slideshow: Make SimpleTransition inherit from ShaderTransition

Many transitions don’t like the simplistic default shader, especially
since it doesn’t handle lighting or reflections properly.

Those issues are addressed in the following commits.  TODO: except
lighting.

Change-Id: Ia99308deb87c97d9bbe1da32aac64d0437061a84

slideshow/Package_opengl.mk

@@ -11,6 +11,7 @@ $(eval $(call gb_Package_Package,slideshow_opengl_shader,$(SRCDIR)/slideshow/ope
 
 $(eval $(call gb_Package_add_files,slideshow_opengl_shader,$(LIBO_ETC_FOLDER)/opengl,\
 		basicVertexShader.glsl \
+		basicFragmentShader.glsl \
 		dissolveFragmentShader.glsl \
 		staticFragmentShader.glsl \
 		vortexFragmentShader.glsl \

slideshow/opengl/basicFragmentShader.glsl

+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*************************************************************************
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * Copyright 2015 by Collabora, Ltd.
+ *
+ * OpenOffice.org - a multi-platform office productivity suite
+ *
+ * This file is part of OpenOffice.org.
+ *
+ * OpenOffice.org 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.
+ *
+ * OpenOffice.org 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
+ * (a copy is included in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * version 3 along with OpenOffice.org.  If not, see
+ * <http://www.openoffice.org/license.html>
+ * for a copy of the LGPLv3 License.
+ *
+ ************************************************************************/
+
+#version 120
+
+uniform sampler2D slideTexture;
+varying vec2 v_texturePosition;
+
+void main() {
+     // TODO: handle lighting.
+     gl_FragColor = texture2D(slideTexture, v_texturePosition);
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */

slideshow/source/engine/OGLTrans/generic/OGLTrans_TransitionImpl.hxx

@@ -168,8 +168,6 @@ protected:
         , maSettings(rSettings)
     {}
 
-    OGLTransitionImpl() {}
-
     TransitionScene const& getScene() const
     {
         return maScene;