kc3-lang/SDL

diff --git a/.gitignore b/.gitignore
index 6b0b71d..fd27cb7 100644
--- a/.gitignore
+++ b/.gitignore
@@ -157,6 +157,7 @@ test/testshape
 test/testsprite2
 test/testspriteminimal
 test/teststreaming
+test/testsurround
 test/testthread
 test/testtimer
 test/testurl
diff --git a/VisualC/SDL.sln b/VisualC/SDL.sln
index 23cad71..87b2cf5 100644
--- a/VisualC/SDL.sln
+++ b/VisualC/SDL.sln
@@ -56,6 +56,8 @@ Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "testyuv", "tests\testyuv\te
 EndProject
 Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "testsensor", "tests\testsensor\testsensor.vcxproj", "{C4E04D18-EF76-4B42-B4C2-16A1BACDC0A4}"
 EndProject
+Project("{8BC9CEB8-8B4A-11D0-8D11-00A0C91BC942}") = "testsurround", "tests\testsurround\testsurround.vcxproj", "{70B894A9-E306-49E8-ABC2-932A952A5E5F}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Win32 = Debug|Win32
@@ -280,6 +282,14 @@ Global
 		{C4E04D18-EF76-4B42-B4C2-16A1BACDC0A4}.Release|Win32.Build.0 = Release|Win32
 		{C4E04D18-EF76-4B42-B4C2-16A1BACDC0A4}.Release|x64.ActiveCfg = Release|x64
 		{C4E04D18-EF76-4B42-B4C2-16A1BACDC0A4}.Release|x64.Build.0 = Release|x64
+		{70B894A9-E306-49E8-ABC2-932A952A5E5F}.Debug|Win32.ActiveCfg = Debug|Win32
+		{70B894A9-E306-49E8-ABC2-932A952A5E5F}.Debug|Win32.Build.0 = Debug|Win32
+		{70B894A9-E306-49E8-ABC2-932A952A5E5F}.Debug|x64.ActiveCfg = Debug|x64
+		{70B894A9-E306-49E8-ABC2-932A952A5E5F}.Debug|x64.Build.0 = Debug|x64
+		{70B894A9-E306-49E8-ABC2-932A952A5E5F}.Release|Win32.ActiveCfg = Release|Win32
+		{70B894A9-E306-49E8-ABC2-932A952A5E5F}.Release|Win32.Build.0 = Release|Win32
+		{70B894A9-E306-49E8-ABC2-932A952A5E5F}.Release|x64.ActiveCfg = Release|x64
+		{70B894A9-E306-49E8-ABC2-932A952A5E5F}.Release|x64.Build.0 = Release|x64
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -309,6 +319,7 @@ Global
 		{C4E04D18-EF76-4B42-B4C2-16A1BACDC0A5} = {D69D5741-611F-4E14-8541-1FEE94F50B5A}
 		{40FB7794-D3C3-4CFE-BCF4-A80C97635682} = {D69D5741-611F-4E14-8541-1FEE94F50B5A}
 		{C4E04D18-EF76-4B42-B4C2-16A1BACDC0A4} = {D69D5741-611F-4E14-8541-1FEE94F50B5A}
+		{70B894A9-E306-49E8-ABC2-932A952A5E5F} = {D69D5741-611F-4E14-8541-1FEE94F50B5A}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {C320C9F2-1A8F-41D7-B02B-6338F872BCAD}
diff --git a/VisualC/tests/testsurround/testsurround.vcxproj b/VisualC/tests/testsurround/testsurround.vcxproj
new file mode 100644
index 0000000..3286052
--- /dev/null
+++ b/VisualC/tests/testsurround/testsurround.vcxproj
@@ -0,0 +1,210 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{70B894A9-E306-49E8-ABC2-932A952A5E5F}</ProjectGuid>
+    <RootNamespace>testsurround</RootNamespace>
+    <VisualStudioVersion Condition="'$(VisualStudioVersion)' == ''">10.0</VisualStudioVersion>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <PlatformToolset Condition="'$(VisualStudioVersion)' != '10.0'">$(DefaultPlatformToolset)</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <PlatformToolset Condition="'$(VisualStudioVersion)' != '10.0'">$(DefaultPlatformToolset)</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <PlatformToolset Condition="'$(VisualStudioVersion)' != '10.0'">$(DefaultPlatformToolset)</PlatformToolset>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
+    <ConfigurationType>Application</ConfigurationType>
+    <PlatformToolset Condition="'$(VisualStudioVersion)' != '10.0'">$(DefaultPlatformToolset)</PlatformToolset>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />
+  <ImportGroup Label="ExtensionSettings">
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="$(VCTargetsPath)Microsoft.CPP.UpgradeFromVC70.props" />
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+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="$(VCTargetsPath)Microsoft.CPP.UpgradeFromVC70.props" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="$(VCTargetsPath)Microsoft.CPP.UpgradeFromVC70.props" />
