SDL2奇妙な色を取得する

Question

SDL2を使用して単純なタイルベースのゲームを作成しています。私は2つの層にタイルを描いています。問題は、何らかの理由で下の画像で見ることができるように、すでに下に描画されているものが赤みを帯びた色調になっているタイルであることです。草のためのコーナータイルとサイドタイルは、例えば全く同じ色でなければなりません。ここで

は私の問題の画像です：

ここに私のtilesheetです：

そしてここでは私のコードです：

#include <iostream> 
#include <string> 
#include <SDL.h> 
#include <SDL_image.h> 

//Screen dimension constants 
const int SCREEN_WIDTH = 640; 
const int SCREEN_HEIGHT = 640; 
//The window we'll be rendering to 
SDL_Window* window = NULL; 
//The surface contained by the window 
SDL_Surface* screenSurface = NULL; 
//Holds built base layer of tilemap. 
SDL_Surface* baseLayer = NULL; 
//Map Data array 
char mapLayerOne[20][20] = { 
{4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4 }, 
{4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4 }, 
{4,4,4,6,6,6,6,6,6,4,4,4,4,4,4,4,4,4,4,4 }, 
{4,4,4,6,8,8,6,6,6,6,6,6,6,4,4,4,4,4,4,4 }, 
{4,4,4,6,8,8,6,6,6,6,6,6,6,4,4,4,4,4,4,4 }, 
{4,4,4,6,6,8,6,6,6,6,6,6,6,4,4,4,4,4,4,4 }, 
{4,4,4,6,6,8,8,8,8,6,6,6,6,6,4,4,4,4,4,4 }, 
{4,4,4,6,6,6,6,6,8,6,6,6,6,6,6,4,4,4,4,4 }, 
{4,4,4,6,6,14,6,6,8,8,6,6,6,6,6,4,4,4,4,4 }, 
{4,4,4,6,14,16,14,6,6,8,6,6,6,6,6,4,4,4,4,4 }, 
{4,4,4,14,16,16,16,12,8,8,8,8,6,6,6,4,4,4,4,4 }, 
{4,4,4,6,16,16,16,6,6,6,6,8,8,8,6,4,4,4,4,4 }, 
{4,4,4,6,6,16,6,6,6,6,6,6,6,8,6,4,4,4,4,4 }, 
{4,4,13,6,6,6,6,6,6,6,6,6,6,8,6,4,4,4,4,4 }, 
{4,4,4,14,14,14,14,14,14,14,14,14,14,14,14,15,4,4,4,4 }, 
{4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4 }, 
{4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4 }, 
{4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4 }, 
{4,4,4,4,4,4,4,4,4,4,4,4,6,6,6,6,4,4,4,4 }, 
{4,4,4,4,4,4,4,4,4,4,4,6,6,6,6,6,4,4,4,4 } 
}; 
char mapLayerTwo[20][20] = { 
{ 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0 }, 
{ 0,0,1,2,2,2,2,2,3,0,0,0,0,0,0,0,0,0,0,0 }, 
{ 0,0,5,0,0,0,0,0,0,2,2,2,2,3,0,0,0,0,0,0 }, 
{ 0,0,5,0,0,0,0,0,0,0,0,0,0,7,0,0,0,0,0,0 }, 
{ 0,0,5,0,0,0,0,0,0,0,0,0,0,7,0,0,0,0,0,0 }, 
{ 0,0,5,0,0,0,0,0,0,0,0,0,0,7,0,0,0,0,0,0 }, 
{ 0,0,5,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0 }, 
{ 0,0,5,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0 }, 
{ 0,0,5,0,0,10,0,0,0,0,0,0,0,0,0,7,0,0,0,0 }, 
{ 0,0,5,0,11,18,9,0,0,0,0,0,0,0,0,7,0,0,0,0 }, 
{ 0,0,5,7,19,0,12,12,0,0,0,0,0,0,0,7,0,0,0,0 }, 
{ 0,0,5,0,3,0,1,0,0,0,0,0,0,0,0,7,0,0,0,0 }, 
{ 0,0,5,0,0,2,0,0,0,0,0,0,0,0,0,7,0,0,0,0 }, 
{ 0,0,9,0,0,0,0,0,0,0,0,0,0,0,0,7,0,0,0,0 }, 
{ 0,0,17,9,10,10,10,10,10,10,10,10,10,12,10,11,0,0,0,0 }, 
{ 0,0,0,17,18,18,18,18,18,18,18,18,18,12,18,19,0,0,0,0 }, 
{ 0,0,0,0,0,0,0,0,0,0,0,0,0,12,0,0,0,0,0,0 }, 
{ 0,0,0,0,0,0,0,0,0,0,0,1,2,12,2,3,0,0,0,0 }, 
{ 0,0,0,0,0,0,0,0,0,0,0,5,0,8,0,0,3,0,0,0 }, 
{ 0,0,0,0,0,0,0,0,0,0,1,0,0,8,0,0,7,0,0,0 } 
}; 
bool init(); 
void DrawTiles(SDL_Surface *image, char mapLayer); 

int main(int argc, char* args[]) 
{ 
    //Main loop flag 
    bool quit = false; 
    //Event handler 
    SDL_Event e; 

    if(init()) 
    { 
    //Load images 
    SDL_Surface *image = IMG_Load("Images/TileSheet_01.png"); 
    if (!image) 
    std::cout << "Failed to load TileSheet_01.png!" << std::endl; 
    //Create BaseLayers of map 
    DrawTiles(image, 1); 
    DrawTiles(image, 2); 

