From b42e71f0d9004c704c64b8c72bdcb0b71fe2dad2 Mon Sep 17 00:00:00 2001
From: Tyler Perkins <tyler@clortox.com>
Date: Sat, 9 Dec 2023 19:38:15 -0500
Subject: [PATCH] Add audio

---
 C/audio/README.md | 14 ++++++++++
 C/audio/waves.c   | 67 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+)
 create mode 100644 C/audio/README.md
 create mode 100644 C/audio/waves.c

diff --git a/C/audio/README.md b/C/audio/README.md
new file mode 100644
index 0000000..0b48c77
--- /dev/null
+++ b/C/audio/README.md
@@ -0,0 +1,14 @@
+# Audio
+
+Compile the program with
+
+
+```bash
+gcc -lm waves.c
+```
+
+Execute and hear the output with
+
+```bash
+./a.out | aplay
+```
diff --git a/C/audio/waves.c b/C/audio/waves.c
new file mode 100644
index 0000000..863cd8f
--- /dev/null
+++ b/C/audio/waves.c
@@ -0,0 +1,67 @@
+///////////////////////////////////////////////////////////////////////////////////////////////////
+// Tyler Perkins
+// 12-30-20
+// Testing command line audio
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <math.h>
+
+int main(int argc, char** argv){
+    if(argc != 1){
+        printf("Usage: %s\n", argv[0]);
+        return -1;
+    }
+
+    //sawtooth wave
+    for(int t=0, osc=0; t<8000; t++, osc += 14){
+        putchar(osc);
+    }
+
+    //square wave
+    for(int t=0, osc=0; t<8000; t++, osc += 14){
+        putchar(osc & 0x80);
+    }
+
+    //sine wave
+    for(int t=0, osc=0; t<8000; t++, osc += 14){
+        putchar(127 * sin(osc/255.0*2*3.1415) + 128);
+    }
+
+    
+    /* kinda bass guitar?
+     *
+     * The idea here is an array full of random data, with 
+     * an array size equal to the period of the wave
+     * (for 440 its ~18) then loop the array. 
+     * Then we average out the current value and next one
+     * Till we get a faded noise to silence
+     *
+     * Pretty cool ngl
+     */
+
+    unsigned char a[18];
+
+    //init the array with random data
+    FILE *fp;
+    fp = fopen("/dev/random", "r");
+    if(fp == NULL){
+        printf("Couldnt open random stream!\n");
+        return -1;
+    }
+    if(fgets(a,sizeof(a),fp)==NULL){
+        printf("Failed to read the random stream!\n");
+        return -1;
+    }
+    fclose(fp);
+
+    //play the bass guitar
+    for(int t=0;t<8000;t++){
+        int i = t % sizeof(a);
+        int j = (t+1) % sizeof(a);
+        putchar(a[i] = (a[i] + a[j])/2);
+    }
+
+    return 0;
+}
-- 
2.45.2