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C02/doc/include/paddle.txt
2021-12-18 19:28:47 -05:00

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Joystick Functions for C02 Programs
This module contains constants and a function for reading paddles and
analog joysticks. It can also be used with devices that emulate paddles,
such as the Koala Pad and some mice.
The constants and assembly code vary by system, so when invoking the
cross-compilers, the command line option -s must be used to ensure that
the correct header files are included.
At the beginning of the program use the directives
#include <paddle.h02>
The following constants are defined:
#PADDLS Maximum number of joysticks supported by system.
#BUTTNS Maximum number of paddle buttons supported by system.
For systems with no paddle support, both of these
will be 0
The following functions are defined:
p = paddle(n); Returns the current state of paddle n, the first
paddle having the number 0.
If n is greater than or equal to #PADDLS then 0
will be returned. Otherwise, a byte between 0 and
$FF representing the current paddle position will
be returned.
b = button(n); Returns the current state of button n, the first
paddle having the number 0. This number may or may
not correspond to a particular paddle number.
If n is greater than or equal to #BUTTNS then 0
will be returned. Otherwise, the number 255 (TRUE)
will be returned if the button is depressed, while
the number 0 (FALSE) will be returned if it is not.
System Specific Notes:
Atari Style Paddles These are used on Atari and Commodore 8-bit systems.
The paddles are grouped in pairs. Therefore, the
paddles in the first controller port will be
numbered 0 and 1, the paddles in the second port
will be numbered 2 and 3, and so on. The button
numbers directly correspond with the paddle numbers.
When using a Koala Pad, mouse in paddle emulation
mode, or similar device, two calls to the paddle()
and/or button() functions must be made. Using the
even paddle number (0 or 2) returns the horizontal
value, while the odd paddle number (1 or 3) returns
the vertical value. Likewise, using the even button
number reads the left button, while the odd button
reads the right button.
Apple II When using paddle controllers, the first paddle
and its button are both numbered 0 while the second
paddle and its button are both numbered 1.
When using joystick controllers, the first joystick's
horizontal and vertical positions are read using
paddle(0) and paddle(1) respectively, and its button
is read using button(0), while the second joystick's
horizontal and vertical positions are read using
paddle(2) and paddle(3) respectively, and its button
is read using button(1)
Note: This library has no external dependencies.