Defining variables esp32 - c++

Question

i am trying to figure out a way in esp32 to have (a list) for lack of better terms, that i could call upon as a variable input. I have a void playwav(); function. I want to use a global variable to define the file that should be played. ie playwav('alarm'). I had a case switch setup but was using the a b c method. As my code is growing (next step is going to add 71 new wav files), i am quickly realizing that method will no longer work. I have been told to do an array but for the life of me no matter what ive read i just cant grasp how to do it nor call upon the files by name. Does anyone have advice on what i should do? Any help is much appreciated.
This is what i currently have.
void playWAV (char effect, int bg1248_general_volume)
{
Serial.println("Entered playWAV");
switch (effect)
{
case 'a':
file = new AudioFileSourceSD("/wav/alarm.wav");
break;
case 'b':
file = new AudioFileSourceSD("/wav/alarmhigh.wav");
break;
case 'c':
file = new AudioFileSourceSD("/wav/alarmlow.wav");
break;
case 'd':
file = new AudioFileSourceSD("/wav/error.wav");
break;
case 'e':
file = new AudioFileSourceSD("/wav/error1.wav");
break;
case 'f':
file = new AudioFileSourceSD("/wav/noread.wav");
break;
case 'g':
file = new AudioFileSourceSD("/wav/noreadings.wav");
break;
case 'h':
file = new AudioFileSourceSD("/wav/normalrange.wav");
break;
case 'i':
file = new AudioFileSourceSD("/wav/warning.wav");
break;
case 'j':
file = new AudioFileSourceSD("/wav/warninghigh.wav");
break;
case 'k':
file = new AudioFileSourceSD("/wav/warninglow.wav");
break;
case 'l':
file = new AudioFileSourceSD("/wav/startup.wav");
break;
case 'm':
file = new AudioFileSourceSD("/wav/startup.wav");
break;
case 'n':
file = new AudioFileSourceSD("/wav/update.wav");
break;
case 'o':
file = new AudioFileSourceSD("/wav/startup_dev.wav");
}
float volumeGain = ((float)bg1248_general_volume / 100.0) * 39.0;
Serial.print("volumeGain:");
Serial.println(volumeGain);
id3 = new AudioFileSourceID3(file);
out = new AudioOutputI2S(0, 0); // Output to builtInDAC
out->SetPinout(12, 0, 2);
out->SetOutputModeMono(true);
out->SetGain(volumeGain);
wav = new AudioGeneratorWAV();
wav->begin(id3, out);
However because I used the alphabet im going to run out of cases very very soon. I want to be able to call for a specific wav file anywhere in the project preferably like playWAV(filename) or something similar.
I call the function(file) like this (example condition)
if((ns->sensSgv<=cfg.snd_alarm) && (ns->sensSgv>=0.1)) {
// red alarm state
// M5.Lcd.fillRect(110, 220, 100, 20, TFT_RED);
Serial.println("ALARM LOW");
M5.Lcd.fillRect(0, 220, 320, 20, TFT_RED);
M5.Lcd.setTextColor(TFT_BLACK, TFT_RED);
int stw=M5.Lcd.textWidth(tmpStr);
M5.Lcd.drawString(tmpStr, 159-stw/2, 220, GFXFF);
if( (alarmDifSec>cfg.alarm_repeat*60) && (snoozeRemaining<=0) ) {
playWAV('a', 100);
'a'=case 100 = volume.
Alan, this is what I currently had in my enum, i was following a tutorial but doubt i did it right. even if i did i was getting errors saying i had duplicate cases when i don't.
EDIT:
The condition is set using this:
if((ns->sensSgv<=cfg.snd_alarm) && (ns->sensSgv>=0.1))
and if you notice at the bottom there is:
if( (alarmDifSec>cfg.alarm_repeat*60) && (snoozeRemaining<=0) ) {
playWAV('a', 100);
The a corelates to the case A in the switch case. shown above. currently all the places that use the playWAV function are manually specified.

Answer 1

My understanding was using the alphabets in switch case will ran out soon because of large no. of files (>26). So, I implemented the logic using enum first and below is the complete code.
#include<stdio.h>
enum soundEffects {
alarm,
alarm_high,
alarm_low,
Dev_startup,
error,
error1,
noread,
noreadings,
normalrange,
startup,
startup_dev,
update,
warning,
warning_high,
warning_low,
};
void playWav (enum soundEffects effect, int paci_volume)
{
//Serial.println("Entered paciplay_day");
//printf("Entered paciplay_day\n");
switch (effect)
{
case alarm:
//file = new AudioFileSourceSD("/wav/alarm.wav");
printf("/wav/alarm.wav\n");
break;
case alarm_high:
//file = new AudioFileSourceSD("/wav/alarmhigh.wav");
printf("/wav/alarmhigh.wav\n");
break;
case alarm_low:
//file = new AudioFileSourceSD("/wav/alarmlow.wav");
printf("/wav/alarmlow.wav\n");
break;
case error:
//file = new AudioFileSourceSD("/wav/error.wav");
printf("/wav/error.wav\n");
break;
case error1:
//file = new AudioFileSourceSD("/wav/error1.wav");
printf("/wav/error1.wav\n");
break;
case noread:
//file = new AudioFileSourceSD("/wav/noread.wav");
printf("/wav/noread.wav\n");
break;
case noreadings:
//file = new AudioFileSourceSD("/wav/noreadings.wav");
printf("/wav/noreadings.wav\n");
break;
case normalrange:
//file = new AudioFileSourceSD("/wav/normalrange.wav");
printf("/wav/normalrange.wav\n");
break;
case warning:
//file = new AudioFileSourceSD("/wav/warning.wav");
printf("/wav/warning.wav\n");
break;
case warning_high:
//file = new AudioFileSourceSD("/wav/warninghigh.wav");
printf("/wav/warninghigh.wav\n");
break;
case warning_low:
//file = new AudioFileSourceSD("/wav/warninglow.wav");
printf("/wav/warninglow.wav\n");
break;
case startup:
//file = new AudioFileSourceSD("/wav/startup.wav");
printf("/wav/startup.wav\n");
break;
case update:
//file = new AudioFileSourceSD("/wav/update.wav");
printf("/wav/update.wav\n");
break;
}
}
int main()
{
//below are the 3 ways of calling your playWav() function
//1 - using direct numbers
//this will throw compilation error when compiled using cpp compilers
for (int i = 0; i<14; i++)
{
printf("enum value: %d\n", i);
playWav(i, 50);
}
//2 - directly calling using the enum
playWav(startup, 100);
//3 - Just another way of calling
enum soundEffects sound;
sound = error;
playWav(sound, 100);
return 0;
}
Also, I implemented this same logic using double array's. Please do find it below. This uses the name of the file as a parameter so altogether we can eliminate the use of switch statement.
#include<stdio.h>
void playWav (const char *filename, int paci_volume)
{
//Serial.println("Entered paciplay_day");
printf("Entered paciplay_day\n");
//file = new AudioFileSourceSD("/wav/update.wav");
printf("/wav/%s\n", filename);
}
int main()
{
const char list_of_files[][25] = { "startup.wav", "update.wav", "warning.wav", "alarm.wav" };
for (int i = 0; i<4; i++)
{
printf("name: %s\n", list_of_files[i]);
playWav(list_of_files[i], 50);
}
return 0;
}
Please omit my printf statements which I used for debugging. I hope this is useful.