Added Renderer::enable()/disable().

Should be preferred to Renderer::setFeature() to avoid unnecessary
branching. Also a bit shorter to write.

src/Magnum/DebugMessage.h

@@ -56,8 +56,8 @@ using @ref setCallback() or use the default one provided in
 @ref setDefaultCallback():
 
 @code
-Renderer::setFeature(Renderer::Feature::DebugOutput, true);
+Renderer::enable(Renderer::Feature::DebugOutput);
-Renderer::setFeature(Renderer::Feature::DebugOutputSynchronous, true);
+Renderer::enable(Renderer::Feature::DebugOutputSynchronous);
 
 DebugMessage::setDefaultCallback();
 DebugMessage::insert(DebugMessage::Source::Application, DebugMessage::Type::Marker,

src/Magnum/Renderer.cpp

@@ -35,8 +35,16 @@
 
 namespace Magnum {
 
+void Renderer::enable(const Feature feature) {
+    glEnable(GLenum(feature));
+}
+
+void Renderer::disable(const Feature feature) {
+    glDisable(GLenum(feature));
+}
+
 void Renderer::setFeature(const Feature feature, const bool enabled) {
-    enabled ? glEnable(GLenum(feature)) : glDisable(GLenum(feature));
+    enabled ? enable(feature) : disable(feature);
 }
 
 void Renderer::setHint(const Hint target, const HintMode mode) {

src/Magnum/Renderer.h

@@ -74,7 +74,7 @@ class MAGNUM_EXPORT Renderer {
          * @brief Features
          *
          * All features are disabled by default unless specified otherwise.
-         * @see @ref setFeature()
+         * @see @ref enable(), @ref disable(), @ref setFeature()
          */
         enum class Feature: GLenum {
             /**
@@ -219,9 +219,28 @@ class MAGNUM_EXPORT Renderer {
         };
 
         /**
-         * @brief Set feature
+         * @brief Enable feature
          *
-         * @see @fn_gl{Enable}/@fn_gl{Disable}
+         * @see @ref disable(), @ref setFeature(), @fn_gl{Enable}
+         */
+        static void enable(Feature feature);
+
+        /**
+         * @brief Disable feature
+         *
+         * @see @ref enable(), @ref setFeature(), @fn_gl{Disable}
+         */
+        static void disable(Feature feature);
+
+        /**
+         * @brief Enable or disable feature
+         *
+         * Convenience equivalent to the following:
+         * @code
+         * enabled ? Renderer::enable(feature) : Renderer::disable(feature)
+         * @endcode
+         * Prefer to use @ref enable() and @ref disable() directly to avoid
+         * unnecessary branching.
          */
         static void setFeature(Feature feature, bool enabled);
 

src/Magnum/SceneGraph/Drawable.h

@@ -109,9 +109,9 @@ void MyApplication::drawEvent() {
           .setAmbientColor(ambientColor);
     camera.draw(phongObjects);
 
-    Renderer::setFeature(Renderer::Feature::Blending, true);
+    Renderer::enable(Renderer::Feature::Blending);
     camera.draw(transparentObjects);
-    Renderer::setFeature(Renderer::Feature::Blending, false);
+    Renderer::disable(Renderer::Feature::Blending);
 
     // ...
 }

src/Magnum/Test/AbstractOpenGLTester.h

@@ -53,8 +53,8 @@ class AbstractOpenGLTester: public TestSuite::Tester, public Platform::Windowles
 
 AbstractOpenGLTester::AbstractOpenGLTester(): Platform::WindowlessApplication({zero, nullptr}) {
     if(Context::current()->isExtensionSupported<Extensions::GL::KHR::debug>()) {
-        Renderer::setFeature(Renderer::Feature::DebugOutput, true);
+        Renderer::enable(Renderer::Feature::DebugOutput);
-        Renderer::setFeature(Renderer::Feature::DebugOutputSynchronous, true);
+        Renderer::enable(Renderer::Feature::DebugOutputSynchronous);
         DebugMessage::setDefaultCallback();
     }
 }

src/Magnum/Test/DebugGLTest.cpp

@@ -77,16 +77,16 @@ void DebugGLTest::insertMessage() {
     if(!Context::current()->isExtensionSupported<Extensions::GL::KHR::debug>())
         CORRADE_SKIP(Extensions::GL::KHR::debug::string() + std::string(" is not supported"));
 
-    Renderer::setFeature(Renderer::Feature::DebugOutput, true);
+    Renderer::enable(Renderer::Feature::DebugOutput);
 
-    Renderer::setFeature(Renderer::Feature::DebugOutputSynchronous, true);
+    Renderer::enable(Renderer::Feature::DebugOutputSynchronous);
     std::ostringstream out;
     Debug::setOutput(&out);
     DebugMessage::setDefaultCallback();
     DebugMessage::insert(DebugMessage::Source::Application, DebugMessage::Type::Marker,
         1337, DebugMessage::Severity::Notification, "Hello from OpenGL command stream!");
 
-    Renderer::setFeature(Renderer::Feature::DebugOutput, false);
+    Renderer::enable(Renderer::Feature::DebugOutput);
 
     MAGNUM_VERIFY_NO_ERROR();
     CORRADE_COMPARE(out.str(),

src/Magnum/Test/TimeQueryGLTest.cpp

@@ -60,7 +60,7 @@ void TimeQueryGLTest::queryTime() {
 
     TimeQuery q2;
     q2.begin(TimeQuery::Target::TimeElapsed);
-    Renderer::setFeature(Renderer::Feature::Blending, true);
+    Renderer::enable(Renderer::Feature::Blending);
     Renderer::finish();
     q2.end();
     const auto result2 = q2.result<UnsignedInt>();
@@ -80,7 +80,7 @@ void TimeQueryGLTest::queryTimestamp() {
     q1.timestamp();
 
     q.begin(TimeQuery::Target::TimeElapsed);
-    Renderer::setFeature(Renderer::Feature::Blending, true);
+    Renderer::enable(Renderer::Feature::Blending);
     Renderer::finish();
     q.end();