Document experimental opengl es 2 support

Task-number: QT3DS-145
Change-Id: I3dbae59914d24225587743195707398698431806
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>

2 files changed, 83 insertions, 0 deletions

diff --git a/doc/src/00-concepts.qdoc b/doc/src/00-concepts.qdoc
index bec19c93..6c6aaa4f 100644
--- a/doc/src/00-concepts.qdoc
+++ b/doc/src/00-concepts.qdoc
@@ -47,6 +47,7 @@
     \endomit
     \li \l {Best Practices}
     \li \l {Requirements}
+    \li \l {Experimental Features}
     \li \l {Examples}
     \li \l {Copyright Notices}
 \endlist
diff --git a/doc/src/experimental-features.qdoc b/doc/src/experimental-features.qdoc
new file mode 100644
index 00000000..1638b594
--- /dev/null
+++ b/doc/src/experimental-features.qdoc
@@ -0,0 +1,82 @@
+/****************************************************************************
+**
+** Copyright (C) 2018 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt 3D Studio.
+**
+** $QT_BEGIN_LICENSE:FDL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Free Documentation License Usage
+** Alternatively, this file may be used under the terms of the GNU Free
+** Documentation License version 1.3 as published by the Free Software
+** Foundation and appearing in the file included in the packaging of
+** this file. Please review the following information to ensure
+** the GNU Free Documentation License version 1.3 requirements
+** will be met: https://www.gnu.org/licenses/fdl-1.3.html.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+/*!
+
+\title Experimental Features
+\page experimental-features.html
+
+\section1 OpenGL ES 2 Support
+
+This section lists all features that do \b not work in devices running on
+OpenGL ES 2 renderer as well as features that have limited support. It must
+be noted that most of the default material features, such as lighting,
+bumpmapping, normal mapping and specular mapping among other things, will work
+in the ES 2 renderer but due to limited HW capabilities many of them might not
+work simultaniously.
+
+\section2 Unsupported Features
+
+These features are not supported either due to hardware requirements or missing
+implementation for ES 2 renderer.
+
+\list
+\li Advanced blending modes (overlay, color burn, color dodge)
+\li Ambient occlusion
+\li Dynamic shadows
+\li HDR textures and lightmaps (converted to LDR during loading)
+\li Light probes
+\endlist
+
+\section2 Custom Material and Effect Support
+
+Custom materials and effects have very limited support with ES 2 renderer. Most
+of the materials coming with studio do not work with ES 2 renderer. Additionally, effects and
+materials can be written by the user, so they might use some shader feature not available
+in OpenGL ES 2 Shader Language. One should write separate ES 2 specific effects and
+materials. Parts of the studio shader library also have requirements beyond ES 2.
+
+The support for effects is much better. Only the following effects do not work
+with ES 2 renderer.
+\list
+\li Depth of Field Bokeh
+\li FXAA
+\li Screen space AO
+\li SMAA1X
+\endlist
+
+\section2 Required OpenGL Extensions
+
+These extensions are required for most of the features to work properly.
+
+\list
+\li EXT_shader_texture_lod
+\li OES_standard_derivatives
+\li OES_vertex_array_object
+\endlist
+
+*/