SDL: WASAPI_WaitDevice: Check current padding before waiting on event

From 09fbb2a07dfca7f3daf4f9c24d5bc0c8ee62cfce Mon Sep 17 00:00:00 2001
From: Brick <[EMAIL REDACTED]>
Date: Mon, 6 May 2024 23:48:19 +0100
Subject: [PATCH] WASAPI_WaitDevice: Check current padding before waiting on
 event

During playback, don't queue another buffer unless there are none in the queue.

During capture, there may be multiple buffers of audio available.
WASAPI_CaptureFromDevice only processes one buffer, and if we always wait on the next event, we will never catch up if it falls behind.
---
 src/audio/wasapi/SDL_wasapi.c | 26 ++++++++++++++------------
 1 file changed, 14 insertions(+), 12 deletions(-)

diff --git a/src/audio/wasapi/SDL_wasapi.c b/src/audio/wasapi/SDL_wasapi.c
index 99c8d7c21253f..c7d0fb328288b 100644
--- a/src/audio/wasapi/SDL_wasapi.c
+++ b/src/audio/wasapi/SDL_wasapi.c
@@ -463,20 +463,22 @@ static int WASAPI_WaitDevice(SDL_AudioDevice *device)
 {
     // WaitDevice does not hold the device lock, so check for recovery/disconnect details here.
     while (RecoverWasapiIfLost(device) && device->hidden->client && device->hidden->event) {
-        DWORD waitResult = WaitForSingleObjectEx(device->hidden->event, 200, FALSE);
-        if (waitResult == WAIT_OBJECT_0) {
+        UINT32 padding = 0;
+        if (!WasapiFailed(device, IAudioClient_GetCurrentPadding(device->hidden->client, &padding))) {
             const UINT32 maxpadding = device->sample_frames;
-            UINT32 padding = 0;
-            if (!WasapiFailed(device, IAudioClient_GetCurrentPadding(device->hidden->client, &padding))) {
-                //SDL_Log("WASAPI EVENT! padding=%u maxpadding=%u", (unsigned int)padding, (unsigned int)maxpadding);*/
-                if (device->iscapture && (padding > 0)) {
-                    break;
-                } else if (!device->iscapture && (padding <= maxpadding)) {
-                    break;
-                }
+            //SDL_Log("WASAPI %s EVENT! padding=%u maxpadding=%u", device->iscapture ? "CAPTURE" : "PLAYBACK", (unsigned int)padding, (unsigned int)maxpadding);
+            if (device->iscapture ? (padding > 0) : (padding < maxpadding)) {
+                break;
             }
-        } else if (waitResult != WAIT_TIMEOUT) {
-            //SDL_Log("WASAPI FAILED EVENT!");*/
+        }
+
+        switch (WaitForSingleObjectEx(device->hidden->event, 200, FALSE)) {
+        case WAIT_OBJECT_0:
+        case WAIT_TIMEOUT:
+            break;
+
+        default:
+            //SDL_Log("WASAPI FAILED EVENT!");
             IAudioClient_Stop(device->hidden->client);
             return -1;
         }