Tracking framebuffer binding.

src/AbstractFramebuffer.cpp

@@ -20,6 +20,9 @@
 #include "Extensions.h"
 #include "Image.h"
 
+#include "Implementation/FramebufferState.h"
+#include "Implementation/State.h"
+
 namespace Magnum {
 
 #ifndef DOXYGEN_GENERATING_OUTPUT
@@ -27,6 +30,24 @@ AbstractFramebuffer::Target AbstractFramebuffer::readTarget = AbstractFramebuffe
 AbstractFramebuffer::Target AbstractFramebuffer::drawTarget = AbstractFramebuffer::Target::ReadDraw;
 #endif
 
+void AbstractFramebuffer::bind(Target target) {
+    Implementation::FramebufferState* state = Context::current()->state()->framebuffer;
+
+    /* If already bound, done, otherwise update tracked state */
+    if(target == Target::Read) {
+        if(state->readBinding == _id) return;
+        state->readBinding = _id;
+    } else if(target == Target::Draw) {
+        if(state->drawBinding == _id) return;
+        state->drawBinding = _id;
+    } else if(target == Target::ReadDraw) {
+        if(state->readBinding == _id && state->drawBinding == _id) return;
+        state->readBinding = state->drawBinding = _id;
+    } else CORRADE_INTERNAL_ASSERT(false);
+
+    glBindFramebuffer(static_cast<GLenum>(target), _id);
+}
+
 void AbstractFramebuffer::read(const Vector2i& offset, const Vector2i& size, AbstractImage::Format format, AbstractImage::Type type, Image2D* image) {
     bind(readTarget);
     char* data = new char[AbstractImage::pixelSize(format, type)*size.product()];

src/AbstractFramebuffer.h

@@ -31,6 +31,12 @@ namespace Magnum {
 @brief Base for default and named framebuffers
 
 See DefaultFramebuffer and Framebuffer for more information.
+
+@section AbstractFramebuffer-performance-optimization Performance optimizations
+
+The engine tracks currently bound framebuffer to avoid unnecessary calls to
+@fn_gl{BindFramebuffer}.
+
 @todo @extension{ARB,viewport_array}
 */
 class MAGNUM_EXPORT AbstractFramebuffer {
@@ -199,15 +205,13 @@ class MAGNUM_EXPORT AbstractFramebuffer {
          *      DefaultFramebuffer::mapForDraw(), Framebuffer::mapForDraw(),
          *      @fn_gl{BindFramebuffer}
          */
-        inline void bind(Target target) {
-            glBindFramebuffer(static_cast<GLenum>(target), _id);
-        }
+        void bind(Target target);
 
         /**
          * @brief Set viewport size
          *
          * Call when window size changes.
-         * @see @fn_gl{Viewport}
+         * @see @fn_gl{BindFramebuffer}, @fn_gl{Viewport}
          */
         inline void setViewport(const Vector2i& position, const Vector2i& size) {
             bind(drawTarget);
@@ -219,7 +223,8 @@ class MAGNUM_EXPORT AbstractFramebuffer {
          * @param mask              Which buffers to clear
          *
          * @see Renderer::setClearColor(), Renderer::setClearDepth(),
-         *      Renderer::setClearStencil(), @fn_gl{Clear}
+         *      Renderer::setClearStencil(), @fn_gl{BindFramebuffer},
+         *      @fn_gl{Clear}
          */
         inline void clear(ClearMask mask) {
             bind(drawTarget);
@@ -234,7 +239,7 @@ class MAGNUM_EXPORT AbstractFramebuffer {
          * @param type              Data type of pixel data
          * @param image             %Image where to put the data
          *
-         * @see @fn_gl{ReadPixels}
+         * @see @fn_gl{BindFramebuffer}, @fn_gl{ReadPixels}
          */
         void read(const Vector2i& offset, const Vector2i& size, AbstractImage::Format format, AbstractImage::Type type, Image2D* image);
 
