From 8d7d5d12a1c169e266e950fe5c9d6aa3cb97a8cc Mon Sep 17 00:00:00 2001
From: Robert Osfield <robert@openscenegraph.com>
Date: Wed, 29 Jun 2016 11:26:54 +0100
Subject: [PATCH] Added osg::ViewportIndexed that adds support for
 glViewportIndexed

---
 include/osg/ViewportIndexed | 73 +++++++++++++++++++++++++++++++++++++
 src/osg/ViewportIndexed.cpp | 53 +++++++++++++++++++++++++++
 2 files changed, 126 insertions(+)
 create mode 100644 include/osg/ViewportIndexed
 create mode 100644 src/osg/ViewportIndexed.cpp

diff --git a/include/osg/ViewportIndexed b/include/osg/ViewportIndexed
new file mode 100644
index 000000000..414cde690
--- /dev/null
+++ b/include/osg/ViewportIndexed
@@ -0,0 +1,73 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2014 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library 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
+ * OpenSceneGraph Public License for more details.
+*/
+
+#ifndef OSG_VIEWPORTINDEXED
+#define OSG_VIEWPORTINDEXED 1
+
+#include <osg/Viewport>
+
+namespace osg {
+
+/** Encapsulates glViewportIndexed function : the index version of glViewport for multiple render target.
+*/
+class OSG_EXPORT ViewportIndexed : public Viewport
+{
+    public :
+
+        ViewportIndexed();
+
+        ViewportIndexed(unsigned int index, value_type x,value_type y,value_type width,value_type height):
+            Viewport(x,y,width,height),
+            _index(index) {}
+
+        /** Copy constructor using CopyOp to manage deep vs shallow copy. */
+        ViewportIndexed(const ViewportIndexed& cm,const CopyOp& copyop=CopyOp::SHALLOW_COPY):
+            Viewport(cm,copyop),
+            _index(cm._index) {}
+
+        META_StateAttribute(osg, ViewportIndexed, VIEWPORT);
+
+        /** Return -1 if *this < *rhs, 0 if *this==*rhs, 1 if *this>*rhs. */
+        virtual int compare(const StateAttribute& sa) const
+        {
+            // Check for equal types, then create the rhs variable
+            // used by the COMPARE_StateAttribute_Parameter macros below.
+            COMPARE_StateAttribute_Types(ViewportIndexed,sa)
+
+            COMPARE_StateAttribute_Parameter(_index);
+
+            return Viewport::compare(sa);
+        }
+
+        /** Return the buffer index as the member identifier.*/
+        virtual unsigned int getMember() const { return _index; }
+
+        /** Set the index of the ViewportIndexed. */
+        void setIndex(unsigned int index);
+
+        /** Get the index of the ViewportIndexed. */
+        unsigned int getIndex() const { return _index; }
+
+        virtual void apply(State& state) const;
+
+    protected:
+
+        virtual ~ViewportIndexed();
+
+        unsigned int    _index;
+
+};
+
+}
+
+#endif
diff --git a/src/osg/ViewportIndexed.cpp b/src/osg/ViewportIndexed.cpp
new file mode 100644
index 000000000..1ae9149df
--- /dev/null
+++ b/src/osg/ViewportIndexed.cpp
@@ -0,0 +1,53 @@
+/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2014 Robert Osfield
+ *
+ * This library is open source and may be redistributed and/or modified under
+ * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
+ * (at your option) any later version.  The full license is in LICENSE file
+ * included with this distribution, and on the openscenegraph.org website.
+ *
+ * This library 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
+ * OpenSceneGraph Public License for more details.
+*/
+#include <osg/ViewportIndexed>
+#include <osg/GLExtensions>
+#include <osg/State>
+
+using namespace osg;
+
+ViewportIndexed::ViewportIndexed():
+    _index(0)
+{
+}
+
+ViewportIndexed::~ViewportIndexed()
+{
+}
+
+void ViewportIndexed::setIndex(unsigned int index)
+{
+    if (_index==index) return;
+
+    ReassignToParents needToReassingToParentsWhenMemberValueChanges(this);
+
+    _index = index;
+}
+
+void ViewportIndexed::apply(State& state) const
+{
+    const GLExtensions* extensions = state.get<GLExtensions>();
+    if (extensions->glViewportIndexedf)
+    {
+        extensions->glViewportIndexedf(static_cast<GLuint>(_index),
+                                       static_cast<GLfloat>(_x),
+                                       static_cast<GLfloat>(_y),
+                                       static_cast<GLfloat>(_width),
+                                       static_cast<GLfloat>(_height));
+    }
+    else
+    {
+        OSG_WARN<<"Warning: ViewportIndexed::apply(..) failed, glViewportIndexed is not support by OpenGL driver."<<std::endl;
+    }
+}
+