sdl_macwm.c

SDL库 在进行视频显示程序spcaview安装时必须的库文件

		
		devCount = 0;												/* reset iteration */
		hGDevice = GetDeviceList ();
		do
		{
			pSysGammaOut->devGamma [devCount] = (precDeviceGamma) NewPtr (sizeof (recDeviceGamma));	  /* new device record */
			if (pSysGammaOut->devGamma [devCount])					/* if we actually allocated memory */
			{
				pSysGammaOut->devGamma [devCount]->hGD = hGDevice;										  /* stuff handle */
				pSysGammaOut->devGamma [devCount]->pDeviceGamma = (GammaTblPtr)GetDeviceGamma (hGDevice); /* copy gamma table */
			}
			else													/* otherwise dump record on exit */
			 fail = true;
			devCount++;												/* next device */
			hGDevice = GetNextDevice (hGDevice);						
		} while (hGDevice);
	}
	if (!fail)														/* if we did not fail */
		return (Ptr) pSysGammaOut;									/* return pointer to structure */
	else
	{
		DisposeSystemGammas ((Ptr *) &pSysGammaOut);					/* otherwise dump the current structures (dispose does error checking) */
		return NULL;												/* could not complete */
	}
}

static void RestoreDeviceGamma (GDHandle hGD, Ptr pGammaTable)
{
	VDSetEntryRecord setEntriesRec;
	VDGammaRecord	gameRecRestore;
	CTabHandle      hCTabDeviceColors;
	Ptr				csPtr;
	OSErr			err = noErr;
	
	if (pGammaTable)												/* if we have a table to restore								 */
	{
		gameRecRestore.csGTable = pGammaTable;						/* setup restore record */
		csPtr = (Ptr) &gameRecRestore;
		err = Control((**hGD).gdRefNum, cscSetGamma, (Ptr) &csPtr);	/* restore gamma */

		if ((noErr == err) && (8 == (**(**hGD).gdPMap).pixelSize))	/* if successful and on an 8 bit device */
		{
			hCTabDeviceColors = (**(**hGD).gdPMap).pmTable;			/* do SetEntries to force CLUT update */
			setEntriesRec.csTable = (ColorSpec *) &(**hCTabDeviceColors).ctTable;
			setEntriesRec.csStart = 0;
			setEntriesRec.csCount = (**hCTabDeviceColors).ctSize;
			csPtr = (Ptr) &setEntriesRec;
			
			err = Control((**hGD).gdRefNum, cscSetEntries, (Ptr) &csPtr); /* SetEntries in CLUT */
		}
	}
}

static void RestoreSystemGammas (Ptr pSystemGammas)
{
	short i;
	precSystemGamma pSysGammaIn = (precSystemGamma) pSystemGammas;
	if (pSysGammaIn)
		for (i = 0; i < pSysGammaIn->numDevices; i++)			/* for all devices */
			RestoreDeviceGamma (pSysGammaIn->devGamma [i]->hGD, (Ptr) pSysGammaIn->devGamma [i]->pDeviceGamma);	/* restore gamma */
}

static Ptr CreateEmptyGammaTable (short channels, short entries, short bits)
{
	GammaTblPtr		pTableGammaOut = NULL;
	short			tableSize, dataWidth;

	dataWidth = (bits + 7) / 8;										/* number of bytes per entry */
	tableSize = sizeof (GammaTbl) + (channels * entries * dataWidth);
	pTableGammaOut = (GammaTblPtr) NewPtrClear (tableSize);			/* allocate new tabel */

	if (pTableGammaOut)												/* if we successfully allocated */
	{
		pTableGammaOut->gVersion = 0;								/* set parameters based on input */
		pTableGammaOut->gType = 0;
		pTableGammaOut->gFormulaSize = 0;
		pTableGammaOut->gChanCnt = channels;
		pTableGammaOut->gDataCnt = entries;
		pTableGammaOut->gDataWidth = bits;
	}
	return (Ptr)pTableGammaOut;										/* return whatever we allocated */
}

static Boolean SetDeviceGammaRampGD (GDHandle hGD, Ptr pRamp)
{
	VDSetEntryRecord setEntriesRec;
	VDGammaRecord	gameRecRestore;
	GammaTblPtr		pTableGammaNew;
	GammaTblPtr		pTableGammaCurrent = NULL;
	CTabHandle      hCTabDeviceColors;
	Ptr				csPtr;
	OSErr			err;
	short 			dataBits, entries, channels = 3;						/* force three channels in the gamma table */
	
