• Mark Harviston (33/33) Mar 27 2006 I'm using the SDL and D to make a simple 2D game.
• lanael (6/9) Apr 10 2006 I'm not sure about your problem, but don't forget that the SDL
• Tom S (48/61) Apr 10 2006 Don't forget that character literals are allocated with an implicit \0
• lanael (5/12) Apr 10 2006 right. I wrote this a long time ago; when I wasn't sure about the D

Mark Harviston <infinull gmail.com> writes:

I'm using the SDL and D to make a simple 2D game.
I'm having trouble with loading Sounds
I'd like to do something like this:

class someobject {
static Mix_Chunk* sound_effect;
static this(){
sound_effect = Mix_LoadWAV("seffect.wav");
}
int draw(){
//..other code..//
if( Mix_PlayChannel( -1, sound_effect, 0 ) == -1 ) { assert(); }
//..more code..//
}
}


but that fails, the sound isn't loaded so I have to do:
class someobject {
static Mix_Chunk* sound_effect;
int draw(){
//..other code..//
if(sound_effect is null) {
sound_effect = Mix_LoadWAV("seffect.wav");
}
if( Mix_PlayChannel( -1, sound_effect, 0 ) == -1 ) { assert(); }
//..more code..//
}
}

do I need to declare the Mix_Chunks as auto?
Is this a GC problem?
Is this and SDL problem?
(for the record I have the same problem with fonts)
I honestly had no clue where to ask this question, I figured this was as 
a good as any.
--Mark

"lanael" <no mail.never> writes:

 I'm using the SDL and D to make a simple 2D game.
 I'm having trouble with loading Sounds


 sound_effect = Mix_LoadWAV("seffect.wav");

I'm not sure about your problem, but don't forget that the SDL 
functions are C functions so they take zero terminated strings. I, 
personnaly, use that :

char[] aSoundFile="sound.wav";
Mix_Chunk *sample=null;
sample=Mix_LoadWAV_RW(SDL_RWFromFile(toStringz(aSoundFile), "rb"), 1);

Tom S <h3r3tic -remove-.mat.uni.torun.pl> writes:

lanael wrote:
 I'm using the SDL and D to make a simple 2D game.
 I'm having trouble with loading Sounds

 
 
 sound_effect = Mix_LoadWAV("seffect.wav");

 
 I'm not sure about your problem, but don't forget that the SDL functions 
 are C functions so they take zero terminated strings. I, personnaly, use 
 that :
 
 char[] aSoundFile="sound.wav";
 Mix_Chunk *sample=null;
 sample=Mix_LoadWAV_RW(SDL_RWFromFile(toStringz(aSoundFile), "rb"), 1);

Don't forget that character literals are allocated with an implicit \0 
at their ends, so this code:

sample = Mix_LoadWAV_RW(SDL_RWFromFile("sound.wav", "rb"), 1);

will be perfectly fine :)

Moreover, references and pointers are initialized to null in D, so you 
don't have to write 'Mix_Chunk* sample = null;", simply stating 
"Mix_Chunk* sample;" will be enough.


As for Mark's original problem:

The D language spec states that "A static constructor is defined as a 
function that performs initializations before the main() function gets 
control", thus you're probably trying to load sounds using SDL before it 
even gets a chance to initialize itself. You might try doing the following:

class SomeObject
{
     static Mix_Chunk* soundEffect;
     this() {
         static bool soundEffectLoaded = false;
         if (!soundEffectLoaded) {
             soundEffect = Mix_LoadWAV("seffect.wav");
             soundEffectLoaded = true;
         }
     }
}

You might also do it this way:

class SomeObject
{
     static Mix_Chunk* soundEffect;
     this() {
         if (soundEffect is null) {
             soundEffect = Mix_LoadWAV("seffect.wav");
         }
     }
}

The difference is that, when you use the second code and SDL fails to 
load the .wav file, it will try to load it in any subsequent constructor 
runs for the SomeObject class.

Make sure that you're not creating any SomeObject instances before you 
initialize SDL. That or create some kind of a postponed loading system, 
where you only create /loading requests/ which are processed as soon as 
the subsystem responsible for fulfilling them has been initialized.


-- 
-----BEGIN GEEK CODE BLOCK-----
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GCS/M d-pu s+: a-->----- C+++$>++++ UL P+ L+ E--- W++ N++ o? K? w++ !O 
!M V? PS- PE- Y PGP t 5 X? R tv-- b DI- D+ G e>+++ h>++ !r !y
------END GEEK CODE BLOCK------

Tomasz Stachowiak  /+ a.k.a. h3r3tic +/

"lanael" <no mail.never> writes:

 Don't forget that character literals are allocated with an implicit \0 at 
 their ends, so this code:

 sample = Mix_LoadWAV_RW(SDL_RWFromFile("sound.wav", "rb"), 1);

 will be perfectly fine :)

yep; but I usually don't hardcode filenames ! :)


 Moreover, references and pointers are initialized to null in D, so you don't 
 have to write 'Mix_Chunk* sample = null;", simply stating "Mix_Chunk* 
 sample;" will be enough.

right. I wrote this a long time ago; when I wasn't sure about the D 
behavior !  You never know ! :)

Anyway, great explanation about the static stuffs. ( which I don't use 
at all : I don't know how to use them )