Hi, I am using a DirectX wrapper called CDX, currently I am using a 16-bit color mode, but when I use it in FullScreen, and load a 24-bit BMP(Since I cant save a 16-bit bmp), my image colors look a bit different, it seems a bit different like it seems on Paint shop pro or Photoshop. Recently I read an article about 24-bit to 16-bit image coonversion, which compute a new values for each BMP pixel, but I mean , how can I load BMP on a Buffer, and if it is really needed to get my correct colors? Here ese how to convert a 24-bit pixel to 16-bit pixel RedValue = RedValue & 248; GreenValue = GreenValue & 252; BlueValue = BlueValue & 248; RedValue = RedValue << 8 GreenValue = GreenValue << 3 BlueValue = BlueValue >> 3 pixelvalue = RedValue | GreenValue | BlueValue; thanks! Oscar Gracián Tampico Tamaulipas México ogracian@hotmail.com

Hey Oscar,

the computations you are using don''t look right at all!

I use 16bit all the time. This is how i do the conversion:

ZeroMemory(&ddPF, sizeof(ddPF));
ddPF.dwSize = sizeof(ddPF);

// get the information from the back surface
ddret = lpSurface->GetPixelFormat(&ddPF);

DWORD dwRBM = ddPF.dwRBitMask;
DWORD dwGBM = ddPF.dwGBitMask;
DWORD dwBBM = ddPF.dwBBitMask;
// calculate shift left amount
for (iRSHL=0; (dwRBM&1)!=1; iRSHL++) dwRBM>>=1;
for (iGSHL=0; (dwGBM&1)!=1; iGSHL++) dwGBM>>=1;
for (iBSHL=0; (dwBBM&1)!=1; iBSHL++) dwBBM>>=1;
// calculate shift right amount
for (iRSHR=8; (dwRBM&1)==1; iRSHR--) dwRBM>>=1;
for (iGSHR=8; (dwGBM&1)==1; iGSHR--) dwGBM>>=1;
for (iBSHR=8; (dwBBM&1)==1; iBSHR--) dwBBM>>=1;


// for every pixel...
BlueValue = BlueValue>>iBSHR;
GreenValue = GreenValue>>iGSHR;
RedValue = RedValue>>iRSHR;
PixelValue = (BlueValue<<iBSHL) | (GreenValue<<iGSHL) | (RedValue<<iRSHL);

the bottom line got cut off!!

    PixelValue = (BlueValue<<iBSHL) | (GreenValue<<iGSHL) | (RedValue<<iRSHL);    

hope that helps...

Edited by - zenic on August 24, 2000 8:59:46 PM

Hi, and thakns for your help, but I have another question which I really apreciate if you could answer me.

Well I have looked at your code but the new Pixel values that I must compute is accesing the Data that I have loaded in My DirectX surface, or I must read the BMP byte by byte and apply the formulas?

Thanks!
Oscar

Ok, I will do that, thanks for your help.

Regards!!
Oscar