	if (pRamp)																/* ensure pRamp is allocated */
	{
		err= GetGammaTable (hGD, &pTableGammaCurrent);						/* get pointer to current table */
		if ((noErr == err) && pTableGammaCurrent)
		{
			dataBits = pTableGammaCurrent->gDataWidth;						/* table must have same data width */
			entries = pTableGammaCurrent->gDataCnt;							/* table must be same size */
			pTableGammaNew = (GammaTblPtr) CreateEmptyGammaTable (channels, entries, dataBits); /* our new table */
			if (pTableGammaNew)												/* if successful fill table */
			{	
				unsigned char * pGammaBase = (unsigned char *) &pTableGammaNew->gFormulaData + pTableGammaNew->gFormulaSize; /* base of table */
				if ((256 == entries) && (8 == dataBits)) 						/* simple case: direct mapping */
					BlockMove ((Ptr)pRamp, (Ptr)pGammaBase, channels * entries); /* move everything */
				else														/* tough case handle entry, channel and data size disparities */
				{
					short indexChan, indexEntry;
					short bytesPerEntry = (dataBits + 7) / 8; 				/* size, in bytes, of the device table entries */
					short shiftRightValue = 8 - dataBits;					/* number of right shifts ramp -> device */
					shiftRightValue += ((bytesPerEntry - 1) * 8);  			/* multibyte entries and the need to map a byte at a time most sig. to least sig. */
					for (indexChan = 0; indexChan < channels; indexChan++) /* for all the channels */
						for (indexEntry = 0; indexEntry < entries; indexEntry++) /* for all the entries */
						{
							short currentShift = shiftRightValue;			/* reset current bit shift */
							long temp = *((unsigned char *)pRamp + (indexChan << 8) + (indexEntry << 8) / entries); /* get data from ramp */
							short indexByte;
							for (indexByte = 0; indexByte < bytesPerEntry; indexByte++) /* for all bytes */
							{
								if (currentShift < 0)						/* shift data correctly for current byte */
									*(pGammaBase++) = temp << -currentShift;
								else
									*(pGammaBase++) = temp >> currentShift;
								currentShift -= 8;							/* increment shift to align to next less sig. byte */
							}
						}
				}
				
				/* set gamma */
				gameRecRestore.csGTable = (Ptr) pTableGammaNew;				/* setup restore record */
				csPtr = (Ptr) &gameRecRestore;
				err = Control((**hGD).gdRefNum, cscSetGamma, (Ptr) &csPtr);	/* restore gamma (note, display drivers may delay returning from this until VBL) */
				
				if ((8 == (**(**hGD).gdPMap).pixelSize) && (noErr == err))	/* if successful and on an 8 bit device */
				{
					hCTabDeviceColors = (**(**hGD).gdPMap).pmTable;			/* do SetEntries to force CLUT update */
					setEntriesRec.csTable = (ColorSpec *) &(**hCTabDeviceColors).ctTable;
					setEntriesRec.csStart = 0;
					setEntriesRec.csCount = (**hCTabDeviceColors).ctSize;
					csPtr = (Ptr) &setEntriesRec;
					err = Control((**hGD).gdRefNum, cscSetEntries, (Ptr) &csPtr);	/* SetEntries in CLUT */
				}
				DisposeGammaTable ((Ptr) pTableGammaNew);					/* dump table */
				if (noErr == err)
					return true;
			}
		}
	}
	else																	/* set NULL gamma -> results in linear map */
	{
		gameRecRestore.csGTable = (Ptr) NULL;								/* setup restore record */
		csPtr = (Ptr) &gameRecRestore;
		err = Control((**hGD).gdRefNum, cscSetGamma, (Ptr) &csPtr);			/* restore gamma */
		
		if ((8 == (**(**hGD).gdPMap).pixelSize) && (noErr == err))			/* if successful and on an 8 bit device */
		{
			hCTabDeviceColors = (**(**hGD).gdPMap).pmTable;					/* do SetEntries to force CLUT update */
			setEntriesRec.csTable = (ColorSpec *) &(**hCTabDeviceColors).ctTable;
			setEntriesRec.csStart = 0;
			setEntriesRec.csCount = (**hCTabDeviceColors).ctSize;
			csPtr = (Ptr) &setEntriesRec;
			err = Control((**hGD).gdRefNum, cscSetEntries, (Ptr) &csPtr);	/* SetEntries in CLUT */
		}
		if (noErr == err)
			return true;
	}
	return false;															/* memory allocation or device control failed if we get here */
}

/* end of ADC Gamma Ramp support code... */

static Ptr systemGammaPtr;

void Mac_QuitGamma(_THIS)
{
	if (systemGammaPtr)
	{
		RestoreSystemGammas(systemGammaPtr);
		DisposeSystemGammas(&systemGammaPtr);
	}
}

static unsigned char shiftedRamp[3 * 256];

int Mac_SetGammaRamp(_THIS, Uint16 *ramp)
{
	int i;
	if (!systemGammaPtr)
		systemGammaPtr = GetSystemGammas();
	for (i = 0; i < 3 * 256; i++)
	{
		shiftedRamp[i] = ramp[i] >> 8;
	}

	if (SetDeviceGammaRampGD(GetMainDevice(), (Ptr) shiftedRamp))
		return 0;
	else
		return -1;
}

int Mac_GetGammaRamp(_THIS, Uint16 *ramp)
{
	if (GetDeviceGammaRampGD(GetMainDevice(), (Ptr) shiftedRamp))
	{
		int i;
		for (i = 0; i < 3 * 256; i++)
		{
			ramp[i] = shiftedRamp[i] << 8;
		}
		return 0;
	}
	else
		return -1;
}

#endif  /* SDL_MACCLASSIC_GAMMA_SUPPORT */