SDL/include/SDL3/SDL_test_compare.h

/*
  Simple DirectMedia Layer
  Copyright (C) 1997-2023 Sam Lantinga <[email protected]>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not
     claim that you wrote the original software. If you use this software
     in a product, an acknowledgment in the product documentation would be
     appreciated but is not required.
  2. Altered source versions must be plainly marked as such, and must not be
     misrepresented as being the original software.
  3. This notice may not be removed or altered from any source distribution.
*/

/**
 *  \file SDL_test_compare.h
 *
 *  Comparison function of SDL test framework.
 *
 *  This code is a part of the SDL test library, not the main SDL library.
 */

/*

 Defines comparison functions (i.e. for surfaces).

*/

#ifndef SDL_test_compare_h_
#define SDL_test_compare_h_

#include <SDL3/SDL.h>

#include <SDL3/SDL_begin_code.h>
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
extern "C" {
#endif

/**
 * Retrieves a single pixel from a surface.
 *
 * This function prioritizes correctness over speed: it is suitable for
 * unit tests, but is not intended for use in a game engine.
 *
 * Like SDL_GetRGBA, this uses the entire 0..255 range when converting
 * color components from pixel formats with less than 8 bits per RGB
 * component.
 *
 * \param surface The surface
 * \param x Horizontal coordinate, 0 <= x < width
 * \param y Vertical coordinate, 0 <= y < height
 * \param r Pointer to location to store red channel, 0-255
 * \param g Pointer to location to store green channel, 0-255
 * \param b Pointer to location to store blue channel, 0-255
 * \param a Pointer to location to store alpha channel, 0-255
 * \returns 0 if the surface is valid and the coordinates are in-bounds
 */
int SDLTest_ReadSurfacePixel(SDL_Surface *surface, int x, int y, Uint8 *r, Uint8 *g, Uint8 *b, Uint8 *a);

/**
 * Compares a surface and with reference image data for equality
 *
 * \param surface Surface used in comparison
 * \param referenceSurface Test Surface used in comparison
 * \param allowable_error Allowable difference (=sum of squared difference for each RGB component) in blending accuracy.
 *
 * \returns 0 if comparison succeeded, >0 (=number of pixels for which the comparison failed) if comparison failed, -1 if any of the surfaces were NULL, -2 if the surface sizes differ.
 */
int SDLTest_CompareSurfaces(SDL_Surface *surface, SDL_Surface *referenceSurface, int allowable_error);


/* Ends C function definitions when using C++ */
#ifdef __cplusplus
}
#endif
#include <SDL3/SDL_close_code.h>

#endif /* SDL_test_compare_h_ */