From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 15 Sep 2010 19:14:55 +0000 (+0000)
Subject: Rewrite Framebuffer to defer attach/detach operations until bound
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=3663bed18358a2399b2a8a8f7779d85e0ed81bd0

Rewrite Framebuffer to defer attach/detach operations until bound
Set draw buffer and depth mask automatically according to attachments
Treat system framebuffer as an object as well
Move the clear function inside the Framebuffer class
Use temporary binding in RenderBuffer::storage
---

diff --git a/source/framebuffer.cpp b/source/framebuffer.cpp
index cf3761d0..8dbd2d0e 100644
--- a/source/framebuffer.cpp
+++ b/source/framebuffer.cpp
@@ -17,152 +17,202 @@ using namespace std;
 namespace Msp {
 namespace GL {
 
+Framebuffer::Framebuffer(unsigned i):
+	id(i),
+	dirty(0)
+{
+	if(id)
+		throw InvalidParameterValue("System framebuffer must have id 0");
+
+	int viewport[4];
+	glGetIntegerv(GL_VIEWPORT, viewport);
+	width = viewport[2];
+	height = viewport[3];
+}
+
 Framebuffer::Framebuffer():
 	width(0),
-	height(0)
+	height(0),
+	dirty(0)
 {
 	static RequireExtension _ext("GL_EXT_framebuffer_object");
 
 	glGenFramebuffersEXT(1, &id);
-	bind();
 }
 
 Framebuffer::~Framebuffer()
 {
-	glDeleteFramebuffersEXT(1, &id);
+	if(id)
+		glDeleteFramebuffersEXT(1, &id);
+	if(current()==this)
+		unbind();
 }
 
-void Framebuffer::bind() const
+void Framebuffer::update_attachment(unsigned mask) const
 {
-	const Framebuffer *old = current();
-	if(set_current(this))
+	if(current()==this)
 	{
-		if(!old)
-			get(GL_VIEWPORT, sys_viewport);
-		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, id);
-		if(width && height)
-			viewport(0, 0, width, height);
+		bool has_color = false;
+		bool has_depth = false;
+		for(unsigned i=0; i<attachments.size(); ++i)
+		{
+			const Attachment &attch = attachments[i];
+			if(mask&(1<<i))
+			{
+				if(attch.type==GL_RENDERBUFFER_EXT)
+					glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, attch.attachment, GL_RENDERBUFFER_EXT, attch.rbuf->get_id());
+				else if(attch.type==GL_TEXTURE_2D)
+					glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, attch.attachment, attch.type, attch.tex->get_id(), attch.level);
+				else
+					glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, attch.attachment, 0, 0);
+			}
+
+			if(attch.attachment>=COLOR_ATTACHMENT0 && attch.attachment<=COLOR_ATTACHMENT3)
+				has_color = true;
+			if(attch.attachment==DEPTH_ATTACHMENT)
+				has_depth = true;
+		}
+
+		glDrawBuffer(has_color ? GL_FRONT : GL_NONE);
+		glDepthMask(has_depth);
 	}
+	else
+		dirty |= mask;
+}
+
+void Framebuffer::check_size()
+{
+	for(vector<Attachment>::iterator i=attachments.begin(); i!=attachments.end(); ++i)
+		if(i->type)
+		{
+			if(i->type==GL_RENDERBUFFER_EXT)
+			{
+				width = i->rbuf->get_width();
+				height = i->rbuf->get_height();
+			}
+			else if(i->type==GL_TEXTURE_2D)
+			{
+				Texture2D *tex = static_cast<Texture2D *>(i->tex);
+				width = tex->get_width();
+				height = tex->get_height();
+			}
+			if(current()==this)
+				glViewport(0, 0, width, height);
+			break;
+		}
 }
 
 void Framebuffer::attach(FramebufferAttachment attch, Renderbuffer &rbuf)
 {
-	bind();
-	glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, attch, GL_RENDERBUFFER_EXT, rbuf.get_id());
-	get_or_create_attachment(attch) = rbuf;
+	if(!id)
+		throw InvalidState("Can't attach to system framebuffer");
+
+	unsigned i = get_attachment_index(attch);
+	attachments[i].set(rbuf);
+	update_attachment(1<<i);
 	check_size();
 }
 
 void Framebuffer::attach(FramebufferAttachment attch, Texture2D &tex, int level)
 {
-	bind();
-	glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, attch, tex.get_target(), tex.get_id(), level);
-	get_or_create_attachment(attch) = tex;
+	if(!id)
+		throw InvalidState("Can't attach to system framebuffer");
+
+	unsigned i = get_attachment_index(attch);
+	attachments[i].set(tex, level);
+	update_attachment(1<<i);
 	check_size();
 }
 