+  </ImportGroup>
+  <ImportGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="PropertySheets">
+    <Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
+    <Import Project="$(VCTargetsPath)Microsoft.CPP.UpgradeFromVC70.props" />
+  </ImportGroup>
+  <PropertyGroup Label="UserMacros" />
+  <PropertyGroup>
+    <_ProjectFileVersion>10.0.40219.1</_ProjectFileVersion>
+    <OutDir Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">$(SolutionDir)$(Platform)\$(Configuration)\</OutDir>
+    <IntDir Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">$(Platform)\$(Configuration)\</IntDir>
+    <OutDir Condition="'$(Configuration)|$(Platform)'=='Release|x64'">$(SolutionDir)$(Platform)\$(Configuration)\</OutDir>
+    <IntDir Condition="'$(Configuration)|$(Platform)'=='Release|x64'">$(Platform)\$(Configuration)\</IntDir>
+    <OutDir Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">$(SolutionDir)$(Platform)\$(Configuration)\</OutDir>
+    <IntDir Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">$(Platform)\$(Configuration)\</IntDir>
+    <OutDir Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">$(SolutionDir)$(Platform)\$(Configuration)\</OutDir>
+    <IntDir Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">$(Platform)\$(Configuration)\</IntDir>
+    <CodeAnalysisRuleSet Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">AllRules.ruleset</CodeAnalysisRuleSet>
+    <CodeAnalysisRules Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" />
+    <CodeAnalysisRuleAssemblies Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" />
+    <CodeAnalysisRuleSet Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">AllRules.ruleset</CodeAnalysisRuleSet>
+    <CodeAnalysisRules Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" />
+    <CodeAnalysisRuleAssemblies Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" />
+    <CodeAnalysisRuleSet Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">AllRules.ruleset</CodeAnalysisRuleSet>
+    <CodeAnalysisRules Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" />
+    <CodeAnalysisRuleAssemblies Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" />
+    <CodeAnalysisRuleSet Condition="'$(Configuration)|$(Platform)'=='Release|x64'">AllRules.ruleset</CodeAnalysisRuleSet>
+    <CodeAnalysisRules Condition="'$(Configuration)|$(Platform)'=='Release|x64'" />
+    <CodeAnalysisRuleAssemblies Condition="'$(Configuration)|$(Platform)'=='Release|x64'" />
+  </PropertyGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
+    <Midl>
+      <PreprocessorDefinitions>NDEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <MkTypLibCompatible>true</MkTypLibCompatible>
+      <SuppressStartupBanner>true</SuppressStartupBanner>
+      <TargetEnvironment>Win32</TargetEnvironment>
+      <TypeLibraryName>.\Release/testsurround.tlb</TypeLibraryName>
+    </Midl>
+    <ClCompile>
+      <AdditionalIncludeDirectories>$(SolutionDir)/../include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalUsingDirectories>%(AdditionalUsingDirectories)</AdditionalUsingDirectories>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
+      <PrecompiledHeader>
+      </PrecompiledHeader>
+      <PrecompiledHeaderOutputFile>.\Release/testsurround.pch</PrecompiledHeaderOutputFile>
+      <WarningLevel>Level3</WarningLevel>
+    </ClCompile>
+    <ResourceCompile>
+      <PreprocessorDefinitions>NDEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <Culture>0x0409</Culture>
+    </ResourceCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
+    <Midl>
+      <PreprocessorDefinitions>NDEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <MkTypLibCompatible>true</MkTypLibCompatible>
