Mercurial > sdl-ios-xcode
view src/video/x11/SDL_x11dyn.h @ 3333:b334b4f7dfa0
[SDL] Bad math in SDL_RenderCopy
Mason Wheeler to sdl
When I tried to render an image using something other than NULL for srcrect, it got horribly distorted. I traced it down to the fact that the math in the rectangle adjustments performed just before the call to renderer->RenderCopy is written inside out. It should look like this:
if (dstrect->w != real_dstrect.w) {
int deltax = (dstrect->x - real_dstrect.x);
int deltaw = (dstrect->w - real_dstrect.w);
real_srcrect.x += (deltax * real_srcrect.w) / dstrect->w;
real_srcrect.w += (deltaw * real_srcrect.w) / dstrect->w;
}
if (dstrect->h != real_dstrect.h) {
int deltay = (dstrect->y - real_dstrect.y);
int deltah = (dstrect->h - real_dstrect.h);
real_srcrect.y += (deltay * real_srcrect.h) / dstrect->h;
real_srcrect.h += (deltah * real_srcrect.h) / dstrect->h;
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sat, 03 Oct 2009 16:23:16 +0000 |
parents | 99210400e8b9 |
children | 81dde1b00bf1 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2009 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Library General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Library General Public License for more details. You should have received a copy of the GNU Library General Public License along with this library; if not, write to the Free Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA Sam Lantinga slouken@libsdl.org */ #include "SDL_config.h" #ifndef _SDL_x11dyn_h #define _SDL_x11dyn_h #include <X11/Xlib.h> #include <X11/Xutil.h> #include <X11/Xatom.h> #include <X11/Xlibint.h> #include <X11/Xproto.h> #include "../Xext/extensions/Xext.h" #include "../Xext/extensions/extutil.h" #ifndef NO_SHARED_MEMORY #include <sys/ipc.h> #include <sys/shm.h> #include <X11/extensions/XShm.h> #endif #if SDL_VIDEO_DRIVER_X11_XRANDR #include <X11/extensions/Xrandr.h> #endif #if SDL_VIDEO_DRIVER_X11_XINPUT #include <X11/extensions/XInput.h> #endif /* * When using the "dynamic X11" functionality, we duplicate all the Xlib * symbols that would be referenced by SDL inside of SDL itself. * These duplicated symbols just serve as passthroughs to the functions * in Xlib, that was dynamically loaded. * * This allows us to use Xlib as-is when linking against it directly, but * also handles all the strange cases where there was code in the Xlib * headers that may or may not exist or vary on a given platform. */ #ifdef __cplusplus extern "C" { #endif /* evil function signatures... */ typedef Bool(*SDL_X11_XESetWireToEventRetType) (Display *, XEvent *, xEvent *); typedef int (*SDL_X11_XSynchronizeRetType) (Display *); typedef Status(*SDL_X11_XESetEventToWireRetType) (Display *, XEvent *, xEvent *); int SDL_X11_LoadSymbols(void); void SDL_X11_UnloadSymbols(void); /* That's really annoying...make these function pointers no matter what. */ #ifdef X_HAVE_UTF8_STRING extern XIC(*pXCreateIC) (XIM, ...); extern char *(*pXGetICValues) (XIC, ...); #endif /* These SDL_X11_HAVE_* flags are here whether you have dynamic X11 or not. */ #define SDL_X11_MODULE(modname) extern int SDL_X11_HAVE_##modname; #define SDL_X11_SYM(rc,fn,params,args,ret) #include "SDL_x11sym.h" #undef SDL_X11_MODULE #undef SDL_X11_SYM #ifdef __cplusplus } #endif #endif /* !defined _SDL_x11dyn_h */ /* vi: set ts=4 sw=4 expandtab: */