author Sam Lantinga <>
Wed, 30 Nov 2016 22:06:05 -0800
changeset 10668 1889c850fafc
parent 8874 48d4f2d74d67
child 11605 b914622c734e
permissions -rw-r--r--
Fixed bug 3340 - SDL_BlitScaled causes access violation in some cases.

Simon Hug

The SDL_BlitScaled function runs into an access violation for specific blit coordinates and surface sizes. The attached testcase blits a 800x600 surface to a 1280x720 surface at the coordinates -640,-345 scaled to 1280x720. The blit function that moves the data then runs over and reads after the pixel data from the src surface causing an access violation.

I can't say where exactly it goes wrong, but I think it could have something to do with the rounding in SDL_UpperBlitScaled. final_src.y is 288 and final_src.h is 313. Together that's 601, which I believe is one too much, but I just don't know the code enough to make sure that's the problem.


I think this patch fix the issue, but maybe it's worth re-writing "SDL_UpperBlitScaled" using SDL_FRect.
     1 if (NOT EXISTS "@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt")
     2     message(FATAL_ERROR "Cannot find install manifest: \"@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt\"")
     3 endif(NOT EXISTS "@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt")
     5 file(READ "@CMAKE_CURRENT_BINARY_DIR@/install_manifest.txt" files)
     6 string(REGEX REPLACE "\n" ";" files "${files}")
     7 foreach (file ${files})
     8     message(STATUS "Uninstalling \"$ENV{DESTDIR}${file}\"")
     9     execute_process(
    10         COMMAND @CMAKE_COMMAND@ -E remove "$ENV{DESTDIR}${file}"
    11         OUTPUT_VARIABLE rm_out
    12         RESULT_VARIABLE rm_retval
    13     )
    14     if(NOT ${rm_retval} EQUAL 0)
    15         message(FATAL_ERROR "Problem when removing \"$ENV{DESTDIR}${file}\"")
    16     endif (NOT ${rm_retval} EQUAL 0)
    17 endforeach(file)