Direct Input

Allows device independent access/control to the KB, mouse, joystick & all other forms of input devices in a uniform manner.

Ned’s Turkey Farm doesn’t use DirectInput, it uses the Win API.

Direct Input recognizes 3 types of devices:

· keyboard,

· mouse and

· all others are considered joysticks.

Consists of:

· run-time dlls

· dinput.h

· dinput.lib

To use:

· create DI object with DirectInput8Create()

· create one or more input devices with CreateDevice() passing it the GUID of the device to create.

o GUID_SysKeyboard: your primary KB

o GUID_SysMouse: your mouse

· set the cooperation level for each device with SetCooperativeLevel()

· set the data format of each device with SetDataFormat() and set any special properties with SetProperty()

· attach each device to your application with Acquire()

· receive input with GetDeviceState() or call Poll() if device needs manual polling (most joysticks require polling)

DI works so well you can completely cut Windows out of the loop.

Creating a DI object

HRESULT DirectInputCreate(<hinst>, // app handle

<version>, // set to DIRECTINPUT_VERSION

<reference ID> // set to IID_IDIRECTINPUT8

<ptr DI obj>, // addr of ptr to DI interface

NULL);

Ex:

#include <DINPUT.H>

LPDIRECTINPUT8 lpdi = NULL; // DI obj ptr

If (DirectInputCreate(hinstance, DIRECTINPUT_VERSION,

_IDIRECTINPUT8, (void**)&lpdi, NULL) != DI_OK)

{/* error */}

and when done using the interface, free resources with:

if (lpdi) lpdi->Release();

Note. Always release all the DI devices you created first!

The Keyboard

· create KB device – this is an interface to the desired device

· set cooperative level for KB

· set data format

· acquire the KB

creating KB device

HRESULT CreateDevice(GUID_<device type>,

<device ptr>, NULL);

Ex:

#define INITGUID // defines kb guid

#include <OBJBASE.H>

#include <dinput.h>

…

LPDIRECTINPUTDEVICE8 lpdiKey = NULL; // KB ptr

If ( CreateDevice(GUID_SysKeyboard, &lpdiKey, NULL) !=

DI_OK)

{/* error */}

At this point lpdiKey points to you KB interface, so you can now call its methods

(use GUID_SysMouse for the mouse, call EnumDevices() to get a globally unique ID for all other devices.)

and when done using the device, free resources with:

if (lpdiKey) lpdiKey->Release(); // do before lpdi->Release()

Seting coop level

HRESULT SetCooperativeLevel(<hwnd>, <flags>);

Flag value

DISCL_BACKGROUND	Can use DI device in foreground or background
DISCL _FOREGROUND	Requires foreground access
DISCL _EXCLUSIVE	After you acquire device no other app. can request exclusive access to it, but can request nonexclusive
DISCL _NONEXCLUSIVE	Shareable access

Use DISCL_BACKGROUND | DISCL_NONEXCLUSIVE for most applications. FORGROUND will not send it data unless it is on top.

Ex:

If (SetCooperativeLevel(hwnd, DISCL_BACKGROUND | DISCL_NONEXCLUSIVE) != DD_OK) // error

Set Data Format

HRESULT SetDataFormat(<fmt ptr>);

typedef struct

{ DWORD dwSize;

DWORD dwObjSize; // bytes in OBJ below

DWORD dwFlags;

DWORD dwDataSize; // data packet size

DWORD dwNumObjs; //# obj in next array

LPDIOBJECTDATAFORMAT rgodf; // array of objs

} DIDATAFORMAT, * LPDIDATAFORMAT;

This is such a mess that MS created 3 predefined structs:

· c_dfDIKeyboard

· c_dfDIMouse

· c_dfDIJoystick

· c_dfDIJoystick2 – force feedback device

therefore you only need to

lpdikey->SetDataFormat(&c_dfDIKeyboard);

now:

lpdikey->Acquire();

Reading the Device

When you’re ready to read some data from the KB use:

HRESULT GetDeviceState(<data size>, < buff ptr>);

Ex:

UCHAR keyState[256]; // buff to hold state info

// read the KB

If (lpdikey->GetDeviceState(256, keyState) != DI_OK)

{/* error */}

else

{ // test for key press

if (keyState[DIK_RIGHT] & 0X80) // right arrow pressed

…

Values:

DIK_ESCAPE/0-9/A-Z/RETURN/LCONTROL/RCONTROL /SPACE/F1-F12/UP/DOWN/LEFT/RIGHT/PRIOR/NEXT

(see help for complete list)

When done with kb:

lpdiKey->Unacquire();

lpdiKey->Release();

KB demo:

// WINX GAME PROGRAMMING CONSOLE FUNCTIONS

int GameInit(void *parms)