    //While application is running 
    while (!quit) 
    { 
     //Handle events on queue 
     while (SDL_PollEvent(&e) != 0) 
     { 
      //User requests quit 
      if (e.type == SDL_QUIT) 
       quit = true; 
     } 
     //Get window surface 
     screenSurface = SDL_GetWindowSurface(window); 

     //Blit base layer of map to screenSurface 
     SDL_BlitSurface(baseLayer, NULL, screenSurface, NULL); 
     //Update the surface 
     SDL_UpdateWindowSurface(window); 
     //Delay in milliseconds to improve performance 
     SDL_Delay(1); 
    } 
    } 
    //Destroy window 
    SDL_DestroyWindow(window); 
    //Quit SDL subsystems 
    SDL_Quit(); 
    return 0; 
} 

void DrawTiles(SDL_Surface *image, char mapLayer) 
{ 
    SDL_Rect baseTile[20]; 
    int tileX = 0; 
    int tileY = 0; 
    for (int i = 1; i < 20; i++) 
    { 
    baseTile[i].h = 32; 
    baseTile[i].w = 32; 
    baseTile[i].x = tileX; 
    baseTile[i].y = tileY; 
    tileX += 32; 
    if (tileX == 128) { tileY += 32; tileX = 0; } 
    } 
    //Fill the surface 
    SDL_FillRect(screenSurface, NULL, SDL_MapRGB(screenSurface->format, 150, 50, 50)); 
    SDL_Rect tileLoc; 
    tileLoc.x = 0; 
    tileLoc.y = 0; 
    // Draw tiles 
    for (int i = 0; i < 20; i++) 
    { 
    for (int j = 0; j < 20; j++) 
    { 
     if (mapLayer == 1 && mapLayerOne[i][j] != 0) 
      SDL_BlitSurface(image, &baseTile[mapLayerOne[i][j]], baseLayer, &tileLoc); 
     else if (mapLayer == 2 && mapLayerTwo[i][j] != 0) 
      SDL_BlitSurface(image, &baseTile[mapLayerTwo[i][j]], baseLayer, &tileLoc); 
     tileLoc.x += 32; 
     if (tileLoc.x == 640) 
     { 
      tileLoc.x = 0; 
      tileLoc.y += 32; 
     } 
    } 
    } 
} 

bool init() 
{ 
    //Initialization flag 
    bool success = true; 

    //Initialize SDL 
    if (SDL_Init(SDL_INIT_VIDEO) < 0) 
    { 
    std::cout << "SDL could not initialize!" << std::endl; 
    success = false; 
    } 
    else 
    { 
    //Create window 
    window = SDL_CreateWindow("My SDL TileMap", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, SCREEN_WIDTH, SCREEN_HEIGHT, SDL_WINDOW_SHOWN); 
    if (window == NULL) 
    { 
     std::cout << "Window could not be created!" << std::endl; 
     success = false; 
    } 
    else 
    { 
     //Initialize PNG loading 
     int imgFlags = IMG_INIT_PNG; 
     if (!(IMG_Init(imgFlags) & imgFlags)) 
     { 
      //std::cout << "SDL_image could not initialize!" << std::endl; 
      printf("SDL_image could not initialize! SDL_image Error: %s\n", IMG_GetError()); 
      success = false; 
     } 
     else 
     { 
      //Get window surface 
      screenSurface = SDL_GetWindowSurface(window); 
      //Surface to hold baselayer of map. 
      baseLayer = SDL_CreateRGBSurface(0, SCREEN_WIDTH, SCREEN_HEIGHT, 16, 0, 0, 0, 0); 
     } 
    } 
} 
SDL_Delay(300); 
return success; 
} 

この原因は何ですか？

Answer 1

baseLayer = SDL_CreateRGBSurface(0, SCREEN_WIDTH, SCREEN_HEIGHT, 16, 0, 0, 0, 0); 
                    ^^ ...but you're using 32bpp PNGs 

利用代わりに16の32ビットの表面と移入マスク：StackOverflowのへようこそ

// https://wiki.libsdl.org/SDL_CreateRGBSurface#Code_Examples 
#if SDL_BYTEORDER == SDL_BIG_ENDIAN 
    const Uint32 rmask = 0xff000000; 
    const Uint32 gmask = 0x00ff0000; 
    const Uint32 bmask = 0x0000ff00; 
    const Uint32 amask = 0x000000ff; 
#else 
    const Uint32 rmask = 0x000000ff; 
    const Uint32 gmask = 0x0000ff00; 
    const Uint32 bmask = 0x00ff0000; 
    const Uint32 amask = 0xff000000; 
#endif 
    baseLayer = SDL_CreateRGBSurface(0, SCREEN_WIDTH, SCREEN_HEIGHT, 32, rmask, gmask, bmask, amask);