GL: implement ARB_framebuffer_no_attachments and related ES3.1 API.

doc/changelog.dox

@@ -94,6 +94,9 @@ See also:
     have undefined behavior and may cause stability issues. This option is also
     programatically settable via a new
     @ref GL::Context::Configuration::Flag::GpuValidationNoError flag.
+-   Implemented the GL 4.3 @gl_extension{ARB,framebuffer_no_attachments}
+    extension and matching GLES 3.1 functionality, exposed as
+    @ref GL::Framebuffer::setDefaultSize() and related APIs
 -   Implemented @gl_extension{EXT,texture_norm16} and
     @webgl_extension{EXT,texture_norm16} ES and WebGL extensions, making
     normalized 16-bit texture and renderbuffer formats available on all

doc/opengl-mapping.dox

@@ -163,7 +163,7 @@ OpenGL function                         | Matching API
 @fn_gl{Finish}                          | @ref GL::Renderer::finish()
 @fn_gl{Flush}                           | @ref GL::Renderer::flush()
 @fn_gl{FlushMappedBufferRange}, \n `glFlushMappedNamedBufferRange()` | @ref GL::Buffer::flushMappedRange()
-@fn_gl2{FramebufferParameter,FramebufferParameteri}, \n `glNamedFramebufferParameter()` | |
+@fn_gl2{FramebufferParameter,FramebufferParameteri}, \n `glNamedFramebufferParameter()` | @ref GL::Framebuffer::setDefaultSize(), \n @ref GL::Framebuffer::setDefaultLayerCount(), \n @ref GL::Framebuffer::setDefaultSampleCount(), \n @ref GL::Framebuffer::setDefaultFixedSampleLocations()
 @fn_gl{FramebufferRenderbuffer}, \n `glNamedFramebufferRenderbuffer()` | @ref GL::Framebuffer::attachRenderbuffer(), \n @ref GL::Framebuffer::detach()
 @fn_gl_extension{FramebufferSampleLocationsfv,ARB,sample_locations}, \n `glNamedFramebufferSampleLocationsfvARB` | |
 @fn_gl{FramebufferTexture}, \n `glNamedFramebufferTexture()` | @ref GL::Framebuffer::attachLayeredTexture()

doc/opengl-support.dox

@@ -203,7 +203,7 @@ GLSL 4.30                                   | done
 @gl_extension{KHR,debug}                    | missing log retrieval, sync, pipeline and sampler label
 @gl_extension{ARB,explicit_uniform_location} | done
 @gl_extension{ARB,fragment_layer_viewport}  | done (shading language only)
-@gl_extension{ARB,framebuffer_no_attachments} | |
+@gl_extension{ARB,framebuffer_no_attachments} | done
 @gl_extension{ARB,internalformat_query2}    | only compressed texture block queries
 @gl_extension{ARB,invalidate_subdata}       | done
 @gl_extension{ARB,multi_draw_indirect}      | |

src/Magnum/GL/Framebuffer.cpp

@@ -356,6 +356,29 @@ Framebuffer& Framebuffer::detach(const BufferAttachment attachment) {
     return *this;
 }
 
+#if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+Framebuffer& Framebuffer::setDefaultSize(const Vector2i& size) {
+    Context::current().state().framebuffer.parameterImplementation(*this, GL_FRAMEBUFFER_DEFAULT_WIDTH, size.x());
+    Context::current().state().framebuffer.parameterImplementation(*this, GL_FRAMEBUFFER_DEFAULT_HEIGHT, size.y());
+    return *this;
+}
+
+Framebuffer& Framebuffer::setDefaultLayerCount(const Int count) {
+    Context::current().state().framebuffer.parameterImplementation(*this, GL_FRAMEBUFFER_DEFAULT_LAYERS, count);
+    return *this;
+}
+
+Framebuffer& Framebuffer::setDefaultSampleCount(const Int count) {
+    Context::current().state().framebuffer.parameterImplementation(*this, GL_FRAMEBUFFER_DEFAULT_SAMPLES, count);
+    return *this;
+}
+
+Framebuffer& Framebuffer::setDefaultFixedSampleLocations(bool fixed) {
+    Context::current().state().framebuffer.parameterImplementation(*this, GL_FRAMEBUFFER_DEFAULT_FIXED_SAMPLE_LOCATIONS, fixed ? GL_TRUE : GL_FALSE);
+    return *this;
+}
+#endif
+
 void Framebuffer::renderbufferImplementationDefault(Framebuffer& self, const BufferAttachment attachment, const GLuint renderbufferId) {
     glFramebufferRenderbuffer(GLenum(self.bindInternal()), GLenum(attachment), GL_RENDERBUFFER, renderbufferId);
 }
@@ -419,6 +442,18 @@ void Framebuffer::textureLayerImplementationDSA(Framebuffer& self, const BufferA
 }
 #endif
 
