cpu fps etc...

cpu fps etc...

karistouf

Member #5,126

October 2004

hi again.
ok, this is surely once again THE CLASSICAL QUESTIOn about CPU weight and allegro and blablablabla.

I begin without the app:
{"name":"state0.jpg","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/5\/0\/5076464c4a2ed765dbb2a2fdd59a9e3a.jpg","w":511,"h":500,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/5\/0\/5076464c4a2ed765dbb2a2fdd59a9e3a"}

The old version, without any rest(1) nor timer function:
{"name":"schwz3_state.jpg","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/8\/3\/83af845627c7ee305ada2bea96a85b09.jpg","w":992,"h":468,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/8\/3\/83af845627c7ee305ada2bea96a85b09"}

I have put in my main loop a rest of 1 sec, and putted in volatile funct activated by the timer all my printing to screen.
Notice here that I have only a poor bmp of 32k and less for mouse cursor...

Modification to the program with a rest and timer function, FPS 100:
{"name":"fps100.jpg","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/4\/5\/45dac6f09ba88ffcdcb54dd614e4603a.jpg","w":962,"h":435,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/4\/5\/45dac6f09ba88ffcdcb54dd614e4603a"}

FPS 50:
{"name":"fps50.jpg","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/a\/d\/ad05f6a1c21056bbebca180a3c788b4b.jpg","w":955,"h":447,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/a\/d\/ad05f6a1c21056bbebca180a3c788b4b"}

Here is part of the code, I do not arrive to do less to not charge the CPU. Any idea ?

:-[

1////////////////////////////////////////////////////////////////////////////////
2 
3volatile long screen_unit=0;
4void screen_printing(void)
5{
6screen_unit++;
7   
8//... mes functions d affichage
9     rectfill(buffer,0,0,440,400,makecol(255,255,255));
10     textprintf_ex(buffer,font, 105,20,makecol(255,0,0),-1,AppliName);//affichage nom appi
11     draw_sprite(buffer,fond1,(int)-5,0);   
12     
13     if (index_view_graph==1)
14     {    rectfill(buffer, 320,350,330,360,makecol(255,0,0));
15          view_midi_visual();       
16     }
17     
18     if (index_view_midiapps==1) 
19     { rectfill(buffer, 150,350,160,360,makecol(255,0,0));
20       listOfAppl();
21     }
22     
23      
24      if ( index_write_deb==1){
25      rectfill(buffer, 415, 370,425, 380,makecol(255,0,0));
26      }
27      
28      
29     show_connected_to_midishare();  
30   textprintf_ex(buffer,font, 10,200,makecol(255,0,0),-1,"Midi INPUT: ");        
31   textprintf_ex(buffer,font, 10,210,makecol(255,0,0),-1,"%s", my_midi_string);
32 
33     show_udp();      
34     choices();
35     textprintf_ex(buffer,font, 10,180,makecol(255,0,0),-1,"FPS: %d ",  FPS_defini);
36     draw_sprite(buffer,mouse,(int)mouse_x,mouse_y); 
37     blit(buffer,screen,0,0,0,0,442,442);
38 
39}
40END_OF_FUNCTION(screen_printing)
41 
42 
43 
44////////////////////////////////////////////////////////////////////////////////
45int main()
46{
47  allegro_init();
48    install_keyboard();
49    install_mouse();  
50    install_timer();
51    LOCK_FUNCTION(screen_printing);
52    LOCK_VARIABLE(screen_unit);
53  
54    set_color_depth(16);
55    set_gfx_mode(GFX_AUTODETECT_WINDOWED,442,442,0,0);
56     if(set_gfx_mode(GFX_AUTODETECT_WINDOWED,440,400,0,0)!=0)
57   {
58     set_gfx_mode(GFX_TEXT,0,0,0,0);
59     allegro_message("%s\nSchwartz_Peter's Video Mode:\n 1024x768 and Higher\n16 or 32 bits better look\n\n", allegro_error);
60     quit_funct();return 1;
61     }
62      fond1=load_bitmap("chaton2.tga",NULL);
63      mouse=load_bitmap("curseur1.bmp",NULL);  
64 
65     buffer=create_bitmap(SCREEN_W,SCREEN_H);     
66     blit(buffer,screen,0,0,0,0,442,442);
67 
68    if(set_display_switch_mode(SWITCH_BACKGROUND))
69  {set_display_switch_mode(SWITCH_BACKAMNESIA);}
70  
71  
72  load_ip_conf();
73  SetUpMidi(); 
74 
75    initialisation_client();
76 
77 
78     while (index_quit==0)
79     {
80     rest(1);
81 
82 
83   
84     install_int_ex(screen_printing,BPS_TO_TIMER(FPS_defini));
85 
86 
87 
88     }
89 
90     
91quit_funct();
92 
93 
94     
95return 0;     
96}     
97END_OF_MAIN();