{

// this function is where you do all the initialization

// for your game

int index; // looping var

char filename[80]; // used to build up files names

// initialize directdraw

DD_Init(SCREEN_WIDTH, SCREEN_HEIGHT, SCREEN_BPP);

// keyboard creation section

// first create the direct input object

if (DirectInputCreate(mainInstance,DIRECTINPUT_VERSION,&lpdi,NULL)!=DI_OK)

return(0);

// create a keyboard device

if (lpdi->CreateDevice(GUID_SysKeyboard, &lpdikey, NULL)!=DI_OK)

return(0);

// set cooperation level

if (lpdikey->SetCooperativeLevel(mainWindowHandle,

DISCL_NONEXCLUSIVE | DISCL_BACKGROUND)!=DI_OK)

return(0);

// set data format

if (lpdikey->SetDataFormat(&c_dfDIKeyboard)!=DI_OK)

return(0);

// acquire the keyboard

if (lpdikey->Acquire()!=DI_OK)

return(0);

// load the background

Load_Bitmap_File(&bitmap8bit, "REACTOR.BMP");

// set the palette to background image palette

Set_Palette(bitmap8bit.palette);

// create and load the reactor bitmap image

Create_Bitmap(&reactor, 0,0, 640, 480);

Load_Image_Bitmap(&reactor,&bitmap8bit,0,0,BITMAP_EXTRACT_MODE_ABS);

Unload_Bitmap_File(&bitmap8bit);

// now let's load in all the frames for the skelaton!!!

// create skelaton bob

if (!Create_BOB(&skelaton,0,0,56,72,32,

BOB_ATTR_VISIBLE | BOB_ATTR_MULTI_ANIM,DDSCAPS_SYSTEMMEMORY))

return(0);

// load the frames in 8 directions, 4 frames each

// each set of frames has a walk and a fire, frame sets

// are loaded in counter clockwise order looking down

// from a birds eys view or the x-z plane

for (int direction = 0; direction < 8; direction++)

{

// build up file name

sprintf(filename,"SKELSP%d.BMP",direction);

// load in new bitmap file

Load_Bitmap_File(&bitmap8bit,filename);

Load_Frame_BOB(&skelaton,&bitmap8bit,0+direction*4,0,0,BITMAP_EXTRACT_MODE_CELL);

Load_Frame_BOB(&skelaton,&bitmap8bit,1+direction*4,1,0,BITMAP_EXTRACT_MODE_CELL);

Load_Frame_BOB(&skelaton,&bitmap8bit,2+direction*4,2,0,BITMAP_EXTRACT_MODE_CELL);

Load_Frame_BOB(&skelaton,&bitmap8bit,3+direction*4,0,1,BITMAP_EXTRACT_MODE_CELL);

// unload the bitmap file

Unload_Bitmap_File(&bitmap8bit);

// set the animation sequences for skelaton

Load_Animation_BOB(&skelaton,direction,4,skelaton_anims[direction]);

} // end for direction

// set up stating state of skelaton

Set_Animation_BOB(&skelaton, 0);

Set_Anim_Speed_BOB(&skelaton, 4);

Set_Vel_BOB(&skelaton, 0,0);

Set_Pos_BOB(&skelaton, 0, 128);

// set clipping rectangle to screen extents so mouse cursor

// doens't mess up at edges

RECT screen_rect = {0,0,screen_width,screen_height};

lpddclipper = DD_Attach_Clipper(lpddsback,1,&screen_rect);

// hide the mouse

ShowCursor(FALSE);

// return success

return(1);

} // end GameInit

int GameShutdown(void *parms)

{

// this function is where you shutdown your game and

// release all resources that you allocated

// kill the reactor

Destroy_Bitmap(&reactor);

// kill skelaton

Destroy_BOB(&skelaton);

// release keyboard

lpdikey->Unacquire();

lpdikey->Release();

lpdi->Release();

// shutdown directdraw

DD_Shutdown();

// return success

return(1);

} // end GameShutdown

int GameMain(void *parms)

{

// this is the workhorse of your game it will be called

// continuously in real-time this is like main() in C

// all the calls for you game go here!

int index; // looping var

int dx,dy; // general deltas used in collision detection

static int player_moving = 0; // tracks player motion

static PALETTEENTRY glow = {0,0,0,PC_NOCOLLAPSE}; // used to animation red border

// check of user is trying to exit

if (KEY_DOWN(VK_ESCAPE) || KEY_DOWN(VK_SPACE))

PostMessage(mainWindowHandle, WM_DESTROY,0,0);

// start the timing clock

Start_Clock();

// clear the drawing surface

DD_Fill_Surface(lpddsback, 0);

// lock the back buffer

DD_Lock_Back_Surface();

