the given type or a type that is more derived. On contra-variance, if you are saying you need an function that will accept a string, you can just as easily give it an function that accepts an object.  In other words, if you say “give me an function that will process dogs”, I could pass you a method that will process any animal, because all dogs are animals.  On the co-variance side, if you are saying you need a function that returns an object, you can just as easily pass it a function that returns a string because any string returned from the given method can be accepted by a delegate expecting an object result, since string is more derived.  Once again, in other words, if you say “give me a method that creates an animal”, I can pass you a method that will create a dog, because all dogs are animals. It really all makes sense, you can pass a more specific thing to a less specific parameter, and you can return a more specific thing as a less specific result.  In other words, pay attention to the direction the item travels (parameters go in, results come out).  Keeping that in mind, you can always pass more specific things in and return more specific things out. For example, in the code below, we have a method that takes a Func<object> to generate an object, but we can pass it a Func<string> because the return type of object can obviously accept a return value of string as well: 1: // since Func<object> is co-variant, this will access Func<string>, etc... 2: public static string Sequence(int count, Func<object> generator) 3: { 4: var builder = new StringBuilder(); 5:  6: for (int i=0; i<count; i++) 7: { 8: object value = generator(); 9: builder.Append(value); 10: } 11:  12: return builder.ToString(); 13: } Even though the method above takes a Func<object>, we can pass a Func<string> because the TResult type placeholder is co-variant and accepts types that are more derived as well: 1: // delegate that's typed to return string. 2: Func<string> stringGenerator = () => DateTime.Now.ToString(); 3:  4: // This will work in .NET 4.0, but not in previous versions 5: Sequence(100, stringGenerator); Previous versions of .NET implemented some forms of co-variance and contra-variance before, but .NET 4.0 goes one step further and allows you to pass or assign an Func<A, BResult> to a Func<Y, ZResult> as long as A is less derived (or same) as Y, and BResult is more derived (or same) as ZResult. Sidebar: The Func and the Predicate A method that takes one argument and returns a bool is generally thought of as a predicate.  Predicates are used to examine an item and determine whether that item satisfies a particular condition.  Predicates are typically unary, but you may also have binary and other predicates as well. Predicates are often used to filter results, such as in the LINQ Where() extension method: 1: var numbers = new[] { 1, 2, 4, 13, 8, 10, 27 }; 2:  3: // call Where() using a predicate which determines if the number is even 4: var evens = numbers.Where(num => num % 2 == 0); As of .NET 3.5, predicates are typically represented as Func<T, bool> where T is the type of the item to examine.  Previous to .NET 3.5, there was a Predicate<T> type that tended to be used (which we’ll discuss next week) and is still supported, but most developers recommend using Func<T, bool> now, as it prevents confusion with overloads that accept unary predicates and binary predicates, etc.: 1: // this seems more confusing as an overload set, because of Predicate vs Func 2: public static SomeMethod(Predicate<int> unaryPredicate) { } 3: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } 4:  5: // this seems more consistent as an overload set, since just uses Func 6: public static SomeMethod(Func<int, bool> unaryPredicate) { } 7: public static SomeMethod(Func<int, int, bool> binaryPredicate) { } Also, even though Predicate<T> and Func<T, bool> match the same signatures, they are separate types!  Thus you cannot assign a Predicate<T> instance to a Func<T, bool> instance and vice versa: 1: // the same method, lambda expression, etc can be assigned to both 2: Predicate<int> isEven = i => (i % 2) == 0; 3: Func<int, bool> alsoIsEven = i => (i % 2) == 0; 4:  5: // but the delegate instances cannot be directly assigned, strongly typed! 6: // ERROR: cannot convert type... 7: isEven = alsoIsEven; 8:  9: // however, you can assign by wrapping in a new instance: 10: isEven = new Predicate<int>(alsoIsEven); 11: alsoIsEven = new Func<int, bool>(isEven); So, the general advice that seems to come from most developers is that Predicate<T> is still supported, but we should use Func<T, bool> for consistency in .NET 3.5 and above. Sidebar: Func as a Generator for Unit Testing One area of difficulty in unit testing can be unit testing code that is based on time of day.  We’d still want to unit test our code to make sure the logic is accurate, but we don’t want the results of our unit tests to be dependent on the time they are run. One way (of many) around this is to create an internal generator that will produce the “current” time of day.  This would default to returning result from DateTime.Now (or some other method), but we could inject specific times for our unit testing.  Generators are typically methods that return (generate) a value for use in a class/method. For example, say we are creating a CacheItem<T> class that represents an item in the cache, and we want to make sure the item shows as expired if the age is more than 30 seconds.  Such a class could look like: 1: // responsible for maintaining an item of type T in the cache 2: public sealed class CacheItem<T> 3: { 4: // helper method that returns the current time 5: private static Func<DateTime> _timeGenerator = () => DateTime.Now; 6:  7: // allows internal access to the time generator 8: internal static Func<DateTime> TimeGenerator 9: { 10: get { return _timeGenerator; } 11: set { _timeGenerator = value; } 12: } 13:  14: // time the item was cached 15: public DateTime CachedTime { get; private set; } 16:  17: // the item cached 18: public T Value { get; private set; } 19:  20: // item is expired if older than 30 seconds 21: public bool IsExpired 22: { 23: get { return _timeGenerator() - CachedTime > TimeSpan.FromSeconds(30.0); } 24: } 25:  26: // creates the new cached item, setting cached time to "current" time 27: public CacheItem(T value) 28: { 29: Value = value; 30: CachedTime = _timeGenerator(); 31: } 32: } Then, we can use this construct to unit test our CacheItem<T> without any time dependencies: 1: var baseTime = DateTime.Now; 2:  3: // start with current time stored above (so doesn't drift) 4: CacheItem<int>.TimeGenerator = () => baseTime; 5:  6: var target = new CacheItem<int>(13); 7:  8: // now add 15 seconds, should still be non-expired 9: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(15); 10:  11: Assert.IsFalse(target.IsExpired); 12:  13: // now add 31 seconds, should now be expired 14: CacheItem<int>.TimeGenerator = () => baseTime.AddSeconds(31); 15:  16: Assert.IsTrue(target.IsExpired); Now we can unit test for 1 second before, 1 second after, 1 millisecond before, 1 day after, etc.  Func delegates can be a handy tool for this type of value generation to support more testable code.  Summary Generic delegates give us a lot of power to make truly generic algorithms and classes.  The Func family of delegates is a great way to be able to specify functions to calculate a result based on 0-16 arguments.  Stay tuned in the weeks that follow for other generic delegates in the .NET Framework!   Tweet Technorati Tags: .NET, C#, CSharp, Little Wonders, Generics, Func, Delegates

