Jianyu Guan
I found I make a big mistake that when dstA==0, I just simply let *dstp=*srcp and forgot to make dstRGB = srcRGB*srcA.
The if consition "(*dstp & amask) == 0" in BlitRGBtoRGBPixelAlphaMMX and BlitRGBtoRGBPixelAlphaMMX3dNow should be removed.
I see the Remarks of function SDL_BlitSurface shows that "when SDL_BLENDMODE_BLEND, we have dstA = srcA + (dstA * (1-srcA))". however, I tested some pictures but the result implies "dstA=arcA" actually. I stepped into the source code, and found after I set SDL_BLENDMODE_BLEND for the source surface, the final blit function is BlitRGBtoRGBPixelAlphaMMX when I use SDL_BlitSurface on my computer. And I found these codes:
else if (alpha == amask) {
/* opaque alpha -- copy RGB, keep dst alpha */
*dstp = (*srcp & chanmask) | (*dstp & ~chanmask);
The same code is used in BlitRGBtoRGBPixelAlphaMMX3DNOW and BlitRGBtoRGBPixelAlpha. So I think they still keep dst alpha.
Best regards,
Jianyu Guan
If the app is in landscape mode and the user presses the power button, a pause
is followed immediately by a surfaceChanged event because the lock screen
is shown in portrait mode. This triggers a "false" resume.
So, we just pause and resume following the onWindowFocusChanged events.
Also, wait for SDL_APP_WILLENTERBACKGROUND and SDL_APP_DIDENTERBACKGROUND before
blocking the event pump.
Otherwise, you can pause audio and still have the callback running, or run
one more time. This makes sure the callback is definitely stopped by the
time you return from SDL_PauseAudio().
norfanin
There are a few potential buffer overflows in the Windows IME code located in the SDL_windowskeyboard.c file. [1] They mainly happen because the code passes the number of bytes instead of the number of characters to the wide-character string functions wcslcpy and wcslcat. In another place, the code assumes that the composition cursor position can never go beyond the size of the composition string buffer.
Some of these overflows and overruns can occur with the Japanese IME on Vista and simplified Chinese IME on XP. I don't actually speak those languages and it's my first time using the IMEs, so I probably pushed them to the limit where nobody would still be compositing proper words. They don't cause any immediate access violation, although the possibility of trashing the SDL_VideoData structure is never good.
I've attached a patch that fixes those I found, but because I'm very new to the code it may be worthwhile if someone else also has a look over the code.
I'll go over the changes in my patch and explain what, why and how.
In the function IME_GetReadingString, there is a wcslcpy to copy the reading string from the IMC memory to the SDL reading string buffer. [2] This assumes that the length of the reading string never exceeds the SDL buffer size. I guess that is possible and I wasn't able to get a long reading string in my tests, but the patch adds a simple check anyway.
In the function IME_GetCompositionString, the first line calls ImmGetCompositionStringW to get the composition string. [3] The Microsoft documentation states that the fourth argument is for the destination buffer size in bytes (even with unicode) and the code correctly passes the value of sizeof. However, at the end of IME_GetCompositionString, the string is terminated by setting the element at index 'length' to 0. 'length' is calculated by dividing the number of bytes (those written by ImmGetCompositionStringW) by 2. If it managed to write 64 bytes, the code sets element 32 to 0, which would be the beginning of the reading string if the alignment places it there. My patch adds a subtraction to the fourth argument, essentially making it always pass 62 instead.
In the same function, the code assumes that the composition cursor position doesn't go beyond the buffer size. [4] My patch adds a simple range check in front of the indirection.
In the function IME_SendEditingEvent, the size for the wide-character string functions is passed in bytes instead of characters. [5] Oddly, the current code subtracts 'len' from the size in one function call. This results in truncation in certain situations as the third argument is the number of characters available in the destination buffer. If I'm understanding it correctly, this is supposed to copy x characters of the composition buffer, then concatenate the whole reading string buffer, and then the rest of the composition buffer (where x is the composition cursor position). I don't see how a truncation of the rest would be helpful here. Perhaps this is just an error? My patch removes the subtraction.
In the function UIElementSink_UpdateUIElement, bytes instead of characters is used again for a wcslcpy call. [6]
PoopiSan
GLES2_RenderReadPixels, GLES_RenderReadPixels, GL_RenderReadPixels and possibly other backends is incorrectly implemented.
If the current target viewport is different than window size the function is reading garbage and according to the function documentation should work with any rendering target "Read pixels from the current rendering target.".
this seems to be caused by this line:
...
SDL_GetWindowSize(window, &w, &h);
The hack appeared to work in the Windows Simulator, but not on real hardware, and
notably not on a Surface RT. Room may exist for a different, and more thorough hack.