"step by step"
http://karistouf.free.fr

GullRaDriel

Member #3,861

September 2003

umpf !!!

Chris, n'appelle install_int_ex qu'une seule fois ! et en dehors de la boucle while !

Apres quoi tu pourras boucler sur ton rest(1); tranquillement !

"Code is like shit - it only smells if it is not yours"
Allegro Wiki, full of examples and articles !!

bamccaig

Member #7,536

July 2006

First of all you shouldn't be doing so much work in a timer function. Setting a flag or incrementing a counter and responding to it in the game loop is the preferred (and feasible) approach. I'm not sure why you repeatedly call install_int_ex, but that seems shifty as well...

--
I mean the best with what I say. It doesn't always sound that way.

gnolam

Member #2,030

March 2002

I'm surprised that doesn't outright crash, what with Allegro's notorious thread unsafety and all.

--
Move to the Democratic People's Republic of Vivendi Universal (formerly known as Sweden) - officially democracy- and privacy-free since 2008-06-18!

Audric

Member #907

January 2001

You can attempt to rest() for more than 1ms at once.
Try 5, 10, 15, 20.

edit
As for the drawing part, chances are the biggest job for the CPU is the

blit(buffer,screen,0,0,0,0,442,442);

Considering that less than 10% of the screen surface may have changed, you could just blit these parts individually, like a "dirty rectangles" system.

(Additionally, you can memorize if these screen parts HAVE changed at all. For example, the top text: No need to redraw the paragraph if it has the same content as when it was last redrawn.)

Goalie Ca

Member #2,579

July 2002

Is it Tuesday again?

Voyez: http://wiki.allegro.cc/Timers#Yielding_the_CPU

-------------
Bah weep granah weep nini bong!

Vanneto

Member #8,643

May 2007

Are there any advantages of using semaphores over normal high-res timers?

In capitalist America bank robs you.

karistouf

Member #5,126

October 2004

ooooups, i didn t know it was an error, I have an hudge programm wich is running with install_ex inside of the main loop since 4 years of dev... without any error i mean errors of timers (and its real time manipulation)...

but its still doing nothing o my troubles of CPU...
with:

     while (index_quit==0)
     {
     rest(1);
//nothing... but refreshment is done in the volatile as previous and first code

     }

CPU weight is still from 41 % and up to 70%

{"name":"outofloop.jpg","src":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/0\/3\/032ede2c76a20c40b9e54221cb2392ea.jpg","w":983,"h":510,"tn":"\/\/djungxnpq2nug.cloudfront.net\/image\/cache\/0\/3\/032ede2c76a20c40b9e54221cb2392ea"}

so? I mean install_ex is there tomake use of timer in an easy manner, to avoid calculations of tclock ?

"step by step"
http://karistouf.free.fr

GullRaDriel

Member #3,861

September 2003

install_int* granularity can vary from 1 msec to 14-20 msec

"Code is like shit - it only smells if it is not yours"
Allegro Wiki, full of examples and articles !!

Goalie Ca

Member #2,579

July 2002

Quote:

Are there any advantages of using semaphores over normal high-res timers?

Yay. Someone asked the RIGHT question.

Why did i use a locking semaphore? Because allegro timers spawn their own thread, wake it up, run user code (increment value), and then go back to sleep.

