Apple Developer Connection 1998 Fall: Game Toolkit/Disc.iso/SDKs/Apple Game Sprockets/DrawSprocket/GoggleSprocket/GoggleSprocketTest Sources/GSpTest_DSpSupport.cp

Text File | 1998-03-12 | 7.7 KB | 327 lines | [TEXT/CWIE]

/*
********************************************************************************
**
** Name: GSpTest_DSpSupport.cp
**
** Description:
**
**    Support routines for using DrawSprocket.
**
********************************************************************************
*/
#include "DrawSprocket.h"

#include "GSpTest_DSpSupport.h"
#include "GSpTest_Main.h"

/*
********************************************************************************
** constants
********************************************************************************
*/
#define kDisplayWidth        640
#define kDisplayHeight        480
#define kDisplayDepth        8
#define kDisplayPages        2

/*
********************************************************************************
** globals
********************************************************************************
*/
DSpContextAttributes gDSpContextAttributes;
DSpContextReference gDSpContext;

/*
********************************************************************************
** private globals
********************************************************************************
*/
static Boolean gDSpStarted = false;

/*
********************************************************************************
** local prototypes
********************************************************************************
*/
static void MyInitContextAttributes( DSpContextAttributes *inAttributes );

/*
********************************************************************************
**
** Name: DisplayInit()
**
** Description:
**
**    Find the best context to use and reserve it.
**
********************************************************************************
*/
OSStatus            // result code
DisplayInit( void )
{
    OSStatus theError;

    // startup DrawSprocket
    theError = DSpStartup();
    if( theError )
        return theError;
    gDSpStarted = true;

    // find the best context
    MyInitContextAttributes( &gDSpContextAttributes );
    theError = DSpFindBestContext( &gDSpContextAttributes, &gDSpContext );
    if( theError )
        return theError;

    // reserve the context
    theError = DSpContext_Reserve( gDSpContext, &gDSpContextAttributes );
    if( theError )
    {
        gDSpContext = NULL;
        return theError;
    }

    return noErr;
}

/*
********************************************************************************
**
** Name: DisplayActivate()
**
** Description:
**
**    Activate the display.
**
********************************************************************************
*/
OSStatus            // result code
DisplayActivate( void )
{
    // make sure we have a context
    if( NULL == gDSpContext )
        return noErr;

    return DSpContext_SetState( gDSpContext, kDSpContextState_Active );
}

/*
********************************************************************************
**
** Name: DisplayPause()
**
** Description:
**
**    Pause the display.
**
********************************************************************************
*/
OSStatus            // result code
DisplayPause( void )
{
    DSpContextState theState;
    OSStatus theError;

    // make sure we have a context
    if( NULL == gDSpContext )
        return noErr;

    // a context must be active before it can be paused
    theError = DSpContext_GetState( gDSpContext, &theState );
    if( theError )
        return theError;
    if( theState != kDSpContextState_Active )
    {
        theError = DisplayActivate();
        if( theError )
            return theError;
    }

    return DSpContext_SetState( gDSpContext, kDSpContextState_Paused );
}

/*
********************************************************************************
**
** Name: DisplayFadeOut()
**
** Description:
**
**    Fade the display out.
**
********************************************************************************
*/
OSStatus            // result code
DisplayFadeOut( void )
{
    // make sure we have a context
    if( NULL == gDSpContext )
        return noErr;

    return DSpContext_FadeGammaOut( NULL, NULL );
}

/*
********************************************************************************
**
** Name: DisplayFadeIn()
**
** Description:
**
**    Fade the display in.
**
********************************************************************************
*/
OSStatus            // result code
DisplayFadeIn( void )
{
    // make sure we have a context
    if( NULL == gDSpContext )
        return noErr;

    return DSpContext_FadeGammaIn( NULL, NULL );
}

/*
********************************************************************************
**
** Name: DisplayRelease
**
** Description:
**
**    Release the display.
**
********************************************************************************
*/
OSStatus            // result code
DisplayRelease( void )
{
    OSStatus theError;

    // make sure we have a context
    if( NULL == gDSpContext )
        return noErr;

    // fade out the display
    DisplayFadeOut();

    // inactivate it
    DSpContext_SetState( gDSpContext, kDSpContextState_Inactive );

    // fade in the display
    DisplayFadeIn();

    // release it
    theError = DSpContext_Release( gDSpContext );
    gDSpContext = NULL;

    // shutdown DrawSprocket
    if( gDSpStarted )
    {
        DSpShutdown();
        gDSpStarted = false;
    }

    return theError;
}

/*
********************************************************************************
**
** Name: DisplayGetBuffer
**
** Description:
**
**    Get the current drawing buffer for the display.
**
********************************************************************************
*/
CGrafPtr
DisplayGetBuffer( void )
{
    OSStatus theError;
    CGrafPtr theBuffer = NULL;

    // get the buffer
    theError = DSpContext_GetBackBuffer( gDSpContext, kDSpBufferKind_Normal,
        &theBuffer );
    if( theError )
        HandleError( theError, true );

    return theBuffer;
}

/*
********************************************************************************
**
** Name: DisplayShowBuffer
**
** Description:
**
**    Show the current drawing buffer for the display.
**
********************************************************************************
*/
OSStatus
DisplayShowBuffer( void )
{
    return DSpContext_SwapBuffers( gDSpContext, NULL, NULL );
}

/******************************************************************************/
#pragma mark -
#pragma mark ## static functions ##

/*
********************************************************************************
**
** Name: MyInitContextAttributes
**
** Description:
**
**    Initialize a context attributes structure so that there is no garbage
**    data in it.  This is important to do because DS will return an error
**    if some fields are set incorrectly (including the "reserved" fields not
**    being set to zero), and some things can actually cause a crash (such
**    as a bogus color table handle).
**
********************************************************************************
*/
static void
MyInitContextAttributes(
    DSpContextAttributes *inAttributes        /* attr structure to init */
)
{
    // init the context attributes structure
    inAttributes->frequency                    = 0;
    inAttributes->displayWidth                = 0;
    inAttributes->displayHeight                = 0;
    inAttributes->reserved1                    = 0;
    inAttributes->reserved2                    = 0;
    inAttributes->colorNeeds                = 0;
    inAttributes->colorTable                = NULL;
    inAttributes->contextOptions            = 0;
    inAttributes->backBufferDepthMask        = 0;
    inAttributes->displayDepthMask            = 0;
    inAttributes->backBufferBestDepth        = 0;
    inAttributes->displayBestDepth            = 0;
    inAttributes->pageCount                    = 0;
    inAttributes->gameMustConfirmSwitch        = false;
    inAttributes->reserved3[0]                = 0;
    inAttributes->reserved3[1]                = 0;
    inAttributes->reserved3[2]                = 0;
    inAttributes->reserved3[3]                = 0;

    // override the values that I want to customize
    inAttributes->displayWidth            = kDisplayWidth;
    inAttributes->displayHeight            = kDisplayHeight;
    inAttributes->colorNeeds            = kDSpColorNeeds_Require;
    inAttributes->colorTable            = NULL;
    inAttributes->backBufferDepthMask    = kDisplayDepth;
    inAttributes->backBufferBestDepth    = kDisplayDepth;
    inAttributes->displayDepthMask        = kDisplayDepth;
    inAttributes->displayBestDepth        = kDisplayDepth;
    inAttributes->pageCount                = kDisplayPages;
}