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The Reindeer Effect
Loading A BMP
Author
I am having some problems with a little project of mine. I really haven''t learned C file I/O functions the way I should have I assume. Anyways ... I can load the BITMAPFILEHEADER and BITMAPINFOHEADER just fine. Since it is a 24-bit bmp, I assume that means that there is no pallete. So I go directly onto trying to load the pixel data ... but I have no clue how to.
I had planned to store the pixel data in - BYTE* pData;
Whenever I find the biWidth and biHeight, I do -
pData = new BYTE[ 3 * biWidth * biHeight].
Then:
temp = 3 * biWidth * biHeight;
for( int i = 0; i < temp; i++)
fread( &pData, sizeof( BYTE ), 1, in );
for some reason I am having problems ... cuz I impelented a test. I tried to output all the data basically the same way i got it, cept i used fwrite( .. );
When I try to open the file, it says not a current bmp file formay. After tinkering for 20 minutes, I have only managed to make a 593 mb file, the original is like 50k
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The Reindeer Effect
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The Reindeer Effect
Here's my code for reading Windows bitmaps. It's fairly easy to understand, even though it's very non-standard code:
About that last part: Are you loading and saving it in binary mode (the default in Windows is text mode)?
[edited by - Null and Void on June 2, 2002 10:10:05 PM]
using namespace gPixmapFormat;gImageWinBmpHeader Header;gImageWinBmpInfoHeader Info;unsigned int ByteWidth, BytesPP, DataSize, Shift;File.Read(&Header,14,1);File.Read(&Info,40,1);/* This doesn't ever seem to work for me ;)if(Header.OffBits > (14 + 40)) File.Seek(Header.OffBits - (14 + 40),SEEK_CUR);*/// Flip little endian data to native endian datagEndianFixLittle(Header.OffBits);gEndianFixLittle(Header.Type);gEndianFixLittle(Info.Width);gEndianFixLittle(Info.Height);gEndianFixLittle(Info.BitCount);if(Header.Type != 0x4D42) { gError("This isn't a Win32 bitmap.");}if(Info.BitCount != 24) { gError("This bit depth isn't supported.");}BytesPP = Info.BitCount/8;ByteWidth = Info.Width * BytesPP;DataSize = ByteWidth * Info.Height;Shift = ByteWidth % 4;This->SetBytesPP(BytesPP);This->SetWidth(Info.Width);This->SetHeight(Info.Height);This->SetData(gNewArray(gByte,DataSize));This->SetFreeMem(true);if(Shift == 0) { File.Read(This->GetData(),1,DataSize);} else { // Yeah, padding... for(unsigned int a=0; a<Info.Height; ++a) { File.Read(This->GetData(),1,ByteWidth); File.Seek(Shift,SEEK_CUR); }}This->SetFormat(External::BGR);This->FlipVert(); About that last part: Are you loading and saving it in binary mode (the default in Windows is text mode)?
[edited by - Null and Void on June 2, 2002 10:10:05 PM]
Author
What headers / libs do I need to use that?
[edited by - The Reindeer Effect on June 2, 2002 10:13:07 PM]
[edited by - The Reindeer Effect on June 2, 2002 10:13:07 PM]
Sorry about the ''update right after I post'' thing, I hit reply too quickly.
Well, you''d need most of my GTW engine
. I was posting it as a ''reference'' for you to go by. Some notes: My file functions are based directly off the C file I/O functions (but they throw exceptions on error), and my gWinBmp*Header structs are just like the Win32 API''s BITMAP*HEADER structs (I needed my own copy to maintain portability).
quote:Original post by The Reindeer Effect
What headers / libs do I need to use that?
Well, you''d need most of my GTW engine
. I was posting it as a ''reference'' for you to go by. Some notes: My file functions are based directly off the C file I/O functions (but they throw exceptions on error), and my gWinBmp*Header structs are just like the Win32 API''s BITMAP*HEADER structs (I needed my own copy to maintain portability).
Author
AHHHHHHH ... I think it was because I thought that only the pixel data was in little endian.
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The Reindeer Effect
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The Reindeer Effect
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