I used a semaphore because i wanted to put the mail loop to sleep and have the timer wake it up like it should happen. You only want your main loop to execute when the timer beeps! Allegro timer simplifies this possibility away but certain operating systems (not all) libraries can handle this without a problem.

Rest is basically a way to stop constant spin locking by taking shifts. It will tell the operating system to put the thread to sleep... but only for a really short time. It then checks again.. whenever the operating system feels like it. It may check almost right away (bad because more cpu wasted) but the general rule of thumb is that rest is only accurate to within 15ms.

To summarize: rest still wastes tons of cpu. It constantly wakes up and goes back to sleep.

With my locking mechanism i can get my own (graphically simple) allegrogl games to use < 1% cpu.

-------------
Bah weep granah weep nini bong!

bamccaig

Member #7,536

July 2006

That's really cool Goalie Ca, but how portable is it...? :-/ Will your example work on Windows and Linux? :-/ Do you need to install third party libraries or anything?

--
I mean the best with what I say. It doesn't always sound that way.

Goalie Ca

Member #2,579

July 2002

If your OS is posix then you have it. All linux, mac, and older winnt. For new windows you need to download pthread. http://sourceware.org/pthreads-win32/
If you really wanted to you could use windows locking mechanism. It is in winapi and does the same thing.

-------------
Bah weep granah weep nini bong!

bamccaig

Member #7,536

July 2006

I guess I will attempt to learn to use semaphores then. Until then, here is my revised raw timer template...

1/*
2 * Name:          fps.h
3 * Author:        bamccaig->members.allegro.cc
4 * Purpose:       Example of using Allegro timer routines to limit frames-per-second
5 *                    in a game.
6 * Disclaimer:    Use at own risk. :P
7 */
8#include <allegro.h>
9#include <stdio.h>
10#include <stdlib.h>
11 
12#define bool short int
13#define false 0
14#define true -1
15 
16#define SECS_PER_MIN 60
17#define MINS_PER_HOUR 60
18#define HOURS_PER_DAY 24
19#define TARGET_FPS 30
20#define WHITE makecol(255, 255, 255)
21 
22volatile bool                  gblnCloseButtonPressed = false;    // Flag for window close (X) button status.
23volatile unsigned short int    gushrFramesPerSecond = 0;          // Count of frames last second (Set).
24volatile unsigned short int    gushrFramesThisSecond = 0;         // Count of frames this second (Increment).
25volatile unsigned int          guintPendingFrames = 0;            // Number of frames OK'd to be processed.
26volatile unsigned int          guintTotalFrames = 0;              // Total number of frames.
27 
28volatile unsigned short int    gushrSeconds = 0;
29unsigned short int             gushrMinutes = 0;
30unsigned short int             gushrHours = 0;
31unsigned short int             gushrDays = 0;
32 
33void    add_frame(void);                    // Timer routine.
34void    close_button_handler(void);         // Window X button handler on supported platforms.
35void    draw(BITMAP*);                      // Draws the scene.
36int     initialize(void);                   // Initializes the application.
37void    logic(void);                        // Processes gameplay.
38void    tick(void);                         // Timer routine.
39void    update_time(void);                  // Updates clock variables.

