ARB_direct_state_access support for creating framebuffers.

src/Magnum/Framebuffer.cpp

@@ -81,12 +81,22 @@ Int Framebuffer::maxColorAttachments() {
 
 Framebuffer::Framebuffer(const Range2Di& viewport) {
     _viewport = viewport;
-    _created = false;
+    (this->*Context::current()->state().framebuffer->createImplementation)();
+    CORRADE_INTERNAL_ASSERT(_id != Implementation::State::DisengagedBinding);
+}
 
+void Framebuffer::createImplementationDefault() {
     glGenFramebuffers(1, &_id);
-    CORRADE_INTERNAL_ASSERT(_id != Implementation::State::DisengagedBinding);
+    _created = false;
 }
 
+#ifndef MAGNUM_TARGET_GLES
+void Framebuffer::createImplementationDSA() {
+    glCreateFramebuffers(1, &_id);
+    _created = true;
+}
+#endif
+
 Framebuffer::~Framebuffer() {
     /* Moved out, nothing to do */
     if(!_id) return;

src/Magnum/Framebuffer.h

@@ -302,8 +302,11 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractObje
         /**
          * @brief Constructor
          *
-         * Generates new OpenGL framebuffer.
+         * Generates new OpenGL framebuffer object. If @extension{ARB,direct_state_access}
-         * @see @ref setViewport(), @fn_gl{GenFramebuffers}
+         * (part of OpenGL 4.5) is not supported, the framebuffer is created on
+         * first use.
+         * @see @ref setViewport(), @fn_gl{CreateFramebuffers}, eventually
+         *      @fn_gl{GenFramebuffers}
          */
         explicit Framebuffer(const Range2Di& viewport);
 
@@ -316,7 +319,7 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractObje
         /**
          * @brief Destructor
          *
-         * Deletes associated OpenGL framebuffer.
+         * Deletes associated OpenGL framebuffer object.
          * @see @fn_gl{DeleteFramebuffers}
          */
         ~Framebuffer();
@@ -635,6 +638,11 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractObje
         #endif
 
     private:
+        void MAGNUM_LOCAL createImplementationDefault();
+        #ifndef MAGNUM_TARGET_GLES
+        void MAGNUM_LOCAL createImplementationDSA();
+        #endif
+
         Framebuffer& setLabelInternal(Containers::ArrayReference<const char> label);
 
         void MAGNUM_LOCAL renderbufferImplementationDefault(BufferAttachment attachment, Renderbuffer& renderbuffer);

src/Magnum/Implementation/FramebufferState.cpp

@@ -38,6 +38,18 @@ FramebufferState::FramebufferState(Context& context, std::vector<std::string>& e
     , maxDualSourceDrawBuffers(0)
     #endif
 {
+    /* Create implementation */
+    #ifndef MAGNUM_TARGET_GLES
+    if(context.isExtensionSupported<Extensions::GL::ARB::direct_state_access>()) {
+        extensions.push_back(Extensions::GL::ARB::direct_state_access::string());
+        createImplementation = &Framebuffer::createImplementationDSA;
+
+    } else
+    #endif
+    {
+        createImplementation = &Framebuffer::createImplementationDefault;
+    }
+
     /* DSA/non-DSA implementation */
     #ifndef MAGNUM_TARGET_GLES
     if(context.isExtensionSupported<Extensions::GL::EXT::direct_state_access>()) {

src/Magnum/Implementation/FramebufferState.h

@@ -49,6 +49,7 @@ struct FramebufferState {
     void(AbstractFramebuffer::*invalidateSubImplementation)(GLsizei, const GLenum*, const Range2Di&);
     #endif
 
+    void(Framebuffer::*createImplementation)();
     void(Framebuffer::*renderbufferImplementation)(Framebuffer::BufferAttachment, Renderbuffer&);
     #ifndef MAGNUM_TARGET_GLES
     void(Framebuffer::*texture1DImplementation)(Framebuffer::BufferAttachment, GLuint, GLint);