From fe5bf090db687ef1dd1084218156bcbc0b801081 Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 29 Dec 2012 14:13:20 +0200
Subject: [PATCH] Add a function to require the completeness of a framebuffer

---
 source/framebuffer.cpp | 43 ++++++++++++++++++++++++++++++++++++++++++
 source/framebuffer.h   | 11 +++++++++++
 2 files changed, 54 insertions(+)

diff --git a/source/framebuffer.cpp b/source/framebuffer.cpp
index 98722195..4d6c1752 100644
--- a/source/framebuffer.cpp
+++ b/source/framebuffer.cpp
@@ -12,6 +12,42 @@ using namespace std;
 namespace Msp {
 namespace GL {
 
+void operator<<(LexicalConverter &conv, FramebufferStatus status)
+{
+	switch(status)
+	{
+	case FRAMEBUFFER_INCOMPLETE_ATTACHMENT:
+		conv.result("incomplete attachment");
+		break;
+	case FRAMEBUFFER_INCOMPLETE_MISSING_ATTACHMENT:
+		conv.result("missing attachment");
+		break;
+	case FRAMEBUFFER_INCOMPLETE_DIMENSIONS:
+		conv.result("mismatched attachment dimensions");
+		break;
+	case FRAMEBUFFER_INCOMPLETE_FORMATS:
+		conv.result("mismatched attachment formats");
+		break;
+	case FRAMEBUFFER_INCOMPLETE_DRAW_BUFFER:
+		conv.result("missing draw buffer attachment");
+		break;
+	case FRAMEBUFFER_INCOMPLETE_READ_BUFFER:
+		conv.result("missing read buffer attachment");
+		break;
+	case FRAMEBUFFER_UNSUPPORTED:
+		conv.result("unsupported");
+		break;
+	default:
+		conv.result(lexical_cast<string, unsigned>(status, "%#x"));
+		break;
+	}
+}
+
+framebuffer_incomplete::framebuffer_incomplete(FramebufferStatus status):
+	runtime_error(lexical_cast<string>(status))
+{ }
+
+
 Framebuffer::Framebuffer(unsigned i):
 	id(i),
 	dirty(0)
@@ -174,6 +210,13 @@ FramebufferStatus Framebuffer::check_status() const
 	return static_cast<FramebufferStatus>(glCheckFramebufferStatus(GL_FRAMEBUFFER));
 }
 
+void Framebuffer::require_complete() const
+{
+	FramebufferStatus status = check_status();
+	if(status!=FRAMEBUFFER_COMPLETE)
+		throw framebuffer_incomplete(status);
+}
+
 void Framebuffer::clear(BufferBits bits)
 {
 	Bind _bind(this, true);
diff --git a/source/framebuffer.h b/source/framebuffer.h
index 236d29e6..e25967ac 100644
--- a/source/framebuffer.h
+++ b/source/framebuffer.h
@@ -57,6 +57,13 @@ enum RWBuffer
 	FRONT_AND_BACK = GL_FRONT_AND_BACK
 };
 
+class framebuffer_incomplete: public std::runtime_error
+{
+public:
+	framebuffer_incomplete(FramebufferStatus);
+	virtual ~framebuffer_incomplete() throw() { }
+};
+
 /**
 Framebuffer objects can be used to perform offscreen rendering.  The most
 common application is rendering to a texture, which can then be used for
@@ -119,6 +126,10 @@ public:
 	or one of the error status codes otherwise. */
 	FramebufferStatus check_status() const;
 
+	/** Ensures that the framebuffer is complete, throwing an exception if it
+	isn't. */
+	void require_complete() const;
+
 	void clear(BufferBits);
 
 	/** Blits a region from another framebuffer into this one.  If the source
-- 
2.43.0