Decide about used extensions on only one place.

Having the same branch cascade twice for debug output and for actual
feature selection is not good for maintenance. Put the extensions into
some list and then make it unique instead.

src/Magnum/Implementation/DebugState.cpp

@@ -31,8 +31,10 @@
 
 namespace Magnum { namespace Implementation {
 
-DebugState::DebugState(Context& context): maxLabelLength(0), maxLoggedMessages(0), maxMessageLength(0), messageCallback(nullptr) {
+DebugState::DebugState(Context& context, std::vector<std::string>& extensions): maxLabelLength(0), maxLoggedMessages(0), maxMessageLength(0), messageCallback(nullptr) {
     if(context.isExtensionSupported<Extensions::GL::KHR::debug>()) {
+        extensions.push_back(Extensions::GL::KHR::debug::string());
+
         getLabelImplementation = &AbstractObject::getLabelImplementationKhr;
         labelImplementation = &AbstractObject::labelImplementationKhr;
         messageInsertImplementation = &DebugMessage::insertImplementationKhr;
@@ -40,6 +42,8 @@ DebugState::DebugState(Context& context): maxLabelLength(0), maxLoggedMessages(0
 
     } else {
         if(context.isExtensionSupported<Extensions::GL::EXT::debug_label>()) {
+            extensions.push_back(Extensions::GL::EXT::debug_label::string());
+
             getLabelImplementation = &AbstractObject::getLabelImplementationExt;
             labelImplementation = &AbstractObject::labelImplementationExt;
         } else {
@@ -47,14 +51,17 @@ DebugState::DebugState(Context& context): maxLabelLength(0), maxLoggedMessages(0
             labelImplementation = &AbstractObject::labelImplementationNoOp;
         }
 
-        if(context.isExtensionSupported<Extensions::GL::EXT::debug_marker>())
+        if(context.isExtensionSupported<Extensions::GL::EXT::debug_marker>()) {
+            extensions.push_back(Extensions::GL::EXT::debug_marker::string());
+
             messageInsertImplementation = &DebugMessage::insertImplementationExt;
         #ifndef MAGNUM_TARGET_GLES
-        else if(context.isExtensionSupported<Extensions::GL::GREMEDY::string_marker>())
+        } else if(context.isExtensionSupported<Extensions::GL::GREMEDY::string_marker>()) {
+            extensions.push_back(Extensions::GL::GREMEDY::string_marker::string());
+
             messageInsertImplementation = &DebugMessage::insertImplementationGremedy;
         #endif
-        else
-            messageInsertImplementation = &DebugMessage::insertImplementationNoOp;
+        } else messageInsertImplementation = &DebugMessage::insertImplementationNoOp;
 
         messageCallbackImplementation = &DebugMessage::callbackImplementationNoOp;
     }

src/Magnum/Implementation/DebugState.h

@@ -26,13 +26,14 @@
 */
 
 #include <string>
+#include <vector>
 
 #include "Magnum/DebugMessage.h"
 
 namespace Magnum { namespace Implementation {
 
 struct DebugState {
-    DebugState(Context& context);
+    explicit DebugState(Context& context, std::vector<std::string>& extensions);
 
     std::string(*getLabelImplementation)(GLenum, GLuint);
     void(*labelImplementation)(GLenum, GLuint, const std::string&);

src/Magnum/Implementation/State.cpp

@@ -25,6 +25,8 @@
 
 #include "State.h"
 
+#include <algorithm>
+
 #include "Magnum/Context.h"
 #include "Magnum/Extensions.h"
 
@@ -39,32 +41,31 @@
 
 namespace Magnum { namespace Implementation {
 
-State::State(Context& context):
-    buffer(new BufferState),
-    debug(new DebugState(context)),
-    framebuffer(new FramebufferState),
-    mesh(new MeshState),
-    renderer(new RendererState),
-    shader(new ShaderState),
-    shaderProgram(new ShaderProgramState),
-    texture(new TextureState)
-{
+State::State(Context& context) {
+    /* List of extensions used in current context. Guesstimate count to avoid
+       unnecessary reallocations. */
+    std::vector<std::string> extensions;
+    #ifndef MAGNUM_TARGET_GLES
+    extensions.reserve(32);
+    #else
+    extensions.reserve(8);
+    #endif
 
-    Debug() << "Using optional features:";
+    buffer = new BufferState;
+    debug = new DebugState(context, extensions);
+    framebuffer = new FramebufferState;
+    mesh = new MeshState;
+    renderer = new RendererState;
+    shader = new ShaderState;
+    shaderProgram = new ShaderProgramState;
+    texture = new TextureState;
 
-    if(context.isExtensionSupported<Extensions::GL::KHR::debug>())
-        Debug() << "   " << Extensions::GL::KHR::debug::string();
-    else {
-        if(context.isExtensionSupported<Extensions::GL::EXT::debug_label>())
-            Debug() << "   " << Extensions::GL::EXT::debug_label::string();
+    /* Sort the features and remove duplicates */
+    std::sort(extensions.begin(), extensions.end());
+    extensions.erase(std::unique(extensions.begin(), extensions.end()), extensions.end());
 
-        if(context.isExtensionSupported<Extensions::GL::EXT::debug_marker>())
-            Debug() << "   " << Extensions::GL::EXT::debug_marker::string();
-        #ifndef MAGNUM_TARGET_GLES
-        else if(context.isExtensionSupported<Extensions::GL::GREMEDY::string_marker>())
-            Debug() << "   " << Extensions::GL::GREMEDY::string_marker::string();
-        #endif
-    }
+    Debug() << "Using optional features:";
+    for(const auto& ext: extensions) Debug() << "   " << ext;
 }
 
 State::~State() {

src/Magnum/Implementation/State.h

@@ -44,14 +44,14 @@ struct State {
 
     ~State();
 
-    BufferState* const buffer;
-    DebugState* const debug;
-    FramebufferState* const framebuffer;
-    MeshState* const mesh;
-    RendererState* const renderer;
-    ShaderState* const shader;
-    ShaderProgramState* const shaderProgram;
-    TextureState* const texture;
+    BufferState* buffer;
+    DebugState* debug;
+    FramebufferState* framebuffer;
+    MeshState* mesh;
+    RendererState* renderer;
+    ShaderState* shader;
+    ShaderProgramState* shaderProgram;
+    TextureState* texture;
 };
 
 }}