Joystick

Simple sample to show you how to read all the joystick inputs.

Using library

GP2X minimal library by rlyeh, 2005

License

• Free for non-commercial projects (it would be nice receiving a mail from you).  Other cases, ask me first.
• GamePark Holdings is not allowed to use this library and/or use parts from it.

Source code

#include "minimal.h"

int main(int argc, char *argv[])
{
 gp2x_init(1000, 16, 11025,16,1,60, 1);

 while(1)
 {
  unsigned long pad=gp2x_joystick_read();

  gp2x_printf(NULL,(320-28*6)/2,(240-15*10)/2,
   "UP              : %s\n"
   "DOWN            : %s\n"
   "LEFT            : %s\n"
   "RIGHT           : %s\n"
   "PUSH BUTTON     : %s\n"
   "L TRIGGER       : %s\n"
   "R TRIGGER       : %s\n"
   "A BUTTON        : %s\n"
   "B BUTTON        : %s\n"
   "X BUTTON        : %s\n"
   "Y BUTTON        : %s\n"
   "SELECT BUTTON   : %s\n"
   "START BUTTON    : %s\n"
   "VOLUME - BUTTON : %s\n"
   "VOLUME + BUTTON : %s\n",
   (pad & GP2X_UP       ? "pressed    " : "not pressed" ),
   (pad & GP2X_DOWN     ? "pressed    " : "not pressed" ),
   (pad & GP2X_LEFT     ? "pressed    " : "not pressed" ),
   (pad & GP2X_RIGHT    ? "pressed    " : "not pressed" ),
   (pad & GP2X_PUSH     ? "pressed    " : "not pressed" ),
   (pad & GP2X_L        ? "pressed    " : "not pressed" ),
   (pad & GP2X_R        ? "pressed    " : "not pressed" ),
   (pad & GP2X_A        ? "pressed    " : "not pressed" ),
   (pad & GP2X_B        ? "pressed    " : "not pressed" ),
   (pad & GP2X_X        ? "pressed    " : "not pressed" ),
   (pad & GP2X_Y        ? "pressed    " : "not pressed" ),
   (pad & GP2X_SELECT   ? "pressed    " : "not pressed" ),
   (pad & GP2X_START    ? "pressed    " : "not pressed" ),
   (pad & GP2X_VOL_DOWN ? "pressed    " : "not pressed" ),
   (pad & GP2X_VOL_UP   ? "pressed    " : "not pressed" )
   );

  if(pad & GP2X_VOL_DOWN) if(pad & GP2X_START) exit(0);

  gp2x_video_RGB_flip(0);
 }
}

void gp2x_sound_frame(void *blah, void *buff, int samples) {}

Explanation

• Our gp2x_init line inits the whole library.  We set 1000 ticks per second, 16 bits video mode, 11025/16bits/stereo/60Hz sound mode, and solid font.
• Our gp2x_joystick_read line reads the joystick.  In this case we do a loop until any press is found.
• Our gp2x_printf line writes all joystick inputs by checking the pad variable.  It writes the string at center of screen and using default font.
• Our gp2x_video_RGB_flip line updates the whole screen and sets up the next hidden screen area.
• Our gp2x_sound_frame line fills our sound buffer.  Note that this function will not generate any sound since we have written a void function.

C Compilation

arm-linux-gcc minimal.c joystick.c -static -lpthread -lm

C++ Compilation

arm-linux-g++ minimal.c joystick.c -static -lpthread -lm

Output

• this program prints all the joystick inputs.
• press volume down and start buttons to exit.