CODEWITHSUNDEEP
c++keyboardglut
epochwolf
epochwolf

Reputation: 12772

Using OpenGL /GLUT how would I detect if two keys are held down at the same time?

Using OpenGL /GLUT how would I detect if two keys, say 'a' and 'j' are held down at the same time?

(This program needs to compile with OSX GCC, Windows GCC, Windows VS2005 so no OS dependent hacks please.)

Upvotes: 13

Views: 10388

Answers (2)

user2977702
user2977702

Reputation: 27

by "nicer alternative" if you mean simpler and glut-independant input function then got with GetAsyncKeyState function...

MSDN - GetAsyncKeyState function

Upvotes: 0

Trillian
Trillian

Reputation: 6437

Try the following:

  1. Use glutIgnoreKeyRepeat to only get physical keydown/keyup events
  2. Use glutKeyboardFunc to register a callback listening to keydown events.
  3. Use glutKeyboardUpFunc to register a callback listening to keyup events.
  4. Create a bool keystates[256] array to store the state of the keyboard keys.
  5. When receiving an event through your keydown callback, set keystates[key] = true.
  6. When receiving an event through your keyup callback, set keystates[key] = false.
  7. In your run loop, test if (keystates['a'] || keystates['A']) && (keystates['j'] || keystates['J']).

Look in that direction. Although I haven't tested it, it should work. You might also need glutSpecialFunc and glutSpecialUpFunc to receive messages for 'special' keys.

Also, be aware that GLUT is really old stuff and that there are much nicer alternatives.

Upvotes: 21

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