+      <SuppressStartupBanner>true</SuppressStartupBanner>
+      <TargetEnvironment>X64</TargetEnvironment>
+      <TypeLibraryName>.\Release/testsurround.tlb</TypeLibraryName>
+    </Midl>
+    <ClCompile>
+      <AdditionalIncludeDirectories>$(SolutionDir)/../include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalUsingDirectories>%(AdditionalUsingDirectories)</AdditionalUsingDirectories>
+      <PreprocessorDefinitions>WIN32;NDEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
+      <PrecompiledHeader>
+      </PrecompiledHeader>
+      <PrecompiledHeaderOutputFile>.\Release/testsurround.pch</PrecompiledHeaderOutputFile>
+      <WarningLevel>Level3</WarningLevel>
+    </ClCompile>
+    <ResourceCompile>
+      <PreprocessorDefinitions>NDEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <Culture>0x0409</Culture>
+    </ResourceCompile>
+    <Link>
+      <SubSystem>Console</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'">
+    <Midl>
+      <PreprocessorDefinitions>_DEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <MkTypLibCompatible>true</MkTypLibCompatible>
+      <SuppressStartupBanner>true</SuppressStartupBanner>
+      <TargetEnvironment>Win32</TargetEnvironment>
+      <TypeLibraryName>.\Debug/testsurround.tlb</TypeLibraryName>
+    </Midl>
+    <ClCompile>
+      <Optimization>Disabled</Optimization>
+      <AdditionalIncludeDirectories>$(SolutionDir)/../include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalUsingDirectories>%(AdditionalUsingDirectories)</AdditionalUsingDirectories>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreadedDLL</RuntimeLibrary>
+      <WarningLevel>Level3</WarningLevel>
+      <DebugInformationFormat>OldStyle</DebugInformationFormat>
+    </ClCompile>
+    <ResourceCompile>
+      <PreprocessorDefinitions>_DEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <Culture>0x0409</Culture>
+    </ResourceCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Console</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
+    <Midl>
+      <PreprocessorDefinitions>_DEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <MkTypLibCompatible>true</MkTypLibCompatible>
+      <SuppressStartupBanner>true</SuppressStartupBanner>
+      <TargetEnvironment>X64</TargetEnvironment>
+      <TypeLibraryName>.\Debug/testsurround.tlb</TypeLibraryName>
+    </Midl>
+    <ClCompile>
+      <Optimization>Disabled</Optimization>
+      <AdditionalIncludeDirectories>$(SolutionDir)/../include;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
+      <AdditionalUsingDirectories>%(AdditionalUsingDirectories)</AdditionalUsingDirectories>
+      <PreprocessorDefinitions>WIN32;_DEBUG;_WINDOWS;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <RuntimeLibrary>MultiThreadedDebugDLL</RuntimeLibrary>
+      <WarningLevel>Level3</WarningLevel>
+      <DebugInformationFormat>OldStyle</DebugInformationFormat>
+    </ClCompile>
+    <ResourceCompile>
+      <PreprocessorDefinitions>_DEBUG;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <Culture>0x0409</Culture>
+    </ResourceCompile>
+    <Link>
+      <GenerateDebugInformation>true</GenerateDebugInformation>
+      <SubSystem>Console</SubSystem>
+    </Link>
+  </ItemDefinitionGroup>
+  <ItemGroup>
+    <ProjectReference Include="..\..\SDL\SDL.vcxproj">
+      <Project>{81ce8daf-ebb2-4761-8e45-b71abcca8c68}</Project>
+      <Private>false</Private>
+      <CopyLocalSatelliteAssemblies>false</CopyLocalSatelliteAssemblies>
+      <ReferenceOutputAssembly>true</ReferenceOutputAssembly>
+    </ProjectReference>
+    <ProjectReference Include="..\..\SDLmain\SDLmain.vcxproj">
+      <Project>{da956fd3-e142-46f2-9dd5-c78bebb56b7a}</Project>
+      <Private>false</Private>
+      <CopyLocalSatelliteAssemblies>false</CopyLocalSatelliteAssemblies>
+      <ReferenceOutputAssembly>true</ReferenceOutputAssembly>