    Read the article

  • Which programming language should I learn? [on hold]

    - by Ashkan
    I'm Ashkan and I'm from Iran, I started programming when I was 13 and I learned a lot of stuff since then, But now I'm totally lost. Since I live in Iran there are no counselor or any professionals out there to help me, so I decided to ask here. I started with Visual Basic and after 1 year I started to learn HTML , CSS , Javascript and JQuery. And for the past 6 months I've been learning PHP,and I have a basic understanding of OOP. I want to move to America to continue my studies and I was wondering which programming language helps me the most to get there? Should I learn C++ or JAVA or should I study Computer Science and Math? also since We are not in a good place financially, I want a programming language that helps me in college and lets me make some money? Thanks in advance and sorry for my poor English skills.

    Read the article

  • libgdx rotation (animation, arrays) issues and help needed

    - by johnny-b
    well i am a noob at java and libgdx. i got the homing bullet working with the help of someone. now i am smashing my head as to how i can make it rotate so it faces the ball (which is the main character) when it goes around it or when it is coming towards it. the bullet is facing <--- and the code below is what i have done so far. also i used sprites for the bullet and also animation method. Also how do i make it an array/arraylist which is best so i can have multiple bullets at random or placed places. i tried many things nothing workd :( thank you for the help. // below is the bullet or enemy if you want to call it. public class Bullet extends Sprite { public static final float BULLET_HOMING = 6000; public static final float BULLET_SPEED = 300; private Vector2 velocity; private float lifetime; public Bullet(float x, float y) { velocity = new Vector2(0, 0); setPosition(x, y); } public void update(float delta) { float targetX = GameWorld.getBall().getX(); float targetY = GameWorld.getBall().getY(); float dx = targetX - getX(); float dy = targetY - getY(); float distToTarget = (float) Math.sqrt(dx * dx + dy * dy); dx /= distToTarget; dy /= distToTarget; dx *= BULLET_HOMING; dy *= BULLET_HOMING; velocity.x += dx * delta; velocity.y += dy * delta; float vMag = (float) Math.sqrt(velocity.x * velocity.x + velocity.y * velocity.y); velocity.x /= vMag; velocity.y /= vMag; velocity.x *= BULLET_SPEED; velocity.y *= BULLET_SPEED; Vector2 v = velocity.cpy().scl(delta); setPosition(getX() + v.x, getY() + v.y); setOriginCenter(); setRotation(velocity.angle()); lifetime += delta; setRegion(AssetLoader.bulletAnimation.getKeyFrame(lifetime)); } } // this is where i load the images. public class AssetLoader { public static Animation bulletAnimation; public static Sprite bullet1, bullet2; public static void load() { texture = new Texture(Gdx.files.internal("SpriteN1.png")); texture.setFilter(TextureFilter.Nearest, TextureFilter.Nearest); bullet1 = new Sprite(texture, 380, 350, 45, 20); bullet1.flip(false, true); bullet2 = new Sprite(texture, 425, 350, 45, 20); bullet2.flip(false, true); Sprite[] bullets = { bullet1, bullet2 }; bulletAnimation = new Animation(0.06f, aims); bulletAnimation.setPlayMode(Animation.PlayMode.LOOP); } public static void dispose() { // We must dispose of the texture when we are finished. texture.dispose(); } // this is for the rendering of the images etc public class GameRenderer { private Bullet bullet; private Ball ball; public GameRenderer(GameWorld world) { myWorld = world; cam = new OrthographicCamera(); cam.setToOrtho(true, 480, 320); batcher = new SpriteBatch(); // Attach batcher to camera batcher.setProjectionMatrix(cam.combined); shapeRenderer = new ShapeRenderer(); shapeRenderer.setProjectionMatrix(cam.combined); // Call helper methods to initialize instance variables initGameObjects(); initAssets(); } private void initGameObjects() { ball = GameWorld.getBall(); bullet = myWorld.getBullet(); scroller = myWorld.getScroller(); } private void initAssets() { ballAnimation = AssetLoader.ballAnimation; bulletAnimation = AssetLoader.bulletAnimation; } public void render(float runTime) { Gdx.gl.glClearColor(0, 0, 0, 1); Gdx.gl.glClear(GL30.GL_COLOR_BUFFER_BIT); batcher.begin(); // Disable transparency // This is good for performance when drawing images that do not require // transparency. batcher.disableBlending(); // The ball needs transparency, so we enable that again. batcher.enableBlending(); batcher.draw(AssetLoader.ballAnimation.getKeyFrame(runTime), ball.getX(), ball.getY(), ball.getWidth(), ball.getHeight()); batcher.draw(AssetLoader.bulletAnimation.getKeyFrame(runTime), bullet.getX(), bullet.getY()); // End SpriteBatch batcher.end(); } } // this is to load the image etc on the screen i guess public class GameWorld { public static Ball ball; private Bullet bullet; private ScrollHandler scroller; public GameWorld() { ball = new Ball(480, 273, 32, 32); bullet = new Bullet(10, 10); scroller = new ScrollHandler(0); } public void update(float delta) { ball.update(delta); bullet.update(delta); scroller.update(delta); } public static Ball getBall() { return ball; } public ScrollHandler getScroller() { return scroller; } public Bullet getBullet() { return bullet; } } so there is the whole thing. the images are loaded via the AssetLoader then to the GameRenderer and GameWorld via the Bullet class. i am guessing that is how it is. sorry newbie so still learning. thank you in advace for the help or any advice.

    Read the article

  • Can't fix Plymouth resolution by any means

    - by Uri Herrera
    Due to a bad update to 11.04 i had to completely reinstall Ubuntu, now i got everything pretty much the way it was before, except for plymouth.I've tried every script i found, every turorial i've found, i've installed Plymouth Managaer, i've installed a plymouth theme that worked before...and still, just plain white text, if it feels like showing me something, 'cause at times i don't even get to see the text mode, so, is there anything i can do witthout removing the ATI driver?, can i get rid of plymouth if it's not going to properly work?, are there an alternatives to plymouth?