@@ -248,7 +253,7 @@ class MAGNUM_EXPORT AbstractFramebuffer {
          * @param image             %Buffer image where to put the data
          * @param usage             %Buffer usage
          *
-         * @see Buffer::bind(Target), @fn_gl{ReadPixels}
+         * @see @fn_gl{BindFramebuffer}, @fn_gl{ReadPixels}
          * @requires_gles30 Pixel buffer objects are not available in OpenGL ES 2.0.
          */
         void read(const Vector2i& offset, const Vector2i& size, AbstractImage::Format format, AbstractImage::Type type, BufferImage2D* image, Buffer::Usage usage);

src/DefaultFramebuffer.h

@@ -171,7 +171,7 @@ class MAGNUM_EXPORT DefaultFramebuffer: public AbstractFramebuffer {
          *      @ref DrawAttachment "Attachment::None", given output is not
          *      used.
          *
-         * @see mapForRead(), bind(), @fn_gl{DrawBuffers}
+         * @see mapForRead(), @fn_gl{BindFramebuffer}, @fn_gl{DrawBuffers}
          * @requires_gles30 Draw attachments for default framebuffer are
          *      available only in OpenGL ES 3.0.
          */
@@ -182,7 +182,7 @@ class MAGNUM_EXPORT DefaultFramebuffer: public AbstractFramebuffer {
          * @brief Map given attachment for reading
          * @param attachment        Attachment
          *
-         * @see mapForDraw(), bind(), @fn_gl{ReadBuffer}
+         * @see mapForDraw(), @fn_gl{BindFramebuffer}, @fn_gl{ReadBuffer}
          * @requires_gles30 %Extension @es_extension2{NV,read_buffer,GL_NV_read_buffer}
          */
         inline void mapForRead(ReadAttachment attachment) {

src/Framebuffer.cpp

@@ -16,10 +16,23 @@
 #include "Framebuffer.h"
 
 #include "BufferImage.h"
+#include "Context.h"
 #include "Image.h"
 
+#include "Implementation/State.h"
+#include "Implementation/FramebufferState.h"
+
 namespace Magnum {
 
+Framebuffer::~Framebuffer() {
+    /* If bound, remove itself from state */
+    Implementation::FramebufferState* state = Context::current()->state()->framebuffer;
+    if(state->readBinding == _id) state->readBinding = 0;
+    if(state->drawBinding == _id) state->drawBinding = 0;
+
+    glDeleteFramebuffers(1, &_id);
+}
+
 void Framebuffer::mapForDraw(std::initializer_list<std::int8_t> colorAttachments) {
     GLenum* attachments = new GLenum[colorAttachments.size()];
     for(auto it = colorAttachments.begin(); it != colorAttachments.end(); ++it)

src/Framebuffer.h

@@ -48,14 +48,14 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * Deletes associated OpenGL framebuffer.
          * @see @fn_gl{DeleteFramebuffers}
          */
-        inline ~Framebuffer() { glDeleteFramebuffers(1, &_id); }
+        ~Framebuffer();
 