+#if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+void Framebuffer::parameterImplementationDefault(Framebuffer& self, const GLenum parameter, const GLint value) {
+    glFramebufferParameteri(GLenum(self.bindInternal()), parameter, value);
+}
+#endif
+
+#ifndef MAGNUM_TARGET_GLES
+void Framebuffer::parameterImplementationDSA(Framebuffer& self, const GLenum parameter, const GLint value) {
+    glNamedFramebufferParameteri(self._id, parameter, value);
+}
+#endif
+
 #ifndef DOXYGEN_GENERATING_OUTPUT
 Debug& operator<<(Debug& debug, const Framebuffer::Status value) {
     debug << "GL::Framebuffer::Status" << Debug::nospace;

src/Magnum/GL/Framebuffer.h

@@ -904,6 +904,123 @@ class MAGNUM_GL_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractO
          */
         Framebuffer& detach(BufferAttachment attachment);
 
+        #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+        /**
+         * @brief Set default framebuffer size
+         * @return Reference to self (for method chaining)
+         * @m_since_latest
+         *
+         * Used in case the framebuffer has no attachments. Otherwise the size
+         * is inferred from renderbuffers or textures specified via
+         * @ref attachRenderbuffer(), @ref attachTexture(),
+         * @ref attachCubeMapTexture(), @ref attachTextureLayer() or
+         * @ref attachLayeredTexture() and this setting is ignored. Initial
+         * value is a zero vector.
+         * @see @ref setDefaultLayerCount(), @ref setDefaultSampleCount(),
+         *      @ref setDefaultFixedSampleLocations(),
+         *      @ref Renderbuffer::setStorage(), @ref Texture::setStorage(),
+         *      @ref TextureArray::setStorage(),
+         *      @ref CubeMapTexture::setStorage(),
+         *      @ref CubeMapTextureArray::setStorage(),
+         *      @ref MultisampleTexture::setStorage(),
+         *      @ref RectangleTexture::setStorage(),
+         *      @fn_gl2_keyword{NamedFramebufferParameteri,FramebufferParameteri},
+         *      eventually @fn_gl{BindFramebuffer} and
+         *      @fn_gl_keyword{FramebufferParameteri} with
+         *      @def_gl_keyword{FRAMEBUFFER_DEFAULT_WIDTH} and
+         *      @def_gl_keyword{FRAMEBUFFER_DEFAULT_HEIGHT}
+         * @requires_gl43 @gl_extension{ARB,framebuffer_no_attachments}
+         * @requires_gles31 Attachment-less framebuffers are not available in
+         *      OpenGL ES 3.0 and older.
+         * @requires_gles Attachment-less framebuffers are not available in
+         *      WebGL.
+         */
+        Framebuffer& setDefaultSize(const Vector2i& size);
+
+        /**
+         * @brief Set default framebuffer layer count
+         * @return Reference to self (for method chaining)
+         * @m_since_latest
+         *
+         * Used in case the framebuffer has no attachments. Otherwise the layer
+         * count is inferred from renderbuffers or textures specified via
+         * @ref attachRenderbuffer(), @ref attachTexture(),
+         * @ref attachCubeMapTexture(), @ref attachTextureLayer() or
+         * @ref attachLayeredTexture() and this setting is ignored. Initial
+         * value is @cpp 0 @ce.
+         * @see @ref setDefaultSize(), @ref setDefaultSampleCount(),
+         *      @ref setDefaultFixedSampleLocations(),
+         *      @ref Texture3D::setStorage(), @ref TextureArray::setStorage(),
+         *      @ref CubeMapTexture::setStorage(),
+         *      @ref CubeMapTextureArray::setStorage(),
+         *      @ref MultisampleTexture2DArray::setStorage(),
+         *      @fn_gl2_keyword{NamedFramebufferParameteri,FramebufferParameteri},
+         *      eventually @fn_gl{BindFramebuffer} and
+         *      @fn_gl_keyword{FramebufferParameteri} with
+         *      @def_gl_keyword{FRAMEBUFFER_DEFAULT_LAYERS}
+         * @requires_gl43 @gl_extension{ARB,framebuffer_no_attachments}
+         * @requires_gles31 Attachment-less framebuffers are not available in
+         *      OpenGL ES 3.0 and older.
+         * @requires_gles Attachment-less framebuffers are not available in
+         *      WebGL.
+         */