    Read the article

  • The Fellowship of the Ringwraiths [Video]

    - by Asian Angel
    While we all know what happened during the events of the first LOTR movie for the Fellowship, there were some unanswered questions about the Ringwraiths and their activities. Here finally is your opportunity to see what really happened… Fellowship of the Ringwraiths [via Neatorama] How to Factory Reset Your Android Phone or Tablet When It Won’t Boot Our Geek Trivia App for Windows 8 is Now Available Everywhere How To Boot Your Android Phone or Tablet Into Safe Mode

    Read the article

  • Beginner Geek: How to Link Contacts to Their Social Network Profiles in the Windows 8 People App

    - by Taylor Gibb
    The built-in People app in Windows 8 allows you to pull in your contact lists from a few different social networks. The problem comes when you start to get duplicate entries, here’s how to link contacts together without losing any information. How To Boot Your Android Phone or Tablet Into Safe Mode HTG Explains: Does Your Android Phone Need an Antivirus? How To Use USB Drives With the Nexus 7 and Other Android Devices

    Read the article

  • Linux Sysadmin: How To Manage LVMs With a GUI

    - by Aviad
    We’ve talked about how to use LVM before, but what if you wanted to accomplish the same tasks only with a comfortable graphical interface? HowTo Geek dives into how to manage LVM drives with a GUI. Image by marfis. How To Boot Your Android Phone or Tablet Into Safe Mode HTG Explains: Does Your Android Phone Need an Antivirus? How To Use USB Drives With the Nexus 7 and Other Android Devices

    Read the article

  • Bash command history not working

    - by user12663
    The command history between sessions is not getting saved. I'm using guake and the history for the session is working fine. I noticed that .bash_history had some commands I executed in sudo -s mode and tried the same again and all the commands while in the session got saved so I tried chmod 777 .bash_history Now the old commands appear at the start of a session but no new commands are getting saved Thanx in advance

    Read the article

  • Wireless acting weird ubuntu 12.04 LTS

    - by Philip Yeldhos
    I'm kinda new here, so please bear with me. My wireless driver is acting very weird. It shows my router's name, but when it is connecting (after entering the correct password), the icon on the tray is like, refreshing every once in a second, while showing the animation that it is connecting. And after a few seconds, error message come up saying that wireless network is disconnected. I installed the drive through "additional drivers". What info do you need? Somebody please help. philip@philip-HP-Mini-110-3100:~$ sudo iwconfig lo no wireless extensions. eth1 IEEE 802.11 ESSID:"" Mode:Managed Frequency:2.472 GHz Access Point: Not-Associated Bit Rate:72 Mb/s Tx-Power:24 dBm Retry min limit:7 RTS thr:off Fragment thr:off Power Management:off Link Quality=5/5 Signal level=0 dBm Noise level=-96 dBm Rx invalid nwid:0 Rx invalid crypt:11 Rx invalid frag:0 Tx excessive retries:0 Invalid misc:0 Missed beacon:0 eth0 no wireless extensions. here's what lspci -v gave me: 02:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller (rev 01) Subsystem: Hewlett-Packard Company Device 1483 Flags: bus master, fast devsel, latency 0, IRQ 17 Memory at 52000000 (64-bit, non-prefetchable) [size=16K] Capabilities: [40] Power Management version 3 Capabilities: [58] Vendor Specific Information: Len=78 <?> Capabilities: [48] MSI: Enable- Count=1/1 Maskable- 64bit+ Capabilities: [d0] Express Endpoint, MSI 00 Capabilities: [100] Advanced Error Reporting Capabilities: [13c] Virtual Channel Capabilities: [160] Device Serial Number 00-00-82-ff-ff-3f-e0-2a Capabilities: [16c] Power Budgeting <?> Kernel driver in use: wl Kernel modules: wl, bcma, brcmsmac okay, i removed the driver additional drivers gave me. now, this is what has happened: lsmod gave me: philip@philip-HP-Mini-110-3100:~$ lsmod | grep brc brcmsmac 540875 0 mac80211 436455 1 brcmsmac brcmutil 14675 1 brcmsmac cfg80211 178679 2 brcmsmac,mac80211 crc8 12781 1 brcmsmac cordic 12487 1 brcmsmac and iwconfig gave me: philip@philip-HP-Mini-110-3100:~$ iwconfig lo no wireless extensions. wlan0 IEEE 802.11bgn ESSID:off/any Mode:Managed Access Point: Not-Associated Tx-Power=19 dBm Retry long limit:7 RTS thr:off Fragment thr:off Power Management:off eth0 no wireless extensions. and lspci -v gave me: 02:00.0 Network controller: Broadcom Corporation BCM4313 802.11b/g/n Wireless LAN Controller (rev 01) Subsystem: Hewlett-Packard Company Device 1483 Flags: bus master, fast devsel, latency 0, IRQ 17 Memory at 52000000 (64-bit, non-prefetchable) [size=16K] Capabilities: <access denied> Kernel driver in use: brcmsmac Kernel modules: bcma, brcmsmac

    Read the article

  • Markdown, LaTeX combined in WYSIWYG editor. Is there any?

