Game ProgrammingGame Programming(User Input)(User Input)2011. Spring

The Keyboard

■ The Keyboard Most widely available input device

• The main input device for PC-based games• Also available for mobile phones, some consoles, and

palm devices Disadvantages

• Not very well suited for games• Impractical for small children

User Input : No broad standards are available

The Keyboard■ Keyboard read methods

Synchronous routine• Wait until a key is pressed and then report it to the application• Not well suited for real gameplay• Ex) type information such as the character name in a RPG

Asynchronous routine• Return immediately after being called, and give the application

information about which keys were pressed• Two different routines

A single-key asynchronous call− Test the state of individual keys

A whole keyboard check − Retrieve the whole keyboard state in a single call− Less overhead, more efficient

The Keyboard

■ Asynchronous routine A single-key asynchronous call

• Win32 API (table 5.1)

How to check whether the key is pressed

How to test for the key combination

If ( GetAsynKeyState(VK_LSHIFT) ) { // whatever}

Short GetAsyncKeyState(int keycode);

If ( GetAsynKeyState(VK_LSHIFT) &&GetAsynKeyState(VK_RETRUN) ) { // whatever}

Each key test requires a system call, which can be troublesome for those systems checking a lot of different keys

The Keyboard

■ Asynchronous routine A whole keyboard check

• How to check whether the key is pressed a simple array lookup

Bool GetKeyboardState(PBYTE *lpKeyState);

If ( keyState[VK_RSHIFT] ) { // right shift was pressed}

This mode does not immediately check the keys when you perform the test Undesirable side effects might occur (the array will contain “old” key values)

The Keyboard

■ Keyboard with DirectInput A single call can retrieve the state of the whole keyboard

• Provide fast asynchronous access to key states Encapsulates keyboards, joystick, mice and any other input Setting up a keyboard DirectInput

1. Create the DirectInput object2. Create the keyboard device3. Set the data format for reading it4. Set the cooperative level you will use with the OS5. Read data as needed

The Keyboard

■ DirectInput Declaration : 1. Create the DirectInput object

LPDIRECTINPUT8 g_pDI=NULL; LPDIRECTINPUTDEVICE g_pKeyboard;HRESULT hr;

hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );

hr = g_pDI->CreateDevice( GUID_SysKeyboard, &g_pKeyboard, NULL);hr = g_pKeyboard->SetDataFormat( &c_dfDIKeyboard); hr = g_pKeyboard->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);hr = g_pKeyboard->Acquire();

DirectInput object ready for use :1 parameter: send the instance handle to the application that is creating the DirectInput object2 parameter: pass the current DirectInput version number3 parameter: pass the unique interface identifier for the object we are requesting (can use other parameters to define ANSI or Unicode versions of the interface)4 parameter: pass the pointer so we can receive the already initialized object5 parameter: perform Component Object Model (COM) aggregation

The Keyboard

■ DirectInput Declaration : 2. Create the keyboard device

LPDIRECTINPUT8 g_pDI=NULL; LPDIRECTINPUTDEVICE g_pKeyboard;HRESULT hr;hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );

hr = g_pDI->CreateDevice( GUID_SysKeyboard, &g_pKeyboard, NULL);

hr = g_pKeyboard->SetDataFormat( &c_dfDIKeyboard); hr = g_pKeyboard->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);hr = g_pKeyboard->Acquire();

Request a device from the DirectInput object1 parameter : Receive Global Unique Identifier (GUID) for the desired device GUIDs for the different devices (128-bit structures) GUID_SysKeyboard: default system keyboard GUID_SysMouse: default system mouse2 parameter : the pointer to the newly created device3 parameter : reserved for aggregation

The Keyboard

■ DirectInput Declaration : 3. Set the data format for reading it

LPDIRECTINPUT8 g_pDI=NULL; LPDIRECTINPUTDEVICE g_pKeyboard;HRESULT hr;hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );hr = g_pDI->CreateDevice( GUID_SysKeyboard, &g_pKeyboard, NULL);

hr = g_pKeyboard->SetDataFormat( &c_dfDIKeyboard);

hr = g_pKeyboard->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);hr = g_pKeyboard->Acquire();

Tell the keyboard how we want to exchange data (pp. 127)1 parameter : c_dfDIKeyboard the full keyboard stored in an array of 256 bytes

The Keyboard

■ DirectInput Declaration : 4. Set the cooperative level you will use with the OS

LPDIRECTINPUT8 g_pDI=NULL; LPDIRECTINPUTDEVICE g_pKeyboard;HRESULT hr;hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );hr = g_pDI->CreateDevice( GUID_SysKeyboard, &g_pKeyboard, NULL);hr = g_pKeyboard->SetDataFormat( &c_dfDIKeyboard);

hr = g_pKeyboard->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);

hr = g_pKeyboard->Acquire();Tell DirectInput about the cooperative level1 parameter : pass the window handle2 parameter : the OR of a series of flags that control the cooperative level

