User input
Hubb the great

Im trying to make a save/load box in my editor but how do i get input from the user so the user can write wich file to load/save

redMarvin

I'm working on a similar thing, I can show you
the code when I've finished it...

psundlin

There is so many ways to do that!
One simple way is to use allegro gui functions.
Or write your own and take input from key[] or readkey()

Read the manual and use your imagination!

spellcaster

The most easy way (IMO) would be to use aDime

It's pretty easy to use, so you don't need to bother with the allegro gui.

redMarvin

This is a real crappy well example and it's
not for long finished and contains at least
one bug but as I'm quite new to c++ and
allegro this is the best I've achieved since
my last post:

1 bool string_is_finished=false;
2 char string[256];
3 int cursor;
4 for (cursor=0; cursor<255; string[cursor++]=0);
5 cursor=0;
6 while(!string_is_finished)
7 {
8 if(keypressed())
9 {
10 if(key[KEY_ENTER])
11 {
12 string_is_finished=true;
13 }
14 if (key[KEY_BACKSPACE])
15 {
16 if (cursor>-1)
17 {
18 string[cursor]=0;
19 rest(25);
20 clear_keybuf();
21 if(cursor>0){cursor--;}
22 }
23 }
24 if(!(key[KEY_ENTER]||key[KEY_BACKSPACE]))
25 {
26 string[cursor]=readkey()&0xff;
27 cursor++;
28 }
29 clear_bitmap(screen);
30 textout(screen,font,string,100,50,15);
31 }
32 }

btw: if you or another one do improvement on this
code, please post it so I can learn/use it...

23yrold3yrold

C:

1// edittext.c
2#include <allegro.h>
3 
4int main()
5{
6 BITMAP* buffer = NULL;
7 char edittext[128];
8 int caret = 0;
9 
10 /* typical Allegro initialization */
11 allegro_init();
12 install_keyboard();
13 set_gfx_mode(GFX_AUTODETECT, 320, 240, 0, 0);
14 
15 buffer = create_bitmap(320, 240);
16 
17 do
18 {
19 if(keypressed())
20 {
21 int newkey = readkey();
22 char ASCII = newkey & 0xff;
23 char scancode = newkey >> 8;
24 
25 /* a character key was pressed; add it to the string */
26 if(ASCII >= 32 && ASCII <= 126)
27 {
28 edittext[caret] = ASCII;
29 caret++;
30 edittext[caret] = '\0';
31 }
32 else if(scancode == KEY_BACKSPACE)
33 {
34 caret--;
35 edittext[caret] = '\0';
36 }
37 }
38
39 /* all drawing goes here */
40 clear(buffer);
41 textout(buffer, font, edittext, 0, 10, makecol(255, 255, 255));
42 vline(buffer, caret * 8, 8, 18, makecol(255, 255, 255));
43 blit(buffer, screen, 0, 0, 0, 0, 320, 240);
44 
45 }
46 while(!key[KEY_ESC]);
47
48 destroy_bitmap(buffer);
49 
50 return 0;
51}
52END_OF_MAIN()

C++:

