Fixed bug #2426 - SDL_RenderReadPixels result is unspecified and fails testautomation

Call SDL_RenderPresent after calling SDL_RenderReadPixels.
From "include/SDL_render.h":
"If you're using this on the main rendering target, it should be called after rendering and before SDL_RenderPresent()."

test/testautomation_render.c

@@ -187,14 +187,14 @@ int render_testPrimitives (void *arg)
 
    ret = SDL_RenderDrawLine(renderer, 79, 59, 50, 30 );
    SDLTest_AssertCheck(ret == 0, "Validate result from SDL_RenderDrawLine, expected: 0, got: %i", ret);
-   
-   /* Make current */
-   SDL_RenderPresent(renderer);
-   
+
    /* See if it's the same. */
    referenceSurface = SDLTest_ImagePrimitives();
    _compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE );
 
+   /* Make current */
+   SDL_RenderPresent(renderer);
+
    /* Clean up. */
    SDL_FreeSurface(referenceSurface);
    referenceSurface = NULL;
@@ -335,13 +335,13 @@ int render_testPrimitivesBlend (void *arg)
    SDLTest_AssertCheck(checkFailCount2 == 0, "Validate results from calls to SDL_SetRenderDrawBlendMode, expected: 0, got: %i", checkFailCount2);
    SDLTest_AssertCheck(checkFailCount3 == 0, "Validate results from calls to SDL_RenderDrawPoint, expected: 0, got: %i", checkFailCount3);
 
-   /* Make current */
-   SDL_RenderPresent(renderer);
-
    /* See if it's the same. */
    referenceSurface = SDLTest_ImagePrimitivesBlend();
    _compare(referenceSurface, ALLOWABLE_ERROR_BLENDED );
 
+   /* Make current */
+   SDL_RenderPresent(renderer);
+
    /* Clean up. */
    SDL_FreeSurface(referenceSurface);
    referenceSurface = NULL;
@@ -404,13 +404,13 @@ render_testBlit(void *arg)
    }
    SDLTest_AssertCheck(checkFailCount1 == 0, "Validate results from calls to SDL_RenderCopy, expected: 0, got: %i", checkFailCount1);
 
-   /* Make current */
-   SDL_RenderPresent(renderer);
-
    /* See if it's the same */
    referenceSurface = SDLTest_ImageBlit();
    _compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE );
 
+   /* Make current */
+   SDL_RenderPresent(renderer);
+
    /* Clean up. */
    SDL_DestroyTexture( tface );
    SDL_FreeSurface(referenceSurface);
@@ -478,13 +478,13 @@ render_testBlitColor (void *arg)
    SDLTest_AssertCheck(checkFailCount1 == 0, "Validate results from calls to SDL_SetTextureColorMod, expected: 0, got: %i", checkFailCount1);
    SDLTest_AssertCheck(checkFailCount2 == 0, "Validate results from calls to SDL_RenderCopy, expected: 0, got: %i", checkFailCount2);
 
-   /* Make current */
-   SDL_RenderPresent(renderer);
-
    /* See if it's the same. */
    referenceSurface = SDLTest_ImageBlitColor();
    _compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE );
 
+   /* Make current */
+   SDL_RenderPresent(renderer);
+
    /* Clean up. */
    SDL_DestroyTexture( tface );
    SDL_FreeSurface(referenceSurface);
@@ -555,13 +555,13 @@ render_testBlitAlpha (void *arg)
    SDLTest_AssertCheck(checkFailCount1 == 0, "Validate results from calls to SDL_SetTextureAlphaMod, expected: 0, got: %i", checkFailCount1);
    SDLTest_AssertCheck(checkFailCount2 == 0, "Validate results from calls to SDL_RenderCopy, expected: 0, got: %i", checkFailCount2);
 
-   /* Make current */
-   SDL_RenderPresent(renderer);
-
    /* See if it's the same. */
    referenceSurface = SDLTest_ImageBlitAlpha();
    _compare(referenceSurface, ALLOWABLE_ERROR_BLENDED );
 
+   /* Make current */
+   SDL_RenderPresent(renderer);
+
    /* Clean up. */
    SDL_DestroyTexture( tface );
    SDL_FreeSurface(referenceSurface);
@@ -674,9 +674,10 @@ render_testBlitBlend (void *arg)
    _testBlitBlendMode( tface, SDL_BLENDMODE_NONE );
    referenceSurface = SDLTest_ImageBlitBlendNone();
 
-   /* Make current and compare */
-   SDL_RenderPresent(renderer);
+   /* Compare, then Present */
    _compare(referenceSurface, ALLOWABLE_ERROR_OPAQUE );
+   SDL_RenderPresent(renderer);
+
    SDL_FreeSurface(referenceSurface);
    referenceSurface = NULL;
 
@@ -684,9 +685,10 @@ render_testBlitBlend (void *arg)
    _testBlitBlendMode( tface, SDL_BLENDMODE_BLEND );
    referenceSurface = SDLTest_ImageBlitBlend();
 
-   /* Make current and compare */
-   SDL_RenderPresent(renderer);
+   /* Compare, then Present */
    _compare(referenceSurface, ALLOWABLE_ERROR_BLENDED );
+   SDL_RenderPresent(renderer);
+
    SDL_FreeSurface(referenceSurface);
    referenceSurface = NULL;
 
@@ -694,9 +696,10 @@ render_testBlitBlend (void *arg)
    _testBlitBlendMode( tface, SDL_BLENDMODE_ADD );
    referenceSurface = SDLTest_ImageBlitBlendAdd();
 
-   /* Make current and compare */
-   SDL_RenderPresent(renderer);
+   /* Compare, then Present */
    _compare(referenceSurface, ALLOWABLE_ERROR_BLENDED );
+   SDL_RenderPresent(renderer);
+
    SDL_FreeSurface(referenceSurface);
    referenceSurface = NULL;
 
@@ -704,9 +707,10 @@ render_testBlitBlend (void *arg)
    _testBlitBlendMode( tface, SDL_BLENDMODE_MOD);
    referenceSurface = SDLTest_ImageBlitBlendMod();
 
-   /* Make current and compare */
-   SDL_RenderPresent(renderer);
+   /* Compare, then Present */
    _compare(referenceSurface, ALLOWABLE_ERROR_BLENDED );
+   SDL_RenderPresent(renderer);
+
    SDL_FreeSurface(referenceSurface);
    referenceSurface = NULL;
 
@@ -753,12 +757,13 @@ render_testBlitBlend (void *arg)
    /* Clean up. */
    SDL_DestroyTexture( tface );
 
-   /* Make current */
-   SDL_RenderPresent(renderer);
-
    /* Check to see if final image matches. */
    referenceSurface = SDLTest_ImageBlitBlendAll();
    _compare(referenceSurface, ALLOWABLE_ERROR_BLENDED);
+
+   /* Make current */
+   SDL_RenderPresent(renderer);
+
    SDL_FreeSurface(referenceSurface);
    referenceSurface = NULL;