view src/video/maccommon/SDL_macwm.c @ 4157:baf615f9f2a0 SDL-1.2

Date: Thu, 16 Oct 2008 20:27:34 +0400 From: "Ilya Kasnacheev" <ilya.kasnacheev@gmail.com> To: sdl@lists.libsdl.org Subject: [SDL] SDL for Windows CE: a few GAPI patches Hi *! I've just ported a POWDER roguelike ( http://www.zincland.com/powder/ ) to Windows CE (PDAs, Windows Mobile/Pocket PC). To do that, I had to get libsdl working. Thanks for the awesome project files, it built without a hitch. Nevertheless, I've found quite a few bugs in Windows CE (GAPI) SDL implementation, which I've solved and now present as a serie of patches. I'll try carefully annotate them. Please annotate them so I can work toward accepting them into the main source tree since without them SDL isn't really working on Windows CE (I wonder why nobody fixed them before, btw: why isn't SDL popular as a way to develop Windows CE games? Where are no ports?) These changes can't be considered flawless, but they can be considered working because I've yet to hear complains about things I fixed and POWDER build for Windows CE is now considered stable. Note: my comments start with !!, delete them before applying. diff -bru SDL-1.2.13/src/video/gapi/SDL_gapivideo.c SDL-1.2.13-new/src/video/gapi/SDL_gapivideo.c --- SDL-1.2.13/src/video/gapi/SDL_gapivideo.c 2007-12-31 07:48:00.000000000 +0300 +++ SDL-1.2.13-new/src/video/gapi/SDL_gapivideo.c 2008-10-16 20:02:11.000000000 +0400 @@ -643,6 +643,7 @@ } gapi->userOrientation = SDL_ORIENTATION_UP; + gapi->systemOrientation = SDL_ORIENTATION_UP; video->flags = SDL_FULLSCREEN; /* Clear flags, GAPI supports fullscreen only */ /* GAPI or VGA? */ @@ -661,18 +662,21 @@ } /* detect user landscape mode */ - if( (width > height) && (GetSystemMetrics(SM_CXSCREEN) < GetSystemMetrics(SM_CYSCREEN))) + if( (width > height) && (gapi->gxProperties.cxWidth < gapi->gxProperties.cyHeight)) gapi->userOrientation = SDL_ORIENTATION_RIGHT; + if(GetSystemMetrics(SM_CYSCREEN) < GetSystemMetrics(SM_CXSCREEN)) + gapi->systemOrientation = SDL_ORIENTATION_RIGHT; + /* shall we apply hires fix? for example when we do not use hires resource */ gapi->hiresFix = 0; - if( gapi->userOrientation == SDL_ORIENTATION_RIGHT ) + if( gapi->systemOrientation == gapi->userOrientation ) { - if( (width > GetSystemMetrics(SM_CYSCREEN)) || (height > GetSystemMetrics(SM_CXSCREEN))) + if( (width > GetSystemMetrics(SM_CXSCREEN)) || (height > GetSystemMetrics(SM_CYSCREEN))) gapi->hiresFix = 1; } else - if( (width > GetSystemMetrics(SM_CXSCREEN)) || (height > GetSystemMetrics(SM_CYSCREEN))) - if( !((width == GetSystemMetrics(SM_CYSCREEN)) && (height == GetSystemMetrics(SM_CXSCREEN)))) // user portrait, device landscape + if( (width > GetSystemMetrics(SM_CYSCREEN)) || (height > GetSystemMetrics(SM_CXSCREEN))) +// if( !((width == gapi->gxProperties.cyHeight) && (height == gapi->gxProperties.cxWidth))) // user portrait, device landscape gapi->hiresFix = 1; switch( gapi->userOrientation ) !! It used to query system metrics which return dimensions according to screen !! orientation, which can really be portrait, left landscape or right landscape. !! This is presumably incorrect because we couldn't care less about user mode !! dimensions - all we want are the GAPI framebuffer dimensions, which only match !! user dimensions in one of possible orientations. !! There's a fair dose of cargo cult programming involved in this fix, but it !! used to work only in one orientation (portrait for PDAs, where frame-buffer !! have same orientation as user screen), and now it works on all orientations. @@ -742,21 +746,30 @@ WIN_FlushMessageQueue(); /* Open GAPI display */ - if( !gapi->useVga && this->hidden->useGXOpenDisplay ) + if( !gapi->useVga && this->hidden->useGXOpenDisplay && !this->hidden->alreadyGXOpened ) + { + this->hidden->alreadyGXOpened = 1; if( !gapi->gxFunc.GXOpenDisplay(SDL_Window, GX_FULLSCREEN) ) { SDL_SetError("Couldn't initialize GAPI"); return(NULL); } + } #if REPORT_VIDEO_INFO printf("Video properties:\n"); printf("display bpp: %d\n", gapi->gxProperties.cBPP); printf("display width: %d\n", gapi->gxProperties.cxWidth); printf("display height: %d\n", gapi->gxProperties.cyHeight); + printf("system display width: %d\n", GetSystemMetrics(SM_CXSCREEN)); + printf("system display height: %d\n", GetSystemMetrics(SM_CYSCREEN)); printf("x pitch: %d\n", gapi->gxProperties.cbxPitch); printf("y pitch: %d\n", gapi->gxProperties.cbyPitch); printf("gapi flags: 0x%x\n", gapi->gxProperties.ffFormat); + printf("user orientation: %d\n", gapi->userOrientation); + printf("system orientation: %d\n", gapi->userOrientation); + printf("gapi orientation: %d\n", gapi->gapiOrientation); + if( !gapi->useVga && this->hidden->useGXOpenDisplay && gapi->needUpdate) { !! Previous version used to call gapi->gxFunc.GXOpenDisplay each time the video !! mode would be changed. You shouldn't, because this call has a meaning "Lock the !! GAPI framebuffer, designate it as busy", so the second call will fail (it is !! already locked/busy). !! Testing might not find that because most programs set up the video mode only !! once, but POWDER does this once in a while, so it crashed when in 320x240 mode !! (640x480 mode doesn't use that code, it worked fine). diff -bru SDL-1.2.13/src/video/gapi/SDL_gapivideo.h SDL-1.2.13-new/src/video/gapi/SDL_gapivideo.h --- SDL-1.2.13/src/video/gapi/SDL_gapivideo.h 2007-12-31 07:48:00.000000000 +0300 +++ SDL-1.2.13-new/src/video/gapi/SDL_gapivideo.h 2008-10-16 20:02:11.000000000 +0400 @@ -132,12 +132,17 @@ #define NUM_MODELISTS 4 /* 8, 16, 24, and 32 bits-per-pixel */ int SDL_nummodes[NUM_MODELISTS]; SDL_Rect **SDL_modelist[NUM_MODELISTS]; + // The orientation of the video mode user wants to get + // Probably restricted to UP and RIGHT enum SDL_ScreenOrientation userOrientation; int invert; char hiresFix; // using hires mode without defining hires resource // -------------- int useGXOpenDisplay; /* use GXOpenDispplay */ + int alreadyGXOpened; int w, h; + // The orientation of GAPI framebuffer. + // Never changes on the same device. enum SDL_ScreenOrientation gapiOrientation; void *buffer; // may be 8, 16, 24, 32 bpp @@ -153,6 +158,10 @@ int startOffset; // in bytes int useVga; int suspended; // do not pu anything into video memory + // The orientation of the system, as defined by SM_CXSCREEN and SM_CYSCREEN + // User can change it by using 'screen layout' in system options + // Restricted to UP or RIGHT + enum SDL_ScreenOrientation systemOrientation; }; !! This is a flag variable, see the previous comment !! And yet another orientation: now we have to keep three of them in mind. diff -bru SDL-1.2.13/src/video/wincommon/SDL_sysevents.c SDL-1.2.13-new/src/video/wincommon/SDL_sysevents.c --- SDL-1.2.13/src/video/wincommon/SDL_sysevents.c 2007-12-31 07:48:02.000000000 +0300 +++ SDL-1.2.13-new/src/video/wincommon/SDL_sysevents.c 2008-10-16 20:02:12.000000000 +0400 @@ -160,10 +160,22 @@ #endif */ } break; + // FIXME: Older version used just SDL_VideoSurface->(w, h) + // w and h are "clipped" while x and y are "raw", which caused + // x in former and y in latter case to be clipped in a wrong