 void Framebuffer::detach(FramebufferAttachment attch)
 {
-	bind();
-	for(vector<Attachment>::iterator i=attachments.begin(); i!=attachments.end(); ++i)
-		if(i->attachment==attch)
-		{
-			if(i->type==GL_RENDERBUFFER_EXT)
-				glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, attch, GL_RENDERBUFFER_EXT, 0);
-			else if(i->type==GL_TEXTURE_2D)
-				glFramebufferTexture2DEXT(GL_FRAMEBUFFER_EXT, attch, GL_TEXTURE_2D, 0, 0);
-			attachments.erase(i);
-			check_size();
-			return;
-		}
+	if(!id)
+		throw InvalidState("Can't detach from system framebuffer");
+
+	unsigned i = get_attachment_index(attch);
+	attachments[i].clear();
+	update_attachment(1<<i);
+	check_size();
 }
 
 FramebufferStatus Framebuffer::check_status() const
 {
-	bind();
+	Bind _bind(this, true);
 	return static_cast<FramebufferStatus>(glCheckFramebufferStatusEXT(GL_FRAMEBUFFER_EXT));
 }
 
-void Framebuffer::unbind()
+void Framebuffer::clear(BufferBits bits)
+{
+	Bind _bind(this, true);
+	glClear(bits);
+}
+
+void Framebuffer::bind() const
 {
-	if(set_current(0))
+	if(set_current(this))
 	{
-		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, 0);
-		viewport(sys_viewport[0], sys_viewport[1], sys_viewport[2], sys_viewport[3]);
+		glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, id);
+		if(dirty)
+		{
+			update_attachment(dirty);
+			dirty = 0;
+		}
+		if(width && height)
+			glViewport(0, 0, width, height);
 	}
 }
 
-Framebuffer::Attachment &Framebuffer::get_or_create_attachment(FramebufferAttachment attch)
+const Framebuffer *Framebuffer::current()
+{	
+	if(!cur_obj)
+		cur_obj = &system();
+	return cur_obj;
+}
+
+void Framebuffer::unbind()
 {
-	for(vector<Attachment>::iterator i=attachments.begin(); i!=attachments.end(); ++i)
-		if(i->attachment==attch)
-			return *i;
-	attachments.push_back(Attachment(attch));
-	return attachments.back();
+	system().bind();
 }
 
-void Framebuffer::check_size()
+Framebuffer &Framebuffer::system()
 {
-	if(!attachments.empty())
-	{
-		const Attachment &attch = attachments.front();
-		if(attch.type==GL_RENDERBUFFER_EXT)
-		{
-			width = attch.rbuf->get_width();
-			height = attch.rbuf->get_height();
-		}
-		else if(attch.type==GL_TEXTURE_2D)
-		{
-			Texture2D *tex = static_cast<Texture2D *>(attch.tex);
-			width = tex->get_width();
-			height = tex->get_height();
-		}
-		if(current()==this)
-			viewport(0, 0, width, height);
-	}
+	static Framebuffer sys_framebuf(0);
+	return sys_framebuf;
 }
 
-int Framebuffer::sys_viewport[4] = { 0, 0, 1, 1 };
+unsigned Framebuffer::get_attachment_index(FramebufferAttachment attch)
+{
+	for(unsigned i=0; i<attachments.size(); ++i)
+		if(attachments[i].attachment==attch)
+			return i;
+	attachments.push_back(Attachment(attch));
+	return attachments.size()-1;
+}
 
 
 Framebuffer::Attachment::Attachment(FramebufferAttachment a):
 	attachment(a),
-	type(0)
+	type(0),
+	level(0)
 { }
 
-Framebuffer::Attachment &Framebuffer::Attachment::operator=(Renderbuffer &r)
+void Framebuffer::Attachment::set(Renderbuffer &r)
 {
 	type = GL_RENDERBUFFER_EXT;
 	rbuf = &r;
-	return *this;
+	level = 0;
 }
 
-Framebuffer::Attachment &Framebuffer::Attachment::operator=(Texture &t)
+void Framebuffer::Attachment::set(Texture &t, int l)
 {
 	type = t.get_target();
 	tex = &t;
-	return *this;
-}
-
-
-void viewport(int x, int y, unsigned w, unsigned h)
-{
-	glViewport(x, y, w, h);
-}
-
-void clear(BufferBits bits)
-{
-	glClear(bits);
-}
-
-void draw_buffer(RWBuffer buf)
-{
-	glDrawBuffer(buf);
+	level = l;
 }
 
-void read_buffer(RWBuffer buf)
+void Framebuffer::Attachment::clear()
 {
-	glReadBuffer(buf);
+	type = 0;
 }
 
 } // namespace GL
diff --git a/source/framebuffer.h b/source/framebuffer.h
index b4f43f77..514208d6 100644
--- a/source/framebuffer.h
+++ b/source/framebuffer.h
@@ -86,25 +86,29 @@ private:
 			Renderbuffer *rbuf;
 			Texture *tex;
 		};
+		int level;
 
