Hello,

Under XP everything is displayed properly, all the textures loaded from the surface into OpenGL texture are properly displayed.

Under Windows 7 most of the textures are white rectangles, some are displayed correctly. The format of all images is 32bit with 8bit alpha.

[code]
    SDLw = surface->w;
    SDLh = surface->h;

    Release(); // release the previous memory

    GLfloat coord[4];

    if(surface)
    {
        SDL_Surface *temp = SDL_DisplayFormatAlpha(surface);
        if(temp) //if conversion succeeds, free old surface
        {
            FreeImage(surface);
            surface = temp;
        }
        else    //can't convert, leave surface as is
        {
            Error(CRITICAL,"SDL_DisplayFormatAlpha failed: %s for image: %s",SDL_GetError(), imageFileName.c_str());
        }

        origWidth = rWidth = static_cast<float>(surface->w);
        origHeight = rHeight = static_cast<float>(surface->h);
        rTexID = SurfaceToTexture(surface,coord);
        rTexMinX = coord[0];
        rTexMinY = coord[1];
        rTexMaxX = coord[2];
        rTexMaxY = coord[3];

        rImage = surface;

        // scale the image to the current resolution scale
        if( !DontScale && PEngine::scale != 1.0f ) {
            PermanentScale( PEngine::scale );
        }
[/code]


here is the part where the image data is loaded into OpenGL texture:

[code]
GLuint texture;
    int w, h;
    SDL_Surface *temp;
    SDL_Rect area;
    Uint32 saved_flags;
    Uint8  saved_alpha;

    //expand width and height to nearest powers of 2
    if( w % 2 != 0 || h % 2 != 0 ) {
        w = PowerOfTwo(surface->w);
        h = PowerOfTwo(surface->h);
    }

    if( texcoord != NULL ) {
        texcoord[0] = 0.0f; //min X
        texcoord[1] = 0.0f; //min Y
        texcoord[2] = (GLfloat)surface->w / w;  //max X
        texcoord[3] = (GLfloat)surface->h / h;  //max Y
    }

    temp = SDL_CreateRGBSurface(
        SDL_SWSURFACE,
        w, h,
        32,
#if SDL_BYTEORDER == SDL_LIL_ENDIAN //endian specific color masks
        0x000000FF,
        0x0000FF00,
        0x00FF0000,
        0xFF000000
#else
        0xFF000000,
        0x00FF0000,
        0x0000FF00,
        0x000000FF
#endif
    );
    if(!temp)  //failure in CreateRGBSurface
        return 0;

    //save alpha
    saved_flags = surface->flags&(SDL_SRCALPHA|SDL_RLEACCELOK);
    saved_alpha = surface->format->alpha;
    if((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA)
        SDL_SetAlpha(surface, 0, 0);

    //copy surface (do not alter passed surface to allow this function to be used in special situations)
    area.x = 0;
    area.y = 0;
    area.w = static_cast<Sint16>(surface->w);
    area.h = static_cast<Sint16>(surface->h);
    int r = SDL_BlitSurface(surface, NULL, temp, &area);

    //restore saved alpha
    if((saved_flags & SDL_SRCALPHA) == SDL_SRCALPHA)
        SDL_SetAlpha(surface, saved_flags, saved_alpha);


    // get the number of channels in the SDL surface
        GLint nOfColors = temp->format->BytesPerPixel;
        GLenum texture_format;
        if (nOfColors == 4)     // contains an alpha channel
        {
                if (temp->format->Rmask == 0x000000ff)
                        texture_format = GL_RGBA;
                else
                        texture_format = GL_BGRA;
        } else if (nOfColors == 3)     // no alpha channel
        {
                if (temp->format->Rmask == 0x000000ff)
                        texture_format = GL_RGB;
                else
                        texture_format = GL_BGR;
        } else {
                //printf("warning: the image is not truecolor..  this will probably break\n");
                // this error should not go unhandled
        }


    //create the OpenGL texture
    glGenTextures(1, &texture);
    glBindTexture(GL_TEXTURE_2D, texture);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexImage2D(GL_TEXTURE_2D, 0, nOfColors, w, h, 0, texture_format, GL_UNSIGNED_BYTE, temp->pixels);
    //glTexImage2D(GL_TEXTURE_2D, 0, nOfColors, w, h, 0, texture_format, GL_UNSIGNED_BYTE, temp->pixels);
    SDL_FreeSurface(temp); //temp surface no longer needed

    return texture;
[/code]