From 4f8c7c2f2f2ea979518d2e116e48838df45e7ea6 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <icculus@icculus.org>
Date: Fri, 13 Apr 2018 14:05:12 -0400
Subject: [PATCH] Support SDL audio devices that require float32 samples.

Fixes missing audio when playing on Windows with SDL 2.0.7, which started
using WASAPI, which demands floating point audio.
---
 code/client/cl_avi.c    |  3 +++
 code/client/snd_dma.c   |  2 +-
 code/client/snd_local.h |  1 +
 code/client/snd_mix.c   | 17 ++++++++++++++++-
 code/sdl/sdl_snd.c      |  7 +++++--
 5 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/code/client/cl_avi.c b/code/client/cl_avi.c
index 17fd371f..2f0dffd6 100644
--- a/code/client/cl_avi.c
+++ b/code/client/cl_avi.c
@@ -368,6 +368,9 @@ qboolean CL_OpenAVIForWriting( const char *fileName )
   afd.a.rate = dma.speed;
   afd.a.format = WAV_FORMAT_PCM;
   afd.a.channels = dma.channels;
+  /* !!! FIXME: if CL_WriteAVIAudioFrame() is ever called from somewhere other
+     !!! FIXME:  than S_TransferStereo16(), we will need to handle/convert
+     !!! FIXME:  float32 samples for AVI writing. */
   afd.a.bits = dma.samplebits;
   afd.a.sampleSize = ( afd.a.bits / 8 ) * afd.a.channels;
 
diff --git a/code/client/snd_dma.c b/code/client/snd_dma.c
index 2078b811..382031b6 100644
--- a/code/client/snd_dma.c
+++ b/code/client/snd_dma.c
@@ -100,7 +100,7 @@ void S_Base_SoundInfo(void) {
 	} else {
 		Com_Printf("%5d stereo\n", dma.channels - 1);
 		Com_Printf("%5d samples\n", dma.samples);
-		Com_Printf("%5d samplebits\n", dma.samplebits);
+		Com_Printf("%5d samplebits (%s)\n", dma.samplebits, dma.isfloat ? "float" : "int");
 		Com_Printf("%5d submission_chunk\n", dma.submission_chunk);
 		Com_Printf("%5d speed\n", dma.speed);
 		Com_Printf("%p dma buffer\n", dma.buffer);
diff --git a/code/client/snd_local.h b/code/client/snd_local.h
index e0f5b1d0..053325cf 100644
--- a/code/client/snd_local.h
+++ b/code/client/snd_local.h
@@ -67,6 +67,7 @@ typedef struct {
 	int			samples;				// mono samples in buffer
 	int			submission_chunk;		// don't mix less than this #
 	int			samplebits;
+	int			isfloat;
 	int			speed;
 	byte		*buffer;
 } dma_t;
diff --git a/code/client/snd_mix.c b/code/client/snd_mix.c
index 53230812..99fe03c5 100644
--- a/code/client/snd_mix.c
+++ b/code/client/snd_mix.c
@@ -184,7 +184,22 @@ void S_TransferPaintBuffer(int endtime)
 		out_idx = s_paintedtime * dma.channels & out_mask;
 		step = 3 - dma.channels;
 
-		if (dma.samplebits == 16)
+		if ((dma.isfloat) && (dma.samplebits == 32))
+		{
+			float *out = (float *) pbuf;
+			while (count--)
+			{
+				val = *p >> 8;
+				p+= step;
+				if (val > 0x7fff)
+					val = 0x7fff;
+				else if (val < -32767)  /* clamp to one less than max to make division max out at -1.0f. */
+					val = -32767;
+				out[out_idx] = ((float) val) / 32767.0f;
+				out_idx = (out_idx + 1) & out_mask;
+			}
+		}
+		else if (dma.samplebits == 16)
 		{
 			short *out = (short *) pbuf;
 			while (count--)
diff --git a/code/sdl/sdl_snd.c b/code/sdl/sdl_snd.c
index 609aed9e..2be64e1d 100644
--- a/code/sdl/sdl_snd.c
+++ b/code/sdl/sdl_snd.c
@@ -96,7 +96,9 @@ static struct
 	{ AUDIO_U16LSB, "AUDIO_U16LSB" },
 	{ AUDIO_S16LSB, "AUDIO_S16LSB" },
 	{ AUDIO_U16MSB, "AUDIO_U16MSB" },
-	{ AUDIO_S16MSB, "AUDIO_S16MSB" }
+	{ AUDIO_S16MSB, "AUDIO_S16MSB" },
+	{ AUDIO_F32LSB, "AUDIO_F32LSB" },
+	{ AUDIO_F32MSB, "AUDIO_F32MSB" }
 };
 
 static int formatToStringTableSize = ARRAY_LEN( formatToStringTable );
@@ -228,7 +230,8 @@ qboolean SNDDMA_Init(void)
 	}
 
 	dmapos = 0;
-	dma.samplebits = obtained.format & 0xFF;  // first byte of format is bits.
+	dma.samplebits = SDL_AUDIO_BITSIZE(obtained.format);
+	dma.isfloat = SDL_AUDIO_ISFLOAT(obtained.format);
 	dma.channels = obtained.channels;
 	dma.samples = tmp;
 	dma.submission_chunk = 1;