c++ - 转换透明 png 会使 SDL/OpenGL 崩溃

Question

如果我尝试将透明的 .png SDL_Surface 转换为 OpenGL 纹理，那么当程序尝试从 SDL_Surface 访问任何数据时，它会崩溃。我观察了其他人的代码涉及透明 png，但根据其他提问者的说法，它们是相同的并且不会崩溃。这是我的代码，程序崩溃的部分。它在“n0fColors = surface->format->BytesPerPixel”处崩溃。

GLuint CONVERT_IMAGE(SDL_Surface * surface)
{
    GLuint texture;
    GLenum texture_format;
    GLint nOfColors;

    nOfColors = surface->format->BytesPerPixel;
    if (nOfColors == 4)
    {
        if (surface->format->Rmask == 0x000000ff)
            texture_format = GL_RGBA;
        else
            texture_format = GL_BGRA;
    }
    else if (nOfColors == 3)
    {
        if (surface->format->Rmask == 0x000000ff)
            texture_format = GL_RGB;
        else
            texture_format = GL_BGR;
    }

    glGenTextures( 1, &texture );

glBindTexture( GL_TEXTURE_2D, texture );

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

glTexImage2D( GL_TEXTURE_2D, 0, nOfColors, surface->w, surface->h, 0, texture_format, GL_UNSIGNED_BYTE, surface->pixels );

    delete surface;
    return texture;
};

编辑:我应该注意到 PNG 的透明部分是 %100 透明的。 编辑:这是我对图像的调用:

void image_init()
{
    wall_clay_0 = IMG_Load("images/walls/clay.png");

    walls_image.clay = CONVERT_IMAGE(wall_clay_0);
};

Answer 1

你的加载代码应该是这样的:

void image_init()
{
    wall_clay_0 = IMG_Load("images/walls/clay.png");
    if (!wall_clay_0)
    {
        printf("Error loading mage: %s\n", IMG_GetError());
        abort(); // or whatever your application should do
    }
    walls_image.clay = CONVERT_IMAGE(wall_clay_0);
}