direction, + // thus offsetting the coordinate on 2 x clip pixels + // (like, 128 for 640 -> 512 clipping). + // We will now try to extract and use raw values. + // The way to do that RIGHT is do (orientation-dependent) clipping before + // doing this transform, but it's hardly possible. + + // SEE SDL_mouse.c /ClipOffset to understand these calculations. case SDL_ORIENTATION_RIGHT: if (!SDL_VideoSurface) break; - rotatedX = SDL_VideoSurface->w - *y; + rotatedX = (2 * ((SDL_VideoSurface->offset%SDL_VideoSurface->pitch)/ + SDL_VideoSurface->format->BytesPerPixel)) + + SDL_VideoSurface->w - *y; rotatedY = *x; *x = rotatedX; *y = rotatedY; @@ -172,7 +184,8 @@ if (!SDL_VideoSurface) break; rotatedX = *y; - rotatedY = SDL_VideoSurface->h - *x; + rotatedY = (2 * (SDL_VideoSurface->offset/SDL_VideoSurface->pitch)) + + SDL_VideoSurface->h - *x; *x = rotatedX; *y = rotatedY; break; !! That's the trickest part, hence the long comment. !! GAPI would really support only 320x240 or 640x480 mode, if application !! requested the different screen size (as POWDER did, wishing 256x192), then SDL !! is going to grab the first mode that fits the requested, and pad the screen !! with black bars (as they do with wide-screen films). !! It would also get, say, 240x320 mode, and to turn it into 256x192 it would !! need to rotate mouse clicks. !! It worked, but one bug slipped through: it would receive mouse clicks !! unpadded, then rotate them, and then pad the black bars. The problem is: rotate !! is done by GAPI driver while padding is done by SDL core. SDL core doesn't know !! anything about rotating, so it would pad one of dimensions incorrectly. I understand that some of my claims (or code) might seem unbacked, but you can always grab the POWDER binary, compile your own libsdl with one or more of those fixes turned off, and see how weird it would misbehave. I can even supply you with those custom builds of libsdl if you don't want to set up the build environment for windows ce, you'll just need a PDA or a smartphone with it. I plan to take care of SDL on Windows CE as long as I maintain the POWDER port. POWDER is good for that because it: Employs both padded (with centered image, black bars) and unpadded (image occupies full screen) graphics; initializes video more than once; uses both 320x240 and 640x480 video; uses both stylus and buttons. There's still a list of unresolved issues which I'm planning to fix: 1) Arrow buttons on PDA return weird scancodes compared to PC, this caused the game to misbehave before I've fixed that. You can see it on those diagrams: http://wrar.name/upload/powder-htc.png http://wrar.name/upload/powder-pda.png 2) SDL (or underlying windows) doesn't care to rotate arrow presses when we're in a low-res GAPI mode, but it will rotate them in VGA mode (because of different screen orientations, the same arrow buttons can suddently mean different directions). Solution: we should stick to GAPI user orientation (the orientation the program supposedly wants) and rotate the keys on our own. _______________________________________________ SDL mailing list SDL@lists.libsdl.org http://lists.libsdl.org/listinfo.cgi/sdl-libsdl.org
author Sam Lantinga <slouken@libsdl.org>
date Fri, 07 Nov 2008 04:15:36 +0000
parents 7cdb1d7fc93b
children a1b03ba2fcd0
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#if defined(__APPLE__) && defined(__MACH__)
#include <Carbon/Carbon.h>
#elif TARGET_API_MAC_CARBON && (UNIVERSAL_INTERFACES_VERSION > 0x0335)
#include <Carbon.h>
#else
#include <Windows.h>
#include <Strings.h>
#endif

