Bos Wars: sdlpixel.h Source File

00001 /*      _______   __   __   __   ______   __   __   _______   __   __                 
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00008  *
00009  * Copyright (c) 2004, 2005 darkbits                        Js_./
00010  * Per Larsson a.k.a finalman                          _RqZ{a<^_aa
00011  * Olof Naessén a.k.a jansem/yakslem                _asww7!uY`>  )\a//
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00053  */
00054 
00055 #ifndef GCN_SDLPIXEL_HPP
00056 #define GCN_SDLPIXEL_HPP
00057 
00058 #include "SDL.h"
00059 
00060 #include "guichan/color.h"
00061 
00062 namespace gcn
00063 {
00064 
00073     inline const Color SDLgetPixel(SDL_Surface* surface, int x, int y)
00074     {
00075         int bpp = surface->format->BytesPerPixel;
00076 
00077         SDL_LockSurface(surface);
00078 
00079         Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;
00080     
00081         unsigned int color = 0;
00082     
00083         switch(bpp)
00084         {
00085           case 1:
00086               color = *p;
00087               break;
00088         
00089           case 2:
00090               color = *(Uint16 *)p;
00091               break;
00092         
00093           case 3:
00094               if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
00095               {
00096                   color = p[0] << 16 | p[1] << 8 | p[2];
00097               }
00098               else
00099               {
00100                   color = p[0] | p[1] << 8 | p[2] << 16;
00101               }
00102               break;
00103         
00104           case 4:
00105               color = *(Uint32 *)p;
00106               break;
00107         
00108         }
00109 
00110         Uint8 r,g,b,a;
00111     
00112         SDL_GetRGBA(color, surface->format, &r, &g, &b, &a);
00113         SDL_UnlockSurface(surface);
00114 
00115         return Color(r,g,b,a);
00116     }
00117 
00126     inline void SDLputPixel(SDL_Surface* surface, int x, int y, const Color& color)
00127     {
00128         int bpp = surface->format->BytesPerPixel;
00129         
00130         SDL_LockSurface(surface);
00131 
00132         Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;
00133     
00134         Uint32 pixel = SDL_MapRGB(surface->format, color.r, color.g, color.b);
00135 
00136         switch(bpp)
00137         {
00138           case 1:
00139               *p = pixel;
00140               break;
00141         
00142           case 2:
00143               *(Uint16 *)p = pixel;
00144               break;
00145         
00146           case 3:
00147               if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
00148               {
00149                   p[0] = (pixel >> 16) & 0xff;
00150                   p[1] = (pixel >> 8) & 0xff;
00151                   p[2] = pixel & 0xff;
00152               }
00153               else
00154               {
00155                   p[0] = pixel & 0xff;
00156                   p[1] = (pixel >> 8) & 0xff;
00157                   p[2] = (pixel >> 16) & 0xff;
00158               }
00159               break;
00160         
00161           case 4:
00162               *(Uint32 *)p = pixel;
00163               break;
00164         }
00165     
00166         SDL_UnlockSurface(surface);
00167     }
00168 
00176     inline unsigned int SDLAlpha16(unsigned int src, unsigned int dst, unsigned char a)
00177     {
00178         // Loses precision for speed
00179         a = (255 - a) >> 3;
00180 
00181         src = (((src << 16) | src) & 0x07E0F81F);
00182         dst = ((dst << 16) | dst) & 0x07E0F81F;
00183         dst = ((((dst - src) * a) >> 5) + src) & 0x07E0F81F;
00184         return (dst >> 16) | dst;
00185     }
00186     
00194     inline unsigned int SDLAlpha32(unsigned int src, unsigned int dst, unsigned char a)
00195     {
00196         a = 255 - a;
00197 
00198         unsigned int src2 = (src & 0xFF00FF00) >> 8;
00199         src &= 0x00FF00FF;
00200 
00201         unsigned int dst2 = (dst & 0xFF00FF00) >> 8;
00202         dst &= 0x00FF00FF;
00203 
00204         dst = ((((dst - src) * a) >> 8) + src) & 0x00FF00FF;
00205         dst2 = ((((dst2 - src2) * a) >> 8) + src2) & 0x00FF00FF;
00206         return dst | (dst2 << 8);
00207     }
00208     
00217     inline void SDLputPixelAlpha(SDL_Surface* surface, int x, int y, const Color& color)
00218     {
00219         int bpp = surface->format->BytesPerPixel;
00220         
00221         SDL_LockSurface(surface);
00222 
00223         Uint8 *p = (Uint8 *)surface->pixels + y * surface->pitch + x * bpp;
00224     
00225         Uint32 pixel = SDL_MapRGB(surface->format, color.r, color.g, color.b);
00226 
00227         switch(bpp)
00228         {
00229           case 1:
00230               *p = pixel;
00231               break;
00232         
00233           case 2:
00234               *(Uint16 *)p = SDLAlpha16(pixel, *(Uint16 *)p, color.a);
00235               break;
00236         
00237           case 3:
00238               if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
00239               {
00240                   p[0] = (pixel >> 16) & 0xff;
00241                   p[1] = (pixel >> 8) & 0xff;
00242                   p[2] = pixel & 0xff;
00243               }
00244               else
00245               {
00246                   p[0] = pixel & 0xff;
00247                   p[1] = (pixel >> 8) & 0xff;
00248                   p[2] = (pixel >> 16) & 0xff;
00249               }
00250               break;
00251         
00252           case 4:
00253               *(Uint32 *)p = SDLAlpha32(pixel, *(Uint32 *)p, color.a);
00254               break;
00255         }
00256     
00257         SDL_UnlockSurface(surface);
00258     }
00259 }
00260 
00261 #endif // end GCN_SDLPIXEL_HPP