    - by om-nom-nom
    I really like the way markdown is implemented in SE bunch of sites, where I can easily write code blocks, performing formatting or even use latex on some of sites like writing $\pi$. I also like how this online editor looks and feels. But it's all online. Is there any offline WYSIWYG analogs of notepag or WMD in Ubuntu that optionally supports pdf as an output format? Both markdown and latex desired. I desire to simultaneously use Markdown and LaTeX. I'm planing to use an editor for writing some technical stuff with math, but it's annoying to be constantly in "LaTeX-mode". So it would be awesome to immerse in LaTeX when I need formulas and use markdown when I need to speak on natural language. UPD. Almost all answers was quite useful, but none of them answers directly on my question. I'll accept @N.N. answer as a most complete.

    Read the article

  • Problems with my Intel HD GC

    - by Stevan Hranisavljevic
    I'm running Ubuntu and I have an Intel HD graphic card, I installed Counter Strike 1.6 and I cannot launch wide screen display mode, parts from the both side of my screen are black. Also when I am playing some clips on YouTube, both sides on the screen are black and I don't see the whole picture. When I click on "About this computer" I'm getting this: Intel® Sandybridge Mobile x86/MMX/SSE2 But I can't find the driver for my Intel GC. I have this driver installed: X.Org X server -- Intel i8xx, i9xx

    Read the article

  • Is Error Recovery Control or TLER necessary for software RAID5 using LVM

    - by Vincent Davis
    I ave been told that for RAID configurations you don't what to use standard desktop drives because they when/if they enter a error recovery mode they might time out and get dropped from the raid. Is this true for LVM software RAID or this this a hardware RAID issue primarily?. We are running this server primarily as a backup server and would like to take advantage of the lower price of the desktop drives.

    Read the article

  • How to change the sprite colors

    - by Mr_Qqn
    In my rhythm game, I have a note object which can be of different colors depending on the note chart. I could use a sprite sheet with all the different color variations I use, but I would prefer to parametrize this. (For information, a note sprite is compound with one main color, for example a red note has only red, light red and dark red.) So, how to change the colors of a sprite basing on a new color ? I'm working with opengl, but any algorithm or math explanation will do. :) Thanks