The Keyboard

■ DirectInput Declaration : 5. Read data as needed

LPDIRECTINPUT8 g_pDI=NULL; LPDIRECTINPUTDEVICE g_pKeyboard;HRESULT hr; hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );hr = g_pDI->CreateDevice( GUID_SysKeyboard, &g_pKeyboard, NULL);hr = g_pKeyboard->SetDataFormat( &c_dfDIKeyboard); hr = g_pKeyboard->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);

hr = g_pKeyboard->Acquire();

Acquire the keyboard Can begin querying its state

The Keyboard

■ DirectInput Reading the keyboard

Query a specific key (pp. 128)

Releasing the keyboard

BYTE diks[256]; // DirectInput keyboard state bufferZeroMemory( diks, sizeof(diks) );hr = g_pKeyboard->GetDeviceState( sizeof(diks), diks );If ( FAILED(hr) ) { hr = g_pKeyboard->Acquire(); while ( hr == DIERR_INPUTLOST || hr == DIEER_OTHERAPPHASPRIO) hr = g_pKeyboard->Acquire();}

If ( g_pKeyboard ) g_pKeyboard->Unacquire();SAFE_RELEASE( g_pKeyboard );SAFE_RELEASE( g_pDI );

Bool return_pressed = ( buffer[DIK_RETURN] & 0x80 ) ! = 0);

The most significant bit is activatedIf the key is currently pressed

Mouse

■ The Mouse Not only generate button or key press, but 2D positions as

well The operation of the mouse

• Transmitting positional information• Sending button press and release message

Mouse

■ DirectInput declaration

LPDIRECTINPUT8 g_pDI=NULL;LPDIRECTINPUTDEVICE g_pMouse;HRESULT hr;hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );

hr = g_pDI->CreateDevice( GUID_SysMouse, &g_pMouse, NULL);hr = g_pMouse->SetDataFormat( &c_dfDIMouse); hr = g_pMouse->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);hr = g_pMouse->Acquire();

Mouse

■ DirectInput Reading from the mouse

DIMOUSESTATE dims; // DirectInput mouse state structureZeroMemory( &dims, sizeof(dims) );hr = g_pMouse->GetDeviceState( sizeof(DIMOUSESTATE), &dims );If ( FAILED(hr) ) { hr = g_pMouse->Acquire(); while ( hr == DIERR_INPUTLOST || hr == DIEER_OTHERAPPHASPRIO || hr == DIEER_NOTACTIVATED) hr = g_pMouse->Acquire();}

Mouse■ DirectInput

Access the mouse attributes

• Button 0: left mouse button • Button 1: right mouse button• Button 2: middle button• Relative pointing device

Return the displacement from the last one Release the mouse

If ( g_pMouse ) g_pMouse->Unacquire();SAFE_RELEASE( g_pMouse );SAFE_RELEASE( g_pDI );

Int MouseX=dims.lX;Int MouseY=dims.lY;bool lbutton = ( dims.rgbButtons[0] & 0x80 ) ! = 0);

Buttons are pressed if the high-order bit is set

Typedef struct DIMOUSESTATE { LONG lX, lY, lZ; BYTE rgbButtons[4];} DIMOUSESTATE, *LPDIMOUSESTATE

Mouselook

■ Mouselook The classic mouselook used in many first person shooters

• The keys to change our position X and Z values

• The mouse to reorient our viewpoint A yaw and pitch angle (Ref] Camera)

• Mapping Mouse: Mouselook Left arrow: Strafe left Right arrow: Strafe right Up arrow: Move forward Down arrow: Move back

Mouselook

■ Implementation// strafe and fwd by -1, 0, or 1int strafe = (buffer[DIK_RIGHT] & 0x80) != 0) – (buffer[DIK_LEFT] & 0x80) != 0) ; int fwd = (buffer[DIK_UP] & 0x80) != 0) – (buffer[DIK_DOWN] & 0x80) != 0) ;

// elapsed : elapsed time factor ensure device-independent performancepos.x += fwd*FWDSPEED*elapsed*cos(yaw) + strafe*STRAFESPEED*elapsed*cos(yaw+3.1416/2);pos.z += fwd*FWDSPEED*elapsed*sin(yaw) + strafe*STRAFESPEED*elapsed*sin(yaw+3.1416/2);

yaw += YAWSPEED*elapsed*dims.lX;pitch += PITCHSPEED*elapsed*dims.lY;

// lookat: spherical mapping using the pitch and yawpoint campos( pos.x, pos.y, pos.z );point camlookat( pos.x+cos(yaw)*cos(pitch), pos.y+sin(pitch), pos.z+sin(yaw)*cos(pitch) );

