Gradual fade-in of built building

client/gui/CAnimation.cpp

@@ -94,8 +94,8 @@ public:
 	// Keep the original palette, in order to do color switching operation
 	void savePalette();
 
-	void draw(SDL_Surface * where, int posX=0, int posY=0, const Rect *src=nullptr, ui8 alpha=255) const override;
-	void draw(SDL_Surface * where, const SDL_Rect * dest, const SDL_Rect * src, ui8 alpha=255) const override;
+	void draw(SDL_Surface * where, int posX=0, int posY=0, const Rect *src=nullptr, ui8 alpha=255) override;
+	void draw(SDL_Surface * where, const SDL_Rect * dest, const SDL_Rect * src, ui8 alpha=255) override;
 	std::shared_ptr<IImage> scaleFast(float scale) const override;
 	void exportBitmap(const boost::filesystem::path & path) const override;
 	void playerColored(PlayerColor player) override;
@@ -642,17 +642,17 @@ SDLImage::SDLImage(std::string filename)
 	}
 }
 
-void SDLImage::draw(SDL_Surface *where, int posX, int posY, const Rect *src, ui8 alpha) const
+void SDLImage::draw(SDL_Surface *where, int posX, int posY, const Rect *src, ui8 alpha)
 {
 	if(!surf)
 		return;
 
 	Rect destRect(posX, posY, surf->w, surf->h);
 
-	draw(where, &destRect, src);
+	draw(where, &destRect, src, alpha);
 }
 
-void SDLImage::draw(SDL_Surface* where, const SDL_Rect* dest, const SDL_Rect* src, ui8 alpha) const
+void SDLImage::draw(SDL_Surface* where, const SDL_Rect* dest, const SDL_Rect* src, ui8 alpha)
 {
 	if (!surf)
 		return;
@@ -663,6 +663,12 @@ void SDLImage::draw(SDL_Surface* where, const SDL_Rect* dest, const SDL_Rect* sr
 
 	if(src)
 	{
+		if(alpha != UINT8_MAX)
+		{
+			const ColorShifterMultiplyAndAdd alphaShifter ({255, 255, 255, alpha}, {0, 0, 0, 0});
+			adjustPalette(&alphaShifter);
+		}
+
 		if(src->x < margins.x)
 			destShift.x += margins.x - src->x;
 

client/gui/CAnimation.h

@@ -40,8 +40,8 @@ public:
 	using SpecialPalette = std::array<SDL_Color, 7>;
 
 	//draws image on surface "where" at position
-	virtual void draw(SDL_Surface * where, int posX = 0, int posY = 0, const Rect * src = nullptr, ui8 alpha = 255) const=0;
-	virtual void draw(SDL_Surface * where, const SDL_Rect * dest, const SDL_Rect * src, ui8 alpha = 255) const = 0;
+	virtual void draw(SDL_Surface * where, int posX = 0, int posY = 0, const Rect * src = nullptr, ui8 alpha = 255) = 0;
+	virtual void draw(SDL_Surface * where, const SDL_Rect * dest, const SDL_Rect * src, ui8 alpha = 255) = 0;
 
 	virtual std::shared_ptr<IImage> scaleFast(float scale) const = 0;
 

client/widgets/Images.cpp

@@ -339,7 +339,7 @@ void CAnimImage::playerColored(PlayerColor currPlayer)
 			anim->getImage(0, group)->playerColored(player);
 }
 
-CShowableAnim::CShowableAnim(int x, int y, std::string name, ui8 Flags, ui32 Delay, size_t Group):
+CShowableAnim::CShowableAnim(int x, int y, std::string name, ui8 Flags, ui32 Delay, size_t Group, uint8_t alpha):
 	anim(std::make_shared<CAnimation>(name)),
 	group(Group),
 	frame(0),
@@ -349,7 +349,7 @@ CShowableAnim::CShowableAnim(int x, int y, std::string name, ui8 Flags, ui32 Del
 	flags(Flags),
 	xOffset(0),
 	yOffset(0),
-	alpha(255)
+	alpha(alpha)
 {
 	anim->loadGroup(group);
 	last = anim->size(group);

client/widgets/Images.h

@@ -142,7 +142,7 @@ public:
 	//Set per-surface alpha, 0 = transparent, 255 = opaque
 	void setAlpha(ui32 alphaValue);
 
-	CShowableAnim(int x, int y, std::string name, ui8 flags=0, ui32 Delay=4, size_t Group=0);
+	CShowableAnim(int x, int y, std::string name, ui8 flags=0, ui32 Delay=4, size_t Group=0, uint8_t alpha = 255);
 	~CShowableAnim();
 
 	//set animation to group or part of group