+ /* decrease volume if sound is fading out */
+ if (IS_FADING(mixer[i]) &&
+ mixer[i].volume >= SOUND_FADING_VOLUME_THRESHOLD)
+ mixer[i].volume -= SOUND_FADING_VOLUME_STEP;
+
+ /* adjust volume of actual sound sample */
+ if (mixer[i].volume != PSND_MAX_VOLUME)
+ for(j=0; j<sample_size; j++)
+ premix_first_buffer[j] =
+ (mixer[i].volume * (long)premix_first_buffer[j])
+ >> PSND_MAX_VOLUME_BITS;
+
+ /* fill the last mixing buffer with stereo or mono sound */
+ if (stereo)
+ {
+ int middle_pos = PSND_MAX_LEFT2RIGHT / 2;
+ int left_volume = stereo_volume[middle_pos + mixer[i].stereo];
+ int right_volume= stereo_volume[middle_pos - mixer[i].stereo];
+
+ for(j=0; j<sample_size; j++)
+ {
+ premix_left_buffer[j] =
+ (left_volume * premix_first_buffer[j])
+ >> PSND_MAX_LEFT2RIGHT_BITS;
+ premix_right_buffer[j] =
+ (right_volume * premix_first_buffer[j])
+ >> PSND_MAX_LEFT2RIGHT_BITS;
+
+ premix_last_buffer[2 * j + 0] += premix_left_buffer[j];
+ premix_last_buffer[2 * j + 1] += premix_right_buffer[j];
+ }
+ }
+ else
+ {
+ for(j=0; j<sample_size; j++)
+ premix_last_buffer[j] += premix_first_buffer[j];
+ }
+
+ /* delete completed sound entries from the mixer */
+ if (mixer[i].playingpos >= mixer[i].data_len)
+ {
+ if (IS_LOOP(mixer[i]))
+ mixer[i].playingpos = 0;
+ else
+ Mixer_RemoveSound(i);
+ }
+ else if (mixer[i].volume <= SOUND_FADING_VOLUME_THRESHOLD)
+ Mixer_RemoveSound(i);
+ }
+
+ /* prepare final playing buffer according to system audio format */
+ for(i=0; i<max_sample_size * (stereo ? 2 : 1); i++)
+ {
+ /* cut off at 17 bit value */
+ if (premix_last_buffer[i] < -65535)
+ premix_last_buffer[i] = -65535;
+ else if (premix_last_buffer[i] > 65535)
+ premix_last_buffer[i] = 65535;
+
+ /* shift to 16 bit value */
+ premix_last_buffer[i] >>= 1;
+
+ if (afmt.format & AUDIO_FORMAT_U8)
+ {
+ playing_buffer[i] = (premix_last_buffer[i] >> 8) ^ 0x80;
+ }
+ else if (afmt.format & AUDIO_FORMAT_LE) /* 16 bit */
+ {
+ playing_buffer[2 * i + 0] = premix_last_buffer[i] & 0xff;
+ playing_buffer[2 * i + 1] = premix_last_buffer[i] >> 8;
+ }
+ else /* big endian */
+ {
+ playing_buffer[2 * i + 0] = premix_last_buffer[i] >> 8;
+ playing_buffer[2 * i + 1] = premix_last_buffer[i] & 0xff;
+ }
+ }
+
+ /* finally play the sound fragment */
+ write(audio.device_fd, playing_buffer, fragment_size);
+
+ if (!mixer_active_channels)
+ CloseAudioDevice(&audio.device_fd);
+}
+
+#else /* !AUDIO_STREAMING_DSP */
+
+static int Mixer_Main_SimpleAudio(struct SoundControl snd_ctrl)
+{
+ static short premix_first_buffer[SND_BLOCKSIZE];
+ static byte playing_buffer[SND_BLOCKSIZE];
+ int max_sample_size = SND_BLOCKSIZE;
+ void *sample_ptr;
+ int sample_len;
+ int sample_pos;
+ int sample_size;
+ int i, j;
+
+ i = 1;
+
+ /* pointer, lenght and actual playing position of sound sample */
+ sample_ptr = mixer[i].data_ptr;
+ sample_len = mixer[i].data_len;
+ sample_pos = mixer[i].playingpos;
+ sample_size = MIN(max_sample_size, sample_len - sample_pos);
+ mixer[i].playingpos += sample_size;
+
+ /* copy original sample to first mixing buffer */
+ CopySampleToMixingBuffer(&mixer[i], sample_pos, sample_size,
+ premix_first_buffer);
+
+ /* adjust volume of actual sound sample */
+ if (mixer[i].volume != PSND_MAX_VOLUME)
+ for(j=0; j<sample_size; j++)
+ premix_first_buffer[j] =
+ (mixer[i].volume * (long)premix_first_buffer[j])
+ >> PSND_MAX_VOLUME_BITS;
+
+ /* might be needed for u-law /dev/audio */
+#if 0
+ for(j=0; j<sample_size; j++)
+ playing_buffer[j] =
+ linear_to_ulaw(premix_first_buffer[j]);