+        Framebuffer& setDefaultLayerCount(Int count);
+
+        /**
+         * @brief Set default framebuffer sample count
+         * @return Reference to self (for method chaining)
+         * @m_since_latest
+         *
+         * Used in case the framebuffer has no attachments. Otherwise the
+         * sample count is inferred from renderbuffers or textures specified
+         * via @ref attachRenderbuffer(), @ref attachTexture(),
+         * @ref attachCubeMapTexture(), @ref attachTextureLayer() or
+         * @ref attachLayeredTexture() and this setting is ignored. Initial
+         * value is @cpp 0 @ce.
+         * @see @ref setDefaultSize(), @ref setDefaultLayerCount(),
+         *      @ref setDefaultFixedSampleLocations(),
+         *      @ref Renderbuffer::setStorageMultisample(),
+         *      @ref MultisampleTexture::setStorage(),
+         *      @fn_gl2_keyword{NamedFramebufferParameteri,FramebufferParameteri},
+         *      eventually @fn_gl{BindFramebuffer} and
+         *      @fn_gl_keyword{FramebufferParameteri} with
+         *      @def_gl_keyword{FRAMEBUFFER_DEFAULT_SAMPLES}
+         * @requires_gl43 @gl_extension{ARB,framebuffer_no_attachments}
+         * @requires_gles31 Attachment-less framebuffers are not available in
+         *      OpenGL ES 3.0 and older.
+         * @requires_gles Attachment-less framebuffers are not available in
+         *      WebGL.
+         */
+        Framebuffer& setDefaultSampleCount(Int count);
+
+        /**
+         * @brief Set default framebuffer fixed sample locations
+         * @return Reference to self (for method chaining)
+         * @m_since_latest
+         *
+         * Used in case the framebuffer has no attachments. Otherwise the
+         * fixed sample locations setting is inferred from renderbuffers or
+         * textures specified via @ref attachRenderbuffer(),
+         * @ref attachTexture(), @ref attachCubeMapTexture(),
+         * @ref attachTextureLayer() or @ref attachLayeredTexture() and this
+         * setting is ignored. Initial value is @cpp false @ce.
+         * @see @ref setDefaultSize(), @ref setDefaultLayerCount(),
+         *      @ref setDefaultSampleCount(),
+         *      @ref MultisampleTexture::setStorage(),
+         *      @ref MultisampleTextureSampleLocations,
+         *      @fn_gl2_keyword{NamedFramebufferParameteri,FramebufferParameteri},
+         *      eventually @fn_gl{BindFramebuffer} and
+         *      @fn_gl_keyword{FramebufferParameteri} with
+         *      @def_gl_keyword{FRAMEBUFFER_DEFAULT_FIXED_SAMPLE_LOCATIONS}
+         * @requires_gl43 @gl_extension{ARB,framebuffer_no_attachments}
+         * @requires_gles31 Attachment-less framebuffers are not available in
+         *      OpenGL ES 3.0 and older.
+         * @requires_gles Attachment-less framebuffers are not available in
+         *      WebGL.
+         */
+        Framebuffer& setDefaultFixedSampleLocations(bool fixed);
+        #endif
+
         /* Overloads to remove WTF-factor from method chaining order */
         #ifndef DOXYGEN_GENERATING_OUTPUT
         Framebuffer& setViewport(const Range2Di& rectangle) {
@@ -969,6 +1086,13 @@ class MAGNUM_GL_EXPORT Framebuffer: public AbstractFramebuffer, public AbstractO
         #ifndef MAGNUM_TARGET_GLES
         static void MAGNUM_GL_LOCAL textureLayerImplementationDSA(Framebuffer& self, BufferAttachment attachment, GLuint textureId, GLint level, GLint layer);
         #endif
+
+        #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+        static void MAGNUM_GL_LOCAL parameterImplementationDefault(Framebuffer& self, GLenum parameter, GLint value);
+        #endif
+        #ifndef MAGNUM_TARGET_GLES
+        static void MAGNUM_GL_LOCAL parameterImplementationDSA(Framebuffer& self, GLenum parameter, GLint value);
+        #endif
 };
 
 /** @debugoperatorclassenum{Framebuffer,Framebuffer::Status} */

src/Magnum/GL/Implementation/FramebufferState.cpp

@@ -417,6 +417,33 @@ FramebufferState::FramebufferState(Context& context, Containers::StaticArrayView
     invalidateSubImplementation = &AbstractFramebuffer::invalidateImplementationDefault;
     #endif
 
