Hi,
I noticed that the alpha component in the BMP file (when RGBA or BGRA) is not
being preserved in the image. I would like to proposed the following small
change to correct this problem. Instead of ignoring the alpha component, I
first check if the bytesPerPixel == 4 bytes. If so, then I simply copy the row
alpha to the image alpha component.
Does that make sense? Or am I not following the BMP standard?
Code:
if (dib.bitsPerPixel >= 16)
{
unsigned char* imgp = imageBuffer;
for (int i = 0; i < dib.height; ++i)
{
// read row
unsigned char* rowp = &*rowBuffer.begin();
fin.read((char*) rowp, rowBuffer.size());
// copy to image buffer, swap/unpack BGR to RGB(A)
for (unsigned int j = 0; j < bytesPerRow; j += bytesPerPixel)
{
if (dib.bitsPerPixel == 16)
{
// 16-bit RGB -> 24-bit RGB
unsigned short rgb16 = (rowp[1] << 8) | rowp[0];
if (swap)
osg::swapBytes2((char*) &rgb16);
imgp[0] = (rgb16 & redMask) >> redShift;
imgp[1] = (rgb16 & greenMask) >> greenShift;
imgp[2] = (rgb16 & blueMask) >> blueShift;
// expand range
imgp[0] <<= (8-redMaskWidth);
imgp[1] <<= (8-greenMaskWidth);
imgp[2] <<= (8-blueMaskWidth);
}
else
{
// BGR -> RGB(A)
imgp[0] = rowp[2];
imgp[1] = rowp[1];
imgp[2] = rowp[0];
if (imageBytesPerPixel == 4)
{
// ********* THIS IS MY CHANGE*******
if( bytesPerPixel == 4 )
{
imgp[3] = rowp[3];
}
else
{
imgp[3] = 0xFF;
}
}
}
imgp += imageBytesPerPixel;
rowp += bytesPerPixel;
}
}
}
Regards,
------------------
Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=34271#34271
_______________________________________________
osg-users mailing list
[email protected]
http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
