src/gallium/winsys/xlib/xlib_softpipe.c - fp2-dev/platform/external/mesa3d - Gitiles

 /**************************************************************************
  *
  * Copyright 2007 Tungsten Graphics, Inc., Bismarck, ND., USA
  * All Rights Reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the
  * "Software"), to deal in the Software without restriction, including
  * without limitation the rights to use, copy, modify, merge, publish,
  * distribute, sub license, and/or sell copies of the Software, and to
  * permit persons to whom the Software is furnished to do so, subject to
  * the following conditions:
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
  * THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
  * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
  * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
  * USE OR OTHER DEALINGS IN THE SOFTWARE.
  *
  * The above copyright notice and this permission notice (including the
  * next paragraph) shall be included in all copies or substantial portions
  * of the Software.
  *
  *
  **************************************************************************/

 /*
  * Authors:
  *   Keith Whitwell
  *   Brian Paul
  */


 #include "xm_api.h"

 #undef ASSERT
 #undef Elements

 #include "pipe/internal/p_winsys_screen.h"
 #include "pipe/p_format.h"
 #include "pipe/p_context.h"
 #include "pipe/p_inlines.h"
 #include "util/u_format.h"
 #include "util/u_math.h"
 #include "util/u_memory.h"
 #include "softpipe/sp_winsys.h"
 #include "softpipe/sp_texture.h"

 #include "xlib.h"

 /**
  * Subclass of pipe_buffer for Xlib winsys.
  * Low-level OS/window system memory buffer
  */
 struct xm_buffer
 {
    struct pipe_buffer base;
    boolean userBuffer;  /** Is this a user-space buffer? */
    void *data;
    void *mapped;

    XImage *tempImage;
 #ifdef USE_XSHM
    int shm;
    XShmSegmentInfo shminfo;
 #endif
 };


 /**
  * Subclass of pipe_winsys for Xlib winsys
  */
 struct xmesa_pipe_winsys
 {
    struct pipe_winsys base;
 /*   struct xmesa_visual *xm_visual; */
 };


 /** Cast wrapper */
 static INLINE struct xm_buffer *
 xm_buffer( struct pipe_buffer *buf )
 {
    return (struct xm_buffer *)buf;
 }


 /**
  * X Shared Memory Image extension code
  */

 #ifdef USE_XSHM

 static volatile int mesaXErrorFlag = 0;

 /**
  * Catches potential Xlib errors.
  */
 static int
 mesaHandleXError(Display *dpy, XErrorEvent *event)
 {
    (void) dpy;
    (void) event;
    mesaXErrorFlag = 1;
    return 0;
 }


 static char *alloc_shm(struct xm_buffer *buf, unsigned size)
 {
    XShmSegmentInfo *const shminfo = & buf->shminfo;

    shminfo->shmid = shmget(IPC_PRIVATE, size, IPC_CREAT|0777);
    if (shminfo->shmid < 0) {
       return NULL;
    }

    shminfo->shmaddr = (char *) shmat(shminfo->shmid, 0, 0);
    if (shminfo->shmaddr == (char *) -1) {
       shmctl(shminfo->shmid, IPC_RMID, 0);
       return NULL;
    }

    shminfo->readOnly = False;
    return shminfo->shmaddr;
 }


 /**
  * Allocate a shared memory XImage back buffer for the given XMesaBuffer.
  */
 static void
 alloc_shm_ximage(struct xm_buffer *b, struct xmesa_buffer *xmb,
                  unsigned width, unsigned height)
 {
    /*
     * We have to do a _lot_ of error checking here to be sure we can
     * really use the XSHM extension.  It seems different servers trigger
     * errors at different points if the extension won't work.  Therefore
     * we have to be very careful...
     */
    int (*old_handler)(Display *, XErrorEvent *);

    b->tempImage = XShmCreateImage(xmb->xm_visual->display,
                                   xmb->xm_visual->visinfo->visual,
                                   xmb->xm_visual->visinfo->depth,
                                   ZPixmap,
                                   NULL,
                                   &b->shminfo,
                                   width, height);
    if (b->tempImage == NULL) {
       b->shm = 0;
       return;
    }


