There is glDiscardSubFramebuffer() in EXT_discard_framebuffer.

The relevant functions are now a no-op on ES2.

doc/opengl-mapping.dox

@@ -184,7 +184,7 @@ OpenGL function                        | Matching API
 @fn_gl{InvalidateBufferData}           | @ref Buffer::invalidateData()
 @fn_gl{InvalidateBufferSubData}        | @ref Buffer::invalidateSubData()
 @fn_gl{InvalidateFramebuffer}, \n @fn_gles_extension{DiscardFramebuffer,EXT,discard_framebuffer} | @ref DefaultFramebuffer::invalidate(), \n @ref Framebuffer::invalidate()
-@fn_gl{InvalidateSubFramebuffer}, \n @fn_gles_extension{DiscardSubFramebuffer,EXT,discard_framebuffer} | @ref DefaultFramebuffer::invalidate(), \n @ref Framebuffer::invalidate()
+@fn_gl{InvalidateSubFramebuffer}       | @ref DefaultFramebuffer::invalidate(), \n @ref Framebuffer::invalidate()
 @fn_gl{InvalidateTexImage}             | @ref Texture::invalidateImage(), \n @ref TextureArray::invalidateImage(), \n @ref CubeMapTexture::invalidateImage(), \n @ref CubeMapTextureArray::invalidateImage(), \n @ref RectangleTexture::invalidateImage(), \n @ref MultisampleTexture::invalidateImage()
 @fn_gl{InvalidateTexSubImage}          | @ref Texture::invalidateSubImage(), \n @ref TextureArray::invalidateSubImage(), \n @ref CubeMapTexture::invalidateSubImage(), \n @ref CubeMapTextureArray::invalidateSubImage(), \n @ref RectangleTexture::invalidateSubImage(), \n @ref MultisampleTexture::invalidateSubImage()
 @fn_gl{IsBuffer}, \n @fn_gl{IsFramebuffer}, \n @fn_gl{IsProgram}, \n @fn_gl{IsProgramPipeline}, \n @fn_gl{IsQuery}, \n @fn_gl{IsRenderbuffer}, \n @fn_gl{IsSampler}, \n @fn_gl{IsShader}, \n @fn_gl{IsSync}, \n @fn_gl{IsTexture}, \n @fn_gl{IsTransformFeedback}, \n @fn_gl{IsVertexArray} | not needed, objects are strongly typed

src/Magnum/AbstractFramebuffer.cpp

@@ -221,20 +221,13 @@ void AbstractFramebuffer::invalidateImplementationDefault(const GLsizei count, c
     #endif
 }
 
+#ifndef MAGNUM_TARGET_GLES2
 void AbstractFramebuffer::invalidateImplementationNoOp(GLsizei, const GLenum*, const Range2Di&) {}
 
 void AbstractFramebuffer::invalidateImplementationDefault(const GLsizei count, const GLenum* const attachments, const Range2Di& rectangle) {
-    /** @todo Re-enable when extension loader is available for ES */
-    #ifndef MAGNUM_TARGET_GLES2
     glInvalidateSubFramebuffer(GLenum(bindInternal()), count, attachments, rectangle.left(), rectangle.bottom(), rectangle.sizeX(), rectangle.sizeY());
-    #else
-    static_cast<void>(count);
-    static_cast<void>(attachments);
-    static_cast<void>(rectangle);
-    CORRADE_INTERNAL_ASSERT(false);
-    //glDiscardSubFramebufferEXT(GLenum(bindInternal()), count, attachments, rectangle.left(), rectangle.bottom(), rectangle.width(), rectangle.height());
-    #endif
 }
+#endif
 
 GLenum AbstractFramebuffer::checkStatusImplementationDefault(const FramebufferTarget target) {
     bindInternal(target);

src/Magnum/AbstractFramebuffer.h

@@ -363,8 +363,10 @@ class MAGNUM_EXPORT AbstractFramebuffer {
         void MAGNUM_LOCAL invalidateImplementationNoOp(GLsizei, const GLenum*);
         void MAGNUM_LOCAL invalidateImplementationDefault(GLsizei count, const GLenum* attachments);
 
+        #ifndef MAGNUM_TARGET_GLES2
         void MAGNUM_LOCAL invalidateImplementationNoOp(GLsizei, const GLenum*, const Range2Di&);
         void MAGNUM_LOCAL invalidateImplementationDefault(GLsizei count, const GLenum* attachments, const Range2Di& rectangle);
+        #endif
 };
 
 CORRADE_ENUMSET_OPERATORS(FramebufferClearMask)

src/Magnum/DefaultFramebuffer.cpp

@@ -80,6 +80,7 @@ void DefaultFramebuffer::invalidate(std::initializer_list<InvalidationAttachment
     (this->*Context::current()->state().framebuffer->invalidateImplementation)(attachments.size(), _attachments);
 }
 
+#ifndef MAGNUM_TARGET_GLES2
 void DefaultFramebuffer::invalidate(std::initializer_list<InvalidationAttachment> attachments, const Range2Di& rectangle) {
     /** @todo C++14: use VLA to avoid heap allocation */
     Containers::Array<GLenum> _attachments(attachments.size());
@@ -88,6 +89,7 @@ void DefaultFramebuffer::invalidate(std::initializer_list<InvalidationAttachment
 