         /**
          * @brief Map given color attachments of current framebuffer for drawing
          * @param colorAttachments  Color attachment IDs. If any value is -1,
          *      given output is not used.
          *
-         * @see mapForRead(), bind(), @fn_gl{DrawBuffers}
+         * @see mapForRead(), @fn_gl{BindFramebuffer}, @fn_gl{DrawBuffers}
          * @requires_gles30 %Extension @es_extension2{NV,draw_buffers,GL_NV_draw_buffers}
          */
         void mapForDraw(std::initializer_list<std::int8_t> colorAttachments);
@@ -64,7 +64,7 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @brief Map given color attachment of current framebuffer for reading
          * @param colorAttachment   Color attachment ID
          *
-         * @see mapForDraw(), bind(), @fn_gl{ReadBuffer}
+         * @see mapForDraw(), @fn_gl{BindFramebuffer}, @fn_gl{ReadBuffer}
          * @requires_gles30 %Extension @es_extension2{NV,read_buffer,GL_NV_read_buffer}
          */
         inline void mapForRead(std::uint8_t colorAttachment) {
@@ -105,7 +105,7 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param depthStencilAttachment Depth/stencil attachment
          * @param renderbuffer      %Renderbuffer
          *
-         * @see bind(), @fn_gl{FramebufferRenderbuffer}
+         * @see @fn_gl{BindFramebuffer}, @fn_gl{FramebufferRenderbuffer}
          */
         inline void attachRenderbuffer(Target target, DepthStencilAttachment depthStencilAttachment, Renderbuffer* renderbuffer) {
             bind(target);
@@ -118,7 +118,7 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param colorAttachment   Color attachment ID (number between 0 and 15)
          * @param renderbuffer      %Renderbuffer
          *
-         * @see bind(), @fn_gl{FramebufferRenderbuffer}
+         * @see @fn_gl{BindFramebuffer}, @fn_gl{FramebufferRenderbuffer}
          */
         inline void attachRenderbuffer(Target target, std::uint8_t colorAttachment, Renderbuffer* renderbuffer) {
             bind(target);
@@ -133,7 +133,7 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param texture           1D texture
          * @param mipLevel          Mip level
          *
-         * @see bind(), @fn_gl{FramebufferTexture}
+         * @see @fn_gl{BindFramebuffer}, @fn_gl{FramebufferTexture}
          * @requires_gl Only 2D and 3D textures are available in OpenGL ES.
          */
         inline void attachTexture1D(Target target, DepthStencilAttachment depthStencilAttachment, Texture1D* texture, GLint mipLevel) {
@@ -149,7 +149,7 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param texture           1D texture
          * @param mipLevel          Mip level
          *
-         * @see bind(), @fn_gl{FramebufferTexture}
+         * @see @fn_gl{BindFramebuffer}, @fn_gl{FramebufferTexture}
          * @requires_gl Only 2D and 3D textures are available in OpenGL ES.
          */
         inline void attachTexture1D(Target target, std::uint8_t colorAttachment, Texture1D* texture, GLint mipLevel) {
@@ -167,7 +167,8 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param mipLevel          Mip level. For rectangle textures it
          *      should be always 0.
          *
-         * @see attachCubeMapTexture(), bind(), @fn_gl{FramebufferTexture}
+         * @see attachCubeMapTexture(), @fn_gl{BindFramebuffer},
+         *      @fn_gl{FramebufferTexture}
          */
         inline void attachTexture2D(Target target, DepthStencilAttachment depthStencilAttachment, Texture2D* texture, GLint mipLevel) {
             /** @todo Check for texture target compatibility */
@@ -183,7 +184,8 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param mipLevel          Mip level. For rectangle textures it
          *      should be always 0.
          *
-         * @see attachCubeMapTexture(), bind(), @fn_gl{FramebufferTexture}
+         * @see attachCubeMapTexture(), @fn_gl{BindFramebuffer},
+         *      @fn_gl{FramebufferTexture}
          */
         inline void attachTexture2D(Target target, std::uint8_t colorAttachment, Texture2D* texture, GLint mipLevel) {
             /** @todo Check for texture target compatibility */
@@ -199,7 +201,8 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param coordinate        Cube map coordinate
          * @param mipLevel          Mip level
          *
-         * @see attachTexture2D(), bind(), @fn_gl{FramebufferTexture}
+         * @see attachTexture2D(), @fn_gl{BindFramebuffer},
+         *      @fn_gl{FramebufferTexture}
          */
         inline void attachCubeMapTexture(Target target, DepthStencilAttachment depthStencilAttachment, CubeMapTexture* texture, CubeMapTexture::Coordinate coordinate, GLint mipLevel) {
             /** @todo Check for internal format compatibility */
@@ -215,7 +218,8 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param coordinate        Cube map coordinate
          * @param mipLevel          Mip level
          *
-         * @see attachTexture2D(), bind(), @fn_gl{FramebufferTexture}
+         * @see attachTexture2D(), @fn_gl{BindFramebuffer},
+         *      @fn_gl{FramebufferTexture}
          */
         inline void attachCubeMapTexture(Target target, std::uint8_t colorAttachment, CubeMapTexture* texture, CubeMapTexture::Coordinate coordinate, GLint mipLevel) {
             /** @todo Check for internal format compatibility */
@@ -231,7 +235,7 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param mipLevel          Mip level
          * @param layer             Layer of 2D image within a 3D texture
          *
-         * @see bind(), @fn_gl{FramebufferTexture}
+         * @see @fn_gl{BindFramebuffer}, @fn_gl{FramebufferTexture}
          * @requires_es_extension %Extension @es_extension{OES,texture_3D}
          */
         inline void attachTexture3D(Target target, DepthStencilAttachment depthStencilAttachment, Texture3D* texture, GLint mipLevel, GLint layer) {
@@ -256,7 +260,7 @@ class MAGNUM_EXPORT Framebuffer: public AbstractFramebuffer {
          * @param mipLevel          Mip level
          * @param layer             Layer of 2D image within a 3D texture.
          *
-         * @see bind(), @fn_gl{FramebufferTexture}
+         * @see @fn_gl{BindFramebuffer}, @fn_gl{FramebufferTexture}
          * @requires_es_extension %Extension @es_extension{OES,texture_3D}
          */
         inline void attachTexture3D(Target target, std::uint8_t colorAttachment, Texture3D* texture, GLint mipLevel, GLint layer) {

