HorvatM wrote:
rubengar wrote:
interesting! if someone could give an example of code to make music or sounds would be great!!!!Precisely. All I want is an example of how to program the VSU registers to generate tones and effects. I don’t care whether they freeze the game or not.
It really is as simple as writing to the VSU registers and RAM periodically (such as with the timer interrupt, as you said). But, if you want example code, just run the included example file (test.txt) through DogP’s Virtual Boy Sound Generator and tell it to output VB source along with the WAV file. You can even use it to experiment with the sound registers and hear what it sounds like without the full compile(/program cart)/run cycle.
After you get that, it’s pretty much just figuring out how all those registers and wave patterns affect the sound. Anyone familiar with how digital sound reproduction “works” (especially with regard to basic additive synthesizers like the VSU) and/or has some musical talent: feel free to write a tutorial on that topic for the wiki!
OK, so I put in the example.txt included and it spat out some VB code. I go to put it in my game, and it spat out a huge list of errors. So I change the top line to “#include modlibgccvb.h” and it gave me a much more managable error list. Only trouble is, I don’t know what any of this stuff means.
EDIT: OK, figured it out.
Attachments:
I think you do need to fill the waveform RAM to get sound?
At least in Mednafen…
Anyways, maybe it’s time to share a little 🙂
Here is a basic function from my midi player that plays a single note:
void PlayNote(u8 chan, u16 freq, u8 vol) {
//Set up the frequency the channel will play
SND_REGS[chan].SxFQH = freq >> 8;
SND_REGS[chan].SxFQL = freq & 0xFF;
//Set the volume for the channel (0-15, same for left/right)
SND_REGS[chan].SxLRV = (vol << 4) | vol;
//Envelope for the channel (makes the tone fade out)
SND_REGS[chan].SxEV0 = 0xF7;
SND_REGS[chan].SxEV1 = 0x01;
//Start the channel without interval
SND_REGS[chan].SxINT = 0x9F;
}
Usage:
#include "audio.h" #include "notes.h" #include "voices.h" //Copy the piano "instrument" to soundbank 1 copymem((void*)WAVEDATA1, (void*)PIANO, 128); //Tell channel 0 to use soundbank 1 SND_REGS[0].SxRAM = 0; //Play a "Middle-C" note on channel 0 with volume 8 PlayNote(0, C_4, 8);
The file "voices.h" includes a couple of different "instruments" that I made, to be loaded into the soundbanks.
The file "notes.h" defines all standard notes, fine-tuned manually to fit the VB's frequencies.
This should help you to get some tunes flowing 🙂
Just call PlayNote() with different note values (E_4, D_4, G_4 etc.) within your main loop (or better, on a timer interrupt)
Well, it’s up to you to decide the tempo by controlling how often you call PlayNote()…
To play a simple song, you can do something like:
u16 song[] = {C_4, D_4, E4, FS4, A_5};
u32 songTick = 0;
u8 currNote = 0;
while(1){
//Playing the song in the background is easy,
//just control its tempo by only calling playnote every
//57:th (or whatever) pass through the game loop
if (songTick == 57) {
PlayNote(0, song[currNote], 8);
currNote++;
if (currNote > 4)
currNote = 0;
songTick = 0;
}
//Do other game-stuff
songTick++;
}
For more complex song playing, you’ll have to wait some more for the full midi player 😛