Joysticks

■ Joystick Introduced in the 1970s as a way to represent positional data Controlling a joystick

LPDIRECTINPUT8 g_pDI=NULL; LPDIRECTINPUTDEVICE g_pJoystick;HRESULT hr;hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );

hr = g_pDI->EnumDevice( DI8DEVCLASS_GAMECTRL, EnumJoysticksCallback, NULL, DIEDFL_ATTACHEDONLY);hr = g_pJoystick->SetDataFormat( &c_dfDIJoystick); hr = g_pJoystick->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);g_pJoystick->EnumObjects(EnumObjectsCallback, (VOID*)hwnd, DIDFT_ALL);

Joysticks

■ Controlling a joystickLPDIRECTINPUT8 g_pDI=NULL; LPDIRECTINPUTDEVICE g_pJoystick;HRESULT hr;hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );hr = g_pDI->EnumDevice( DI8DEVCLASS_GAMECTRL, // game pads and joystick EnumJoysticksCallback, NULL, DIEDFL_ATTACHEDONLY);hr = g_pJoystick->SetDataFormat( &c_dfDIJoystick); hr = g_pJoystick->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);g_pJoystick->EnumObjects(EnumObjectsCallback, (VOID*)hwnd, DIDFT_ALL);Ask DirectInput to enumerate any joystick it is detecting:

1 parameter: tells DirectInput which kind of device we want to detect (keyboard DI8DEVCLASS_KEYBOARD, mouse DI8DEVCLASS_POINTER)2 parameter: a callback that will get triggered once for each detected joystick3 parameter: user-defined parameter to be passed to the callback4 parameter: the enumeration flags (DIEDFL_ATTACHEDONLY only detect devices that are properly attached and installed DIEDFL_FORCEFEEDBACK restrict the enumeration to force feedback)

Joysticks

■ Controlling a joystickLPDIRECTINPUT8 g_pDI=NULL; LPDIRECTINPUTDEVICE g_pJoystick;HRESULT hr;hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );hr = g_pDI->EnumDevice( DI8DEVCLASS_GAMECTRL, // game pads and joystick EnumJoysticksCallback, NULL, DIEDFL_ATTACHEDONLY);hr = g_pJoystick->SetDataFormat( &c_dfDIJoystick); hr = g_pJoystick->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);g_pJoystick->EnumObjects(EnumObjectsCallback, (VOID*)hwnd, DIDFT_ALL);BOOL CALLBACK EnumJoysticksCallback(const DIDEVICEINSTANCE *

pdidInstance, VOID* pContext ) { HRESULT hr= g_pDI->createdevice( pdidInstance->guidInstance, &g_pJoystick, NULL); if (FAILED(hr)) return DIENUM_CONTINUE; return DIENUM_STOP;}

Joysticks

■ Controlling a joystickLPDIRECTINPUT8 g_pDI=NULL; LPDIRECTINPUTDEVICE g_pJoystick;HRESULT hr;hr = DirectInput8Create( GetModuleHandle (NULL), DIRECTINPUT_VERSION, IID_IDirectInput8, (VOID**) &g_pDI, NULL );hr = g_pDI->EnumDevice( DI8DEVCLASS_GAMECTRL, // game pads and joystick EnumJoysticksCallback, NULL, DIEDFL_ATTACHEDONLY);hr = g_pJoystick->SetDataFormat( &c_dfDIJoystick); hr = g_pJoystick->SetCooperativeLevel( hwnd, DISCL_FOREGROUND | DISCL_EXCLUSIVE);g_pJoystick->EnumObjects(EnumObjectsCallback, (VOID*)hwnd, DIDFT_ALL);

Set the data format and cooperative level

Joysticks

■ Controlling a joystickg_pJoystick->EnumObjects(EnumObjectsCallback, (VOID*)hwnd, DIDFT_ALL);Set the output range for the joystick (Ex: -1…1 , -100…100 )

1 parameter: Need to a callback that request the objects associated with the joystick (Objects axes, buttons, POVs, and so on)

BOOL CALLBACK EnumObjectsCallback(const DIDEVICEINSTANCE * pdidInstance, VOID* pContext ) { HWND hDlg =(HWND)pContext; if (pdidoi->dwType & DIDFT_AXIS) { DIPROPRANGE diprg; diprg.diph.dwSize = sizeof(DIPROPRANGE); diprg.diph.dwHeaderSize= sizeof(DIPROHEADER); diprg.diph.dwHow = DIPH_BYID; diprg.diph.dwObj = pdidoi->dwType; diprg.diph.lMin = -100; diprg.diph.lMax = 100; if (FAILED(g_pJoystick->SetProperty(DIPROP_RANGE, &diprg.diph))) return DIENUM_STOP; }}