    mesaXErrorFlag = 0;
    old_handler = XSetErrorHandler(mesaHandleXError);
    /* This may trigger the X protocol error we're ready to catch: */
    XShmAttach(xmb->xm_visual->display, &b->shminfo);
    XSync(xmb->xm_visual->display, False);

    if (mesaXErrorFlag) {
       /* we are on a remote display, this error is normal, don't print it */
       XFlush(xmb->xm_visual->display);
       mesaXErrorFlag = 0;
       XDestroyImage(b->tempImage);
       b->tempImage = NULL;
       b->shm = 0;
       (void) XSetErrorHandler(old_handler);
       return;
    }

    b->shm = 1;
 }

 #endif /* USE_XSHM */


 /* Most callbacks map direcly onto dri_bufmgr operations:
  */
 static void *
 xm_buffer_map(struct pipe_winsys *pws, struct pipe_buffer *buf,
               unsigned flags)
 {
    struct xm_buffer *xm_buf = xm_buffer(buf);
    xm_buf->mapped = xm_buf->data;
    return xm_buf->mapped;
 }

 static void
 xm_buffer_unmap(struct pipe_winsys *pws, struct pipe_buffer *buf)
 {
    struct xm_buffer *xm_buf = xm_buffer(buf);
    xm_buf->mapped = NULL;
 }

 static void
 xm_buffer_destroy(struct pipe_buffer *buf)
 {
    struct xm_buffer *oldBuf = xm_buffer(buf);

    if (oldBuf->data) {
 #ifdef USE_XSHM
       if (oldBuf->shminfo.shmid >= 0) {
          shmdt(oldBuf->shminfo.shmaddr);
          shmctl(oldBuf->shminfo.shmid, IPC_RMID, 0);

          oldBuf->shminfo.shmid = -1;
          oldBuf->shminfo.shmaddr = (char *) -1;
       }
       else
 #endif
       {
          if (!oldBuf->userBuffer) {
             align_free(oldBuf->data);
          }
       }

       oldBuf->data = NULL;
    }

    free(oldBuf);
 }


 /**
  * Display/copy the image in the surface into the X window specified
  * by the XMesaBuffer.
  */
 static void
 xlib_softpipe_display_surface(struct xmesa_buffer *b,
                               struct pipe_surface *surf)
 {
    XImage *ximage;
    struct softpipe_texture *spt = softpipe_texture(surf->texture);
    struct xm_buffer *xm_buf = xm_buffer(spt->buffer);
    static boolean no_swap = 0;
    static boolean firsttime = 1;

    if (firsttime) {
       no_swap = getenv("SP_NO_RAST") != NULL;
       firsttime = 0;
    }

    if (no_swap)
       return;

 #ifdef USE_XSHM
    if (xm_buf->shm)
    {
       if (xm_buf->tempImage == NULL)
       {
          assert(util_format_get_blockwidth(surf->texture->format) == 1);
          assert(util_format_get_blockheight(surf->texture->format) == 1);
          alloc_shm_ximage(xm_buf, b, spt->stride[surf->level] /
                           util_format_get_blocksize(surf->texture->format), surf->height);
       }

       ximage = xm_buf->tempImage;
       ximage->data = xm_buf->data;

       /* _debug_printf("XSHM\n"); */
       XShmPutImage(b->xm_visual->display, b->drawable, b->gc,
                    ximage, 0, 0, 0, 0, surf->width, surf->height, False);
    }
    else
 #endif
    {
       /* display image in Window */
       ximage = b->tempImage;
       ximage->data = xm_buf->data;

       /* check that the XImage has been previously initialized */
       assert(ximage->format);
       assert(ximage->bitmap_unit);

       /* update XImage's fields */
       ximage->width = surf->width;
       ximage->height = surf->height;
       ximage->bytes_per_line = spt->stride[surf->level];

       /* _debug_printf("XPUT\n"); */
       XPutImage(b->xm_visual->display, b->drawable, b->gc,
                 ximage, 0, 0, 0, 0, surf->width, surf->height);
    }
 }


 static void
 xm_flush_frontbuffer(struct pipe_winsys *pws,
                      struct pipe_surface *surf,
                      void *context_private)
 {
    /*
     * The front color buffer is actually just another XImage buffer.
     * This function copies that XImage to the actual X Window.
     */
    XMesaContext xmctx = (XMesaContext) context_private;
    xlib_softpipe_display_surface(xmctx->xm_buffer, surf);
    xmesa_check_and_update_buffer_size(xmctx, xmctx->xm_buffer);
 }


 static const char *
 xm_get_name(struct pipe_winsys *pws)
 {
    return "Xlib";
 }


 static struct pipe_buffer *
 xm_buffer_create(struct pipe_winsys *pws,
                  unsigned alignment,
                  unsigned usage,
                  unsigned size)
 {
    struct xm_buffer *buffer = CALLOC_STRUCT(xm_buffer);

    pipe_reference_init(&buffer->base.reference, 1);
    buffer->base.alignment = alignment;
    buffer->base.usage = usage;
    buffer->base.size = size;

    if (buffer->data == NULL) {
       /* align to 16-byte multiple for Cell */
       buffer->data = align_malloc(size, max(alignment, 16));
    }

    return &buffer->base;
 }


 /**
  * Create buffer which wraps user-space data.
  */
 static struct pipe_buffer *
 xm_user_buffer_create(struct pipe_winsys *pws, void *ptr, unsigned bytes)
 {
    struct xm_buffer *buffer = CALLOC_STRUCT(xm_buffer);
    pipe_reference_init(&buffer->base.reference, 1);
    buffer->base.size = bytes;
    buffer->userBuffer = TRUE;
    buffer->data = ptr;

    return &buffer->base;
 }


 static struct pipe_buffer *
 xm_surface_buffer_create(struct pipe_winsys *winsys,
                          unsigned width, unsigned height,
                          enum pipe_format format,
                          unsigned usage,
                          unsigned tex_usage,
                          unsigned *stride)
 {
    const unsigned alignment = 64;
    unsigned nblocksy, size;

    nblocksy = util_format_get_nblocksy(format, height);
    *stride = align(util_format_get_stride(format, width), alignment);
    size = *stride * nblocksy;

 #ifdef USE_XSHM
    if (!debug_get_bool_option("XLIB_NO_SHM", FALSE))
    {
       struct xm_buffer *buffer = CALLOC_STRUCT(xm_buffer);

       pipe_reference_init(&buffer->base.reference, 1);
       buffer->base.alignment = alignment;
       buffer->base.usage = usage;
       buffer->base.size = size;
       buffer->userBuffer = FALSE;
       buffer->shminfo.shmid = -1;
       buffer->shminfo.shmaddr = (char *) -1;
       buffer->shm = TRUE;

       buffer->data = alloc_shm(buffer, size);
       if (!buffer->data)
          goto out;

       return &buffer->base;

    out:
       if (buffer)
          FREE(buffer);
    }
 #endif


    return winsys->buffer_create(winsys, alignment,
                                 usage,
                                 size);
 }


 /*
  * Fence functions - basically nothing to do, as we don't create any actual
  * fence objects.
  */

 static void
 xm_fence_reference(struct pipe_winsys *sws, struct pipe_fence_handle **ptr,
                    struct pipe_fence_handle *fence)
 {
 }


 static int
 xm_fence_signalled(struct pipe_winsys *sws, struct pipe_fence_handle *fence,
                    unsigned flag)
 {
    return 0;
 }


 static int
 xm_fence_finish(struct pipe_winsys *sws, struct pipe_fence_handle *fence,
                 unsigned flag)
 {
    return 0;
 }


 static struct pipe_winsys *
 xlib_create_softpipe_winsys( void )
 {
    static struct xmesa_pipe_winsys *ws = NULL;

    if (!ws) {
       ws = CALLOC_STRUCT(xmesa_pipe_winsys);

