From 14980b25a86f6d4657ed1dfa8e273b62238a3259 Mon Sep 17 00:00:00 2001
From: Sam Lantinga <[EMAIL REDACTED]>
Date: Thu, 2 Nov 2023 22:32:25 -0700
Subject: [PATCH] Clarify documentation for audio callback migration
---
docs/README-migration.md | 20 +++++++++++++++-----
1 file changed, 15 insertions(+), 5 deletions(-)
diff --git a/docs/README-migration.md b/docs/README-migration.md
index 6d0c9131f181..109c5543fc25 100644
--- a/docs/README-migration.md
+++ b/docs/README-migration.md
@@ -62,7 +62,7 @@ In SDL2, you might have done something like this to play audio...
```c
void SDLCALL MyAudioCallback(void *userdata, Uint8 * stream, int len)
{
- /* calculate a little more audio here, maybe using `userdata`, write it to `stream` */
+ /* Calculate a little more audio here, maybe using `userdata`, write it to `stream` */
}
/* ...somewhere near startup... */
@@ -81,15 +81,25 @@ In SDL2, you might have done something like this to play audio...
...in SDL3, you can do this...
```c
- void SDLCALL MyAudioCallback(SDL_AudioStream *stream, int len, void *userdata)
+ void SDLCALL MyAudioCallback3(void *userdata, SDL_AudioStream *stream, int additional_amount, int total_amount)
{
- /* calculate a little more audio here, maybe using `userdata`, write it to `stream` */
- SDL_PutAudioStreamData(stream, newdata, len);
+ /* Calculate a little more audio here, maybe using `userdata`, write it to `stream`
+ *
+ * If you want to reuse the original callback, you could do something like this:
+ */
+ if (additional_amount > 0) {
+ Uint16 *data = SDL_stack_alloc(Uint16, additional_amount / sizeof(Uint16));
+ if (data) {
+ MyAudioCallback(userdata, data, additional_amount);
+ SDL_PutAudioStreamData(stream, data, additional_amount);
+ SDL_stack_free(data);
+ }
+ }
}
/* ...somewhere near startup... */
const SDL_AudioSpec spec = { SDL_AUDIO_S16, 2, 44100 };
- SDL_AudioStream *stream = SDL_OpenAudioDeviceStream(SDL_AUDIO_DEVICE_DEFAULT_OUTPUT, &spec, MyAudioCallback, &my_audio_callback_user_data);
+ SDL_AudioStream *stream = SDL_OpenAudioDeviceStream(SDL_AUDIO_DEVICE_DEFAULT_OUTPUT, &spec, MyAudioCallback3, &my_audio_callback_user_data);
SDL_ResumeAudioDevice(SDL_GetAudioStreamDevice(stream));