1/*
2 * Name:          fps.c
3 * Author:        bamccaig->members.allegro.cc
4 * Purpose:       Example of using Allegro timer routines to limit frames-per-second
5 *                    in a game.
6 * Disclaimer:    Use at own risk. :P
7 */
8#include "fps.h"
9 
10int main(int argc, char* argv[])
11{
12    BITMAP* bmpBuffer = NULL;
13 
14    // Try to initialize game.
15    if(initialize() != 0)
16        exit(-1);
17 
18    // Create and clear screen buffer.
19    bmpBuffer = create_bitmap(800, 600);
20    clear(bmpBuffer);
21 
22    // Main game loop.
23    while(!(key[KEY_ESC] || gblnCloseButtonPressed))
24    {
25        // Rest loop. Nothing to do until next frame so we "go to sleep" temporarily.
26        while(!guintPendingFrames)
27            rest(16);
28 
29        // Logic loop. Changes to the game happen here.
30        while(guintPendingFrames)
31        {
32            logic();
33            guintPendingFrames--;
34        }
35 
36        /*
37         * Draw. Here we draw the current frame first to a buffer in main memory and
38         * then to the video memory (screen).
39         */
40        draw(bmpBuffer);
41    }
42 
43    // Release buffer.
44    destroy_bitmap(bmpBuffer);
45 
46    return(0);
47}
48END_OF_MAIN()
49 
50 
51 
52void add_frame(void)
53/*
54 * This is a timer routine that signals the main game loop to execute the logic (and redraw).
55 * Every time it executes it increments a counter. When the counter is non-zero the main game
56 * loop will execute the logic and then decrement the counter. Logic only happens once
57 * for every execution of this timer routine. Drawing happens at most once, but perhaps less
58 * if the program starts to get behind and needs to catch up again by repeating logic.
59 */
60{
61    guintPendingFrames++;
62}
63END_OF_FUNCTION(add_frame)
64 
65 
66 
67void close_button_handler(void)
68/*
69 * Handles the X button of the window on supported platforms. Signals the main game loop
70 * to exit.
71 */
72{
73    gblnCloseButtonPressed = true;
74}
75END_OF_FUNCTION(close_button_callback)
76 
77 
78 
79void draw(BITMAP* bmpBuffer)
80/*
81 * Draws the current frame to a BITMAP buffer in main memory and then to the video memory (screen).
82 * In this example we're only drawing the total frame count and the frames-per-second count.
83 */
84{
85    // Draw to buffer.
86    textprintf_ex(bmpBuffer, font, 20, 20, WHITE, -1, "frame-count: %d", guintTotalFrames);
87    textprintf_ex(bmpBuffer, font, 20, 40, WHITE, -1, "time: %03d:%02d:%02d:%02d", gushrDays, gushrHours, gushrMinutes, gushrSeconds);
88    textprintf_ex(bmpBuffer, font, 20, 60, WHITE, -1, "fps: %d", gushrFramesPerSecond);
89 
90    // Draw to screen.
91    blit(bmpBuffer, screen, 0, 0, 0, 0, 800, 600);
92    clear(bmpBuffer);
93}
94END_OF_FUNCTION(draw)
95 
96 
97 
98int initialize(void)
99// Initializes the program.
100{
101    char* chrGLaDOS_msg = "If at first you don't succeed,...you fail";
102 
103    // Try to initialize allegro.
104    if(allegro_init() != 0)
105    {
106        printf("%s [to initialize Allegro].\n", chrGLaDOS_msg);
107        return(-1);
108    }
109 
110    // Try to install keyboard.
111    if(install_keyboard() != 0)
112    {
113        printf("%s [to install the keyboard routines].\n", chrGLaDOS_msg);
114        return(-1);
115    }
116 
117    // Try to install timer.
118    if(install_timer() != 0)
119    {
120        printf("%s [to install the timer routines].", chrGLaDOS_msg);
121        return(-1);
122    }
123 
124    // Set color depth.
125    set_color_depth(32);
126 
127    // Try to set graphic mode.
128    if(set_gfx_mode(GFX_AUTODETECT_WINDOWED, 800, 600, 0, 0) != 0)
129    {
130        printf("%s [to set the graphics mode]. %s.\n", chrGLaDOS_msg, allegro_error);
131        return(-1);
132    }
133 
134    /*
135     * Set display switch mode so the game will continue processing even if the
136     * user switches to another window.
137     */
138    if(set_display_switch_mode(SWITCH_BACKGROUND) != 0)
139    {
140        printf("%s [to set display switch mode].\n", chrGLaDOS_msg, allegro_error);
141        return(-1);
142    }
143 
144    // Lock timer variables.
145    LOCK_VARIABLE(gblnCloseButtonPressed);
146    LOCK_VARIABLE(guintPendingFrames);
147    LOCK_VARIABLE(gushrFramesPerSecond);
148    LOCK_VARIABLE(gushrFramesThisSecond);
149    LOCK_VARIABLE(gushrSeconds);
150    LOCK_VARIABLE(gushrMinutes);
151    LOCK_VARIABLE(gushrHours);
152    LOCK_VARIABLE(gushrDays);
153 
154    // Lock timer routines.
155    LOCK_FUNCTION(add_frame);
156    LOCK_FUNCTION(close_button_handler);
157    LOCK_FUNCTION(tick);
158 
159    // Install timer callbacks.
160    install_int_ex(add_frame, BPS_TO_TIMER(TARGET_FPS));
161    install_int_ex(tick, BPS_TO_TIMER(1));
162 
163    // Install close-button callback.
164    set_close_button_callback(close_button_handler);
165 
166    return(0);
167}
168END_OF_FUNCTION(initialize)
169 
170 
171 
172void logic(void)
173/*
174 * Logic. In this example we're only incrementing a total frame counter, a
175 * frames-per-second counter, and updating time variables.
176 */
177{
178    update_time();
179 
180    guintTotalFrames++;
181    gushrFramesThisSecond++;
182}
183END_OF_FUNCTION(logic)
184 
185 
186 
187void tick(void)
188/*
189 * This is another timer routine that executes [approximately] once per second.
190 * It's role is to set the frames-per-second count and reset the
191 * frames-this-second counter.
192 */
193{
194    // Update game time.
195    gushrSeconds++;
196 
197    // Update frames per second.
198    gushrFramesPerSecond = gushrFramesThisSecond;
199    gushrFramesThisSecond = 0;
200}
201END_OF_FUNCTION(tick)
202 
203 
204 
205void update_time(void)
206// Updates time variables.
207{
208    if(gushrSeconds == SECS_PER_MIN)
209    {
210        gushrMinutes++;
211        gushrSeconds = 0;
212    }
213 
214    if(gushrMinutes == MINS_PER_HOUR)
215    {
216        gushrHours++;
217        gushrMinutes = 0;
218    }
219 
220    if(gushrHours == HOURS_PER_DAY)
221    {
222        gushrDays++;
223        gushrHours = 0;
224    }
225}

