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 😛
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)
Since you managed to take a screenshot for the news article where the main character isn’t even visible, I’m providing some better “press photos” here 😉 (In fact, if you could insert these into my first post instead of the anaglyph one and delete this post, it would be great)
