Implement Texture::Update() which takes pixel data from Surface

SDL2pp/Texture.cc

@@ -94,6 +94,24 @@ Texture& Texture::Update(const Optional<Rect>& rect, const void* pixels, int pit
 	return *this;
 }
 
+Texture& Texture::Update(const Optional<Rect>& rect, Surface& surface) {
+	Rect real_rect = rect ? *rect : Rect(0, 0, GetWidth(), GetHeight());
+
+	real_rect.w = std::min(real_rect.w, surface.GetWidth());
+	real_rect.h = std::min(real_rect.h, surface.GetHeight());
+
+	if (GetFormat() == surface.GetFormat()) {
+		Surface::LockHandle lock = surface.Lock();
+
+		return Update(real_rect, lock.GetPixels(), lock.GetPitch());
+	} else {
+		Surface converted = surface.Convert(GetFormat());
+		Surface::LockHandle lock = converted.Lock();
+
+		return Update(real_rect, lock.GetPixels(), lock.GetPitch());
+	}
+}
+
 Texture& Texture::UpdateYUV(const Optional<Rect>& rect, const Uint8* yplane, int ypitch, const Uint8* uplane, int upitch, const Uint8* vplane, int vpitch) {
 	if (SDL_UpdateYUVTexture(texture_, rect ? &*rect : nullptr, yplane, ypitch, uplane, upitch, vplane, vpitch) != 0)
 		throw Exception("SDL_UpdateYUVTexture");

SDL2pp/Texture.hh

@@ -313,6 +313,27 @@ public:
 	////////////////////////////////////////////////////////////
 	Texture& Update(const Optional<Rect>& rect, const void* pixels, int pitch);
 
+	////////////////////////////////////////////////////////////
+	/// \brief Update the given texture rectangle with new pixel data taken from surface
+	///
+	/// \param[in] rect Rect representing the area to update, or NullOpt to
+	///                 update the entire texture
+	/// \param[in] surface Surface to take pixel data from
+	///
+	/// \note No scaling is performed in this routine, so if rect and surface
+	///       sizes do not match, cropping is performed as appropriate
+	/// \note If surface and texture pixel formats do not match, surface is
+	///       automatically converted to texture format
+	///
+	/// \returns Reference to self
+	///
+	/// \throws SDL2pp::Exception
+	///
+	/// \see http://wiki.libsdl.org/SDL_UpdateTexture
+	///
+	////////////////////////////////////////////////////////////
+	Texture& Update(const Optional<Rect>& rect, Surface& surface);
+
 	////////////////////////////////////////////////////////////
 	/// \brief Update the given texture rectangle with new pixel data
 	///