#if SDL_MACCLASSIC_GAMMA_SUPPORT
#include <Devices.h>
#include <Files.h>
#include <MacTypes.h>
#include <QDOffscreen.h>
#include <Quickdraw.h>
#include <Video.h>
#endif

#include "SDL_stdinc.h"
#include "SDL_macwm_c.h"

void Mac_SetCaption(_THIS, const char *title, const char *icon)
{
	/* Don't convert C to P string in place, because it may be read-only */
	Str255		ptitle; /* MJS */
	ptitle[0] = strlen (title);
	SDL_memcpy(ptitle+1, title, ptitle[0]); /* MJS */
	if (SDL_Window)
		SetWTitle(SDL_Window, ptitle); /* MJS */
}

#if SDL_MACCLASSIC_GAMMA_SUPPORT
/*
 * ADC Gamma Ramp support...
 *
 * Mac Gamma Ramp code was originally from sample code provided by
 *  Apple Developer Connection, and not written specifically for SDL:
 * "Contains: Functions to enable Mac OS device gamma adjustments using 3 channel 256 element 8 bit gamma ramps
 *  Written by: Geoff Stahl (ggs)
 *  Copyright: Copyright (c) 1999 Apple Computer, Inc., All Rights Reserved
 *  Disclaimer: You may incorporate this sample code into your applications without
 *              restriction, though the sample code has been provided "AS IS" and the
 *              responsibility for its operation is 100% yours.  However, what you are
 *              not permitted to do is to redistribute the source as "DSC Sample Code"
 *              after having made changes. If you're going to re-distribute the source,
 *              we require that you make it clear in the source that the code was
 *              descended from Apple Sample Code, but that you've made changes."
 * (The sample code has been integrated into this file, and thus is modified from the original Apple sources.)
 */

typedef struct recDeviceGamma											/* storage for device handle and gamma table */
{
	GDHandle hGD;												/* handle to device */
	GammaTblPtr pDeviceGamma;									/* pointer to device gamma table */
} recDeviceGamma;
typedef recDeviceGamma * precDeviceGamma;

typedef struct recSystemGamma											/* storage for system devices and gamma tables */
{
	short numDevices;											/* number of devices */
	precDeviceGamma * devGamma;									/* array of pointers to device gamma records */
} recSystemGamma;
typedef recSystemGamma * precSystemGamma;

static Ptr CopyGammaTable (GammaTblPtr pTableGammaIn)
{
	GammaTblPtr		pTableGammaOut = NULL;
	short			tableSize, dataWidth;

	if (pTableGammaIn)												/* if there is a table to copy  */
	{
		dataWidth = (pTableGammaIn->gDataWidth + 7) / 8;			/* number of bytes per entry */
		tableSize = sizeof (GammaTbl) + pTableGammaIn->gFormulaSize +
					(pTableGammaIn->gChanCnt * pTableGammaIn->gDataCnt * dataWidth);
		pTableGammaOut = (GammaTblPtr) NewPtr (tableSize);			/* allocate new table */
		if (pTableGammaOut)											
			BlockMove( (Ptr)pTableGammaIn, (Ptr)pTableGammaOut, tableSize);	/* move everything */
	}
	return (Ptr)pTableGammaOut;										/* return whatever we allocated, could be NULL */
}

static OSErr GetGammaTable (GDHandle hGD, GammaTblPtr * ppTableGammaOut)
{
	VDGammaRecord   DeviceGammaRec;
	CntrlParam		cParam;
	OSErr			err;
	
	cParam.ioCompletion = NULL;										/* set up control params */
	cParam.ioNamePtr = NULL;
	cParam.ioVRefNum = 0;
	cParam.ioCRefNum = (**hGD).gdRefNum;
	cParam.csCode = cscGetGamma;									/* Get Gamma commnd to device */
	*(Ptr *)cParam.csParam = (Ptr) &DeviceGammaRec;					/* record for gamma */

	err = PBStatusSync( (ParmBlkPtr)&cParam );						/* get gamma */
	
	*ppTableGammaOut = (GammaTblPtr)(DeviceGammaRec.csGTable);		/* pull table out of record */
	
	return err;	
}

static Ptr GetDeviceGamma (GDHandle hGD)
{
	GammaTblPtr		pTableGammaDevice = NULL;
	GammaTblPtr		pTableGammaReturn = NULL;	
	OSErr			err;
	
	err = GetGammaTable (hGD, &pTableGammaDevice);					/* get a pointer to the devices table */
	if ((noErr == err) && pTableGammaDevice)						/* if succesful */
		pTableGammaReturn = (GammaTblPtr) CopyGammaTable (pTableGammaDevice); /* copy to global */

