1.1 --- a/src/test/SDL_test_compare.c	Mon Dec 24 14:43:57 2012 -0800
     1.2 +++ b/src/test/SDL_test_compare.c	Wed Dec 26 22:26:44 2012 -0800
     1.3 @@ -32,7 +32,11 @@
     1.4  #include "SDL_test.h"
     1.5  
     1.6  
     1.7 -int SDLTest_CompareSurfaces( SDL_Surface *surface, SDL_Surface *referenceSurface, int allowable_error )
     1.8 +/* Counter for _CompareSurface calls; used for filename creation when comparisons fail */
     1.9 +static int _CompareSurfaceCount = 0;
    1.10 +
    1.11 +/* Compare surfaces */
    1.12 +int SDLTest_CompareSurfaces(SDL_Surface *surface, SDL_Surface *referenceSurface, int allowable_error)
    1.13  {
    1.14     int ret;
    1.15     int i,j;
    1.16 @@ -41,18 +45,20 @@
    1.17     int dist;
    1.18     Uint8 R, G, B, A;
    1.19     Uint8 Rd, Gd, Bd, Ad;
    1.20 +   char imageFilename[128];
    1.21 +   char referenceFilename[128];
    1.22  
    1.23     /* Validate input surfaces */
    1.24     if (surface == NULL || referenceSurface == NULL) {
    1.25        return -1;
    1.26     }
    1.27  
    1.28 -   /* Make surface size is the same. */
    1.29 +   /* Make sure surface size is the same. */
    1.30     if ((surface->w != referenceSurface->w) || (surface->h != referenceSurface->h)) {
    1.31        return -2;
    1.32     }
    1.33  
    1.34 -   /* Sanitize input */
    1.35 +   /* Sanitize input value */
    1.36     if (allowable_error<0) {
    1.37        allowable_error = 0;
    1.38     }
    1.39 @@ -87,5 +93,15 @@
    1.40     SDL_UnlockSurface( surface );
    1.41     SDL_UnlockSurface( referenceSurface );
    1.42  
    1.43 +   /* Save test image and reference for analysis on failures */
    1.44 +   _CompareSurfaceCount++;
    1.45 +   if (ret != 0) {
    1.46 +      SDL_snprintf(imageFilename, 127, "CompareSurfaces%04d_TestOutput.bmp", _CompareSurfaceCount);
    1.47 +      SDL_SaveBMP(surface, imageFilename);
    1.48 +      SDL_snprintf(referenceFilename, 127, "CompareSurfaces%04d_Reference.bmp", _CompareSurfaceCount);
    1.49 +      SDL_SaveBMP(referenceSurface, referenceFilename);
    1.50 +      SDLTest_LogError("Surfaces from failed comparison saved as '%s' and '%s'", imageFilename, referenceFilename);
    1.51 +   }
    1.52 +
    1.53     return ret;
    1.54  }