       /* Fill in this struct with callbacks that pipe will need to
        * communicate with the window system, buffer manager, etc.
        */
       ws->base.buffer_create = xm_buffer_create;
       ws->base.user_buffer_create = xm_user_buffer_create;
       ws->base.buffer_map = xm_buffer_map;
       ws->base.buffer_unmap = xm_buffer_unmap;
       ws->base.buffer_destroy = xm_buffer_destroy;

       ws->base.surface_buffer_create = xm_surface_buffer_create;

       ws->base.fence_reference = xm_fence_reference;
       ws->base.fence_signalled = xm_fence_signalled;
       ws->base.fence_finish = xm_fence_finish;

       ws->base.flush_frontbuffer = xm_flush_frontbuffer;
       ws->base.get_name = xm_get_name;
    }

    return &ws->base;
 }


 static struct pipe_screen *
 xlib_create_softpipe_screen( void )
 {
    struct pipe_winsys *winsys;
    struct pipe_screen *screen;

    winsys = xlib_create_softpipe_winsys();
    if (winsys == NULL)
       return NULL;

    screen = softpipe_create_screen(winsys);
    if (screen == NULL)
       goto fail;

    return screen;

 fail:
    if (winsys)
       winsys->destroy( winsys );

    return NULL;
 }


 static struct pipe_context *
 xlib_create_softpipe_context( struct pipe_screen *screen,
                               void *context_private )
 {
    struct pipe_context *pipe;

    pipe = softpipe_create(screen);
    if (pipe == NULL)
       goto fail;

    pipe->priv = context_private;
    return pipe;

 fail:
    /* Free stuff here */
    return NULL;
 }

 struct xm_driver xlib_softpipe_driver =
 {
    .create_pipe_screen = xlib_create_softpipe_screen,
    .create_pipe_context = xlib_create_softpipe_context,
    .display_surface = xlib_softpipe_display_surface
 };
	/**************************************************************************
	*
	* Copyright 2007 Tungsten Graphics, Inc., Bismarck, ND., USA
	* All Rights Reserved.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the
	* "Software"), to deal in the Software without restriction, including
	* without limitation the rights to use, copy, modify, merge, publish,
	* distribute, sub license, and/or sell copies of the Software, and to
	* permit persons to whom the Software is furnished to do so, subject to
	* the following conditions:
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDERS, AUTHORS AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM,
	* DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
	* OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
	* USE OR OTHER DEALINGS IN THE SOFTWARE.
	*
	* The above copyright notice and this permission notice (including the
	* next paragraph) shall be included in all copies or substantial portions
	* of the Software.
	*
	*
	**************************************************************************/

	/*
	* Authors:
	* Keith Whitwell
	* Brian Paul
	*/


	#include "xm_api.h"

	#undef ASSERT
	#undef Elements

	#include "pipe/internal/p_winsys_screen.h"
	#include "pipe/p_format.h"
	#include "pipe/p_context.h"
	#include "pipe/p_inlines.h"
	#include "util/u_format.h"
	#include "util/u_math.h"
	#include "util/u_memory.h"
	#include "softpipe/sp_winsys.h"
	#include "softpipe/sp_texture.h"

	#include "xlib.h"

	/**
	* Subclass of pipe_buffer for Xlib winsys.
	* Low-level OS/window system memory buffer
	*/
	struct xm_buffer
	{
	struct pipe_buffer base;
	boolean userBuffer; /** Is this a user-space buffer? */
	void *data;
	void *mapped;

	XImage *tempImage;
	#ifdef USE_XSHM
	int shm;
	XShmSegmentInfo shminfo;
	#endif
	};


	/**
	* Subclass of pipe_winsys for Xlib winsys
	*/
	struct xmesa_pipe_winsys
	{
	struct pipe_winsys base;
	/* struct xmesa_visual xm_visual; /
	};



