1/*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2021 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 */
36static int _CompareSurfaceCount = 0;
37
38/* Compare surfaces */
39int 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 int sampleErrorX = 0, sampleErrorY = 0, sampleDist = 0;
47 Uint8 R, G, B, A;
48 Uint8 Rd, Gd, Bd, Ad;
49 char imageFilename[128];
50 char referenceFilename[128];
51
52 /* Validate input surfaces */
53 if (surface == NULL || referenceSurface == NULL) {
54 return -1;
55 }
56
57 /* Make sure surface size is the same. */
58 if ((surface->w != referenceSurface->w) || (surface->h != referenceSurface->h)) {
59 return -2;
60 }
61
62 /* Sanitize input value */
63 if (allowable_error<0) {
64 allowable_error = 0;
65 }
66
67 SDL_LockSurface( surface );
68 SDL_LockSurface( referenceSurface );
69
70 ret = 0;
71 bpp = surface->format->BytesPerPixel;
72 bpp_reference = referenceSurface->format->BytesPerPixel;
73 /* Compare image - should be same format. */
74 for (j=0; j<surface->h; j++) {
75 for (i=0; i<surface->w; i++) {
76 p = (Uint8 *)surface->pixels + j * surface->pitch + i * bpp;
77 p_reference = (Uint8 *)referenceSurface->pixels + j * referenceSurface->pitch + i * bpp_reference;
78
79 SDL_GetRGBA(*(Uint32*)p, surface->format, &R, &G, &B, &A);
80 SDL_GetRGBA(*(Uint32*)p_reference, referenceSurface->format, &Rd, &Gd, &Bd, &Ad);
81
82 dist = 0;
83 dist += (R-Rd)*(R-Rd);
84 dist += (G-Gd)*(G-Gd);
85 dist += (B-Bd)*(B-Bd);
86
87 /* Allow some difference in blending accuracy */
88 if (dist > allowable_error) {
89 ret++;
90 if (ret == 1) {
91 sampleErrorX = i;
92 sampleErrorY = j;
93 sampleDist = dist;
94 }
95 }
96 }
97 }
98
99 SDL_UnlockSurface( surface );
100 SDL_UnlockSurface( referenceSurface );
101
102 /* Save test image and reference for analysis on failures */
103 _CompareSurfaceCount++;
104 if (ret != 0) {
105 SDLTest_LogError("Comparison of pixels with allowable error of %i failed %i times.", allowable_error, ret);
106 SDLTest_LogError("First detected occurrence at position %i,%i with a squared RGB-difference of %i.", sampleErrorX, sampleErrorY, sampleDist);
107 SDL_snprintf(imageFilename, 127, "CompareSurfaces%04d_TestOutput.bmp", _CompareSurfaceCount);
108 SDL_SaveBMP(surface, imageFilename);
109 SDL_snprintf(referenceFilename, 127, "CompareSurfaces%04d_Reference.bmp", _CompareSurfaceCount);
110 SDL_SaveBMP(referenceSurface, referenceFilename);
111 SDLTest_LogError("Surfaces from failed comparison saved as '%s' and '%s'", imageFilename, referenceFilename);
112 }
113
114 return ret;
115}
116
117/* vi: set ts=4 sw=4 expandtab: */
118