 		Attachment(FramebufferAttachment);
-		Attachment &operator=(Renderbuffer &);
-		Attachment &operator=(Texture &);
+		void set(Renderbuffer &);
+		void set(Texture &, int);
+		void clear();
 	};
 
 	unsigned id;
 	std::vector<Attachment> attachments;
 	unsigned width;
 	unsigned height;
+	mutable unsigned dirty;
 
-	static int sys_viewport[4];
-
+	Framebuffer(unsigned);
 public:
 	Framebuffer();
 	~Framebuffer();
 
-	void bind() const;
-
+private:
+	void update_attachment(unsigned) const;
+	void check_size();
+public:
 	void attach(FramebufferAttachment attch, Renderbuffer &rbuf);
 	void attach(FramebufferAttachment attch, Texture2D &tex, int level);
 	void detach(FramebufferAttachment attch);
@@ -116,21 +120,24 @@ public:
 	*/
 	FramebufferStatus check_status() const;
 
+	void clear(BufferBits);
+
+	void bind() const;
+
+	static const Framebuffer *current();
 	static void unbind();
+
+	static Framebuffer &system();
 private:
-	void maybe_bind() const;
-	Attachment &get_or_create_attachment(FramebufferAttachment);
-	void check_size();
+	unsigned get_attachment_index(FramebufferAttachment);
+
+public:
+	
 };
 
 inline BufferBits operator|(BufferBits a, BufferBits b)
 { return static_cast<BufferBits>(static_cast<int>(a)|static_cast<int>(b)); }
 
-void viewport(int, int, unsigned, unsigned);
-void clear(BufferBits);
-void draw_buffer(RWBuffer);
-void read_buffer(RWBuffer);
-
 } // namespace GL
 } // namespace Msp
 
diff --git a/source/pipeline.cpp b/source/pipeline.cpp
index 54ef25a1..517037a0 100644
--- a/source/pipeline.cpp
+++ b/source/pipeline.cpp
@@ -95,7 +95,6 @@ void Pipeline::add_postprocessor(PostProcessor &pp)
 		depth_buf = new Renderbuffer;
 		depth_buf->storage(DEPTH_COMPONENT, width, height);
 		fbo->attach(DEPTH_ATTACHMENT, *depth_buf);
-		Framebuffer::unbind();
 	}
 }
 
@@ -125,7 +124,7 @@ void Pipeline::render_all() const
 	if(fbo)
 	{
 		fbo->bind();
-		clear(COLOR_BUFFER_BIT|DEPTH_BUFFER_BIT);
+		fbo->clear(COLOR_BUFFER_BIT|DEPTH_BUFFER_BIT);
 	}
 
 	for(vector<Effect *>::const_iterator i=effects.begin(); i!=effects.end(); ++i)
diff --git a/source/renderbuffer.cpp b/source/renderbuffer.cpp
index 0d3a76b5..95cf56b8 100644
--- a/source/renderbuffer.cpp
+++ b/source/renderbuffer.cpp
@@ -27,7 +27,7 @@ Renderbuffer::~Renderbuffer()
 
 void Renderbuffer::storage(PixelFormat fmt, unsigned w, unsigned h)
 {
-	bind();
+	Bind _bind(this, true);
 	width = w;
 	height = h;
 	glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, fmt, width, height);
diff --git a/source/shadowmap.cpp b/source/shadowmap.cpp
index 25b0d6d6..bedfcfd5 100644
--- a/source/shadowmap.cpp
+++ b/source/shadowmap.cpp
@@ -34,8 +34,6 @@ ShadowMap::ShadowMap(unsigned s, const Scene &c, const Light &l):
 	depth_buf.storage(DEPTH_COMPONENT, size, size, 0);
 	depth_buf.image(0, DEPTH_COMPONENT, UNSIGNED_BYTE, 0);
 	fbo.attach(DEPTH_ATTACHMENT, depth_buf, 0);
-	draw_buffer(NO_BUFFER);
-	Framebuffer::unbind();
 }
 
 void ShadowMap::set_target(const Vector3 &t, float r)
@@ -108,19 +106,14 @@ void ShadowMap::prepare()
 		push_matrix();
 		load_matrix(matrix);
 
-		const Framebuffer *old_fbo = Framebuffer::current();
-		fbo.bind();
-		clear(DEPTH_BUFFER_BIT);
+		Bind bind_fbo(fbo, true);
+		fbo.clear(DEPTH_BUFFER_BIT);
 		scene.render("shadow");
 
 		matrix_mode(PROJECTION);
 		pop_matrix();
 		matrix_mode(MODELVIEW);
 		pop_matrix();
-		if(old_fbo)
-			old_fbo->bind();
-		else
-			Framebuffer::unbind();
 	}
 
 	depth_buf.bind_to(unit);