Locking DirectX Surfaces (All the points I have!)

I'm trying to write a simple directX application that opens up a window, and let's me place pixels within it.

So far, I can use the method where I blit 1x1 pixel rectangles to the screen. I'm assuming it's slower than the other method of locking the screen, and then drawing to the memory of the surface.  The only problem being is that I've tried 2 diffrent programs that lock the surface and draw to it, and they've both crashed on attemping to lock the surface.  

Any help on why this ain't working would be awesome!

Thanks is advance!


FirefunkAsked:
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lif081199Commented:
Could you show me your code, with those Lock/Unlock ?

What is your video card ?

Lionel.
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FirefunkAuthor Commented:
My video card is *hides head in shame* S3 Virge

The code I'm using is

void LockAndLoad() {    
DDSURFACEDESC ddsd;  
ddsd.dwSize = sizeof(ddsd);  

assert(SUCCEEDED(front->Lock(0, &ddsd, DDLOCK_WAIT | DDLOCK_SURFACEMEMORYPTR, 0)));  

 unsigned char* surface = reinterpret_cast<unsigned char*>(ddsd.lpSurface);  

for(int x(0); x < 640; x++) {  
int y = 240 - static_cast<int>(sin(x * dx) / dy);
surface[x + y * ddsd.lPitch] = 255;
}
front->Unlock(ddsd.lpSurface);    // unlock the surface  
}


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azarCommented:
The following copies a complete image to a surface.  You can easily modify it to just place your own 'pixels' in vs. the whole image:

(Note - I'm assuming you are using DX7)


//-----------------------------------------------------------------------------
// Name: CopyBitmapToSurface()
// Desc: Copies the image of a bitmap into a surface
//-----------------------------------------------------------------------------
HRESULT TextureContainer::CopyBitmapToSurface()
{
    // Get a DDraw object to create a temporary surface
    LPDIRECTDRAW7 pDD;
    m_pddsSurface->GetDDInterface( (VOID**)&pDD );

    // Get the bitmap structure (to extract width, height, and bpp)
    BITMAP bm;
    GetObject( m_hbmBitmap, sizeof(BITMAP), &bm );

    // Setup the new surface desc
    DDSURFACEDESC2 ddsd;
    ddsd.dwSize = sizeof(ddsd);
    m_pddsSurface->GetSurfaceDesc( &ddsd );
    ddsd.dwFlags          = DDSD_CAPS|DDSD_HEIGHT|DDSD_WIDTH|DDSD_PIXELFORMAT|
                            DDSD_TEXTURESTAGE;
    ddsd.ddsCaps.dwCaps   = DDSCAPS_TEXTURE|DDSCAPS_SYSTEMMEMORY;
    ddsd.ddsCaps.dwCaps2  = 0L;
    ddsd.dwWidth          = bm.bmWidth;
    ddsd.dwHeight         = bm.bmHeight;

    // Create a new surface for the texture
    LPDIRECTDRAWSURFACE7 pddsTempSurface;
    HRESULT hr;
    if( FAILED( hr = pDD->CreateSurface( &ddsd, &pddsTempSurface, NULL ) ) )
    {
        pDD->Release();
        return hr;
    }

    // Get a DC for the bitmap
    HDC hdcBitmap = CreateCompatibleDC( NULL );
    if( NULL == hdcBitmap )
    {
        pddsTempSurface->Release();
        pDD->Release();
        return hr;
    }
    SelectObject( hdcBitmap, m_hbmBitmap );

    // Handle palettized textures. Need to attach a palette
    if( ddsd.ddpfPixelFormat.dwRGBBitCount == 8 )
    {
        LPDIRECTDRAWPALETTE  pPalette;
        DWORD dwPaletteFlags = DDPCAPS_8BIT|DDPCAPS_ALLOW256;
        DWORD pe[256];
        WORD  wNumColors     = GetDIBColorTable( hdcBitmap, 0, 256, (RGBQUAD*)pe );

        // Create the color table
        for( WORD i=0; i<wNumColors; i++ )
        {
            pe[i] = RGB( GetBValue(pe[i]), GetGValue(pe[i]), GetRValue(pe[i]) );

