使用 SDL 使用 SDL 颜色键替换颜色

Question

我正在制作一个简单的 Roguelike 游戏，并使用 SDL 作为显示器。游戏的图形是Codepage 437的图像，背景为黑色，字体为白色。我不想使用许多已经着色的单独图像文件，而是想使用一个图像文件，并在将其加载到内存中时替换颜色。

将代码页拆分为精灵表的代码工作正常，但是当尝试以彩色打印时，所有内容都以白色显示。我过去让它工作过，但不知何故，我在将其从更改打印时的颜色更改为更改加载时的颜色时破坏了代码。这是加载图像的代码：

SDL_Surface *Screen,*Font[2];
SDL_Rect Character[256];

Uint8 ScreenY,ScreenX;
Uint16 PrintX,PrintY,ScreenSizeY,ScreenSizeX;
Uint32 Color[2];

void InitDisplay()
{
    if(SDL_Init(SDL_INIT_VIDEO) == -1) { printf("SDL Init failed\n"); return; }

    ScreenSizeY = 600;
    ScreenSizeX = 800;
    Screen = SDL_SetVideoMode(ScreenSizeX,ScreenSizeY,32,SDL_HWSURFACE | SDL_RESIZABLE);
    SDL_WM_SetCaption("Alpha",NULL);

    SDL_Surface *Load;
    Load = IMG_Load("resource/font.png");
    Font[0] = SDL_DisplayFormat(Load);
    SDL_FreeSurface(Load);

    Color[0] = SDL_MapRGB(Font[0]->format,255,255,255);
    Color[1] = SDL_MapRGB(Font[0]->format,255,0,0);

    Uint8 i,j,k = 0;

    PrintX = 0;
    PrintY = 0;

    for(i = 0; i < 16; i++) { for(j = 0; j < 16; j++)
    {
        Character[k].x = PrintX;
        Character[k].y = PrintY;
        Character[k].w = 8;
        Character[k].h = 12;
        k++;
        PrintX += 8;
    } PrintX = 0; PrintY += 12; }

    PrintX = 0;
    PrintY = 0;

    for(i = 1; i < 2; i++)
    {
        Font[i] = SDL_DisplayFormat(Font[0]);
        SDL_SetColorKey(Font[i],SDL_SRCCOLORKEY,Color[i]);
        SDL_FillRect(Font[i],&Font[i]->clip_rect,Color[i]);
        SDL_BlitSurface(Font[0],NULL,Font[i],NULL);
        SDL_SetColorKey(Font[0],0,Color[0]);
    }
}

问题出在上面的最后一个 for 循环上。我不明白为什么它不起作用。非常感谢任何帮助！

Answer 1

我不久前解决了这个问题。问题源于以错误的顺序进行颜色键控。这是解决的代码：

uint8_t i;
uint8_t j;
uint8_t k = 0;

SDL_FillRect(Screen,NULL,0x00000000);

SDL_Rect Offset;
SDL_Surface *Load;
SDL_Surface *LoadFont;

Load = IMG_Load("resource/font.png");
LoadFont = SDL_DisplayFormat(Load);
SDL_FreeSurface(Load);

Offset.x = 0;
Offset.y = 0;

for(i = 0; i < 16; i++) { for(j = 0; j < 16; j++)
{
    Character[k].x = Offset.x;
    Character[k].y = Offset.y;
    Character[k].w = XWIDTH;
    Character[k].h = YHIEGHT;
    k++;
    Offset.x += XWIDTH;
} Offset.x = 0; Offset.y += 12; }

Color[0][0] = SDL_MapRGB(LoadFont->format,255,255,255);
Color[0][1] = SDL_MapRGB(LoadFont->format,96,96,96);
Color[1][0] = SDL_MapRGB(LoadFont->format,255,0,0);
Color[1][1] = SDL_MapRGB(LoadFont->format,96,0,0);
Color[2][0] = SDL_MapRGB(LoadFont->format,0,255,0);
Color[2][1] = SDL_MapRGB(LoadFont->format,0,96,0);
Color[3][0] = SDL_MapRGB(LoadFont->format,0,0,255);
Color[3][1] = SDL_MapRGB(LoadFont->format,0,0,96);
Color[4][0] = SDL_MapRGB(LoadFont->format,255,255,0);
Color[4][1] = SDL_MapRGB(LoadFont->format,96,96,0);

SDL_SetColorKey(LoadFont,SDL_SRCCOLORKEY,Color[0][0]);

for(i=0; i<6; i++) { for(j=0; j<2; j++)
{
    Font[i][j] = SDL_DisplayFormat(LoadFont);
    SDL_FillRect(Font[i][j],&Font[i][j]->clip_rect,Color[i][j]);
    SDL_BlitSurface(LoadFont,NULL,Font[i][j],NULL);
    SDL_SetColorKey(Font[i][j],SDL_SRCCOLORKEY,SDL_MapRGB(Font[i][j]->format,0,0,0));
}}

SDL_FreeSurface(LoadFont);