gdi裝置獲取的源頭， 同樣是通過底層驅動來進行實現
pgraphics_device
ntapi
engpregistergraphicsdevice(
punicode_string pustrdevicename,
punicode_string pustrdiplaydrivers,
punicode_string pustrdescription,
pdevmodew pdmdefault)
/* try to open the driver */
// 找到gdi裝置獲取的初始源頭了，就是這裡
status = iogetdeviceobjectpointer(pustrdevicename,
file_read_data | file_write_data,
&pfileobject,
&pdeviceobject);
if (!nt_success(status))
/* enable the device */
engfilewrite(pfileobject, &benable, sizeof(bool), &cj);
/* copy the device and file object pointers */
pgraphicsdevice->deviceobject = pdeviceobject;
pgraphicsdevice->fileobject = pfileobject;
/* copy device name */
wcsncpy(pgraphicsdevice->szntdevicename,
pustrdevicename->buffer,
sizeof(pgraphicsdevice->szntdevicename) / sizeof(wchar));
/* create a win device name (fixme: virtual devices!) */
swprintf(pgraphicsdevice->szwindevicename, l"\\\\.\\video%d", (char)gidevnum);
/* allocate a buffer for the strings */
cj = pustrdiplaydrivers->length + pustrdescription->length + sizeof(wchar);
pwsz = exallocatepoolwithtag(pagedpool, cj, gditag_drvsup);
if (!pwsz)
/* copy display driver names */
pgraphicsdevice->pdiplaydrivers = pwsz;
rtlcopymemory(pgraphicsdevice->pdiplaydrivers,
pustrdiplaydrivers->buffer,
pustrdiplaydrivers->length);
/* copy description */
pgraphicsdevice->pwszdescription = pwsz + pustrdiplaydrivers->length / sizeof(wchar);
rtlcopymemory(pgraphicsdevice->pwszdescription,
pustrdescription->buffer,
pustrdescription->length + sizeof(wchar));
/* initialize the pdevmodeinfo list and default index */
pgraphicsdevice->pdevmodeinfo = null;
pgraphicsdevice->idefaultmode = 0;
pgraphicsdevice->icurrentmode = 0;
// fixme: initialize state flags
pgraphicsdevice->stateflags = 0;
/* loop through the driver names
* this is a reg_multi_sz string */
for (; *pwsz; pwsz += wcslen(pwsz) + 1)
/* get the mode list from the driver */
pdminfo = ldevobj_pdmigetmodes(pldev, pdeviceobject);
if (!pdminfo)
/* attach the mode info to the device */
pdminfo->pdminext = pgraphicsdevice->pdevmodeinfo;
pgraphicsdevice->pdevmodeinfo = pdminfo;
/* count devmodes */
pdmend = (devmodew*)((pchar)pdminfo->adevmode + pdminfo->cbdevmode);
for (pdm = pdminfo->adevmode;
pdm + 1 <= pdmend;
pdm = (devmodew*)((pchar)pdm + pdm->dmsize + pdm->dmdriverextra))
// fixme: release the driver again until it's used?
}if (!pgraphicsdevice->pdevmodeinfo || cmodes == 0)
/* allocate an index buffer */
pgraphicsdevice->cdevmodes = cmodes;
pgraphicsdevice->pdevmodelist = exallocatepoolwithtag(pagedpool,
cmodes * sizeof(devmodeentry),
gditag_gdevice);
if (!pgraphicsdevice->pdevmodelist)
/* loop through all devmodeinfos */
for (pdminfo = pgraphicsdevice->pdevmodeinfo, i = 0;
pdminfo;
pdminfo = pdminfo->pdminext)
/* initialize the entry */
pgraphicsdevice->pdevmodelist[i].dwflags = 0;
pgraphicsdevice->pdevmodelist[i].pdm = pdm;
i++;}}
/* lock loader */
engacquiresemaphore(ghsemgraphicsdevicelist);
/* insert the device into the global list */
pgraphicsdevice->pnextgraphicsdevice = gpgraphicsdevicelast;
gpgraphicsdevicelast = pgraphicsdevice;
if (!gpgraphicsdevicefirst)
gpgraphicsdevicefirst = pgraphicsdevice;
/* increment device number */
gidevnum++;
/* unlock loader */
engreleasesemaphore(ghsemgraphicsdevicelist);
dprint("prepared %ld modes for %ls\n", cmodes, pgraphicsdevice->pwszdescription);
return pgraphicsdevice;
}static bool isdirectdrawsupported()
dx9裡面的這個功能原來是直接呼叫 dc裡面的資訊來返回啊，哈哈
gdi和dx其實使用的是同乙個顯示驅動， 只不過由於gdi是專門為桌面系統而進行封裝的， 物件遊戲使用來說顯然效率、易用性方面還大大不足， 於是根據用途不同就分成了gdi和dx的區別
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GDI和GDI 的應用場合思考
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GDI和GDI 的應用場合思考
gdi是微軟公司的著名的二維圖形引擎，gdi 則是微軟公司為了提高顯示效果而推出的一種新型圖形引擎。下面我就我的一些使用經驗闡述二者適用的應用場合 gdi基本能滿足一般的繪圖要求。我覺得gdi最令人詬病的是它畫出來的線顯示的鋸齒實在比較厲害，挑剔的客戶會不滿意 注 autocad的繪製二維線應該是使...