src/test/SDL_test_compare.c
author Sam Lantinga <slouken@libsdl.org>
Wed, 04 Jun 2014 10:56:56 -0700
changeset 8820 0e935d5b193a
parent 8149 681eb46b8ac4
child 9254 6c469ea796e4
permissions -rw-r--r--
Added annotations to help code analysis tools

CR: Bruce Dawson
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 
    22 /*
    23 
    24  Based on automated SDL_Surface tests originally written by Edgar Simo 'bobbens'.
    25 
    26  Rewritten for test lib by Andreas Schiffler.
    27 
    28 */
    29 
    30 #include "SDL_config.h"
    31 
    32 #include "SDL_test.h"
    33 
    34 
    35 /* Counter for _CompareSurface calls; used for filename creation when comparisons fail */
    36 static int _CompareSurfaceCount = 0;
    37 
    38 /* Compare surfaces */
    39 int SDLTest_CompareSurfaces(SDL_Surface *surface, SDL_Surface *referenceSurface, int allowable_error)
    40 {
    41    int ret;
    42    int i,j;
    43    int bpp, bpp_reference;
    44    Uint8 *p, *p_reference;
    45    int dist;
    46    Uint8 R, G, B, A;
    47    Uint8 Rd, Gd, Bd, Ad;
    48    char imageFilename[128];
    49    char referenceFilename[128];
    50 
    51    /* Validate input surfaces */
    52    if (surface == NULL || referenceSurface == NULL) {
    53       return -1;
    54    }
    55 
    56    /* Make sure surface size is the same. */
    57    if ((surface->w != referenceSurface->w) || (surface->h != referenceSurface->h)) {
    58       return -2;
    59    }
    60 
    61    /* Sanitize input value */
    62    if (allowable_error<0) {
    63       allowable_error = 0;
    64    }
    65 
    66    SDL_LockSurface( surface );
    67    SDL_LockSurface( referenceSurface );
    68 
    69    ret = 0;
    70    bpp = surface->format->BytesPerPixel;
    71    bpp_reference = referenceSurface->format->BytesPerPixel;
    72    /* Compare image - should be same format. */
    73    for (j=0; j<surface->h; j++) {
    74       for (i=0; i<surface->w; i++) {
    75          p  = (Uint8 *)surface->pixels + j * surface->pitch + i * bpp;
    76          p_reference = (Uint8 *)referenceSurface->pixels + j * referenceSurface->pitch + i * bpp_reference;
    77 
    78          SDL_GetRGBA(*(Uint32*)p, surface->format, &R, &G, &B, &A);
    79          SDL_GetRGBA(*(Uint32*)p_reference, referenceSurface->format, &Rd, &Gd, &Bd, &Ad);
    80 
    81          dist = 0;
    82          dist += (R-Rd)*(R-Rd);
    83          dist += (G-Gd)*(G-Gd);
    84          dist += (B-Bd)*(B-Bd);
    85 
    86          /* Allow some difference in blending accuracy */
    87          if (dist > allowable_error) {
    88             ret++;
    89          }
    90       }
    91    }
    92 
    93    SDL_UnlockSurface( surface );
    94    SDL_UnlockSurface( referenceSurface );
    95 
    96    /* Save test image and reference for analysis on failures */
    97    _CompareSurfaceCount++;
    98    if (ret != 0) {
    99       SDL_snprintf(imageFilename, 127, "CompareSurfaces%04d_TestOutput.bmp", _CompareSurfaceCount);
   100       SDL_SaveBMP(surface, imageFilename);
   101       SDL_snprintf(referenceFilename, 127, "CompareSurfaces%04d_Reference.bmp", _CompareSurfaceCount);
   102       SDL_SaveBMP(referenceSurface, referenceFilename);
   103       SDLTest_LogError("Surfaces from failed comparison saved as '%s' and '%s'", imageFilename, referenceFilename);
   104    }
   105 
   106    return ret;
   107 }