+    #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+    /* Attachment-less framebuffer implementation on desktop GL */
+    #ifndef MAGNUM_TARGET_GLES
+    if(context.isExtensionSupported<Extensions::ARB::framebuffer_no_attachments>()) {
+        extensions[Extensions::ARB::framebuffer_no_attachments::Index] =
+                   Extensions::ARB::framebuffer_no_attachments::string();
+        if(context.isExtensionSupported<Extensions::ARB::direct_state_access>()) {
+            extensions[Extensions::ARB::direct_state_access::Index] =
+                       Extensions::ARB::direct_state_access::string();
+            parameterImplementation = &Framebuffer::parameterImplementationDSA;
+        } else {
+            parameterImplementation = &Framebuffer::parameterImplementationDefault;
+        }
+    }
+
+    /* Attachment-less framebuffer implementation on ES3 */
+    #else
+    if(context.isVersionSupported(Version::GLES310))
+        parameterImplementation = &Framebuffer::parameterImplementationDefault;
+
+    /* Not available otherwise */
+    #endif
+    else {
+        parameterImplementation = nullptr;
+    }
+    #endif
+
     /* Blit implementation on desktop GL */
     #ifndef MAGNUM_TARGET_GLES
     if(context.isExtensionSupported<Extensions::ARB::direct_state_access>()) {

src/Magnum/GL/Implementation/FramebufferState.h

@@ -90,6 +90,9 @@ struct FramebufferState {
     #if !(defined(MAGNUM_TARGET_WEBGL) && defined(MAGNUM_TARGET_GLES2))
     void(*textureLayerImplementation)(Framebuffer&, Framebuffer::BufferAttachment, GLuint, GLint, GLint);
     #endif
+    #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+    void(*parameterImplementation)(Framebuffer&, GLenum, GLint);
+    #endif
 
     void(*createRenderbufferImplementation)(Renderbuffer&);
     void(*renderbufferStorageImplementation)(Renderbuffer&, RenderbufferFormat, const Vector2i&);

src/Magnum/GL/MultisampleTexture.h

@@ -57,7 +57,8 @@ namespace Implementation {
 /**
 @brief Multisample texture sample locations
 
-@see @ref MultisampleTexture::setStorage()
+@see @ref MultisampleTexture::setStorage(),
+    @ref Framebuffer::setDefaultFixedSampleLocations()
 @m_enum_values_as_keywords
 */
 enum class MultisampleTextureSampleLocations: GLboolean {

src/Magnum/GL/Test/FramebufferGLTest.cpp

@@ -114,6 +114,10 @@ struct FramebufferGLTest: OpenGLTester {
 
     void multipleColorOutputs();
 
+    #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+    void setDefaultSize();
+    #endif
+
     void clear();
     #ifndef MAGNUM_TARGET_GLES2
     void clearColorI();
@@ -260,6 +264,10 @@ FramebufferGLTest::FramebufferGLTest() {
 
               &FramebufferGLTest::multipleColorOutputs,
 
+              #if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+              &FramebufferGLTest::setDefaultSize,
+              #endif
+
               &FramebufferGLTest::clear,
               #ifndef MAGNUM_TARGET_GLES2
               &FramebufferGLTest::clearColorI,
@@ -1041,6 +1049,31 @@ void FramebufferGLTest::detach() {
     MAGNUM_VERIFY_NO_GL_ERROR();
 }
 
+#if !defined(MAGNUM_TARGET_GLES2) && !defined(MAGNUM_TARGET_WEBGL)
+void FramebufferGLTest::setDefaultSize() {
+    #ifndef MAGNUM_TARGET_GLES
+    if(!Context::current().isExtensionSupported<Extensions::ARB::framebuffer_no_attachments>())
+        CORRADE_SKIP(Extensions::ARB::framebuffer_no_attachments::string() << "is not supported.");
+    #else
+    if(!Context::current().isVersionSupported(Version::GLES310))
+        CORRADE_SKIP(Version::GLES310 << "is not supported.");
+    #endif
+
+    Framebuffer framebuffer{{{}, Vector2i{128}}};
+
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE(framebuffer.checkStatus(FramebufferTarget::Draw), Framebuffer::Status::IncompleteMissingAttachment);
+
+    framebuffer.setDefaultSize({256, 256})
+        .setDefaultLayerCount(3)
+        .setDefaultSampleCount(1)
+        .setDefaultFixedSampleLocations(false);
+
+    MAGNUM_VERIFY_NO_GL_ERROR();
+    CORRADE_COMPARE(framebuffer.checkStatus(FramebufferTarget::Draw), Framebuffer::Status::Complete);
+}
+#endif
+
 void FramebufferGLTest::multipleColorOutputs() {
     #ifndef MAGNUM_TARGET_GLES
     if(!Context::current().isExtensionSupported<Extensions::ARB::framebuffer_object>())