Add function for default RenderState (SFML#178)

include/SFML/Graphics/RenderStates.h

@@ -46,5 +46,10 @@ typedef struct
     const sfShader*  shader;    ///< Shader
 } sfRenderStates;
 
+////////////////////////////////////////////////////////////
+/// \brief Define the default values for a RenderState
+///
+////////////////////////////////////////////////////////////
+CSFML_GRAPHICS_API sfRenderStates sfRenderStates_default();
 
 #endif // SFML_RENDERSTATES_H

src/SFML/Graphics/CMakeLists.txt

@@ -30,6 +30,7 @@ set(SRC
     ${SRCROOT}/RectangleShape.cpp
     ${SRCROOT}/RectangleShapeStruct.h
     ${INCROOT}/RectangleShape.h
+    ${SRCROOT}/RenderStates.cpp
     ${SRCROOT}/RenderTexture.cpp
     ${SRCROOT}/RenderTextureStruct.h
     ${INCROOT}/RenderTexture.h

src/SFML/Graphics/RenderStates.cpp

@@ -0,0 +1,40 @@
+////////////////////////////////////////////////////////////
+//
+// SFML - Simple and Fast Multimedia Library
+// Copyright (C) 2007-2018 Laurent Gomila (laurent@sfml-dev.org)
+//
+// This software is provided 'as-is', without any express or implied warranty.
+// In no event will the authors be held liable for any damages arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it freely,
+// subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented;
+//    you must not claim that you wrote the original software.
+//    If you use this software in a product, an acknowledgment
+//    in the product documentation would be appreciated but is not required.
+//
+// 2. Altered source versions must be plainly marked as such,
+//    and must not be misrepresented as being the original software.
+//
+// 3. This notice may not be removed or altered from any source distribution.
+//
+////////////////////////////////////////////////////////////
+
+////////////////////////////////////////////////////////////
+// Headers
+////////////////////////////////////////////////////////////
+#include "SFML/Graphics/RenderStates.h"
+
+
+////////////////////////////////////////////////////////////
+sfRenderStates sfRenderStates_default() {
+    sfRenderStates states = {
+            .blendMode = sfBlendAlpha,
+            .transform = sfTransform_Identity,
+            .texture = 0,
+            .shader = 0,
+    };
+    return states;
+}