How to Check if a Key is Pressed in Basic4GL
Checking whether or not a key is pressed down is the first step of programming more complicated player control using the keyboard. How you check a key will depend on whether it is a "typeable key" or if it is a special key, such as the "arrow" keys.
Checking "Typeable" Key
A typeable key is a key that you type to get a letter, number or character. For these keys, you can use KeyDown().
If KeyDown("A") Then Printr " ' A ' key down. " EndIF
Checking Special Keys
Checking special keys requires ScanKeyDown() and a virtual keycode. A virtual keycode is a built-in constant that refers to that key. They begin with vk_.
If ScanKeyDown(vk_left) Then Printr " ' Left ' key down." EndIF
Complete Source Code
TextMode(TEXT_BUFFERED) Do Cls If KeyDown("A") Then Printr " ' A ' key down. " EndIF If ScanKeyDown(vk_left) Then Printr " ' Left ' key down." EndIF Printr "(press escape to exit)" DrawText() Loop End
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