    Read the article

  • Playing a video logs me out

    - by Kartick Vaddadi
    When I try to play a video in vlc, totem or banshee, it immediately logs me out. Sometimes this happens when I try to full screen the video. This seems to happen only after upgrading to ubuntu 11, and happens for multiple kinds of files, like avi and m4v. The motherboard is Asus a8v-mx. Please help me fix my ubuntu installation. Thanks. Here are the relevant entries from syslog: 21:12:27 enlightenment kernel: [ 488.157457] powernow-k8: Hardware error - pending bit very stuck - no further pstate changes possible May 1 21:12:27 enlightenment kernel: [ 488.158634] powernow-k8: transition frequency failed May 1 21:12:27 enlightenment kernel: [ 488.264015] powernow-k8: failing targ, change pending bit set May 1 21:12:27 enlightenment kernel: [ 488.306466] agpgart-amd64 0000:00:00.0: AGP 3.0 bridge May 1 21:12:27 enlightenment kernel: [ 488.306489] agpgart-amd64 0000:00:00.0: putting AGP V3 device into 8x mode May 1 21:12:27 enlightenment kernel: [ 488.306562] pci 0000:01:00.0: putting AGP V3 device into 8x mode May 1 21:12:27 enlightenment kernel: [ 488.372044] powernow-k8: error - out of sync, fix 0x2 0xa, vid 0x4 0x4 May 1 21:12:27 enlightenment kernel: [ 488.372055] powernow-k8: ph2 null fid transition 0xa May 1 21:12:30 enlightenment rtkit-daemon[1304]: Successfully made thread 1987 of process 1987 (n/a) owned by '105' high priority at nice level -11. May 1 21:12:30 enlightenment rtkit-daemon[1304]: Supervising 1 threads of 1 processes of 1 users. May 1 21:12:30 enlightenment rtkit-daemon[1304]: Successfully made thread 1988 of process 1987 (n/a) owned by '105' RT at priority 5. May 1 21:12:30 enlightenment rtkit-daemon[1304]: Supervising 2 threads of 1 processes of 1 users. May 1 21:12:30 enlightenment rtkit-daemon[1304]: Successfully made thread 1989 of process 1987 (n/a) owned by '105' RT at priority 5. May 1 21:12:30 enlightenment rtkit-daemon[1304]: Supervising 3 threads of 1 processes of 1 users. May 1 21:12:32 enlightenment gdm-simple-greeter[1975]: Gtk-WARNING: /build/buildd/gtk+2.0-2.24.4/gtk/gtkwidget.c:5687: widget not within a GtkWindow May 1 21:12:32 enlightenment gdm-simple-greeter[1975]: WARNING: Unable to load CK history: no seat-id found May 1 21:12:34 enlightenment gdm-session-worker[1978]: GLib-GObject-CRITICAL: g_value_get_boolean: assertion `G_VALUE_HOLDS_BOOLEAN (value)' failed May 1 21:12:38 enlightenment gdm-session-worker[1978]: pam_sm_authenticate: Called May 1 21:12:38 enlightenment gdm-session-worker[1978]: pam_sm_authenticate: username = [rama] May 1 21:12:39 enlightenment rtkit-daemon[1304]: Successfully made thread 2108 of process 2108 (n/a) owned by '1000' high priority at nice level -11. May 1 21:12:39 enlightenment rtkit-daemon[1304]: Supervising 4 threads of 2 processes of 2 users. May 1 21:12:39 enlightenment pulseaudio[2108]: pid.c: Stale PID file, overwriting. May 1 21:12:39 enlightenment rtkit-daemon[1304]: Successfully made thread 2111 of process 2108 (n/a) owned by '1000' RT at priority 5. May 1 21:12:39 enlightenment rtkit-daemon[1304]: Supervising 5 threads of 2 processes of 2 users. May 1 21:12:39 enlightenment rtkit-daemon[1304]: Successfully made thread 2112 of process 2

    Read the article

  • Number crunching algo for learning multithreading?

    - by Austin Henley
    I have never really implemented anything dealing with threads; my only experience with them is reading about them in my undergrad. So I want to change that by writing a program that does some number crunching, but splits it up into several threads. My first ideas for this hopefully simple multithreaded program were: Beal's Conjecture brute force based on my SO question. Bailey-Borwein-Plouffe formula for calculating Pi. Prime number brute force search As you can see I have an interest in math and thought it would be fun to incorporate it into this, rather than coding something such as a server which wouldn't be nearly as fun! But the 3 ideas don't seem very appealing and I have already done some work on them in the past so I was curious if anyone had any ideas in the same spirit as these 3 that I could implement?

    Read the article

  • Sun Blade 6000 Interactive 3D Demo

    - by ferhat
    Three dimensional  fly-by demos of Sun systems are available from your everyday Java-enabled browsers. Oracle's flexible, eco-efficient Sun Blade 6000 chassis integrates Oracle's x86 and SPARC server blade modules with high-capacity networking and storage blades to support a wide range of application environments.  Click on the static picture below to enter the interactive 3D demo mode: Visit Oracle Technology Network pages and product pages for more information on Oracle's Sun Blades Servers.   

    Read the article

  • Why is Spritebatch drawing my Textures out of order?

