TempleOSTS_130315.ISO

TempleOS/Demo/Snd/BeatFreq.CPP

@@ -0,0 +1,68 @@
+Bool beat_done;
+I64 start_buf_num;
+U0 (*fp_task_end_cb)();
+U0 (*fp_old_fill_buf)(SND_OUT_CONTAINER *buf,I64 buf_num)=NULL;
+
+F64 freq1,freq2;
+
+U0 BeatFillBuf(SND_OUT_CONTAINER *buf,I64 buf_num)
+{ //Gets called by HD Audio task -- $LK,"HDAudioTask","MN:HDAudioTask"$().
+  I64 j,m;
+  F64 t;
+  if (beat_done) return;
+  t=ToF64((buf_num-start_buf_num)*(SND_BUF_LEN/SND_OCHANNELS))/SND_SAMPLE_RATE;
+  j=0;
+  while (j<SND_BUF_LEN) {
+    m=MAX_I32*(Sin(freq1*(2*ã)*t)+Sin(freq2*(2*ã)*t));
+
+    //Samples are 24-bit, placed in upper 24 bits of an I32.
+    m*=snd_vol;
+    buf[j++]=ToI64(m)&0xFFFFFF00;	//Left
+    buf[j++]=ToI64(m)&0xFFFFFF00;	//Right
+
+    t+=1.0/SND_SAMPLE_RATE;
+  }
+}
+
+U0 BeatTaskEndCB()
+{
+  beat_done=TRUE;
+  fp_snd_fill_buf=fp_old_fill_buf;
+  if (fp_task_end_cb)
+    (*fp_task_end_cb)();
+  else
+    Exit;
+}
+
+U0 BeatFreq()
+{
+  if (snd_dev!=SD_HD_AUDIO) {
+    "Only works for HD Audio.\n";
+    return;
+  }
+  freq1=600.0;
+  freq2=601.0;
+  beat_done=FALSE;
+  fp_task_end_cb=Fs->task_end_cb;
+  Fs->task_end_cb=&BeatTaskEndCB; //Catch <CTRL-ALT-X> or Kill() task
+  start_buf_num=snd_obuf_num;
+  fp_old_fill_buf=fp_snd_fill_buf;
+  fp_snd_fill_buf=&BeatFillBuf;
+  try {
+    "Pick two frequencies within a few Hz of each other to hear beats.\n"
+    "Pick two frequencies a multiple of two for an octave harmonic.\n"
+    "$$FG,GREEN$$<CTRL-ALT-C>$$FG$$ to exit.\n";
+    while (TRUE) {
+      freq1=PmtF64("Freq #1 (%0.2fHz):",freq1,20,20000);
+      freq2=PmtF64("Freq #2 (%0.2fHz):",freq2,20,20000);
+    }
+  } catch { //Catch <CTRL-ALT-C>, but pass it on to next higher handler.
+    fp_snd_fill_buf=fp_old_fill_buf;
+    Fs->task_end_cb=fp_task_end_cb;
+  }
+  beat_done=TRUE;
+  fp_snd_fill_buf=fp_old_fill_buf;
+  Fs->task_end_cb=fp_task_end_cb;
+}
+
+BeatFreq;