	/** Cast wrapper */
	static INLINE struct xm_buffer *
	xm_buffer( struct pipe_buffer *buf )
	{
	return (struct xm_buffer *)buf;
	}


	/**
	* X Shared Memory Image extension code
	*/

	#ifdef USE_XSHM

	static volatile int mesaXErrorFlag = 0;

	/**
	* Catches potential Xlib errors.
	*/
	static int
	mesaHandleXError(Display dpy, XErrorEvent event)
	{
	(void) dpy;
	(void) event;
	mesaXErrorFlag = 1;
	return 0;
	}


	static char alloc_shm(struct xm_buffer buf, unsigned size)
	{
	XShmSegmentInfo *const shminfo = & buf->shminfo;

	shminfo->shmid = shmget(IPC_PRIVATE, size, IPC_CREAT\|0777);
	if (shminfo->shmid < 0) {
	return NULL;
	}

	shminfo->shmaddr = (char *) shmat(shminfo->shmid, 0, 0);
	if (shminfo->shmaddr == (char *) -1) {
	shmctl(shminfo->shmid, IPC_RMID, 0);
	return NULL;
	}

	shminfo->readOnly = False;
	return shminfo->shmaddr;
	}


	/**
	* Allocate a shared memory XImage back buffer for the given XMesaBuffer.
	*/
	static void
	alloc_shm_ximage(struct xm_buffer b, struct xmesa_buffer xmb,
	unsigned width, unsigned height)
	{
	/*
	* We have to do a _lot_ of error checking here to be sure we can
	* really use the XSHM extension. It seems different servers trigger
	* errors at different points if the extension won't work. Therefore
	* we have to be very careful...
	*/
	int (old_handler)(Display , XErrorEvent *);

	b->tempImage = XShmCreateImage(xmb->xm_visual->display,
	xmb->xm_visual->visinfo->visual,
	xmb->xm_visual->visinfo->depth,
	ZPixmap,
	NULL,
	&b->shminfo,
	width, height);
	if (b->tempImage == NULL) {
	b->shm = 0;
	return;
	}


	mesaXErrorFlag = 0;
	old_handler = XSetErrorHandler(mesaHandleXError);
	/* This may trigger the X protocol error we're ready to catch: */
	XShmAttach(xmb->xm_visual->display, &b->shminfo);
	XSync(xmb->xm_visual->display, False);

	if (mesaXErrorFlag) {
	/* we are on a remote display, this error is normal, don't print it */
	XFlush(xmb->xm_visual->display);
	mesaXErrorFlag = 0;
	XDestroyImage(b->tempImage);
	b->tempImage = NULL;
	b->shm = 0;
	(void) XSetErrorHandler(old_handler);
	return;
	}

	b->shm = 1;
	}

	#endif /* USE_XSHM */



	/* Most callbacks map direcly onto dri_bufmgr operations:
	*/
	static void *
	xm_buffer_map(struct pipe_winsys pws, struct pipe_buffer buf,
	unsigned flags)
	{
	struct xm_buffer *xm_buf = xm_buffer(buf);
	xm_buf->mapped = xm_buf->data;
	return xm_buf->mapped;
	}

	static void
	xm_buffer_unmap(struct pipe_winsys pws, struct pipe_buffer buf)
	{
	struct xm_buffer *xm_buf = xm_buffer(buf);
	xm_buf->mapped = NULL;
	}

	static void
	xm_buffer_destroy(struct pipe_buffer *buf)
	{
	struct xm_buffer *oldBuf = xm_buffer(buf);

	if (oldBuf->data) {
	#ifdef USE_XSHM
	if (oldBuf->shminfo.shmid >= 0) {
	shmdt(oldBuf->shminfo.shmaddr);
	shmctl(oldBuf->shminfo.shmid, IPC_RMID, 0);