    - by Andrew
    I just started working with XNA Studio after programming 2D games in java. Because of this, I have absolutely no experience with Spritebatch and sprite sorting. In java, I could just layer the images by calling the draw methods in order. For a while, my Spritebatch was working fine in deferred sorting mode, but when I made a change to one of my textures, it suddenly started drawing them out of order. I have searched for a solution to this problem, but nothing seems to work. I have tried adding layer depths to the sprites and changing the sort mode to BackToFront or FrontToBack or even immediate, but nothing seems to work. Here is my drawing code: protected override void Draw(GameTime gameTime) { GraphicsDevice.Clear(Color.Gray); Game1.spriteBatch.Begin(SpriteSortMode.Deferred, BlendState.AlphaBlend, SamplerState.PointClamp, null, null); for (int x = 0; x < 5; x++) { for (int y = 0; y < 5; y++) { region[x, y].draw(((float)w / aw)); // Draws the Tile-Based background } } player.draw(spriteBatch, ((float)w / aw));//draws the character (This method is where the problem occurs) enemy.draw(spriteBatch, (float)w/aw); // draws a basic enemy Game1.spriteBatch.End(); base.Draw(gameTime); } player.draw method: public void draw(SpriteBatch sb, float ratio){ //draws the player base (The character without hair or equipment) sb.Draw(playerbase[0], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White,0,Vector2.Zero,SpriteEffects.None,0); //draws the player's hair sb.Draw(playerbase[3], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); //draws the player's shirt sb.Draw(equipment[0], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); //draws the player's pants sb.Draw(equipment[1], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); //draws the player's shoes sb.Draw(equipment[2], new Rectangle((int)(pos.X - (24 * ratio)), (int)(pos.Y - (48 * ratio)), (int)(48 * ratio), (int)(48 * ratio)), new Rectangle(orientation * 48, animFrame * 48, 48, 48), Color.White, 0, Vector2.Zero, SpriteEffects.None, 0); } the game has a top-down perspective much like the early legend of zelda games. It draws sections of the texture depending on which direction the character is facing and the animation frame. However, instead of drawing the character in the order the draw methods are called, it ends up drawing the character out of order. Please help me with this problem.

    Read the article

  • Dell Inspiron 1501 no wired/wireless w/12.04 or13.04

    - by Niven
    I don't know what to do. Every install of either 13.04 and 12.04 on my Dell does not have a working wired or wireless internet connection. However, if I am running from USB in the trial mode I have working internet through a wired connection using the same ethernet cord. I honestly at this point do not know what I can do to fix this issue as I have gone through every possible fix I have found here and in other places.

