issotm / smooth-player-demo

A simple demo program for playing back sound samples on your Game Boy

smooth-player-demo

Make sure you clone this repository recursively! It uses two submodules, src/include/hardware.inc and src/smooth-player. Note that downloading a ZIP of this repo won't work for the same reason.

To compile the project, make sure you have RGBDS (at least 0.5.0), GNU Make and Python 3, and run make within this directory. Then, you can just run bin/smooth-player.gb!

Code organization

This demo also serves as an example of how to integrate and use smooth-player.

Look at the files src/playback.asm, src/sample.asm, src/timer_interrupt.asm, and the end of src/utils.asm. For the sample conversion, you may be interested in the rule near the bottom of Makefile.

This repo is based on gb-boilerplate for the general architecture.

Swapping music tracks

To replace the best music ever, included as an example, with your own, follow the following steps:

• Include the music in raw signed 8-bit format under src/res, for example src/res/samples/nyan_cat.raw.
• Include the sample: include_sample <Label>, "res/samples/nyan_cat.sample", <size>, <bank>. <Label> is up to you; <size> must match the size of the generated .sample file; and <bank> is the first ROM bank in which the sample will be stored (yes, the sample banks are hardcoded due to technical constraints. Sorry!)
• Replace RickSample with <Label> in src/playback.asm. You can also delete the include_sample RickSample, ... line, by the way.
• Compile again, and voilà!

Making the music loop

Add the lines marked with a + to src/playback.asm. Don't add the +es themselves!

     ldh a, [hIsAGB]
     and a
     play_sample RickSample
     ld a, $77
     ldh [rNR50], a
+    ld hl, rTAC
 .lock
+    bit 2, [hl]
+    jr z, SetupPlayback
     ldh a, [rLY]
     and $04
     rra