            // Handle textures with transparent pixels
            if( m_dwFlags & (D3DTEXTR_TRANSPARENTWHITE|D3DTEXTR_TRANSPARENTBLACK) )
            {
                // Set alpha for opaque pixels
                if( m_dwFlags & D3DTEXTR_TRANSPARENTBLACK )
                {
                    if( pe[i] != 0x00000000 )
                        pe[i] |= 0xff000000;
                }
                else if( m_dwFlags & D3DTEXTR_TRANSPARENTWHITE )
                {
                    if( pe[i] != 0x00ffffff )
                        pe[i] |= 0xff000000;
                }
            }
        }
        // Add DDPCAPS_ALPHA flag for textures with transparent pixels
        if( m_dwFlags & (D3DTEXTR_TRANSPARENTWHITE|D3DTEXTR_TRANSPARENTBLACK) )
            dwPaletteFlags |= DDPCAPS_ALPHA;

        // Create & attach a palette
        pDD->CreatePalette( dwPaletteFlags, (PALETTEENTRY*)pe, &pPalette, NULL );
        pddsTempSurface->SetPalette( pPalette );
        m_pddsSurface->SetPalette( pPalette );
        SAFE_RELEASE( pPalette );
    }

    // Copy the bitmap image to the surface.
    HDC hdcSurface;
    if( SUCCEEDED( pddsTempSurface->GetDC( &hdcSurface ) ) )
    {
        BitBlt( hdcSurface, 0, 0, bm.bmWidth, bm.bmHeight, hdcBitmap, 0, 0,
                SRCCOPY );
        pddsTempSurface->ReleaseDC( hdcSurface );
    }
    DeleteDC( hdcBitmap );

    // Copy the temp surface to the real texture surface
    m_pddsSurface->Blt( NULL, pddsTempSurface, NULL, DDBLT_WAIT, NULL );

    // Done with the temp surface
    pddsTempSurface->Release();

    // For textures with real alpha (not palettized), set transparent bits
    if( ddsd.ddpfPixelFormat.dwRGBAlphaBitMask )
    {
        if( m_dwFlags & (D3DTEXTR_TRANSPARENTWHITE|D3DTEXTR_TRANSPARENTBLACK) )
        {
            // Lock the texture surface
            DDSURFACEDESC2 ddsd;
            ddsd.dwSize = sizeof(ddsd);
            while( m_pddsSurface->Lock( NULL, &ddsd, 0, NULL ) ==
                   DDERR_WASSTILLDRAWING );

            DWORD dwAlphaMask = ddsd.ddpfPixelFormat.dwRGBAlphaBitMask;
            DWORD dwRGBMask   = ( ddsd.ddpfPixelFormat.dwRBitMask |
                                  ddsd.ddpfPixelFormat.dwGBitMask |
                                  ddsd.ddpfPixelFormat.dwBBitMask );
            DWORD dwColorkey  = 0x00000000; // Colorkey on black
            if( m_dwFlags & D3DTEXTR_TRANSPARENTWHITE )
                dwColorkey = dwRGBMask;     // Colorkey on white

            // Add an opaque alpha value to each non-colorkeyed pixel
            for( DWORD y=0; y<ddsd.dwHeight; y++ )
            {
                WORD*  p16 =  (WORD*)((BYTE*)ddsd.lpSurface + y*ddsd.lPitch);
                DWORD* p32 = (DWORD*)((BYTE*)ddsd.lpSurface + y*ddsd.lPitch);

                for( DWORD x=0; x<ddsd.dwWidth; x++ )
                {
                    if( ddsd.ddpfPixelFormat.dwRGBBitCount == 16 )
                    {
                        if( ( *p16 &= dwRGBMask ) != dwColorkey )
                            *p16 |= dwAlphaMask;
                        p16++;
                    }
                    if( ddsd.ddpfPixelFormat.dwRGBBitCount == 32 )
                    {
                        if( ( *p32 &= dwRGBMask ) != dwColorkey )
                            *p32 |= dwAlphaMask;
                        p32++;
                    }
                }
            }
            m_pddsSurface->Unlock( NULL );
        }
    }

    pDD->Release();

    return S_OK;;
}
0
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FirefunkAuthor Commented:
I'm sure that this code works, it's just that I have no idea on how to modify it to work...If you could leave instructions, what not, that'd be awesome!

Thanks so much!
0
FirefunkAuthor Commented:
Adjusted points to 35
0
cwguesCommented:
This problem always occurs when you do not unlock the surface after using it...

Check your code carefully to see that it does so...

Use a some debug code to see if it goes through the loop once and crashes on the second iteration.




0

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