    Read the article

  • IIS 7.0 informational HTTP status codes

    - by Samir R. Bhogayta
    1xx - Informational These HTTP status codes indicate a provisional response. The client computer receives one or more 1xx responses before the client computer receives a regular response. IIS 7.0 uses the following informational HTTP status codes: 100 - Continue. 101 - Switching protocols. 2xx - Success These HTTP status codes indicate that the server successfully accepted the request. IIS 7.0 uses the following success HTTP status codes: 200 - OK. The client request has succeeded. 201 - Created. 202 - Accepted. 203 - Nonauthoritative information. 204 - No content. 205 - Reset content. 206 - Partial content. 3xx - Redirection These HTTP status codes indicate that the client browser must take more action to fulfill the request. For example, the client browser may have to request a different page on the server. Or, the client browser may have to repeat the request by using a proxy server. IIS 7.0 uses the following redirection HTTP status codes: 301 - Moved permanently. 302 - Object moved. 304 - Not modified. 307 - Temporary redirect. 4xx - Client error These HTTP status codes indicate that an error occurred and that the client browser appears to be at fault. For example, the client browser may have requested a page that does not exist. Or, the client browser may not have provided valid authentication information. IIS 7.0 uses the following client error HTTP status codes: 400 - Bad request. The request could not be understood by the server due to malformed syntax. The client should not repeat the request without modifications. IIS 7.0 defines the following HTTP status codes that indicate a more specific cause of a 400 error: 400.1 - Invalid Destination Header. 400.2 - Invalid Depth Header. 400.3 - Invalid If Header. 400.4 - Invalid Overwrite Header. 400.5 - Invalid Translate Header. 400.6 - Invalid Request Body. 400.7 - Invalid Content Length. 400.8 - Invalid Timeout. 400.9 - Invalid Lock Token. 401 - Access denied. IIS 7.0 defines several HTTP status codes that indicate a more specific cause of a 401 error. The following specific HTTP status codes are displayed in the client browser but are not displayed in the IIS log: 401.1 - Logon failed. 401.2 - Logon failed due to server configuration. 401.3 - Unauthorized due to ACL on resource. 401.4 - Authorization failed by filter. 401.5 - Authorization failed by ISAPI/CGI application. 403 - Forbidden. IIS 7.0 defines the following HTTP status codes that indicate a more specific cause of a 403 error: 403.1 - Execute access forbidden. 403.2 - Read access forbidden. 403.3 - Write access forbidden. 403.4 - SSL required. 403.5 - SSL 128 required. 403.6 - IP address rejected. 403.7 - Client certificate required. 403.8 - Site access denied. 403.9 - Forbidden: Too many clients are trying to connect to the Web server. 403.10 - Forbidden: Web server is configured to deny Execute access. 403.11 - Forbidden: Password has been changed. 403.12 - Mapper denied access. 403.13 - Client certificate revoked. 403.14 - Directory listing denied. 403.15 - Forbidden: Client access licenses have exceeded limits on the Web server. 403.16 - Client certificate is untrusted or invalid. 403.17 - Client certificate has expired or is not yet valid. 403.18 - Cannot execute requested URL in the current application pool. 403.19 - Cannot execute CGI applications for the client in this application pool. 403.20 - Forbidden: Passport logon failed. 403.21 - Forbidden: Source access denied. 403.22 - Forbidden: Infinite depth is denied. 404 - Not found. IIS 7.0 defines the following HTTP status codes that indicate a more specific cause of a 404 error: 404.0 - Not found. 404.1 - Site Not Found. 404.2 - ISAPI or CGI restriction. 404.3 - MIME type restriction. 404.4 - No handler configured. 