Audio: ability to query various context properties.

And test all this, ugh, the test coverage is ABYSMAL here.

src/Magnum/Audio/Context.cpp

@@ -340,6 +340,12 @@ std::vector<std::string> Context::extensionStrings() const {
     return extensions;
 }
 
+Int Context::frequency() const {
+    Int count;
+    alcGetIntegerv(_device, ALC_FREQUENCY, 1, &count);
+    return count;
+}
+
 bool Context::isHrtfEnabled() const {
     Int enabled;
     alcGetIntegerv(_device, ALC_HRTF_SOFT, 1, &enabled);
@@ -360,6 +366,24 @@ std::string Context::hrtfSpecifierString() const {
     return Utility::String::fromArray(alcGetString(_device, ALC_HRTF_SPECIFIER_SOFT));
 }
 
+Int Context::monoSourceCount() const {
+    Int count;
+    alcGetIntegerv(_device, ALC_MONO_SOURCES, 1, &count);
+    return count;
+}
+
+Int Context::stereoSourceCount() const {
+    Int count;
+    alcGetIntegerv(_device, ALC_STEREO_SOURCES, 1, &count);
+    return count;
+}
+
+Int Context::refreshRate() const {
+    Int count;
+    alcGetIntegerv(_device, ALC_REFRESH, 1, &count);
+    return count;
+}
+
 std::string Context::deviceSpecifierString() const {
     return alcGetString(_device, ALC_DEVICE_SPECIFIER);
 }

src/Magnum/Audio/Context.h

@@ -265,6 +265,14 @@ class MAGNUM_AUDIO_EXPORT Context {
          */
         bool tryCreate(const Configuration& configuration);
 
+        /**
+         * @brief Sampling rate in Hz
+         * @m_since_latest
+         *
+         * @see @ref Configuration::setFrequency()
+         */
+        Int frequency() const;
+
         /**
          * @brief Whether HRTFs (Head Related Transfer Functions) are enabled
          *
@@ -296,6 +304,30 @@ class MAGNUM_AUDIO_EXPORT Context {
          */
         std::string hrtfSpecifierString() const;
 
+        /**
+         * @brief Count of supported mono sources
+         * @m_since_latest
+         *
+         * @see @ref Configuration::setMonoSourceCount()
+         */
+        Int monoSourceCount() const;
+
+        /**
+         * @brief Count of supported stereo sources
+         * @m_since_latest
+         *
+         * @see @ref Configuration::setStereoSourceCount()
+         */
+        Int stereoSourceCount() const;
+
+        /**
+         * @brief Refresh rate in Hz
+         * @m_since_latest
+         *
+         * @see @ref Configuration::setRefreshRate()
+         */
+        Int refreshRate() const;
+
         /**
          * @brief Device specifier string
          *
@@ -459,7 +491,8 @@ class MAGNUM_AUDIO_EXPORT Context::Configuration {
          * @return Reference to self (for method chaining)
          *
          * If set to @cpp -1 @ce (the default), system OpenAL configuration is
-         * used.
+         * used. Use @see @ref Context::frequency() to query the actual used
+         * sampling rate on a created context.
          */
         Configuration& setFrequency(Int hz) {
             _frequency = hz;
@@ -474,7 +507,9 @@ class MAGNUM_AUDIO_EXPORT Context::Configuration {
          * @return Reference to self (for method chaining)
          *
          * If set to @ref Hrtf::Default (the default), system OpenAL
-         * configuration is used.
+         * configuration is used. Use @ref Context::isHrtfEnabled(),
+         * @ref Context::hrtfStatus() and @ref Context::hrtfSpecifierString()
+         * to query the actual used HRTF configuration on a created context.
          * @requires_al_extension Extension @alc_extension{SOFTX,HRTF} or
          *      @alc_extension{SOFT,HRTF}, otherwise the setting will be simply
          *      ignored
@@ -492,7 +527,8 @@ class MAGNUM_AUDIO_EXPORT Context::Configuration {
          * @return Reference to self (for method chaining)
          *
          * If set to @cpp -1 @ce (the default), no hint will be given to
-         * OpenAL.
+         * OpenAL. Use @see @ref Context::monoSourceCount() to query the actual
+         * supported mono source count on a created context.
          */
         Configuration& setMonoSourceCount(Int count) {
             _monoSources = count;
@@ -507,7 +543,8 @@ class MAGNUM_AUDIO_EXPORT Context::Configuration {
          * @return Reference to self (for method chaining)
          *
          * If set to @cpp -1 @ce (the default), no hint will be given to
-         * OpenAL.
+         * OpenAL. Use @see @ref Context::stereoSourceCount() to query the
+         * actual supported stereo source count on a created context.
          */
         Configuration& setStereoSourceCount(Int count) {
             _stereoSources = count;

src/Magnum/Audio/Test/ContextALTest.cpp

@@ -27,6 +27,7 @@
 #include <sstream>
 #include <Corrade/Containers/ArrayView.h>
 #include <Corrade/TestSuite/Tester.h>
+#include <Corrade/TestSuite/Compare/Numeric.h>
 
