testjoystick.c
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/* Simple program to test the SDL joystick routines */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "SDL.h"
#define SCREEN_WIDTH 640
#define SCREEN_HEIGHT 480
void WatchJoystick(SDL_Joystick *joystick)
{
SDL_Surface *screen;
const char *name;
int i, done;
SDL_Event event;
int x, y, draw;
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SDL_Rect axis_area[2];
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/* Set a video mode to display joystick axis position */
screen = SDL_SetVideoMode(SCREEN_WIDTH, SCREEN_HEIGHT, 16, 0);
if ( screen == NULL ) {
fprintf(stderr, "Couldn't set video mode: %s\n",SDL_GetError());
return;
}
/* Print info about the joystick we are watching */
name = SDL_JoystickName(SDL_JoystickIndex(joystick));
printf("Watching joystick %d: (%s)\n", SDL_JoystickIndex(joystick),
name ? name : "Unknown Joystick");
printf("Joystick has %d axes, %d hats, %d balls, and %d buttons\n",
SDL_JoystickNumAxes(joystick), SDL_JoystickNumHats(joystick),
SDL_JoystickNumBalls(joystick),SDL_JoystickNumButtons(joystick));
/* Initialize drawing rectangles */
memset(axis_area, 0, (sizeof axis_area));
draw = 0;
/* Loop, getting joystick events! */
done = 0;
while ( ! done ) {
while ( SDL_PollEvent(&event) ) {
switch (event.type) {
case SDL_JOYAXISMOTION:
printf("Joystick %d axis %d value: %d\n",
event.jaxis.which,
event.jaxis.axis,
event.jaxis.value);
break;
case SDL_JOYHATMOTION:
printf("Joystick %d hat %d value:",
event.jhat.which,
event.jhat.hat);
if ( event.jhat.value == SDL_HAT_CENTERED )
printf(" centered");
if ( event.jhat.value & SDL_HAT_UP )
printf(" up");
if ( event.jhat.value & SDL_HAT_RIGHT )
printf(" right");
if ( event.jhat.value & SDL_HAT_DOWN )
printf(" down");
if ( event.jhat.value & SDL_HAT_LEFT )
printf(" left");
printf("\n");
break;
case SDL_JOYBALLMOTION:
printf("Joystick %d ball %d delta: (%d,%d)\n",
event.jball.which,
event.jball.ball,
event.jball.xrel,
event.jball.yrel);
break;
case SDL_JOYBUTTONDOWN:
printf("Joystick %d button %d down\n",
event.jbutton.which,
event.jbutton.button);
break;
case SDL_JOYBUTTONUP:
printf("Joystick %d button %d up\n",
event.jbutton.which,
event.jbutton.button);
break;
case SDL_KEYDOWN:
if ( event.key.keysym.sym != SDLK_ESCAPE ) {
break;
}
/* Fall through to signal quit */
case SDL_QUIT:
done = 1;
break;
default:
break;
}
}
/* Update visual joystick state */
for ( i=0; i<SDL_JoystickNumButtons(joystick); ++i ) {
SDL_Rect area;
area.x = i*34;
area.y = SCREEN_HEIGHT-34;
area.w = 32;
area.h = 32;
if (SDL_JoystickGetButton(joystick, i) == SDL_PRESSED) {
SDL_FillRect(screen, &area, 0xFFFF);
} else {
SDL_FillRect(screen, &area, 0x0000);
}
SDL_UpdateRects(screen, 1, &area);
}
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/* Erase previous axes */
SDL_FillRect(screen, &axis_area[draw], 0x0000);
/* Draw the X/Y axis */
draw = !draw;
x = (((int)SDL_JoystickGetAxis(joystick, 0))+32768);
x *= SCREEN_WIDTH;
x /= 65535;
if ( x < 0 ) {
x = 0;
} else
if ( x > (SCREEN_WIDTH-16) ) {
x = SCREEN_WIDTH-16;
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}
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y = (((int)SDL_JoystickGetAxis(joystick, 1))+32768);
y *= SCREEN_HEIGHT;
y /= 65535;
if ( y < 0 ) {
y = 0;
} else
if ( y > (SCREEN_HEIGHT-16) ) {
y = SCREEN_HEIGHT-16;
}
axis_area[draw].x = (Sint16)x;
axis_area[draw].y = (Sint16)y;
axis_area[draw].w = 16;
axis_area[draw].h = 16;
SDL_FillRect(screen, &axis_area[draw], 0xFFFF);
SDL_UpdateRects(screen, 2, axis_area);
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}
}
int main(int argc, char *argv[])
{
const char *name;
int i;
SDL_Joystick *joystick;
/* Initialize SDL (Note: video is required to start event loop) */
if ( SDL_Init(SDL_INIT_VIDEO|SDL_INIT_JOYSTICK) < 0 ) {
fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
exit(1);
}
/* Print information about the joysticks */
printf("There are %d joysticks attached\n", SDL_NumJoysticks());
for ( i=0; i<SDL_NumJoysticks(); ++i ) {
name = SDL_JoystickName(i);
printf("Joystick %d: %s\n",i,name ? name : "Unknown Joystick");
}
if ( argv[1] ) {
joystick = SDL_JoystickOpen(atoi(argv[1]));
if ( joystick == NULL ) {
printf("Couldn't open joystick %d: %s\n", atoi(argv[1]),
SDL_GetError());
} else {
WatchJoystick(joystick);
SDL_JoystickClose(joystick);
}
}
SDL_QuitSubSystem(SDL_INIT_VIDEO|SDL_INIT_JOYSTICK);
return(0);
}