	return (Ptr) pTableGammaReturn;
}

static void DisposeGammaTable (Ptr pGamma)
{
	if (pGamma)
		DisposePtr((Ptr) pGamma);									/* get rid of it */
}

static void DisposeSystemGammas (Ptr* ppSystemGammas)
{
	precSystemGamma pSysGammaIn;
	if (ppSystemGammas)
	{
		pSysGammaIn = (precSystemGamma) *ppSystemGammas;
		if (pSysGammaIn)
		{
			short i;
			for (i = 0; i < pSysGammaIn->numDevices; i++)		/* for all devices */
				if (pSysGammaIn->devGamma [i])						/* if pointer is valid */
				{
					DisposeGammaTable ((Ptr) pSysGammaIn->devGamma [i]->pDeviceGamma); /* dump gamma table */
					DisposePtr ((Ptr) pSysGammaIn->devGamma [i]);					   /* dump device info */
				}
			DisposePtr ((Ptr) pSysGammaIn->devGamma);				/* dump device pointer array		 */
			DisposePtr ((Ptr) pSysGammaIn);							/* dump system structure */
			*ppSystemGammas = NULL;
		}	
	}
}

static Boolean GetDeviceGammaRampGD (GDHandle hGD, Ptr pRamp)
{
	GammaTblPtr		pTableGammaTemp = NULL;
	long 			indexChan, indexEntry;
	OSErr			err;
	
	if (pRamp)															/* ensure pRamp is allocated */
	{
		err = GetGammaTable (hGD, &pTableGammaTemp);					/* get a pointer to the current gamma */
		if ((noErr == err) && pTableGammaTemp)							/* if successful */
		{															
			/* fill ramp */
			unsigned char * pEntry = (unsigned char *) &pTableGammaTemp->gFormulaData + pTableGammaTemp->gFormulaSize; /* base of table */
			short bytesPerEntry = (pTableGammaTemp->gDataWidth + 7) / 8; /* size, in bytes, of the device table entries */
			short shiftRightValue = pTableGammaTemp->gDataWidth - 8; 	 /* number of right shifts device -> ramp */
			short channels = pTableGammaTemp->gChanCnt;	
			short entries = pTableGammaTemp->gDataCnt;									
			if (3 == channels)											/* RGB format */
			{															/* note, this will create runs of entries if dest. is bigger (not linear interpolate) */
				for (indexChan = 0; indexChan < channels; indexChan++)
					for (indexEntry = 0; indexEntry < 256; indexEntry++)
						*((unsigned char *) pRamp + (indexChan * 256) + indexEntry) = 
						  *(pEntry + indexChan * entries * bytesPerEntry + indexEntry * entries * bytesPerEntry / 256) >> shiftRightValue;
			}
			else														/* single channel format */
			{
				for (indexChan = 0; indexChan < 768; indexChan += 256)	/* repeat for all 3 channels (step by ramp size) */
					for (indexEntry = 0; indexEntry < 256; indexEntry++) /* for all entries set vramp value */
						*((unsigned char *) pRamp + indexChan + indexEntry) = 
						  *(pEntry + indexEntry * entries * bytesPerEntry / 256) >> shiftRightValue;
			}
			return true;
		}
	}
	return false;
}

static Ptr GetSystemGammas (void)
{
	precSystemGamma pSysGammaOut;									/* return pointer to system device gamma info */
	short devCount = 0;												/* number of devices attached */
	Boolean fail = false;
	GDHandle hGDevice;
	
	pSysGammaOut = (precSystemGamma) NewPtr (sizeof (recSystemGamma)); /* allocate for structure */
	
	hGDevice = GetDeviceList ();							/* top of device list */
	do																/* iterate */
	{
		devCount++;													/* count devices					 */
		hGDevice = GetNextDevice (hGDevice);						/* next device */
	} while (hGDevice);
	
	pSysGammaOut->devGamma = (precDeviceGamma *) NewPtr (sizeof (precDeviceGamma) * devCount); /* allocate for array of pointers to device records */
	if (pSysGammaOut)
	{
		pSysGammaOut->numDevices = devCount;						/* stuff count */
		
		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 */