     (this->*Context::current()->state().framebuffer->invalidateSubImplementation)(attachments.size(), _attachments, rectangle);
 }
+#endif
 
 void DefaultFramebuffer::initializeContextBasedFunctionality(Context& context) {
     Implementation::FramebufferState* state = context.state().framebuffer;

src/Magnum/DefaultFramebuffer.h

@@ -404,12 +404,11 @@ class MAGNUM_EXPORT DefaultFramebuffer: public AbstractFramebuffer {
          * @param rectangle         %Rectangle to invalidate
          *
          * If extension @extension{ARB,invalidate_subdata} (part of OpenGL
-         * 4.3), extension @es_extension{EXT,discard_framebuffer} in OpenGL ES
-         * 2.0 or OpenGL ES 3.0 is not available, this function does nothing.
+         * 4.3) or OpenGL ES 3.0 is not available, this function does nothing.
          * The framebuffer is bound to some target before the operation, if not
          * already.
-         * @see @fn_gl{InvalidateSubFramebuffer} or @fn_gles_extension{DiscardSubFramebuffer,EXT,discard_framebuffer}
-         *      on OpenGL ES 2.0
+         * @see @ref invalidate(std::initializer_list<InvalidationAttachment>),
+         *      @fn_gl{InvalidateSubFramebuffer}
          */
         void invalidate(std::initializer_list<InvalidationAttachment> attachments, const Range2Di& rectangle);
 
@@ -431,6 +430,11 @@ extern DefaultFramebuffer MAGNUM_EXPORT defaultFramebuffer;
 /** @debugoperatorclassenum{Magnum::DefaultFramebuffer,Magnum::DefaultFramebuffer::Status} */
 Debug MAGNUM_EXPORT operator<<(Debug debug, DefaultFramebuffer::Status value);
 
+#ifdef MAGNUM_TARGET_GLES2
+/* No-op implementation on ES2 */
+inline void DefaultFramebuffer::invalidate(std::initializer_list<InvalidationAttachment>, const Range2Di&) {}
+#endif
+
 }
 
 #endif

src/Magnum/Framebuffer.cpp

@@ -157,6 +157,7 @@ void Framebuffer::invalidate(std::initializer_list<InvalidationAttachment> attac
     (this->*Context::current()->state().framebuffer->invalidateImplementation)(attachments.size(), _attachments);
 }
 
+#ifndef MAGNUM_TARGET_GLES2
 void Framebuffer::invalidate(std::initializer_list<InvalidationAttachment> attachments, const Range2Di& rectangle) {
     /** @todo C++14: use VLA to avoid heap allocation */
     Containers::Array<GLenum> _attachments(attachments.size());
@@ -165,6 +166,7 @@ void Framebuffer::invalidate(std::initializer_list<InvalidationAttachment> attac
 
     (this->*Context::current()->state().framebuffer->invalidateSubImplementation)(attachments.size(), _attachments, rectangle);
 }
+#endif
 
 Framebuffer& Framebuffer::attachRenderbuffer(const BufferAttachment attachment, Renderbuffer& renderbuffer) {
     (this->*Context::current()->state().framebuffer->renderbufferImplementation)(attachment, renderbuffer);

src/Magnum/Framebuffer.h

@@ -458,12 +458,11 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractObje
          * @param rectangle         %Rectangle to invalidate
          *
          * If extension @extension{ARB,invalidate_subdata} (part of OpenGL
-         * 4.3), extension @es_extension{EXT,discard_framebuffer} in OpenGL ES
-         * 2.0 or OpenGL ES 3.0 is not available, this function does nothing.
+         * 4.3) or OpenGL ES 3.0 is not available, this function does nothing.
          * The framebuffer is bound to some target before the operation, if not
          * already.
-         * @see @fn_gl{InvalidateFramebuffer} or @fn_gles_extension{DiscardFramebuffer,EXT,discard_framebuffer}
-         *      on OpenGL ES 2.0
+         * @see @ref invalidate(std::initializer_list<InvalidationAttachment>),
+         *      @fn_gl{InvalidateFramebuffer}
          */
         void invalidate(std::initializer_list<InvalidationAttachment> attachments, const Range2Di& rectangle);
 
@@ -672,6 +671,11 @@ inline Framebuffer& Framebuffer::operator=(Framebuffer&& other) noexcept {
     return *this;
 }
 
+#ifdef MAGNUM_TARGET_GLES2
+/* No-op implementation on ES2 */
+inline void Framebuffer::invalidate(std::initializer_list<InvalidationAttachment>, const Range2Di&) {}
+#endif
+
 }
 
 #endif

src/Magnum/Implementation/FramebufferState.cpp

@@ -157,10 +157,8 @@ FramebufferState::FramebufferState(Context& context, std::vector<std::string>& e
         extensions.push_back(Extensions::GL::EXT::discard_framebuffer::string());
 
         invalidateImplementation = &AbstractFramebuffer::invalidateImplementationDefault;
-        invalidateSubImplementation = &AbstractFramebuffer::invalidateImplementationDefault;
     } else {
         invalidateImplementation = &AbstractFramebuffer::invalidateImplementationNoOp;
-        invalidateSubImplementation = &AbstractFramebuffer::invalidateImplementationNoOp;
     }
 
     /* Always available on ES3 */

src/Magnum/Implementation/FramebufferState.h

@@ -42,7 +42,9 @@ struct FramebufferState {
     void(AbstractFramebuffer::*drawBufferImplementation)(GLenum);
     void(AbstractFramebuffer::*readBufferImplementation)(GLenum);
     void(AbstractFramebuffer::*invalidateImplementation)(GLsizei, const GLenum*);
+    #ifndef MAGNUM_TARGET_GLES2
     void(AbstractFramebuffer::*invalidateSubImplementation)(GLsizei, const GLenum*, const Range2Di&);
+    #endif
 
     void(Framebuffer::*renderbufferImplementation)(Framebuffer::BufferAttachment, Renderbuffer&);
     #ifndef MAGNUM_TARGET_GLES