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| #include <stdlib.h>
#include <SDL.h>
Uint32 GetPixel(SDL_Surface *screen, int x, int y)
{
return *(Uint32 *) ((Uint8 *)screen->pixels + y * screen->pitch + x * screen->format->BytesPerPixel);
}
void SetPixel(SDL_Surface *screen, int x, int y, Uint32 pixel)
{
*(Uint32 *) ((Uint8 *)screen->pixels + y * screen->pitch + x * screen->format->BytesPerPixel) = pixel;
}
int main ( int argc, char** argv )
{
SDL_Surface *layer1 = NULL, *layer2 = NULL, *result;
unsigned i, j;
Uint32 pix1, pix2;
Uint8 r1, r2, g1, g2, b1, b2;
initialise SDL video */
if ( SDL_Init( SDL_INIT_VIDEO ) < 0 )
{
fprintf( stderr, "Unable to init SDL: %s\n", SDL_GetError() );
return 1;
}
layer1 = SDL_LoadBMP("layer1.bmp"); // CT
layer2 = SDL_LoadBMP("layer2.bmp"); // PET
if (layer1 && layer2)
{
result = SDL_CreateRGBSurface(SDL_SWSURFACE, layer1->w, layer1->h, 32, 0, 0, 0, 0);
for (i=0; i<layer1->w; i++)
for (j=0; j<layer1->h; j++)
{
pix1 = GetPixel(layer1, i, j);
pix2 = GetPixel(layer2, i, j);
SDL_GetRGB(pix1, layer1->format, &r1, &g1, &b1);
SDL_GetRGB(pix2, layer2->format, &r2, &g2, &b2);
SetPixel(result, i, j, SDL_MapRGB( result->format, (r1*2+r2)/3, (g1+g2)/2, (b1+b2*2)/3 ));
}
SDL_SaveBMP(result, "result.bmp");
}
SDL_Quit();
return 0;
} |