 #include "Magnum/Audio/Extensions.h"
 #include "Magnum/Audio/Context.h"
@@ -36,7 +37,8 @@ namespace Magnum { namespace Audio { namespace Test { namespace {
 struct ContextALTest: TestSuite::Tester {
     explicit ContextALTest();
 
-    void construct();
+    void constructDefault();
+    void constructConfiguration();
     void constructMove();
 
     void quietLog();
@@ -52,7 +54,8 @@ ContextALTest::ContextALTest():
     TestSuite::Tester{TestSuite::Tester::TesterConfiguration{}
         .setSkippedArgumentPrefixes({"magnum"})}
 {
-    addTests({&ContextALTest::construct,
+    addTests({&ContextALTest::constructDefault,
+              &ContextALTest::constructConfiguration,
               &ContextALTest::constructMove});
 
     addInstancedTests({&ContextALTest::quietLog}, 2);
@@ -64,13 +67,64 @@ ContextALTest::ContextALTest():
               &ContextALTest::isExtensionDisabled});
 }
 
-void ContextALTest::construct() {
+void ContextALTest::constructDefault() {
     CORRADE_VERIFY(!Context::hasCurrent());
 
     {
         Context context{arguments().first, arguments().second};
         CORRADE_VERIFY(Context::hasCurrent());
         CORRADE_COMPARE(&Context::current(), &context);
+
+        /* Verify the queries make sense */
+        CORRADE_COMPARE_AS(context.frequency(), 10000,
+            TestSuite::Compare::Greater);
+        CORRADE_COMPARE_AS(context.monoSourceCount(), 2,
+            TestSuite::Compare::GreaterOrEqual);
+        CORRADE_COMPARE_AS(context.stereoSourceCount(), 1,
+            TestSuite::Compare::GreaterOrEqual);
+        CORRADE_COMPARE_AS(context.refreshRate(), 10,
+            TestSuite::Compare::Greater);
+    }
+
+    CORRADE_VERIFY(!Context::hasCurrent());
+}
+
+void ContextALTest::constructConfiguration() {
+    CORRADE_VERIFY(!Context::hasCurrent());
+
+    {
+        Context context{
+            Context::Configuration{}
+                .setFrequency(22050)
+                .setHrtf(Context::Configuration::Hrtf::Enabled)
+                .setMonoSourceCount(5)
+                .setStereoSourceCount(4)
+                .setRefreshRate(25),
+            arguments().first, arguments().second
+        };
+        CORRADE_VERIFY(Context::hasCurrent());
+        CORRADE_COMPARE(&Context::current(), &context);
+
+        /* Verify the queries make sense. All of these are just hints so the
+           actual value used could be higher. */
+        CORRADE_COMPARE_AS(context.frequency(), 22050,
+            TestSuite::Compare::GreaterOrEqual);
+        CORRADE_COMPARE_AS(context.monoSourceCount(), 5,
+            TestSuite::Compare::GreaterOrEqual);
+        CORRADE_COMPARE(context.stereoSourceCount(), 4);
+        CORRADE_COMPARE_AS(context.refreshRate(), 25,
+            TestSuite::Compare::GreaterOrEqual);
+
+        /* HRTF gets enabled only if the extension is supported */
+        if(context.isExtensionSupported<Extensions::ALC::SOFT::HRTF>()) {
+            CORRADE_COMPARE(context.hrtfStatus(), Context::HrtfStatus::Enabled);
+            CORRADE_VERIFY(!context.hrtfSpecifierString().empty());
+        } else if(context.isExtensionSupported<Extensions::ALC::SOFTX::HRTF>()) {
+            CORRADE_COMPARE(context.hrtfStatus(), Context::HrtfStatus::Enabled);
+            CORRADE_VERIFY(context.hrtfSpecifierString().empty());
+        } else {
+            CORRADE_COMPARE(context.hrtfStatus(), Context::HrtfStatus::Disabled);
+        }
     }
 
     CORRADE_VERIFY(!Context::hasCurrent());
@@ -79,10 +133,12 @@ void ContextALTest::construct() {
 void ContextALTest::constructMove() {
     Context context;
     CORRADE_COMPARE(&Context::current(), &context);
+    Int frequency = context.frequency();
 
     {
         Context second{std::move(context)};
         CORRADE_COMPARE(&Context::current(), &second);
+        CORRADE_COMPARE(second.frequency(), frequency);
     }
 
     CORRADE_VERIFY(!Context::hasCurrent());