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/*
* Example program for the Allegro library, by Grzegorz Adam Hankiewicz
*
* This program uses the Allegro library to detect and read the value
* of a joystick. The output of the program is a small target sight
* on the screen which you can move. At the same time the program will
* tell you what you are doing with the joystick (moving or firing).
*/
#include "allegro.h"
int main()
{
BITMAP *bmp; /* we create a pointer to a virtual screen */
int x=160, y=100; /* these will be used to show the target sight */
int analogmode;
AL_CONST char *msg;
int c;
allegro_init(); /* you NEED this man! ;-) */
install_keyboard(); /* ahh... read the docs. I will explain only
* joystick specific routines
*/
if (set_gfx_mode(GFX_SAFE, 320, 200, 0, 0) != 0) {
set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
allegro_message("Unable to set any graphic mode\n%s\n", allegro_error);
return 1;
}
set_palette(default_palette);
clear_bitmap(screen);
textout_centre(screen, font, "Please center the joystick", SCREEN_W/2,
SCREEN_H/2 - 36, palette_color[255]);
textout_centre(screen, font, "and press a key.", SCREEN_W/2,
SCREEN_H/2 - 20, palette_color[255]);
if ((readkey()&0xFF) == 27)
return 0;
/* the first thing is to initialise the joystick driver */
if (install_joystick(JOY_TYPE_AUTODETECT) != 0) {
set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
allegro_message("Error initialising joystick\n%s\n", allegro_error);
return 1;
}
/* make sure that we really do have a joystick */
if (!num_joysticks) {
set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
allegro_message("Error: joystick not found\n");
return 1;
}
/* before using the joystick, we have to calibrate it. This loop only
* calibrates joystick number 0, but you could do the same thing for
* other sticks if they are present (the num_joysticks variable will
* tell you how many there are).
*/
while (joy[0].flags & JOYFLAG_CALIBRATE) {
msg = calibrate_joystick_name(0);
clear_bitmap(screen);
textout_centre(screen, font, msg, SCREEN_W/2, 64, palette_color[255]);
textout_centre(screen, font, "and press a key.", SCREEN_W/2, 80, palette_color[255]);
if ((readkey()&0xFF) == 27)
return 0;
if (calibrate_joystick(0) != 0) {
set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
allegro_message("Error calibrating joystick!\n");
return 1;
}
}
/* if this joystick supports analogue input, ask the user whether to
* use digital or analogue mode. If it is only a digital pad, we don't
* bother with this question.
*/
if (joy[0].stick[0].flags & JOYFLAG_ANALOGUE) {
clear_bitmap(screen);
textout_centre(screen, font, "Now press 'D' to use a digital",
SCREEN_W/2, 64, palette_color[255]);
textout_centre(screen, font, "joystick or 'A' for analogue mode.",
SCREEN_W/2, 80, palette_color[255]);
for (;;) {
c = readkey()&0xFF;
if ((c=='d') || (c=='D')) {
analogmode = FALSE;
break;
}
else if ((c=='a') || (c=='A')) {
analogmode = TRUE;
break;
}
else if (c == 27)
return 0;
}
}
else
analogmode = FALSE;
drawing_mode(DRAW_MODE_XOR, 0, 0, 0);
clear_keybuf();
bmp = create_bitmap(320, 200);
clear_bitmap(bmp);
do {
poll_joystick(); /* we HAVE to do this to read the joystick */
clear_bitmap(bmp);
textout_centre(bmp, font, joystick_driver->name, 160, 150, palette_color[255]);
if (analogmode)
textout_centre(bmp, font, "Analog mode selected", 160, 160, palette_color[255]);
else
textout_centre(bmp, font, "Digital mode selected", 160, 160, palette_color[255]);
textout_centre(bmp, font, "Move the joystick all around", 160, 170, palette_color[255]);
textout_centre(bmp, font, "Press any key to exit", 160, 180, palette_color[255]);
textout_centre(bmp, font, "Made by Grzegorz Adam Hankiewicz", 160, 190, palette_color[255]);
/* if we detect any buttons, we print a message on the screen */
for (c=0; c<joy[0].num_buttons; c++) {
if (joy[0].button[c].b)
textprintf_centre(bmp, font, 160, c*10, palette_color[15], "%s pressed", joy[0].button[c].name);
}
if (!analogmode) {
/* now we have to check individually every possible movement
* and actualize the coordinates of the target sight.
*/
if (joy[0].stick[0].axis[0].d1) {
if (x > 0)
x--;
textout_centre(bmp, font, "Left", 120, 100, palette_color[255]);
}
if (joy[0].stick[0].axis[0].d2) {
if (x < 319)
x++;
textout_centre(bmp, font, "Right", 200, 100, palette_color[255]);
}
if (joy[0].stick[0].axis[1].d1) {
if (y > 0)
y--;
textout_centre(bmp, font, "Up", 160, 70, palette_color[255]);
}
if (joy[0].stick[0].axis[1].d2) {
if (y < 199)
y++;
textout_centre(bmp, font, "Down", 160, 130, palette_color[255]);
}
}
else {
/* yeah! Remember the 'ifs' of the digital part? This looks
* much better, only 2 lines.
*/
x += joy[0].stick[0].axis[0].pos/40;
y += joy[0].stick[0].axis[1].pos/40;
/* for informational purposes, show the input values on screen */
textprintf(bmp, font, 0, 0, palette_color[255], "Axis 0: %d", joy[0].stick[0].axis[0].pos);
textprintf(bmp, font, 0, 10, palette_color[255], "Axis 1: %d", joy[0].stick[0].axis[1].pos);
/* by checking if the values were positive or negative, we
* can know in which the direction the user pulled the joy.
*/
if (joy[0].stick[0].axis[0].pos/40 < 0)
textout_centre(bmp, font, "Left", 120, 100, palette_color[255]);
if (joy[0].stick[0].axis[0].pos/40 > 0)
textout_centre(bmp, font, "Right", 200, 100, palette_color[255]);
if (joy[0].stick[0].axis[1].pos/40 < 0)
textout_centre(bmp, font, "Up", 160, 70, palette_color[255]);
if (joy[0].stick[0].axis[1].pos/40 > 0)
textout_centre(bmp, font, "Down", 160, 130, palette_color[255]);
/* WARNING! An analog joystick can move more than 1 pixel at
* a time and the checks we did with the digital part don't
* work any longer because the steps of the target sight could
* 'jump' over the limits.
* To avoid this, we just check if the target sight has gone
* out of the screen. If yes, we put it back at the border.
*/
if (x > 319)
x = 319;
if (x < 0)
x = 0;
if (y < 0)
y = 0;
if (y > 199)
y = 199;
}
/* this draws the target sight. */
circle(bmp, x, y, 5, palette_color[255]);
putpixel(bmp, x, y, palette_color[255]);
putpixel(bmp, x+1, y, palette_color[255]);
putpixel(bmp, x, y+1, palette_color[255]);
putpixel(bmp, x-1, y, palette_color[255]);
putpixel(bmp, x, y-1, palette_color[255]);
putpixel(bmp, x+5, y, palette_color[255]);
putpixel(bmp, x, y+5, palette_color[255]);
putpixel(bmp, x-5, y, palette_color[255]);
putpixel(bmp, x, y-5, palette_color[255]);
blit(bmp, screen, 0, 0, SCREEN_W/2 - 160, SCREEN_H/2 - 100, 320, 200);
} while (!keypressed());
destroy_bitmap(bmp);
return 0;
}
END_OF_MAIN();
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