To compile it the following commands should work (you must have Allegro installed).

Windows/MinGW: gcc -O2 fps.c -o fps.exe -lalleg

*nix/GCC: gcc -O2 fps.c -o fps $(allegro-config --libs)

--
I mean the best with what I say. It doesn't always sound that way.

Goalie Ca

Member #2,579

July 2002

Quote:

I guess I will attempt to learn to use semaphores then.

Simple. A semaphore is like a locking counter. I've pasted the code i wrote to the wiki and have added a few useful comments. Basically main goes to sleep, ticker wakes it up. No wasted cycles, no extra context switches, no spinlocks.

1#include <allegro.h>
2#include <semaphore.h>
3sem_t ticks; //our new "counter" variable. 
4 
5 
6void ticker(){
7        sem_post(&ticks); //increases count. wakes up first waiting thread (sem_wait) if count > 0
8}END_OF_FUNCTION(ticker)
9 
10void main(){
11        setup_stuff();
12 
13        sem_init(&ticks, 0, 1); //sets a good default value to count. (count = 1)
14        LOCK_FUNCTION(ticker);
15        install_int_ex(ticker,BPS_TO_TIMER(60));
16 
17        while(game_on){
18                sem_wait(&ticks); //decreases count, goes to sleep if count < 0, wakes back up when count >= 0 (through sem_post)
19                update_stuff();
20                draw_stuff();
21        }
22}END_OF_MAIN()

-------------
Bah weep granah weep nini bong!

karistouf

Member #5,126

October 2004

OK finally I founded why it was taking so many weight in memory:
im using

   if(set_display_switch_mode(SWITCH_BACKGROUND))
  {set_display_switch_mode(SWITCH_BACKAMNESIA);}

to enable the visual refreshing of information if I m not on its window.
... oups !

