view docs/html/guideaudioexamples.html @ 3097:0d12e8f1de3c

Date: Thu, 05 Feb 2009 18:07:35 +0100 From: Stefan Klug Subject: [SDL] SDL 1.3 WinCE backend as promised, I've started to work on the WinCE backend of SDL 1.3 I've modified the win32 video backend and the gdi renderer, to work properly in WinCE. The results till now are great, but there is still some work to do. Attached are two patches with my changes. I would be happy if someone could review and propably commit them. The first one (configure.in.patch) should be straight forward without any side effects. The second one does the necessary changes to the win32 backend. I was really unhappy to start slicing this shiny new backend with #ifdef/#endif but I saw no other option. The most problematic issues are: - WinCe has no GetDIBits, so its practically impossible to fill a BITMAPINFO with correct values. I therefore removed the bmi member from the GDI_RenderData in SDL_gdirender.c to prevent usage of a not or not properly initialized bmi. - In SDL_win32window.c I exchanged some ASCII function by their general counterparts, (In CE only the Unicode versions are available). I don't know if this has a negative effect when running in win32 Cheers Stefan
author Sam Lantinga <slouken@libsdl.org>
date Mon, 23 Mar 2009 05:35:21 +0000
parents 355632dca928
children
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>Audio Examples</H1
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>Opening the audio device</H2
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>    SDL_AudioSpec wanted;
    extern void fill_audio(void *udata, Uint8 *stream, int len);

    /* Set the audio format */
    wanted.freq = 22050;
    wanted.format = AUDIO_S16;
    wanted.channels = 2;    /* 1 = mono, 2 = stereo */
    wanted.samples = 1024;  /* Good low-latency value for callback */
    wanted.callback = fill_audio;
    wanted.userdata = NULL;

    /* Open the audio device, forcing the desired format */
    if ( SDL_OpenAudio(&#38;wanted, NULL) &#60; 0 ) {
        fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
        return(-1);
    }
    return(0);</PRE
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>Playing audio</H2
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>    static Uint8 *audio_chunk;
    static Uint32 audio_len;
    static Uint8 *audio_pos;

    /* The audio function callback takes the following parameters:
       stream:  A pointer to the audio buffer to be filled
       len:     The length (in bytes) of the audio buffer
    */
    void fill_audio(void *udata, Uint8 *stream, int len)
    {
        /* Only play if we have data left */
        if ( audio_len == 0 )
            return;

        /* Mix as much data as possible */
        len = ( len &#62; audio_len ? audio_len : len );
        SDL_MixAudio(stream, audio_pos, len, SDL_MIX_MAXVOLUME);
        audio_pos += len;
        audio_len -= len;
    }

    /* Load the audio data ... */

    ;;;;;

    audio_pos = audio_chunk;

    /* Let the callback function play the audio chunk */
    SDL_PauseAudio(0);

    /* Do some processing */

    ;;;;;

    /* Wait for sound to complete */
    while ( audio_len &#62; 0 ) {
        SDL_Delay(100);         /* Sleep 1/10 second */
    }
    SDL_CloseAudio();</PRE
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