bastien.bouclet
When creating two surfaces and blitting them onto the other, SDL's internal reference counting fails, and one of the surfaces is not freed when calling SDL_FreeSurface.
Example code :
SDL_Surface *s1 = SDL_CreateRGBSurfaceWithFormat(0, 640, 480, 32, SDL_PIXELFORMAT_ARGB8888);
SDL_Surface *s2 = SDL_CreateRGBSurfaceWithFormat(0, 640, 480, 32, SDL_PIXELFORMAT_ARGB8888);
SDL_BlitSurface(s1, NULL, s2, NULL);
SDL_BlitSurface(s2, NULL, s1, NULL);
SDL_FreeSurface(s2);
SDL_FreeSurface(s1);
With this example, s1 is not freed after calling SDL_FreeSurface, its refcount attribute is still positive.
Rainer Deyke
I've written a small patch that adds a small SDL_DuplicateSurface function to SDL. I've written the function as part of a larger (as yet unfinished) patch, but I think this function is useful enough that it merits inclusion in SDL on its own.
Edmund Horner
When a 16-bit "565 format" surface has a colour key set, it will blit with correct transparency. If, however, it has its colour key set then is converted to a 32-bit ARGB format surface, the colour key in the converted image will not necessarily be the same pixel value as the transparent pixels. It may not blit correctly, because the colour key does not match the right pixels.
In my case, with an image using 0xB54A for transparency, the colour key was converted to 180,170,82; but the corresponding pixels (with the same original value) were converted to 180,169,82. Blitting the converted image did not use transparency where expected.
I have attached a test case. The bug has been replicated on both x86_64 Linux (SDL 2.0.2), and 32-bit MS C++ 2010 on Windows (SDL 2.0.0).
Sylvain
Let's you have a SDL_Surface that has ColorKey, but no Alpha Modulation.
When this surface is duplicated with SDL_ConvertSurface function, the result has ColorKey and Alpha Modulation (BLEND, and Opaque 255).
I think SDL_ConvertSurface should strictly keeps the input format.
example
=======
SDL_Surface *input; // ... Set up a surface with ColorKey and no AlphaMod
SDL_Surface *output = SDL_ConvertSurface(input, input->format, input->flags);
// "output" surface has a ColorKey but *also* AlphaMod (BLEND, and Opaque 255).
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.
Sylvain
I think this patch fix the issue, but maybe it's worth re-writing "SDL_UpperBlitScaled" using SDL_FRect.
Daniel Gibson
Currently, SDL_CreateRGBSurface() and SDL_CreateRGBSurfaceFrom() take Uint32 masks for RGBA to "describe" the Pixelformat of the surface.
Internally those value are only used to map to one of the SDL_PIXELFORMAT_* enum values that are used for further processing.
I think it would be both handy and more efficient to be able to specify SDL_PIXELFORMAT_* yourself without using SDL_PixelFormatEnumToMasks() to create masks first, so I implemented functions that do that:
SDL_CreateRGBSurfaceWithFormat() and SDL_CreateRGBSurfaceWithFormatFrom() which are like the versions without "WithFormat" but instead of taking 4 Uint32s for R/G/B/A masks, they take one for a SDL_PIXELFORMAT_* enum value.
Together with https://bugzilla.libsdl.org/show_bug.cgi?id=2923 creating a SDL_Surface* from RGBA data (e.g. from stb_image) is as easy as
surf = SDL_SDL_CreateRGBSurfaceWithFormat(0, w, h, bppToUse*8, SDL_PIXELFORMAT_RGBA32);
Patch from Benoit Pierre:
video: fix clipping handling in SDL_UpperBlitScaled
- honor destination clipping rectangle
- update both destination and source rectangles when clipping source
rectangle to source surface and destination rectangle to destination
clip rectangle
- don't change scaling factors when clipping
N.B.:
- when no scaling is involved (source and destination width/height are
the same), SDL_UpperBlit is used (so SDL_BlitScaled behaves like
SDL_BlitSurface)
- the final destination rectangle after all clipping is performed is
saved back to dstrect (like for SDL_UpperBlit)
Wei Mingzhi
surface->map should be invalidated in SDL_SetSurfacePalette(), otherwise the palette would not be effective when blitting to another non-8bit surface which we previously blitted to.
Andreas Ertelt
The problem in question is caused by changeset 7771 (http://hg.libsdl.org/SDL/rev/4434498bf4b9 / https://bugzilla.libsdl.org/show_bug.cgi?id=2121)
The redefinition of __inline__ (introduced by the addition of begin_code.h:128's "|| __STRICT_ANSI__") results in mingw's gcc throwing multiple
warning: always_inline function might not be inlinable [-Wattributes]
as well as a whole bunch of redefinitions of mingw internals which break linking of projects including the SDL2 headers.
To fix this we need to ignore the alpha channel in the colorkey comparison, which is the way colorkey comparisons are defined in SDL.
We also need to reset the alpha and color modulation when converting a surface.
Sylvain
1/ Load an Image XPM with IMG_ReadXPMFromArray()
2/ Try to set a ColorKey on it.
I notice that :
- the SDL_Surface that is created from XPM has a palette !
- the colorkey is a RBG.
it crashes (SIGSEGV) inside the SDL_SetColorKey function:
"surface->format->palette->colors[surface->map->info.colorkey].a"
This lets us change things like this...
if (Failed) {
SDL_SetError("We failed");
return -1;
}
...into this...
if (Failed) {
return SDL_SetError("We failed");
}
Fixes Bugzilla #1778.
bastien.bouclet@gmail.com 2011-06-12 11:08:58 PDT
SDL_LowerBlit doesn't update the blit color map if the source surface has
changed.
A proposed fix is attached, storing the source palette version in the color
map.
Frank Zago to SDL
I've cleaned up a few bugs in the nds code. A few more tests now pass.
There's still a few things to do, but overall I think it's starting to be in a
good shape.
The patch also includes a bug fix for SDL_ConvertSurfaceFormat() (gcc warning).
The bitmap ordering is defined such that the numbering refers to the pixel index from left to right, and the number position refers to the bit position in the byte.
SDL_BITMAPORDER_4321 is the fourth pixel at the high bit and the first pixel at the low bit (LSBFirst)
SDL_BITMAPORDER_1234 is the first pixel at the high bit and the fourth pixel at the low bit (MSBFirst)