src/Implementation/FramebufferState.h

@@ -0,0 +1,30 @@
+#ifndef Magnum_Implementation_FramebufferState_h
+#define Magnum_Implementation_FramebufferState_h
+/*
+    Copyright © 2010, 2011, 2012 Vladimír Vondruš <mosra@centrum.cz>
+
+    This file is part of Magnum.
+
+    Magnum is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License version 3
+    only, as published by the Free Software Foundation.
+
+    Magnum is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+    GNU Lesser General Public License version 3 for more details.
+*/
+
+#include "Magnum.h"
+
+namespace Magnum { namespace Implementation {
+
+struct FramebufferState {
+    inline FramebufferState(): readBinding(0), drawBinding(0) {}
+
+    GLuint readBinding, drawBinding;
+};
+
+}}
+
+#endif

src/Implementation/State.cpp

@@ -16,18 +16,25 @@
 #include "State.h"
 
 #include "BufferState.h"
+#include "FramebufferState.h"
 #include "MeshState.h"
 #include "ShaderProgramState.h"
 #include "TextureState.h"
 
 namespace Magnum { namespace Implementation {
 
-State::State(): buffer(new BufferState), mesh(new MeshState), shaderProgram(new ShaderProgramState), texture(new TextureState) {}
+State::State():
+    buffer(new BufferState),
+    framebuffer(new FramebufferState),
+    mesh(new MeshState),
+    shaderProgram(new ShaderProgramState),
+    texture(new TextureState) {}
 
 State::~State() {
     delete texture;
     delete shaderProgram;
     delete mesh;
+    delete framebuffer;
     delete buffer;
 }
 

src/Implementation/State.h

@@ -20,6 +20,7 @@
 namespace Magnum { namespace Implementation {
 
 struct BufferState;
+struct FramebufferState;
 struct MeshState;
 struct ShaderProgramState;
 struct TextureState;
@@ -29,6 +30,7 @@ struct State {
     ~State();
 
     BufferState* const buffer;
+    FramebufferState* const framebuffer;
     MeshState* const mesh;
     ShaderProgramState* const shaderProgram;
     TextureState* const texture;