"step by step"
http://karistouf.free.fr

Kitty Cat

Member #2,815

October 2002

Quote:

while(game_on){
    sem_wait(&ticks); //decreases count, goes to sleep if count < 0, wakes back up when count >= 0 (through sem_post)
    update_stuff();
    draw_stuff();
}

If you want to do frameskipping, this should work:

while(game_on){
    sem_wait(&ticks);
    do {
        update_stuff();
    } while(sem_trywait(&ticks) == 0);
    draw_stuff();
}

--
"Do not meddle in the affairs of cats, for they are subtle and will pee on your computer." -- Bruce Graham

karistouf

Member #5,126

October 2004

MAOUW its nice, but it need to run , while its not on nor selected.
So in fact putting in an install_ex routines enable not to freeze the tasks, just the screen refreshment is not done ( wich take a HUDGE place in mem)

"step by step"
http://karistouf.free.fr

Thomas Fjellstrom

Member #476

June 2000

Quote:

I'm surprised that doesn't outright crash, what with Allegro's notorious thread unsafety and all.

A lot of the crashieness was "fixed" in the last release or two. But it means theres a ton of locking and unlocking going on, slowing things down and potentially using lots of cpu. That doesn't mean you should use the same allegro resources from multiple thread (in fact you probably shouldn't), unless you're absolutely sure you know what you're doing.

--
Thomas Fjellstrom - [website] - [email] - [Allegro Wiki] - [Allegro TODO]
"If you can't think of a better solution, don't try to make a better solution." -- weapon_S
"The less evidence we have for what we believe is certain, the more violently we defend beliefs against those who don't agree" -- https://twitter.com/neiltyson/status/592870205409353730

bamccaig

Member #7,536

July 2006

1/*
2 * Name:          fps2.h
3 * Author:        bamccaig->members.allegro.cc
4 * Purpose:       Example of using Allegro timer routines and semaphores to limit frames-per-second
5 *                    in a game and reduce wasted cycles.
6 * Disclaimer:    Use at own risk. :P
7 */
8#include <allegro.h>
9#include <semaphore.h>
10#include <stdio.h>
11#include <stdlib.h>
12 
13#define bool short int
14#define false 0
15#define true -1
16 
17#define SECS_PER_MIN 60
18#define MINS_PER_HOUR 60
19#define HOURS_PER_DAY 24
20#define TARGET_FPS 30
21#define WHITE makecol(255, 255, 255)
22 
23sem_t                          gSemaphore;
24 
25volatile bool                  gblnCloseButtonPressed = false;    // Flag for window close (X) button status.
26volatile unsigned short int    gushrFramesPerSecond = 0;          // Count of frames last second (Set).
27volatile unsigned short int    gushrFramesThisSecond = 0;         // Count of frames this second (Increment).
28volatile unsigned int          guintTotalFrames = 0;              // Total number of frames.
29 
30volatile unsigned short int    gushrSeconds = 0;
31unsigned short int             gushrMinutes = 0;
32unsigned short int             gushrHours = 0;
33unsigned short int             gushrDays = 0;
34 
35void    add_frame(void);                    // Timer routine.
36void    close_button_handler(void);         // Window X button handler on supported platforms.
37void    draw(BITMAP*);                      // Draws the scene.
38int     initialize(void);                   // Initializes the application.
39void    logic(void);                        // Processes gameplay.
40void    tick(void);                         // Timer routine.
41void    update_time(void);                  // Updates clock variables.