Joysticks

■ Reading from the joystickhr = g_pMouse->Poll();If ( FAILED(hr) ) { hr = g_pJoystick->Acquire(); while ( hr == DIERR_INPUTLOST || hr == DIEER_OTHERAPPHASPRIO) hr = g_pJoystick->Acquire(); return S_OK;}DIJOYSTATE js;hr = g_pJoystick->GetDeviceState ( sizeof (DIJOYSTATE), &js));

typedef struct DIJOYSTATE { LONG lX, lY, lZ; LONG lRx, lRy, lRz; LONG rglSlider[2]; DWORD rgdwPOV[4]; BYTE rgbButtons[32];} DIJOYSTATE, *LPDIJOYSTATE

Joysticks

POV (point of view) switch

Joysticks

■ Response Curve How analog joysticks map the controller position to a

continuous range of values• Left, Still, Right ??

Response Curve without(left) and with(right) dead zone

Joysticks

■ Analog controller Return a value in a continuous range Need a response curve

Types of Response Curve

Hardware Abstraction■ Platforms that support a variety of input controllers

Ex) Standard controller, aircraft-style-joystick, snowboards, dance pads, fishing rod

■ Coding for such a platform Choose to use only one of the existing controllers

• Ex) strategy games (with a PC mouse) Let the user choose the input method

• Ex) Action games■ Hardware Abstraction

Coding the game with a “virtual” controller Controllers that conform to that abstract profile

• via inheritance

Hardware Abstraction Action mapping

• Allows your device to return not specific state values but game-oriented values

• Assign device events to game events Device independence Ex) “advance left” joystick(a movement on the X-axis)

enum GAME_ACTIONS { WALK, WALK_LEFT, WALK_RIGHT, JUMP, QUIT};

DIACTION g_adiaActionMap[ ] = {// Joystick input mappings{ WALK, DIAXIS_FIGHTINGH_LATERAL, 0, ACTION_NAMES [WALK], },{ JUMP, DIBUTTON_FIGHTINGH_JUMP, 0, ACTION_NAMES [JUMP], },

// Keyboard input mappings{ WALK_LEFT, DIKEYBOARD_LEFT, 0, ACTION_NAMES [WALK_LEFT], },{ WALK_RIGHT, DIKEYBOARD_RIGHT, 0, ACTION_NAMES [WALK_RIGHT], },{ JUMP, DIKEYBOARD_J, 0, ACTION_NAMES [JUMP], },{ QUIT, DIKEYBOARD_Q, DIA_APPFIXED, ACTION_NAMES [QUIT], },

// Mouse input mappings{ WALK, DIMOUSE_XAXIS, 0, ACTION_NAMES [WALK], },{ JUMP, DIMOUSE_BUTTON0, 0, ACTION_NAMES [JUMP], },};

Force Feedback■ Force Feedback

Force Feedback H/W simulates vibration by incorporating one or more motors

■ Programming force feedback devices (platform dependent)1. Create or describe the desired effect (Ex. Force Editor)

• How it affects the controller’s position, and strength, and so on2. The effect must be loaded to the input API3. Reproduce the effect at runtime

MS’s Force Editor

Types of game controllers

■ Game Pad (= joypad) the most common kind of game controller Gamepads generally feature a set of action buttons handled

with the right thumb and a direction controller(D-pad) handled with the left

shoulder buttons placed along the edges of the pad, centrally placed start, select, and mode buttons, and an internal motor to provide force feedback.

Types of game controllers

■ Paddle A paddle is a controller that features a round wheel and one

or more fire buttons The wheel is typically used to control movement of the player

or of an object along one axis of the video screen

■ Trackball A trackball is basically an upside-down mouse that is

manipulated with the palm of one's hand

Types of game controllers

■ Arcade style Joystick It features a shaft that has a ball or drop-shaped handle, and

one or more buttons for in game actions

■ Steering wheel The steering wheel, essentially a larger version of a paddle, is

used for racing simulators■ Pedals

Pedals may be used for driving simulations or flight simulations

Types of game controllers

■ Touch screen A touch screen is an input device that allows the user to

interact with the computer by touching the display screen■ Motion sensing

It uses accelerometers to detect its approximate orientation and acceleration and an image sensor[1] so it can be used as a pointing device

Microsoft has also released the Kinect, similar to Sony's Eyetoy, both of which use cameras to detect the player's motions and translate them into inputs for the game.

Types of game controllers

■ Light gun A light gun is a peripheral used to "shoot" targets on a

screen■ Dance pad

a flat electronic game controller used for input in dance games

■ Balance Board contains multiple pressure sensors that are used to measure

the user's center of balance

Types of game controllers

■ Others Rhythm games controller

• guitars, drums, turntablism or maracas

Fishing rod

Microphone Mind-controlled headset