+    </ProjectReference>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="..\..\..\Test\testsurround.c" />
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
\ No newline at end of file
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 7292e44..629ac5a 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -23,6 +23,7 @@ add_executable(checkkeys checkkeys.c)
 add_executable(checkkeysthreads checkkeysthreads.c)
 add_executable(loopwave loopwave.c)
 add_executable(loopwavequeue loopwavequeue.c)
+add_executable(testsurround testsurround.c)
 add_executable(testresample testresample.c)
 add_executable(testaudioinfo testaudioinfo.c)
 
diff --git a/test/Makefile.in b/test/Makefile.in
index df70b67..846db3a 100644
--- a/test/Makefile.in
+++ b/test/Makefile.in
@@ -62,6 +62,7 @@ TARGETS = \
 	testsprite2$(EXE) \
 	testspriteminimal$(EXE) \
 	teststreaming$(EXE) \
+	testsurround$(EXE) \
 	testthread$(EXE) \
 	testtimer$(EXE) \
 	testurl$(EXE) \
@@ -95,6 +96,9 @@ loopwave$(EXE): $(srcdir)/loopwave.c
 loopwavequeue$(EXE): $(srcdir)/loopwavequeue.c
 	$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
 
+testsurround$(EXE): $(srcdir)/testsurround.c
+	$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
+
 testresample$(EXE): $(srcdir)/testresample.c
 	$(CC) -o $@ $^ $(CFLAGS) $(LIBS)
 
diff --git a/test/README b/test/README
index 83337cf..b1ee089 100644
--- a/test/README
+++ b/test/README
@@ -4,6 +4,7 @@ These are test programs for the SDL library:
 	checkkeys	Watch the key events to check the keyboard
 	loopwave	Audio test -- loop playing a WAV file
 	loopwavequeue	Audio test -- loop playing a WAV file with SDL_QueueAudio
+	testsurround	Audio test -- play test tone on each audio channel
 	testaudioinfo	Lists audio device capabilities
 	testerror	Tests multi-threaded error handling
 	testfile	Tests RWops layer
diff --git a/test/testsurround.c b/test/testsurround.c
new file mode 100644
index 0000000..b1364e1
--- /dev/null
+++ b/test/testsurround.c
@@ -0,0 +1,202 @@
+/*
+  Copyright (C) 1997-2021 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely.
+*/
+
+/* Program to test surround sound audio channels */
+#include "SDL_config.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "SDL.h"
+
+static int total_channels;
+static int active_channel;
+
+#define SAMPLE_RATE_HZ 48000
+#define CHANNEL_TEST_TIME_SEC 5
+#define MAX_AMPLITUDE SDL_MAX_SINT16
+
+#define SINE_FREQ_HZ 500
+#define LFE_SINE_FREQ_HZ 50
+
+/* The channel layout is defined in SDL_audio.h */
+const char*
+get_channel_name(int channel_index, int channel_count)
+{
+    switch (channel_index) {
+    case 0:
+        return "Front Left";
+    case 1:
+        return "Front Right";
+    case 2:
+        switch (channel_count) {
+        case 3:
+            return "Low Frequency Effects";
+        case 4:
+            return "Back Left";
+        default:
+            return "Front Center";
+        }
+    case 3:
+        switch (channel_count) {
+        case 4:
+            return "Back Right";
+        case 5:
+            return "Back Left";
+        default:
+            return "Low Frequency Effects";
+        }
+    case 4:
+        switch (channel_count) {
+        case 5:
+            return "Back Right";
+        case 7:
+            return "Back Center";
+        case 6:
+        case 8:
+            return "Back Left";
+        }
+    case 5:
+        switch (channel_count) {
+        case 7:
+            return "Back Left";
+        case 6:
+        case 8:
+            return "Back Right";
+        }
+    case 6:
+        switch (channel_count) {
+        case 7:
+            return "Back Right";
+        case 8:
+            return "Side Left";
+        }
+    case 7:
+        return "Side Right";
+    }
+
+    return NULL;
+}
+
+SDL_bool