// draw the background reactor image

Draw_Bitmap(&reactor, back_buffer, back_lpitch, 0);

// unlock the back buffer

DD_Unlock_Back_Surface();

// get player input

// get the keyboard data

lpdikey->GetDeviceState(256, (LPVOID)keyboard_state);

// reset motion flag

player_moving = 0;

// test direction of motion, this is a good example of testing the keyboard

// although the code could be optimized this is more educational

if (keyboard_state[DIK_RIGHT] && keyboard_state[DIK_UP])

{

// move skelaton

skelaton.x+=2;

skelaton.y-=2;

dx=2; dy=-2;

// set motion flag

player_moving = 1;

// check animation needs to change

if (skelaton.curr_animation != SKELATON_NEAST)

Set_Animation_BOB(&skelaton,SKELATON_NEAST);

} // end if

else if (keyboard_state[DIK_LEFT] && keyboard_state[DIK_UP])

{

// move skelaton

skelaton.x-=2;

skelaton.y-=2;

dx=-2; dy=-2;

// set motion flag

player_moving = 1;

// check animation needs to change

if (skelaton.curr_animation != SKELATON_NWEST)

Set_Animation_BOB(&skelaton,SKELATON_NWEST);

} // end if

else if (keyboard_state[DIK_LEFT] && keyboard_state[DIK_DOWN])

{

// move skelaton

skelaton.x-=2;

skelaton.y+=2;

dx=-2; dy=2;

// set motion flag

player_moving = 1;

// check animation needs to change

if (skelaton.curr_animation != SKELATON_SWEST)

Set_Animation_BOB(&skelaton,SKELATON_SWEST);

} // end if

else if (keyboard_state[DIK_RIGHT] && keyboard_state[DIK_DOWN])

{

// move skelaton

skelaton.x+=2;

skelaton.y+=2;

dx=2; dy=2;

// set motion flag

player_moving = 1;

// check animation needs to change

if (skelaton.curr_animation != SKELATON_SEAST)

Set_Animation_BOB(&skelaton,SKELATON_SEAST);

} // end if

else if (keyboard_state[DIK_RIGHT])

{

// move skelaton

skelaton.x+=2;

dx=2; dy=0;

// set motion flag

player_moving = 1;

// check animation needs to change

if (skelaton.curr_animation != SKELATON_EAST)

Set_Animation_BOB(&skelaton,SKELATON_EAST);

} // end if

else if (keyboard_state[DIK_LEFT])

{

// move skelaton

skelaton.x-=2;

dx=-2; dy=0;

// set motion flag

player_moving = 1;

// check animation needs to change

if (skelaton.curr_animation != SKELATON_WEST)

Set_Animation_BOB(&skelaton,SKELATON_WEST);

} // end if

else if (keyboard_state[DIK_UP])

{

// move skelaton

skelaton.y-=2;

dx=0; dy=-2;

// set motion flag

player_moving = 1;

// check animation needs to change

if (skelaton.curr_animation != SKELATON_NORTH)

Set_Animation_BOB(&skelaton,SKELATON_NORTH);

} // end if

else if (keyboard_state[DIK_DOWN])

{

// move skelaton

skelaton.y+=2;

dx=0; dy=+2;

// set motion flag

player_moving = 1;

// check animation needs to change

if (skelaton.curr_animation != SKELATON_SOUTH)

Set_Animation_BOB(&skelaton,SKELATON_SOUTH);

} // end if

// only animate if player is moving

if (player_moving)

{

// animate skelaton

Animate_BOB(&skelaton);

// see if skelaton hit a wall

// lock surface, so we can scan it

DD_Lock_Back_Surface();

// call the color scanner with 29, the color of the glowing wall

// try to center the scan in the center of the object to make it

// more realistic

if (Color_Scan(skelaton.x+16, skelaton.y+16,

skelaton.x+skelaton.width-16, skelaton.y+skelaton.height-16,

29, back_buffer,back_lpitch))

{

// back the skelaton up along its last trajectory

skelaton.x-=dx;

skelaton.y-=dy;

} // end if

// done, so unlock

DD_Unlock_Back_Surface();

} // end if

// draw the skelaton

Draw_BOB(&skelaton, lpddsback);

// animate green energy border

glow.peGreen = rand()%256;

Set_Palette_Entry(29, &glow);

// draw some text

Draw_Text_GDI("WHERE IS EVERYBODY? I HAVE A BONE TO PICK!",0,0,RGB(0,0,255),lpddsback);

Draw_Text_GDI("USE ARROW KEYS TO MOVE ME.",0,SCREEN_HEIGHT-32,RGB(10,10,10),lpddsback);

// flip the surfaces

DD_Flip();

// sync to 3o fps

Wait_Clock(30);

// return success

return(1);

} // end GameMain