Question

几个星期以来，我和我的朋友正在开展一个项目。准确的游戏。我们遇到了一个破坏游戏玩法的巨大问题。玩家的透明部分应该是黑色的。

MergeSurfaces功能，是blit。本身将rects写入SDL_Rect，并执行blit

void MergeSurfaces(SDL_Surface *From, SDL_Surface *To, int FromX, int FromY, int FromWidth, int FromLenght, int ToX, int ToY){




            SDL_Rect srcRect;    
            srcRect.x = FromX;    
            srcRect.y = FromY;
            srcRect.w = FromWidth;   
            srcRect.h = FromLenght;

            SDL_Rect dstRect;    
            dstRect.x = ToX;    
            dstRect.y = ToY;    

            SDL_BlitSurface(From, &srcRect, To, &dstRect);
        }

这是玩家形成功能。

//------------------------------------------------------------------------------------------
//----MAIN LOAD FUNCTION
//------------------------------------------------------------------------------------------    

    void LoadPlayerGraphics(SDL_Surface* BodyID[], int PlayerHeight, int PlayerWidth, long EquipmentID[], int MovementAmountX, int MovementAmountY){
        SDL_Surface* Image;
        SDL_Surface* EquipmentColorization;
        std::string FileName;
        int ID;


        Clean(BodyID,MovementAmountX*MovementAmountY,PlayerWidth,PlayerHeight);


        for(int i = -1; i < 8; i++){
            ID = 0;
            //here we put a small exception to firstly load the player. And only then dress Him
            if(i == -1){
                FileName = "resource/images/Player/WhiteMaleBody.png";
                goto playerbody;
            }
            if(EquipmentID[i] != 0){
                GetFileNameByID(EquipmentID[i],FileName);
            playerbody:
                Image = IMG_Load(FileName.c_str());
                if(Image == NULL){
                    exit(1);
                }

                //Needed for equipment coloring. At this point we will put RGB masks in order to color the armor by it's type
                EquipmentColorization = SDL_CreateRGBSurface(SDL_HWSURFACE | SDL_SRCALPHA, MovementAmountX*PlayerWidth, MovementAmountY*PlayerHeight, 32, 0, 0, 0, 0);


                GraphicsFunctions.MergeSurfaces(Image,EquipmentColorization,0,0,MovementAmountX*PlayerWidth,MovementAmountY*PlayerHeight,0,0);

                for(int i = 0; i < MovementAmountY; i++){
                    for(int j = 0; j < MovementAmountX; j++){
                        ID++;   
                        //We put the graphics on and on on top. So we dress the frames. BodyID[ID] are frames by motion ID. We just fill this up.
                        GraphicsFunctions.MergeSurfaces(    EquipmentColorization,BodyID[ID],
                                                            (j * PlayerWidth),
                                                            (i * PlayerHeight),
                                                            PlayerWidth,PlayerHeight,
                                                            0,0);

                        if(BodyID[i] == NULL){
                            exit(2);
                        }
                    }
                }
            }

        }
    }

清洁功能，如果你想知道它做了什么。我还没有释放表面。因为我在程序结束时这样做，所以到目前为止它已加载一次。所以基本上它只是为了填充它们来创建那些表面。

void Clean(SDL_Surface* TheSurface[], int MovementAmount, int PlayerWidth, int PlayerHeight){
        GraphicsFunctions.Setrgba();
        for(int i = 0; i <= MovementAmount; i++){
            TheSurface[i] = SDL_CreateRGBSurface(SDL_HWSURFACE | SDL_SRCALPHA, PlayerWidth, PlayerHeight, 32, 0, 0, 0, 0);
        }
    }

接下来是框架部分，或使角色看起来正在移动。它被称为其他地方，因此我可以轻松控制速度。

void Variate(SDL_Surface* Graphical_Output){
        GraphicsFunctions.MergeSurfaces(BodyID[MovementVariationID[MovementID][Variation]], Graphical_Output, 0, 0, PlayerWidth, PlayerHeight, 0, 0);
        Variation++;
        if(Variation == MovementVariationIn[MovementID]){
            Variation = 0;
        }
    }

这是主线程控制。主系统线程，Blits和Flip到表面你看到的。

//------------------------------------------------------------------------------------------
//----MAIN Thread Function (As Thread Repeat to infinity LOL)
//------------------------------------------------------------------------------------------
    int Player_Main(void *unused){

        GraphicsFunctions.Setrgba();
        PlayerGraphics = SDL_CreateRGBSurface(SDL_HWSURFACE | SDL_SRCALPHA, 1024, 768, 32, GraphicsFunctions.r, GraphicsFunctions.g, GraphicsFunctions.b, GraphicsFunctions.a);
        while(!EndProgram){

            PlayerMovementGraphics::Variate(PlayerGraphics);

            SDL_Delay(200);
        }
        return 0;
    }

当然，这里需要改进。但自从几周前我开始研究SDL以来。我还有很多东西需要学习。这基本上就是现在所有的图形。所以也许你可以发现为什么玩家本身应该是透明的黑色。

Answer 1

你写道：

SDL_CreateRGBSurface( SDL_HWSURFACE | SDL_SRCALPHA,
                      PlayerWidth, PlayerHeight, 
                      32, 0, 0, 0, 0 );

来自documentation：

使用零作为RGB蒙版根据深度设置默认值。但是，对Amask使用零会导致Amask为0.

如果你想要一个alpha通道，你需要明确指定你的面具：

SDL_CreateRGBSurface( SDL_HWSURFACE | SDL_SRCALPHA,
                      PlayerWidth, PlayerHeight, 32,
                      0xFF000000, 0x00FF0000, 0x0000FF00, 0x000000FF );

SDL在blit上，失去透明度并变黑

1 个答案: