src/render/software/SDL_rotate.c


Log

Author Commit Date CI Message
Sam Lantinga 0d24495b 2016-11-15T01:24:58 Removed unused constants Except for SDL_bmp.c where they are historically interesting and I've left them in.
Sam Lantinga ab8bd3d9 2016-11-15T01:12:27 Fixed bug 3359 - Software renderer does incorrect blending with SDL_RenderCopyEx Simon Hug The software renderer produces incorrect results when blending textures at an angle with certain blend modes. It seems that there were some edge cases that weren't considered when the SW_RenderCopyEx function was last changed. Or another bug possibly covered up the problem. (More on that in another bug report.) Most of the issues come from the fact that the rotating function sets a black colorkey. This is problematic because black is most likely appearing in the surface and the final blit will ignore these pixels. Unless a colorkey is already set (the software renderer currently never sets one), it's very hard to find a free color. Of course it could scan over the whole image until one is found, but that seems inefficient. The following blend modes have issues when drawn at an angle. NONE: The black pixels get ignored, making them essentially transparent. This breaks the 'dstRGBA = srcRGBA' definition of the NONE blend mode. MOD: Again, the black pixels get ignored. This also breaks the 'dstRGB = dstRGB * srcRGB' definition of the MOD blend mode, where black pixels would make the destination black as well. A white colorkey will work though, with some preparations. BLEND: There are some issues when blending a texture with a translucent RGBA target texture. I - uh - forgot what the problem here exactly is. This patch fixes the issues mentioned above. It mainly changes the code so it tries to do things without the colorkey and removes the automatic format conversion part from the SDLgfx_rotateSurface function. Getting the format right is something the caller has to do now and the required code has been added to the SW_RenderCopyEx function. There's a small change to the SW_CreateTexture function. RLE encoding a surface with an alpha mask can be a lossy process. Depending on how the user uses the RGBA channels, this may be undesired. The change that surfaces with an alpha mask don't get encoded makes the software renderer consistent with the other renderers. The SW_RenderCopyEx function now does these steps: Lock the source surface if necessary. Create a clone of the source by using the pixel buffer directly. Check the format and set a flag if a conversion is necessary. Check if scaling or cropping is necessary and set the flag for that as well. Check if color and alpha modulation has to be done before the rotate. Check if the source is an opaque surface. If not, it creates a mask surface that is necessary for the NONE blend mode. If any of the flags were set, a new surface is created and the source will be converted, scaled, cropped, and modulated. The rest of the function stays somewhat the same. The mask also needs to be rotated of course and then there is the NONE blend mode... It's surprisingly hard to get the pixel from a rotated surface to the destination buffer without affecting the pixel outside the rotated area. I found a way to do this with three blits which is pretty hard on the performance. Perhaps someone has an idea how to do this faster? As mentioned above, the SDLgfx_rotateSurface now only takes 8-bit paletted or 32-bit with alpha mask surfaces. It additionally sets the new surfaces up for the MOD blend mode. I shortly tested the 8-bit path of SDLgfx_rotateSurface and it seemed to work so far. This path is not used by the software renderer anyway.
Sam Lantinga 57d01d7d 2016-11-13T22:57:41 Patch from Sylvain to fix clang warnings
Sam Lantinga 77000ff8 2016-11-11T13:38:39 Fixed bug 1822 - Inconsistent renderer behaviour on rotation Sylvain 2016-11-07 08:49:34 UTC when rotated +90 or -90, some transparent lines appears, though there is no Alpha or ColorKey. if you set a dummy colorkey, it will remove the line ... if you set a some alpha mod, the +90/-90 get transparent but not the 0/180 ...
Sam Lantinga 36e40d30 2016-10-11T23:19:05 Fixed bug 2923 - Add SDL_PIXELFORMAT_RGBA32 for byte-wise 32bit RGBA data Daniel Gibson Ok, I followed the simple approach of just making SDL_PIXELFORMAT_RGBA32 an alias of SDL_PIXELFORMAT_RGBA8888/SDL_PIXELFORMAT_ABGR8888, depending on endianess. And I did the same for SDL_PIXELFORMAT_ARGB32, .._BGRA, .._ABGR. SDL_GetPixelFormatName() will of course return SDL_PIXELFORMAT_RGBA8888 (or SDL_PIXELFORMAT_ABGR8888) instead of SDL_PIXELFORMAT_RGBA32, but as long as that's mentioned in the docs it shouldn't be a problem.
Sam Lantinga 9c483655 2016-10-07T18:00:30 Fixed bug 3029 - software renderer cuts off edges when rotate-blitting with a multiple of 90 degrees Adam M. When doing a rotated texture copy with the software renderer, where the angle is a multiple of 90 degrees, one or two edges of the image get cut off. This is because of the following line in sw_rotate.c: if ((unsigned)dx < (unsigned)sw && (unsigned)dy < (unsigned)sh) { which is effectively saying: if (dx >= 0 && dx < src->w-1 && dy >= 0 && dy < src->h-1) { As a result, it doesn't process pixels in the right column or bottom row of the source image (except when they're accessed as part of the bilinear filtering for nearby pixels). This causes it to look like the edges are cut off, and it's especially obvious with an exact multiple of 90 degrees.
Sam Lantinga bf076c22 2016-10-07T17:30:21 Fixed bug 2957 - De-reference rz_src without NULL check in SDLgfx_rotateSurface function Nitz In function SDLgfx_rotateSurface: rz_dst = SDL_CreateRGBSurface(SDL_SWSURFACE, dstwidth, dstheight + GUARD_ROWS, rz_src->format->Rmask, rz_src->format->Gmask, rz_src->format->Bmask, rz_src->format->Amask); Here rz_src get De-referenced without NULL check, which is risky.
Sam Lantinga 86d4b099 2016-09-13T18:44:28 Fixed spacing
Alex Szpakowski f0505766 2016-09-13T22:18:06 Initial Apple TV / tvOS support. The Apple TV remote is currently exposed as a joystick with its touch surface treated as two axes. Key presses are also generated when its buttons and touch surface are used. A new hint has been added to help deal with deciding whether to background the app when the remote's menu button is pressed: SDL_HINT_APPLE_TV_CONTROLLER_UI_EVENTS.
Ryan C. Gordon ded3a16e 2015-06-23T01:44:44 Fixed compiler warning about shadowed local variables.
Philipp Wiesemann 0e45984f 2015-06-21T17:33:46 Fixed crash if initialization of EGL failed but was tried again later. The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly uninitialized data structure if loading the library first failed. A later try to use EGL then skipped initialization and assumed it was previously successful because the data structure now already existed. This led to at least one crash in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was dereferenced to make a call to eglBindAPI().