New try for pixel-perfect rendering -- waiting for feedbacks

git-svn-id: https://sfml.svn.sourceforge.net/svnroot/sfml/branches/sfml2@1390 4e206d99-4929-0410-ac5d-dfc041789085

include/SFML/Graphics/Renderer.hpp

@@ -372,7 +372,6 @@ private :
     bool          myShaderIsValid;    ///< Is the cached shader valid? (if not, the cached value is ignored)
     bool          myBlendModeIsValid; ///< Is the cached blend mode valid? (if not, the cached value is ignored)
     bool          myViewportIsValid;  ///< Is the cached viewport valid? (if not, the cached value is ignored)
-    Vector2f      myViewportSize;     ///< Half-size of the current viewport, stored for optimiation purpose
 };
 
 } // namespace sf
@@ -384,4 +383,19 @@ private :
 ////////////////////////////////////////////////////////////
 /// \class sf::Renderer
 ///
+/// sf::Renderer is the abstraction layer between SFML code
+/// and the low-level drawing API (OpenGL). It manages
+/// render states efficiently, and provides a lightweight
+/// abstraction for rendering geometry.
+///
+/// The purpose of this class is to provide a single abstract
+/// entry point for everything related to low-level rendering.
+/// Hiding everything behind sf::Renderer makes optimizing
+/// easy, as well as porting to other technologies in the future
+/// (like OpenGL ES or OpenGL 3.x).
+///
+/// This class is mainly meant for internal usage, you should
+/// never care about it unless you write your own sf::Drawable
+/// class that uses raw geometry in its Render function.
+///
 ////////////////////////////////////////////////////////////

src/SFML/Graphics/Renderer.cpp

@@ -31,34 +31,6 @@
 #include <SFML/Graphics/GLCheck.hpp>
 
 
-////////////////////////////////////////////////////////////
-// Private data
-////////////////////////////////////////////////////////////
-namespace
-{
-    // Fast float to int conversion
-    inline sf::Int32 Round(double value)
-    {
-        // Use a union rather than reinterpret_cast, because it doesn't break strict-aliasing
-        // rules and results in a correct behaviour when compiling in optimized mode
-        union DoubleToInt
-        {
-            double d; 
-            sf::Int32 i[2];
-        };
-
-        DoubleToInt u;
-        u.d = value + 6755399441055744.0;
-
-        #if defined(SFML_ENDIAN_LITTLE)
-            return u.i[0];
-        #else
-            return u.i[1];
-        #endif
-    } 
-}
-
-
 namespace sf
 {
 ////////////////////////////////////////////////////////////
@@ -215,10 +187,6 @@ void Renderer::SetViewport(const IntRect& viewport)
         // Store it
         myViewport = viewport;
         myViewportIsValid = true;
-
-        // Store the half-size of the viewport for later computations
-        myViewportSize.x = myViewport.GetSize().x / 2.f;
-        myViewportSize.y = myViewport.GetSize().y / 2.f;
     }
 }
 
@@ -365,12 +333,6 @@ void Renderer::ProcessVertex(float x, float y, float u, float v, float r, float
     // Transform the vertex position by the current model-view-projection matrix
     Vector2f position = myTransform.Transform(Vector2f(x, y));
 
-    // Round the vertex position so that it matches the
-    // viewport's pixels, and thus avoid rendering artifacts
-    // @todo remove and find a better solution :)
-    position.x = Round((position.x + 1.f) * myViewportSize.x) / myViewportSize.x - 1.f;
-    position.y = Round((position.y + 1.f) * myViewportSize.y) / myViewportSize.y - 1.f;
-
     // Modulate the vertex color with the current global color
     r *= myStates->r;
     g *= myStates->g;

src/SFML/Window/Win32/ContextWGL.cpp

@@ -45,7 +45,9 @@ myDeviceContext(NULL),
 myContext      (NULL),
 myOwnsWindow   (true)
 {
-    // TODO : try to create a bitmap in memory instead of a dummy window
+    // Creating a dummy window is mandatory: we could create a memory DC but then
+    // its pixel format wouldn't match the regular contexts' format, and thus
+    // wglShareLists would always fail. Too bad...
 
     // Create a dummy window (disabled and hidden)
     myWindow = CreateWindowA("STATIC", "", WS_POPUP | WS_DISABLED, 0, 0, 1, 1, NULL, NULL, GetModuleHandle(NULL), NULL);