1/*
2 * Name:          fps2.c
3 * Author:        bamccaig->members.allegro.cc
4 * Purpose:       Example of using Allegro timer routines and semaphores to limit frames-per-second
5 *                    in a game and reduce wasted cycles.
6 * Disclaimer:    Use at own risk. :P
7 */
8#include "fps2.h"
9 
10int main(int argc, char* argv[])
11{
12    BITMAP* bmpBuffer = NULL;
13 
14    // Try to initialize game.
15    if(initialize() != 0)
16        exit(-1);
17 
18    // Initalize semaphore.
19    sem_init(&gSemaphore, 0, 1);
20 
21    // Create and clear screen buffer.
22    bmpBuffer = create_bitmap(800, 600);
23    clear(bmpBuffer);
24 
25    // Main game loop.
26    while(!(key[KEY_ESC] || gblnCloseButtonPressed))
27    {
28        // Sleep until next frame.
29        sem_wait(&gSemaphore);
30 
31        // Logic loop. Changes to the game happen here.
32        logic();
33 
34        /*
35         * Draw. Here we draw the current frame first to a buffer in main memory and
36         * then to the video memory (screen).
37         */
38        draw(bmpBuffer);
39    }
40 
41    // Release buffer.
42    destroy_bitmap(bmpBuffer);
43 
44    return(0);
45}
46END_OF_MAIN()
47 
48 
49 
50void add_frame(void)
51/*
52 * This is a timer routine that signals the main game loop to execute the logic (and redraw).
53 */
54{
55    // Wake up game.
56    sem_post(&gSemaphore);
57}
58END_OF_FUNCTION(add_frame)
59 
60 
61 
62void close_button_handler(void)
63/*
64 * Handles the X button of the window on supported platforms. Signals the main game loop
65 * to exit.
66 */
67{
68    gblnCloseButtonPressed = true;
69}
70END_OF_FUNCTION(close_button_callback)
71 
72 
73 
74void draw(BITMAP* bmpBuffer)
75/*
76 * Draws the current frame to a BITMAP buffer in main memory and then to the video memory (screen).
77 * In this example we're only drawing the total frame count and the frames-per-second count.
78 */
79{
80    // To buffer.
81    textprintf_ex(bmpBuffer, font, 20, 20, WHITE, -1, "frame-count: %d", guintTotalFrames);
82    textprintf_ex(bmpBuffer, font, 20, 40, WHITE, -1, "time: %03d:%02d:%02d:%02d", gushrDays, gushrHours, gushrMinutes, gushrSeconds);
83    textprintf_ex(bmpBuffer, font, 20, 60, WHITE, -1, "fps: %d", gushrFramesPerSecond);
84 
85    // To screen.
86    blit(bmpBuffer, screen, 0, 0, 0, 0, 800, 600);
87    clear(bmpBuffer);
88}
89END_OF_FUNCTION(draw)
90 
91 
92 
93int initialize(void)
94// Initializes the program.
95{
96    char* chrGLaDOS_msg = "If at first you don't succeed,...you fail";
97 
98    // Try to initialize allegro.
99    if(allegro_init() != 0)
100    {
101        printf("%s [to initialize Allegro]. %s.\n", chrGLaDOS_msg, allegro_error);
102        return(-1);
103    }
104 
105    // Try to install keyboard.
106    if(install_keyboard() != 0)
107    {
108        printf("%s [to install the keyboard routines].\n", chrGLaDOS_msg);
109        return(-1);
110    }
111 
112    // Try to install timer.
113    if(install_timer() != 0)
114    {
115        printf("%s [to install the timer routines].", chrGLaDOS_msg);
116        return(-1);
117    }
118 
119    // Set color depth.
120    set_color_depth(32);
121 
122    // Try to set graphic mode.
123    if(set_gfx_mode(GFX_AUTODETECT_WINDOWED, 800, 600, 0, 0) != 0)
124    {
125        printf("%s [to set the graphics mode]. %s.\n", chrGLaDOS_msg, allegro_error);
126        return(-1);
127    }
128 
129    /*
130     * Set display switch mode so the game will continue processing even if the
131     * user switches to another window.
132     */
133    if(set_display_switch_mode(SWITCH_BACKGROUND) != 0)
134    {
135        printf("%s [to set display switch mode].\n", chrGLaDOS_msg, allegro_error);
136        return(-1);
137    }
138 
139    // Lock timer variables.
140    LOCK_VARIABLE(gblnCloseButtonPressed);
141    LOCK_VARIABLE(guintPendingFrames);
142    LOCK_VARIABLE(gushrFramesPerSecond);
143    LOCK_VARIABLE(gushrFramesThisSecond);
144    LOCK_VARIABLE(gushrSeconds);
145    LOCK_VARIABLE(gushrMinutes);
146    LOCK_VARIABLE(gushrHours);
147    LOCK_VARIABLE(gushrDays);
148 
149    // Lock timer routines.
150    LOCK_FUNCTION(add_frame);
151    LOCK_FUNCTION(close_button_handler);
152    LOCK_FUNCTION(tick);
153 
154    // Install timer callbacks.
155    install_int_ex(add_frame, BPS_TO_TIMER(TARGET_FPS));
156    install_int_ex(tick, BPS_TO_TIMER(1));
157 
158    // Install close-button callback.
159    set_close_button_callback(close_button_handler);
160 
161    return(0);
162}
163END_OF_FUNCTION(initialize)
164 
165 
166 
167void logic(void)
168/*
169 * Logic. In this example we're only incrementing a total frame counter, a
170 * frames-per-second counter, and updating time variables.
171 */
172{
173    update_time();
174 
175    guintTotalFrames++;
176    gushrFramesThisSecond++;
177}
178END_OF_FUNCTION(logic)
179 
180 
181 
182void tick(void)
183/*
184 * This is another timer routine that executes [approximately] once per second.
185 * It's role is to set the frames-per-second count and reset the
186 * frames-this-second counter.
187 */
188{
189    // Update game time.
190    gushrSeconds++;
191 
192    // Update frames per second.
193    gushrFramesPerSecond = gushrFramesThisSecond;
194    gushrFramesThisSecond = 0;
195}
196END_OF_FUNCTION(tick)
197 
198 
199 
200void update_time(void)
201// Updates time variables.
202{
203    if(gushrSeconds == SECS_PER_MIN)
204    {
205        gushrMinutes++;
206        gushrSeconds = 0;
207    }
208 
209    if(gushrMinutes == MINS_PER_HOUR)
210    {
211        gushrHours++;
212        gushrMinutes = 0;
213    }
214 
215    if(gushrHours == HOURS_PER_DAY)
216    {
217        gushrDays++;
218        gushrHours = 0;
219    }
220}

