Thread: Some Bit Issures, Confused?

I'm trying to set up an 8bit palette and it's being fussy

Code in question - crap trimmed out

Code:

    // 3 - 3 - 2 bit layout for palette

    for(unsigned char color = 0; color < 255; color++)
    {
        int greenzone = color & 0xE0;    // 11100000
        int redzone = color & 0x1C;        // 00011100
        int bluezone = color & 0x03;    // 00000011

        bitset<3> b(greenzone); cout << b << " ";
        bitset<3> c(redzone); cout << c << " ";
        bitset<2> d(bluezone); cout << d << " ";
        bits << "\t" << bitset<8>(color) << std::endl;
    }

Yielding - note my markup, information loss, confuzion, blergh

Code:

000 000 00     00000000
000 000 01     00000001
000 000 10     00000010
000 000 11     00000011
000 100 00     00000100 * // Why on the left
000 100 01     00000101
000 100 10     00000110
000 100 11     00000111
000 000 00     00001000 * // Why
000 000 01     00001001
000 000 10     00001010
000 000 11     00001011
000 100 00     00001100
000 100 01     00001101
000 100 10     00001110
000 100 11     00001111
000 000 00     00010000
000 000 01     00010001

Why are the two columns different (no not the spacing, the data)

You need to shift the bits before placing them in the bitsets.

For example, if color is 00000100, then greenzone is 00000000, redzone is 00000100 and bluezone is 00000000. Obviously b and d become 0, but c is a 3 bit value initialized with 00000100. That means c becomes 100.

If you shift the bits first, then assign them to the bitset, you will get the appropriate values. You can do this before or after assigning to the zone variables. 00000100 >> 2 is 00000001, which when assigned to the c bitset will be 001. That's what you want. Of course, you'd have to bit shift the greenzone by more than 2.

Oo. Thanksy.

Just thought I'd share the fruits of my labours.

http://img.photobucket.com/albums/v2...Picture026.jpg
http://img.photobucket.com/albums/v2...o1/shadazz.jpg
http://img.photobucket.com/albums/v2...o1/swiggle.jpg

Kool 8bit palette + my 8bit shrine. Atari + NES not pictured, because I left them at home (in college now)

8bit Fractal Gravity

http://smg.photobucket.com/albums/v2...Picture033.jpg
http://smg.photobucket.com/albums/v2...Picture030.jpg
http://smg.photobucket.com/albums/v2...Picture031.jpg