sdlimageloader.cpp

Linux系统下的《红色警戒》游戏

/*      _______   __   __   __   ______   __   __   _______   __   __                 
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 * /______/ //______/ //_/ //_____/\ /_/ //_/ //_/ //_/ //_/ /|_/ /                    
 * \______\/ \______\/ \_\/ \_____\/ \_\/ \_\/ \_\/ \_\/ \_\/ \_\/                      
 *
 * Copyright (c) 2004, 2005 darkbits                        Js_./
 * Per Larsson a.k.a finalman                          _RqZ{a<^_aa
 * Olof Naess閚 a.k.a jansem/yakslem                _asww7!uY`>  )\a//
 *                                                 _Qhm`] _f "'c  1!5m
 * Visit: http://guichan.darkbits.org             )Qk<P ` _: :+' .'  "{[
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/*
 * For comments regarding functions please see the header file. 
 */
#ifdef USE_SDL_IMAGE
#include <SDL/SDL_image.h>

#include "guichan/sdl/sdlimageloader.h"
#include "guichan/exception.h"
#include "guichan/sdl/sdlpixel.h"

namespace gcn
{

    SDLImageLoader::SDLImageLoader()
    {
        mCurrentImage = NULL;    
    }
  
    void SDLImageLoader::prepare(const std::string& filename)
    {
        if (mCurrentImage != NULL)
        {
            throw GCN_EXCEPTION("Function called before finalizing or discarding last loaded image.");
        }

        SDL_Surface* tmp = IMG_Load(filename.c_str());

        if (tmp == NULL)
        {
            throw GCN_EXCEPTION(std::string("Unable to load image file: ")+filename);
        }

        Uint32 rmask, gmask, bmask, amask;
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
        rmask = 0xff000000;
        gmask = 0x00ff0000;
        bmask = 0x0000ff00;
        amask = 0x000000ff;
#else
        rmask = 0x000000ff;
        gmask = 0x0000ff00;
        bmask = 0x00ff0000;
        amask = 0xff000000;
#endif
    
        mCurrentImage = SDL_CreateRGBSurface(SDL_SWSURFACE, 0, 0, 32,
                                             rmask, gmask, bmask, amask);
    
        if (mCurrentImage == NULL)
        {
            throw GCN_EXCEPTION(std::string("Not enough memory to load: ")+filename);
        }
    
        SDL_Surface* tmp2 = SDL_ConvertSurface(tmp, mCurrentImage->format, SDL_SWSURFACE);
        SDL_FreeSurface(tmp);
        SDL_FreeSurface(mCurrentImage);

        mCurrentImage = tmp2;    
    }

    void* SDLImageLoader::getRawData()
    {
        return mCurrentImage->pixels;
    }
  
    void* SDLImageLoader::finalize()
    {
        if (mCurrentImage == NULL)
        {
            throw GCN_EXCEPTION("No image prepared.");
        }

        int i;
        bool hasPink = false;
        bool hasAlpha = false;
    
        for (i = 0; i < mCurrentImage->w * mCurrentImage->h; ++i)
        {
            if (((unsigned int*)mCurrentImage->pixels)[i] == SDL_MapRGB(mCurrentImage->format,255,0,255))
            {
                hasPink = true;
                break;
            }
        }
    
        for (i = 0; i < mCurrentImage->w * mCurrentImage->h; ++i)
        {
            Uint8 r, g, b, a;
      
            SDL_GetRGBA(((unsigned int*)mCurrentImage->pixels)[i], mCurrentImage->format,
                        &r, &g, &b, &a);

            if (a != 255)
            {
                hasAlpha = true;
                break;
            }      
        }

        // Don't convert 32bpp images with alpha, it will destroy the
        // alpha channel.
        SDL_Surface *temp;
        if (hasAlpha)
        {
            temp = mCurrentImage;
            mCurrentImage = NULL;
        }
        else
        {
            temp = SDL_DisplayFormat(mCurrentImage);
            SDL_FreeSurface(mCurrentImage);
            mCurrentImage = NULL;
        }
    
        if (hasPink)
        {
            SDL_SetColorKey(temp, SDL_SRCCOLORKEY,
                            SDL_MapRGB(temp->format,255,0,255));
        }
        if (hasAlpha)
        {
            SDL_SetAlpha(temp, SDL_SRCALPHA, 255);
        }
    
        return temp;    
    }
  
    void SDLImageLoader::discard()
    {
        if (mCurrentImage == NULL)
        {
            throw GCN_EXCEPTION("No image prepared.");
        }
    
        SDL_FreeSurface(mCurrentImage);
    
        mCurrentImage = NULL;    
    }
  
    void SDLImageLoader::free(Image* image)
    {
        if (image->_getData() == NULL)
        {
            throw GCN_EXCEPTION("Image data points to null.");
        }
    
        SDL_FreeSurface((SDL_Surface*)image->_getData());    
    }
  
    int SDLImageLoader::getWidth() const
    {
        if (mCurrentImage == NULL)
        {
            throw GCN_EXCEPTION("No image prepared.");
        }
    
        return mCurrentImage->w;
    }

    int SDLImageLoader::getHeight() const
    {
        if (mCurrentImage == NULL)
        {
            throw GCN_EXCEPTION("No image prepared.");
        }
    
        return mCurrentImage->h;
    }

    Color SDLImageLoader::getPixel(int x, int y)
    {
        if (mCurrentImage == NULL)
        {
            throw GCN_EXCEPTION("No image prepared.");
        }

        if (x < 0 || y < 0 || x >= mCurrentImage->w || y >= mCurrentImage->h)
        {
            throw GCN_EXCEPTION("x and y out of image bound.");
        }

        return SDLgetPixel(mCurrentImage, x, y);    
    }

    void SDLImageLoader::putPixel(int x, int y, const Color& color)
    {
        if (mCurrentImage == NULL)
        {
            throw GCN_EXCEPTION("No image prepared.");
        }

        if (x < 0 || y < 0 || x >= mCurrentImage->w || y >= mCurrentImage->h)
        {
            throw GCN_EXCEPTION("x and y out of image bound.");
        }
    
        SDLputPixel(mCurrentImage, x, y, color);    
    }
}
#endif