+is_lfe_channel(int channel_index, int channel_count)
+{
+    return (channel_count == 3 && channel_index == 2) || (channel_count >= 6 && channel_index == 3);
+}
+
+void SDLCALL
+fill_buffer(void* unused, Uint8* stream, int len)
+{
+    Sint16* buffer = (Sint16*)stream;
+    int samples = len / sizeof(int16_t);
+    static int total_samples = 0;
+    int i;
+
+    SDL_memset(stream, 0, len);
+
+    /* This can happen for a short time when switching devices */
+    if (active_channel == total_channels) {
+        return;
+    }
+
+    /* Play a sine wave on the active channel only */
+    for (i = active_channel; i < samples; i += total_channels) {
+        float time = (float)total_samples++ / SAMPLE_RATE_HZ;
+        int sine_freq = is_lfe_channel(active_channel, total_channels) ? LFE_SINE_FREQ_HZ : SINE_FREQ_HZ;
+        int amplitude;
+
+        /* Gradually ramp up and down to avoid audible pops when switching between channels */
+        if (total_samples < SAMPLE_RATE_HZ) {
+            amplitude = total_samples * MAX_AMPLITUDE / SAMPLE_RATE_HZ;
+        } else if (total_samples > (CHANNEL_TEST_TIME_SEC - 1) * SAMPLE_RATE_HZ) {
+            amplitude = (CHANNEL_TEST_TIME_SEC * SAMPLE_RATE_HZ - total_samples) * MAX_AMPLITUDE / SAMPLE_RATE_HZ;
+        } else {
+            amplitude = MAX_AMPLITUDE;
+        }
+
+        buffer[i] = (Sint16)(SDL_sin(6.283185f * sine_freq * time) * amplitude);
+
+        /* Reset our state for next callback if this channel test is finished */
+        if (total_samples == CHANNEL_TEST_TIME_SEC * SAMPLE_RATE_HZ) {
+            total_samples = 0;
+            active_channel++;
+            break;
+        }
+    }
+}
+
+int
+main(int argc, char *argv[])
+{
+    int i;
+
+    /* Enable standard application logging */
+    SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
+
+    if (SDL_Init(SDL_INIT_AUDIO) < 0) {
+        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
+        return 1;
+    }
+
+    /* Show the list of available drivers */
+    SDL_Log("Available audio drivers:");
+    for (i = 0; i < SDL_GetNumAudioDrivers(); ++i) {
+        SDL_Log("%i: %s", i, SDL_GetAudioDriver(i));
+    }
+
+    SDL_Log("Using audio driver: %s\n", SDL_GetCurrentAudioDriver());
+
+    for (i = 0; i < SDL_GetNumAudioDevices(0); i++) {
+        const char *devname = SDL_GetAudioDeviceName(i, 0);
+        int j;
+        SDL_AudioSpec spec;
+        SDL_AudioDeviceID dev;
+        
+        if (SDL_GetAudioDeviceSpec(i, 0, &spec) != 0) {
+            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL_GetAudioSpec() failed: %s\n", SDL_GetError());
+            continue;
+        }
+
+        spec.freq = SAMPLE_RATE_HZ;
+        spec.format = AUDIO_S16SYS;
+        spec.samples = 4096;
+        spec.callback = fill_buffer;
+
+        dev = SDL_OpenAudioDevice(devname, 0, &spec, NULL, 0);
+        if (dev == 0) {
+            SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "SDL_OpenAudioDevice() failed: %s\n", SDL_GetError());
+            continue;
+        }
+
+        SDL_Log("Testing audio device: %s (%d channels)\n", devname, spec.channels);
+
+        /* These are used by the fill_buffer callback */
+        total_channels = spec.channels;
+        active_channel = 0;
+
+        SDL_PauseAudioDevice(dev, 0);
+
+        for (j = 0; j < total_channels; j++) {
+            int sine_freq = is_lfe_channel(j, total_channels) ? LFE_SINE_FREQ_HZ : SINE_FREQ_HZ;
+
+            SDL_Log("Playing %d Hz test tone on channel: %s\n", sine_freq, get_channel_name(j, total_channels));
+
+            /* fill_buffer() will increment the active channel */
+            SDL_Delay(CHANNEL_TEST_TIME_SEC * 1000);
+        }
+
+        SDL_CloseAudioDevice(dev);
+    }
+
+    SDL_Quit();
+    return 0;
+}
\ No newline at end of file