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root/cebix/Frodo4/Src/SID_linux.h
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Comparing Frodo4/Src/SID_linux.h (file contents):
Revision 1.4 by cebix, 2004-01-12T15:13:20Z vs.
Revision 1.5 by cebix, 2004-12-04T13:24:35Z

# Line 44 | Line 44
44  
45   void DigitalRenderer::init_sound(void)
46   {
47 <    int tmp;
48 <    unsigned long format;
47 >        int arg;
48 >        unsigned long format;
49  
50 <    ready = false;
51 <    devfd = open("/dev/dsp", O_WRONLY);
52 <    if (devfd < 0)
53 <        return;
54 <
55 <    ioctl(devfd, SNDCTL_DSP_GETFMTS, &format);
56 <    if (!(format & AFMT_S16_LE))
57 <        return;
58 <    format = AFMT_S16_LE;
59 <    ioctl(devfd, SNDCTL_DSP_SETFMT, &format);
60 <            
61 <    /*
62 <     * Buffer size: 2^9 == 512 bytes. Note that too large buffers will not work
63 <     * very well: The speed of the C64 is slowed down to an average speed of
64 <     * 100% by the blocking write() call in EmulateLine(). If you use a buffer
65 <     * of, say 4096 bytes, that will happen only about every 4 frames, which
66 <     * means that the emulation runs much faster in some frames, and much
67 <     * slower in others.
68 <     * On really fast machines, it might make sense to use an even smaller
69 <     * buffer size.
70 <     */
71 <    tmp = 0x00100009;
72 <    ioctl(devfd, SNDCTL_DSP_SETFRAGMENT, &tmp);
73 <    tmp = 0;
74 <    ioctl(devfd, SNDCTL_DSP_STEREO, &tmp);
75 <    tmp = 44100;
76 <    ioctl(devfd, SNDCTL_DSP_SPEED, &tmp);
77 <    ioctl(devfd, SOUND_PCM_READ_RATE, &tmp);
78 <    if (tmp < 43000 || tmp > 45000)
79 <        return;
80 <
81 <    ioctl(devfd, SNDCTL_DSP_GETBLKSIZE, &sndbufsize);
82 <    sound_buffer = new int16[sndbufsize];
83 <    ready = true;
50 >        ready = false;
51 >        devfd = open("/dev/dsp", O_WRONLY);
52 >        if (devfd < 0)
53 >                return;
54 >
55 >        ioctl(devfd, SNDCTL_DSP_GETFMTS, &format);
56 >        if (!(format & AFMT_S16_LE))
57 >                return;
58 >        format = AFMT_S16_LE;
59 >        ioctl(devfd, SNDCTL_DSP_SETFMT, &format);
60 >
61 >        // Buffer size: 2^9 == 512 bytes. Note that too large buffers will not work
62 >        // very well: The speed of the C64 is slowed down to an average speed of
63 >        // 100% by the blocking write() call in EmulateLine(). If you use a buffer
64 >        // of, say 4096 bytes, that will happen only about every 4 frames, which
65 >        // means that the emulation runs much faster in some frames, and much
66 >        // slower in others.
67 >        // On really fast machines, it might make sense to use an even smaller
68 >        // buffer size.
69 >        arg = 0x00100009;
70 >        ioctl(devfd, SNDCTL_DSP_SETFRAGMENT, &arg);
71 >        arg = 0;
72 >        ioctl(devfd, SNDCTL_DSP_STEREO, &arg);
73 >        arg = 44100;
74 >        ioctl(devfd, SNDCTL_DSP_SPEED, &arg);
75 >        ioctl(devfd, SOUND_PCM_READ_RATE, &arg);
76 >        if (arg < 43000 || arg > 45000)
77 >                return;
78 >
79 >        ioctl(devfd, SNDCTL_DSP_GETBLKSIZE, &sndbufsize);
80 >        sound_buffer = new int16[sndbufsize];
81 >        ready = true;
82   }
83  
84  
# Line 90 | Line 88 | void DigitalRenderer::init_sound(void)
88  
89   DigitalRenderer::~DigitalRenderer()
90   {
91 <    if (devfd >= 0)
92 <        close(devfd);
91 >        if (devfd >= 0)
92 >                close(devfd);
93   }
94  
95  
# Line 119 | Line 117 | void DigitalRenderer::Resume(void)
117  
118   void DigitalRenderer::EmulateLine(void)
119   {
120 <    static int divisor = 0;
121 <    static int to_output = 0;
122 <    static int buffer_pos = 0;
120 >        static int divisor = 0;
121 >        static int to_output = 0;
122 >        static int buffer_pos = 0;
123  
124 <    if (!ready)
125 <        return;
124 >        if (!ready)
125 >                return;
126  
127          sample_buf[sample_in_ptr] = volume;
128          sample_in_ptr = (sample_in_ptr + 1) % SAMPLE_BUF_SIZE;
129  
130 <    /*
131 <     * Now see how many samples have to be added for this line
132 <     */
133 <    divisor += SAMPLE_FREQ;
134 <    while (divisor >= 0)
135 <        divisor -= TOTAL_RASTERS*SCREEN_FREQ, to_output++;
136 <
137 <    /*
138 <     * Calculate the sound data only when we have enough to fill
139 <     * the buffer entirely.
140 <     */
141 <    if ((buffer_pos + to_output) >= sndbufsize) {
142 <        int datalen = sndbufsize - buffer_pos;
143 <        to_output -= datalen;
146 <        calc_buffer(sound_buffer + buffer_pos, datalen*2);
147 <        write(devfd, sound_buffer, sndbufsize*2);
148 <        buffer_pos = 0;
149 <    }    
130 >        // Now see how many samples have to be added for this line
131 >        divisor += SAMPLE_FREQ;
132 >        while (divisor >= 0)
133 >                divisor -= TOTAL_RASTERS*SCREEN_FREQ, to_output++;
134 >
135 >        // Calculate the sound data only when we have enough to fill
136 >        // the buffer entirely
137 >        if ((buffer_pos + to_output) >= sndbufsize) {
138 >                int datalen = sndbufsize - buffer_pos;
139 >                to_output -= datalen;
140 >                calc_buffer(sound_buffer + buffer_pos, datalen*2);
141 >                write(devfd, sound_buffer, sndbufsize*2);
142 >                buffer_pos = 0;
143 >        }
144   }
145  
146  
# Line 154 | Line 148 | void DigitalRenderer::EmulateLine(void)
148   *  Renderer for Catweasel card
149   */
150  
151 < // Rendere class
151 > // Renderer class
152   class CatweaselRenderer : public SIDRenderer {
153   public:
154          CatweaselRenderer();

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