Difference between revisions of "Intermediate C++ Game Programming Tutorial 23"
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** Used in libraries such as the Windows API, DirectX, in STL | ** Used in libraries such as the Windows API, DirectX, in STL | ||
| − | ** Each value is represented by a single bit set in their binary representation | + | ** Each value is represented by a single bit set in their binary representation |
| + | ** For example: <code>enum Options { option1 = 0b01, option2 = 0b10 };</code> | ||
** Check for options with Bitwise AND: if you have an <code>int options</code>, check the option flag using <code>if( options & option1 )</code> | ** Check for options with Bitwise AND: if you have an <code>int options</code>, check the option flag using <code>if( options & option1 )</code> | ||
** Combine options with Bitwise OR: make an <code>int options = option1 | option3;</code> | ** Combine options with Bitwise OR: make an <code>int options = option1 | option3;</code> | ||
Revision as of 07:16, 27 November 2019
Bit twiddling is a lot of bullshit that is usually avoided when possible because it leads to ass code. Still, it is necessary in various situations, so you gotta learn this shit, and now is as good a time as any I guess.
Topics Covered
- Bitwise AND (&), OR (|), and shift left/right (>> and <<)
- Unary bitwise NOT/complement (~) and bitwise XOR (^)
- Masking with & and combining with |
- Packing and unpacking smaller data in larger types
- Bit flags
- Bitwise arithmetic optimizations
Video Timestamp Index
[Expand]
- Converting integers to their binary representation 0:15
- Bitwise operators AND (
&), OR (|) 1:50
- Shifting operations left (
<<), right (>>) 5:10
- Packing and unpacking data, masking with
&and mashing/combining with|7:07
- Example use case: The
Colorclass in the Framework 12:20
- Packing flag values into a single integer parameter 14:29
- Advanced Bitwise operators NOT (
~), XOR (^) 16:48
- Don't use Bitwise AND in logical operations like
if ( a & b )19:49
- Bitwise arithmetic optimizations 22:30
Homework
- Figure out how the binary string formatter routine works
- Figure out why
x % 16compiles tox & 0xF
The solution for the problems will not have its own video. Feel free to come on the discord and compare your answers with others, or to ask specific questions if you are having trouble understanding.