1// edittext.cpp
2#include <allegro.h>
3#include <string>
4using namespace std;
5 
6#define WHITE makecol(255, 255, 255)
7 
8int main()
9{
10 // typical Allegro initialization
11 allegro_init();
12 install_keyboard();
13 set_gfx_mode(GFX_AUTODETECT, 320, 240, 0, 0);
14 
15 // all variables are here
16 BITMAP* buffer = create_bitmap(320, 240); // initialize the double buffer
17 string edittext; // an empty string for editting
18 string::iterator iter = edittext.begin(); // string iterator
19 int caret = 0; // tracks the text caret
20 bool insert = true; // true of should text be inserted
21
22 // the game loop
23 do
24 {
25 while(keypressed())
26 {
27 int newkey = readkey();
28 char ASCII = newkey & 0xff;
29 char scancode = newkey >> 8;
30 
31 // a character key was pressed; add it to the string
32 if(ASCII >= 32 && ASCII <= 126)
33 {
34 // add the new char, inserting or replacing as need be
35 if(insert || iter == edittext.end())
36 iter = edittext.insert(iter, ASCII);
37 else
38 edittext.replace(caret, 1, 1, ASCII);
39 
40 // increment both the caret and the iterator
41 caret++;
42 iter++;
43 }
44 // some other, "special" key was pressed; handle it here
45 else
46 switch(scancode)
47 {
48 case KEY_DEL:
49 if(iter != edittext.end()) iter = edittext.erase(iter);
50 break;
51 
52 case KEY_BACKSPACE:
53 if(iter != edittext.begin())
54 {
55 caret--;
56 iter--;
57 iter = edittext.erase(iter);
58 }
59 break;
60
61 case KEY_RIGHT:
62 if(iter != edittext.end()) caret++, iter++;
63 break;
64
65 case KEY_LEFT:
66 if(iter != edittext.begin()) caret--, iter--;
67 break;
68
69 case KEY_INSERT:
70 if(insert) insert = 0; else insert = 1;
71 break;
72 
73 default:
74 
75 break;
76 }
77 }
78
79 // clear screen
80 clear(buffer);
81 
82 // output the string to the screen
83 textout(buffer, font, edittext.c_str(), 0, 10, WHITE);
84 
85 // output some stats using Allegro's printf functions
86 textprintf(buffer, font, 0, 20, WHITE, "length: %d", edittext.length());
87 textprintf(buffer, font, 0, 30, WHITE, "capacity: %d", edittext.capacity());
88 textprintf(buffer, font, 0, 40, WHITE, "empty?: %d", edittext.empty());
89 if(insert)
90 textout(buffer, font, "Inserting", 0, 50, WHITE);
91 else
92 textout(buffer, font, "Replacing", 0, 50, WHITE);
93 
94 // draw the caret
95 vline(buffer, caret * 8, 8, 18, WHITE);
96 
97 // blit to screen
98 blit(buffer, screen, 0, 0, 0, 0, 320, 240);
99 
100 }while(!key[KEY_ESC]); // end of game loop
101
102 // clean up
103 destroy_bitmap(buffer);
104 set_gfx_mode(GFX_TEXT, 0, 0, 0, 0);
105
106 return 0;
107}
108END_OF_MAIN()

The C++ version has some extra functionality, I think (gotta love the string class). 8-)

Carrus85

Hmm... I smell an AMC library around the corner. This would make a fairly nice AMC module, so you don't have to reprogram input all of the time.

MiquelFire

I see a possible buffer overflow with 23's C code ;)

23yrold3yrold

Yeah. In the C code. Stupid language. ;)

MiquelFire

A simple check to see if you're at the end of the string buffer is all you need really to prevent it (both the beginning and the end :o, stick with C++ you! ;))

23yrold3yrold

I know, I know ;) If your game stops gameplay long enough for me to enter 128 characters it probably sucks anyway ;)

gillius

If only it were that easy to rag on C.

Typically unless you provide the explicit checks on buffer size that you NEED in C, C++-style code unfortunately usually turns the problem from a buffer overflow exploit/crash into a process that runs and runs until it runs out of memory from a 1GB long string (causing a crash anyway and making the system slow in the process). One might say that C++ is more dangerous from taking too much data because it just makes the system slow and crashes softly, whereas in C you crash hard and fast and the system moves on. Although you do prevent root exploits which is the most important of all.

EDIT: haha 23 I like that line of reasoning!

23yrold3yrold

Here; is it fixed now? Might as well correct it since I post it a fair bit ;)

1// edittext.c
2#include <allegro.h>
3 
4#define BUFFERSIZE 128
5 
6int main()
7{
8 BITMAP* buffer = NULL;
9 char edittext[BUFFERSIZE];
10 int caret = 0;
11 
12 /* typical Allegro initialization */
13 allegro_init();
14 install_keyboard();
15 set_gfx_mode(GFX_AUTODETECT, 320, 240, 0, 0);
16 
17 buffer = create_bitmap(320, 240);
18 
19 do
20 {
21 if(keypressed())
22 {
23 int newkey = readkey();
24 char ASCII = newkey & 0xff;
25 char scancode = newkey >> 8;
26 
27 /* a character key was pressed; add it to the string */
28 if(ASCII >= 32 && ASCII <= 126)
29 {
30 if(caret < BUFFERSIZE - 1)
31 {
32 edittext[caret] = ASCII;
33 caret++;
34 edittext[caret] = '\0';
35 }
36 }
37 else if(scancode == KEY_BACKSPACE)
38 {
39 if (caret > 0) caret--;
40 edittext[caret] = '\0';
41 }
42 }
43
44 /* all drawing goes here */
45 clear(buffer);
46 textout(buffer, font, edittext, 0, 10, makecol(255, 255, 255));
47 vline(buffer, caret * 8, 8, 18, makecol(255, 255, 255));
48 blit(buffer, screen, 0, 0, 0, 0, 320, 240);
49 
50 }
51 while(!key[KEY_ESC]);
52
53 destroy_bitmap(buffer);
54 
55 return 0;
56}
57END_OF_MAIN()

Thread #283416. Printed from Allegro.cc