Solution to the backbuffer problem of DirectDraw on WM Simulator

The program failed to run because ddscaps_backbuffer is not supported when the simulator ran to create a backup buffer, google found that some people on the M $ website and other forums have asked similar questions. The answer seems to be that the emlator cannot run ddraw or d3d programs. To test, only device is used, as a matter of fact, you only need to create a backup buffer and simulate flip with bits to run on the simulator. It is not because the simulator has not implemented ddraw at all, I just didn't implement hardware backup buffering, flip, and other operations (in fact, there should be no efficiency difference between the two methods on the current PC simulator ).
Code:

// *********************************** <Br //> // method: initddraw initialize ddraw <br/> // fullname: initddraw <br/> // access: Public <br/> // returns: bool <br/> // qualifier: <br/> // parameter: void <br/> //********************************* * ** <br/> bool initddraw (void) <br/>{< br/> ddsurfacedesc ddsd; <br/> hresult HRET; <br/> ddcaps ddhelcaps; <br/> // ddraw object <br/> HRET = directdrawcreate (Null, & g_pdd, null); <br/> If (HRET! = Dd_ OK) <br/>{< br/> initfail (g_hgamewnd, HRET, _ T ("ddraw failed to create! "); <Br/> return false; <br/>}< br/> // full-screen exclusive mode <br/> HRET = g_pdd-> setcooperativelevel (g_hgamewnd, ddscl_fullscreen); <br/> If (HRET! = Dd_ OK) <br/>{< br/> initfail (g_hgamewnd, HRET, _ T ("failed to set cooperative level! "); <Br/> return false; <br/>}< br/> // get ddraw availability <br/> g_pdd-> getcaps (& ddcaps, & ddhelcaps); <br/> // If (! (Ddcaps. ddscaps. dwcaps & ddscaps_backbuffer) |! (Ddcaps. ddscaps. dwcaps & ddscaps_flip) <br/>{< br/> // single buffer mode <br/> g_bsinglebuffer = true; <br/>}< br/> // Display Mode settings <br/> memset (& ddsd, 0, sizeof (ddsd); <br/> ddsd. dwsize = sizeof (ddsd); </P> <p> HRET = g_pdd-> getdisplaymode (& ddsd); </P> <p> If (HRET! = Dd_ OK) <br/>{< br/> initfail (g_hgamewnd, HRET, _ T ("getdisplaymode failed! "); <Br/> return false; <br/>}</P> <p> g_dwscreenx = ddsd. dwwidth; <br/> g_dwscreeny = ddsd. dwheight; <br/> g_dwscreenbpp = ddsd. ddpfpixelformat. dwrgbbitcount; </P> <p> // Color Key hardware capability <br/> g_dwtranstype = ddblt_keysrc; <br/> ddcaps. dwsize = sizeof (ddcaps); <br/> If (g_bsinglebuffer) <br/>{< br/> ddsd. dwflags = ddsd_caps; <br/> ddsd. ddscaps. dwcaps = ddscaps_primarysurface; <br/>}< br/> else <br/>{< br/> ddsd. d Wflags = ddsd_caps | ddsd_backbuffercount; <br/> ddsd. ddscaps. dwcaps = ddscaps_primarysurface | ddscaps_flip; <br/> ddsd. dwbackbuffercount = 1; <br/>}< br/> // primary buffer creation <br/> HRET = g_pdd-> createsurface (& ddsd, & g_pddsprimary, null ); </P> <p> If (HRET! = Dd_ OK) <br/>{< br/> If (HRET = dderr_nofliphw) <br/>{< br/> initfail (g_hgamewnd, HRET, _ T ("********* display driver doesn' t support flipping surfaces. * ******* "); <br/> return false; <br/>}< br/> initfail (g_hgamewnd, HRET, _ T ("createsurface frontbuffer failed! "); <Br/> return false; <br/>}</P> <p> If (g_bsinglebuffer) <br/>{< br/> ddsd. dwflags = ddsd_width | ddsd_height; <br/> ddsd. dwwidth = g_dwscreenx; <br/> ddsd. dwheight = g_dwscreeny; <br/> HRET = g_pdd-> createsurface (& ddsd, & g_pddsback, null); <br/> If (HRET! = Dd_ OK) <br/>{< br/> initfail (g_hgamewnd, HRET, _ T ("backbuffer failed to create! "); <Br/> return false; <br/>}< br/> else <br/> {<br/> // get a pointer to the back buffer <br/> HRET = g_pddsprimary -> enumattachedsurfaces (& g_pddsback, enumfunction); <br/> If (HRET! = Dd_ OK) <br/>{< br/> initfail (g_hgamewnd, HRET, _ T ("enumattachedsurfaces failed! "); <Br/> return false; <br/>}< br/> return true; <br/>}</P> <p>

In the drawing loop, handle flip as follows:

Hresult ddrval; <br/> rect SRC, DEST; </P> <p> SRC. left = 0; <br/> SRC. top = 0; <br/> SRC. right = g_dwscreenx; <br/> SRC. bottom = g_dwscreeny; </P> <p> DeST. left = 0; <br/> DeST. top = 0; <br/> DeST. right = g_dwscreenx; <br/> DeST. bottom = g_dwscreeny; </P> <p> // flip the surfaces <br/> while (1) <br/>{< br/> If (g_bsinglebuffer) <br/> {<br/> // copy back buffer to front. <br/> ddrval = g_pddsprimary-> BLT (& DEST, g_pdd Sback, & SRC, ddblt_waitnotbusy, null); <br/>}< br/> else <br/>{< br/> ddrval = g_pddsprimary-> flip (null, 0); <br/>}</P> <p> If (ddrval = dd_ OK) <br/>{< br/> break; <br/>}< br/> If (ddrval = dderr_surfacelost) <br/>{< br/> If (! Restoresurfaces () <br/>{< br/> return 0; <br/>}< br/> If (ddrval! = Dderr_wasstilldrawing) <br/>{< br/> break; <br/>}</P> <p>