To compile it the following commands should work (you must have Allegro [and pthreads installed - Windows users, this probably means you]).

Windows/MinGW: gcc -O2 fps2.c -o fps2.exe -lalleg -lpthreadGC2

*nix/GCC: gcc -O2 fps2.c -o fps2.exe $(allegro-config --libs) -lpthread

--
I mean the best with what I say. It doesn't always sound that way.

karistouf

Member #5,126

October 2004

Quote:

I'm surprised that doesn't outright crash, what with Allegro's notorious thread unsafety and all.

never crashed... 4 years this damn calling inside main loop... hundred of performances and theatre play without crash...

Quote:

unless you're absolutely sure you know what you're doing.

well, or people have made studies, and better than say'until you know what you are doing' they can explain WHY and HOW ( more constructiv), or they didn t ... no ?

"step by step"
http://karistouf.free.fr

Thomas Fjellstrom

Member #476

June 2000

Quote:

well, or people have made studies, and better than say'until you know what you are doing' they can explain WHY and HOW ( more constructiv), or they didn t ... no ?

I don't understand a thing you just said.

However, what i meant was, if you know the issues inherent with threading, and know what to work around them, do as you please.

bamccaig

Member #7,536

July 2006

On a side note, should a semaphore (sem_t) be volatile? :-/

--
I mean the best with what I say. It doesn't always sound that way.

Thomas Fjellstrom

Member #476

June 2000

No. Just ignore that keyword. It doesn't do what most people think it does.

Goalie Ca

Member #2,579

July 2002

Quote:

On a side note, should a semaphore (sem_t) be volatile?

Actually it relies on a special CPU instruction called (roughly) "test and set lock". It is an entirely atomic operation. sem_t itself is a struct.

-------------
Bah weep granah weep nini bong!

bamccaig

Member #7,536

July 2006

Thomas Fjellstrom said:

No. Just ignore that keyword. It doesn't do what most people think it does.

Is this not what it does? :-/

--
I mean the best with what I say. It doesn't always sound that way.