	oldBuf->shminfo.shmid = -1;
	oldBuf->shminfo.shmaddr = (char *) -1;
	}
	else
	#endif
	{
	if (!oldBuf->userBuffer) {
	align_free(oldBuf->data);
	}
	}

	oldBuf->data = NULL;
	}

	free(oldBuf);
	}


	/**
	* Display/copy the image in the surface into the X window specified
	* by the XMesaBuffer.
	*/
	static void
	xlib_softpipe_display_surface(struct xmesa_buffer *b,
	struct pipe_surface *surf)
	{
	XImage *ximage;
	struct softpipe_texture *spt = softpipe_texture(surf->texture);
	struct xm_buffer *xm_buf = xm_buffer(spt->buffer);
	static boolean no_swap = 0;
	static boolean firsttime = 1;

	if (firsttime) {
	no_swap = getenv("SP_NO_RAST") != NULL;
	firsttime = 0;
	}

	if (no_swap)
	return;

	#ifdef USE_XSHM
	if (xm_buf->shm)
	{
	if (xm_buf->tempImage == NULL)
	{
	assert(util_format_get_blockwidth(surf->texture->format) == 1);
	assert(util_format_get_blockheight(surf->texture->format) == 1);
	alloc_shm_ximage(xm_buf, b, spt->stride[surf->level] /
	util_format_get_blocksize(surf->texture->format), surf->height);
	}

	ximage = xm_buf->tempImage;
	ximage->data = xm_buf->data;

	/* _debug_printf("XSHM\n"); */
	XShmPutImage(b->xm_visual->display, b->drawable, b->gc,
	ximage, 0, 0, 0, 0, surf->width, surf->height, False);
	}
	else
	#endif
	{
	/* display image in Window */
	ximage = b->tempImage;
	ximage->data = xm_buf->data;

	/* check that the XImage has been previously initialized */
	assert(ximage->format);
	assert(ximage->bitmap_unit);

	/* update XImage's fields */
	ximage->width = surf->width;
	ximage->height = surf->height;
	ximage->bytes_per_line = spt->stride[surf->level];

	/* _debug_printf("XPUT\n"); */
	XPutImage(b->xm_visual->display, b->drawable, b->gc,
	ximage, 0, 0, 0, 0, surf->width, surf->height);
	}
	}


	static void
	xm_flush_frontbuffer(struct pipe_winsys *pws,
	struct pipe_surface *surf,
	void *context_private)
	{
	/*
	* The front color buffer is actually just another XImage buffer.
	* This function copies that XImage to the actual X Window.
	*/
	XMesaContext xmctx = (XMesaContext) context_private;
	xlib_softpipe_display_surface(xmctx->xm_buffer, surf);
	xmesa_check_and_update_buffer_size(xmctx, xmctx->xm_buffer);
	}



	static const char *
	xm_get_name(struct pipe_winsys *pws)
	{
	return "Xlib";
	}


	static struct pipe_buffer *
	xm_buffer_create(struct pipe_winsys *pws,
	unsigned alignment,
	unsigned usage,
	unsigned size)
	{
	struct xm_buffer *buffer = CALLOC_STRUCT(xm_buffer);

	pipe_reference_init(&buffer->base.reference, 1);
	buffer->base.alignment = alignment;
	buffer->base.usage = usage;
	buffer->base.size = size;

	if (buffer->data == NULL) {
	/* align to 16-byte multiple for Cell */
	buffer->data = align_malloc(size, max(alignment, 16));
	}

	return &buffer->base;
	}


	/**
	* Create buffer which wraps user-space data.
	*/
	static struct pipe_buffer *
	xm_user_buffer_create(struct pipe_winsys pws, void ptr, unsigned bytes)
	{
	struct xm_buffer *buffer = CALLOC_STRUCT(xm_buffer);
	pipe_reference_init(&buffer->base.reference, 1);
	buffer->base.size = bytes;
	buffer->userBuffer = TRUE;
	buffer->data = ptr;

	return &buffer->base;
	}


	static struct pipe_buffer *
	xm_surface_buffer_create(struct pipe_winsys *winsys,
	unsigned width, unsigned height,
	enum pipe_format format,
	unsigned usage,
	unsigned tex_usage,
	unsigned *stride)
	{
	const unsigned alignment = 64;
	unsigned nblocksy, size;

	nblocksy = util_format_get_nblocksy(format, height);
	*stride = align(util_format_get_stride(format, width), alignment);
	size = stride nblocksy;