404.5 - Denied by request filtering configuration. 404.6 - Verb denied. 404.7 - File extension denied. 404.8 - Hidden namespace. 404.9 - File attribute hidden. 404.10 - Request header too long. 404.11 - Request contains double escape sequence. 404.12 - Request contains high-bit characters. 404.13 - Content length too large. 404.14 - Request URL too long. 404.15 - Query string too long. 404.16 - DAV request sent to the static file handler. 404.17 - Dynamic content mapped to the static file handler via a wildcard MIME mapping. 404.18 - Querystring sequence denied. 404.19 - Denied by filtering rule. 405 - Method Not Allowed. 406 - Client browser does not accept the MIME type of the requested page. 408 - Request timed out. 412 - Precondition failed. 5xx - Server error These HTTP status codes indicate that the server cannot complete the request because the server encounters an error. IIS 7.0 uses the following server error HTTP status codes: 500 - Internal server error. IIS 7.0 defines the following HTTP status codes that indicate a more specific cause of a 500 error: 500.0 - Module or ISAPI error occurred. 500.11 - Application is shutting down on the Web server. 500.12 - Application is busy restarting on the Web server. 500.13 - Web server is too busy. 500.15 - Direct requests for Global.asax are not allowed. 500.19 - Configuration data is invalid. 500.21 - Module not recognized. 500.22 - An ASP.NET httpModules configuration does not apply in Managed Pipeline mode. 500.23 - An ASP.NET httpHandlers configuration does not apply in Managed Pipeline mode. 500.24 - An ASP.NET impersonation configuration does not apply in Managed Pipeline mode. 500.50 - A rewrite error occurred during RQ_BEGIN_REQUEST notification handling. A configuration or inbound rule execution error occurred. Note Here is where the distributed rules configuration is read for both inbound and outbound rules. 500.51 - A rewrite error occurred during GL_PRE_BEGIN_REQUEST notification handling. A global configuration or global rule execution error occurred. Note Here is where the global rules configuration is read. 500.52 - A rewrite error occurred during RQ_SEND_RESPONSE notification handling. An outbound rule execution occurred. 500.53 - A rewrite error occurred during RQ_RELEASE_REQUEST_STATE notification handling. An outbound rule execution error occurred. The rule is configured to be executed before the output user cache gets updated. 500.100 - Internal ASP error. 501 - Header values specify a configuration that is not implemented. 502 - Web server received an invalid response while acting as a gateway or proxy. IIS 7.0 defines the following HTTP status codes that indicate a more specific cause of a 502 error: 502.1 - CGI application timeout. 502.2 - Bad gateway. 503 - Service unavailable. IIS 7.0 defines the following HTTP status codes that indicate a more specific cause of a 503 error: 503.0 - Application pool unavailable. 503.2 - Concurrent request limit exceeded.

    Read the article

  • AI control for a ship with physics model

    - by Petteri Hietavirta
    I am looking for ideas how to implement following in 2D space. Unfortunately I don't know much about AI/path finding/autonomous control yet. Let's say this ship can move freely but it has mass and momentum. Also, external forces might affect it (explosions etc). The player can set a target for the ship at any time and it should reach that spot and stop. Without physics this would be simple, just point to the direction and go. But how to deal with existing momentum and then stopping on the spot? I don't want to modify ship's placement directly. edit: Just to make clear, the physics related math of the ship itself is not the problem.

    Read the article

< Previous Page | 207 208 209 210 211 212 213 214 215 216 217 218  | Next Page >