From da332ab43bac0f343504852cc1ff78f77e78c35b Mon Sep 17 00:00:00 2001
From: Norayr Chilingarian <norayr@arnet.am>
Date: Mon, 3 Feb 2014 20:27:18 +0400
Subject: [PATCH] added audio example

Former-commit-id: f77ccb00588038263cfc91f6241c4ee18f123077
---
 src/test/sound/Readme.md |  3 +++
 src/test/sound/beep.Mod  | 58 ++++++++++++++++++++++++++++++++++++++++
 src/test/sound/makefile  |  9 +++++++
 3 files changed, 70 insertions(+)
 create mode 100644 src/test/sound/Readme.md
 create mode 100644 src/test/sound/beep.Mod
 create mode 100644 src/test/sound/makefile

diff --git a/src/test/sound/Readme.md b/src/test/sound/Readme.md
new file mode 100644
index 00000000..6d6c60ce
--- /dev/null
+++ b/src/test/sound/Readme.md
@@ -0,0 +1,3 @@
+This is a modified example of sound generation taken from www.waltzballs.org/other/prog.html#audio
+
+
diff --git a/src/test/sound/beep.Mod b/src/test/sound/beep.Mod
new file mode 100644
index 00000000..1c23bddb
--- /dev/null
+++ b/src/test/sound/beep.Mod
@@ -0,0 +1,58 @@
+MODULE beep;
+IMPORT Files := OakFiles, rm:=oocRealMath, Unix;
+
+CONST (*pi2=6.28318;*)
+pi2 = 6.2831802368164062;
+rate=44.1E3;
+lf=20.0;
+seconds=2.0;
+
+VAR t,a,b,freq,xkm1,ykm1,est,gf:REAL; 
+    i,e:LONGINT;
+    ai:INTEGER;
+    outvar: Files.File;
+    outfile: Files.Rider;
+    first: BOOLEAN;
+
+PROCEDURE highpass(t,fhp,xk:REAL;VAR yk:REAL);
+BEGIN
+IF first THEN 
+   est:=rm.exp(-pi2*fhp*t);
+   gf:=(1+est)/(1-est);first:=FALSE; 
+END(*IF*);
+
+yk:=(xk-xkm1)/2;
+xkm1:=xk; 
+xk:=yk;
+yk:=est*ykm1+(1-est)*xk;
+ykm1:=yk;
+yk:=gf*yk;
+END highpass;
+
+BEGIN
+t:=1.0/rate; xkm1:=0.0; ykm1:=0.0; first:=TRUE;
+
+outvar:=Files.New("beepfile");
+IF outvar # NIL THEN
+   Files.Set(outfile, outvar, 0);
+ELSE
+   HALT(1)
+END;
+
+e:=ENTIER(rate*seconds);freq:=1000;
+
+FOR i:=1 TO e DO
+   a:=3000*rm.sin(pi2*freq*i/rate);
+(*   highpass(t,lf,a,b);*)
+(*   ai:=SHORT(ENTIER(b));*)
+   ai:=SHORT(ENTIER(a));
+   IF i>ENTIER(rate*10/lf)THEN
+      Files.WriteInt(outfile, ai);;
+   END;
+END;
+
+Files.Register(outvar);
+i:=Unix.System("oggenc -r -C 1 beepfile");
+i:=Unix.System("ogg123 beepfile.ogg");
+END beep.
+
diff --git a/src/test/sound/makefile b/src/test/sound/makefile
new file mode 100644
index 00000000..26d21ebc
--- /dev/null
+++ b/src/test/sound/makefile
@@ -0,0 +1,9 @@
+
+VOC = /opt/voc/bin/voc
+
+all:
+	$(VOC) -M beep.Mod
+
+clean:
+	rm *.o
+	rm *.c