	#ifdef USE_XSHM
	if (!debug_get_bool_option("XLIB_NO_SHM", FALSE))
	{
	struct xm_buffer *buffer = CALLOC_STRUCT(xm_buffer);

	pipe_reference_init(&buffer->base.reference, 1);
	buffer->base.alignment = alignment;
	buffer->base.usage = usage;
	buffer->base.size = size;
	buffer->userBuffer = FALSE;
	buffer->shminfo.shmid = -1;
	buffer->shminfo.shmaddr = (char *) -1;
	buffer->shm = TRUE;

	buffer->data = alloc_shm(buffer, size);
	if (!buffer->data)
	goto out;

	return &buffer->base;

	out:
	if (buffer)
	FREE(buffer);
	}
	#endif


	return winsys->buffer_create(winsys, alignment,
	usage,
	size);
	}


	/*
	* Fence functions - basically nothing to do, as we don't create any actual
	* fence objects.
	*/

	static void
	xm_fence_reference(struct pipe_winsys sws, struct pipe_fence_handle *ptr,
	struct pipe_fence_handle *fence)
	{
	}


	static int
	xm_fence_signalled(struct pipe_winsys sws, struct pipe_fence_handle fence,
	unsigned flag)
	{
	return 0;
	}


	static int
	xm_fence_finish(struct pipe_winsys sws, struct pipe_fence_handle fence,
	unsigned flag)
	{
	return 0;
	}



	static struct pipe_winsys *
	xlib_create_softpipe_winsys( void )
	{
	static struct xmesa_pipe_winsys *ws = NULL;

	if (!ws) {
	ws = CALLOC_STRUCT(xmesa_pipe_winsys);

	/* Fill in this struct with callbacks that pipe will need to
	* communicate with the window system, buffer manager, etc.
	*/
	ws->base.buffer_create = xm_buffer_create;
	ws->base.user_buffer_create = xm_user_buffer_create;
	ws->base.buffer_map = xm_buffer_map;
	ws->base.buffer_unmap = xm_buffer_unmap;
	ws->base.buffer_destroy = xm_buffer_destroy;

	ws->base.surface_buffer_create = xm_surface_buffer_create;

	ws->base.fence_reference = xm_fence_reference;
	ws->base.fence_signalled = xm_fence_signalled;
	ws->base.fence_finish = xm_fence_finish;

	ws->base.flush_frontbuffer = xm_flush_frontbuffer;
	ws->base.get_name = xm_get_name;
	}

	return &ws->base;
	}


	static struct pipe_screen *
	xlib_create_softpipe_screen( void )
	{
	struct pipe_winsys *winsys;
	struct pipe_screen *screen;

	winsys = xlib_create_softpipe_winsys();
	if (winsys == NULL)
	return NULL;

	screen = softpipe_create_screen(winsys);
	if (screen == NULL)
	goto fail;

	return screen;

	fail:
	if (winsys)
	winsys->destroy( winsys );

	return NULL;
	}


	static struct pipe_context *
	xlib_create_softpipe_context( struct pipe_screen *screen,
	void *context_private )
	{
	struct pipe_context *pipe;

	pipe = softpipe_create(screen);
	if (pipe == NULL)
	goto fail;

	pipe->priv = context_private;
	return pipe;

	fail:
	/* Free stuff here */
	return NULL;
	}

	struct xm_driver xlib_softpipe_driver =
	{
	.create_pipe_screen = xlib_create_softpipe_screen,
	.create_pipe_context = xlib_create_softpipe_context,
	.display_surface = xlib_softpipe_display_surface
	};