Bitmap loading in opengl in c++ WITHOUT any libraries
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helo everyone! i realy need your help: i want to make a class for my game engine that loads bitmaps from file e.g (bool Bitmap::Loadbitmap(const char* filename, GLuint &texture) without any library like the AUX or SDL. Can you please help me?
My own source that works with 24-bit bitmaps:
http://www.nife.1go.dk/c++.php?id=1
And one for targa if you need it some day (24 and 32-bit):
http://www.nife.1go.dk/c++.php?id=2
http://www.nife.1go.dk/c++.php?id=1
And one for targa if you need it some day (24 and 32-bit):
http://www.nife.1go.dk/c++.php?id=2
if you're going to use a bitmap then you may as well step up and use a .tga because they support an alpha channel.
Well, here's some code if it helps.. by the way, just replace the stream.get(), stream.read(), and so on with standard c library calls... for example.. stream.get() because fgetc(), read becomes fread(), etc.
Btw, here's some of the simple types
S8 - signed char (1 byte)
U8 - unsigned char (1 byte)
S16 - signed short (2 bytes)
U16 - unsigned short (2 bytes)
S32 - signed long (4 bytes)
U32 - unsigned long (4 bytes)
Btw, here's some of the simple types
S8 - signed char (1 byte)
U8 - unsigned char (1 byte)
S16 - signed short (2 bytes)
U16 - unsigned short (2 bytes)
S32 - signed long (4 bytes)
U32 - unsigned long (4 bytes)
bool Bitmap::loadBmp( IStream &stream ) { if (!stream.initialized()) return false; S16 id; U32 offset; U32 headerSize; U32 width, height; U16 bpp; U32 compression; U32 dataSize; stream.read(&id, sizeof(S16)); if (id != 'MB') return false; stream.seek(8, STREAM_CUR); stream.read(&offset, sizeof(U32)); stream.read(&headerSize, sizeof(U32)); if (headerSize != 40) return false; stream.read(&width, sizeof(U32)); stream.read(&height, sizeof(U32)); stream.seek(2, STREAM_CUR); stream.read(&bpp, sizeof(U16)); if (bpp != 24) // currently only support 24-bit bitmaps return false; stream.read(&compression, sizeof(U32)); if (compression != 0) // currently only support non-compressed bmp's return false; stream.read(&dataSize, sizeof(U32)); if (dataSize == 0) dataSize = (width * bpp + 7) / 8 * abs(height); stream.seek(-(S32)dataSize, STREAM_END); mWidth = width; mHeight = abs(height); mData = new U8[mWidth * mHeight * 3]; if (!mData) return false; // read in data, flipping it as we read vertically, plus converting BGR -> RGB U8 *p = mData + (mHeight - 1) * mWidth * 3; U8 byte1, byte2, byte3; // if mWidth is not a multiple of 4, then there is extra crap at the end of every line S32 paddedBytes = (mWidth % 4) ? (4 - ((mWidth * 3) % 4)) : 0; for(S32 y = 0; y < mHeight; y++) { for(S32 x = 0; x < mWidth; x++) { if (stream.eos()) { destroy(); return false; } // test for last pixel to read if( y == mHeight - 1 && x == mWidth - 1) { int z = z * 65; } byte1 = (U8)stream.get(); byte2 = (U8)stream.get(); byte3 = (U8)stream.get(); *p++ = byte3; // swap BGR->RGB *p++ = byte2; *p++ = byte1; } // read the extra crap (align on 32-bit (4 byte) boundary) for (S32 padCount=0; padCount<paddedBytes; padCount++) stream.get(); // work bottom to top p -= (mWidth * 3) * 2; } mFormat = BITMAP_FMT_24; return true;}This topic is closed to new replies.
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