Mercurial > sdl-ios-xcode
view src/video/bwindow/SDL_BView.h @ 2752:edd2839b36f7
http://sources.redhat.com/ml/newlib/2002/msg00230.html
Stephen L Moshier wrote:
>
> pow(x,y) returns 0 when x is very close to -1.0 and y is very large.
> The following test program prints
>
> pow(1.0000000000000002e+00 4.5035996273704970e+15) = 2.7182818284590455e+00
> pow(-1.0000000000000002e+00 4.5035996273704970e+15) =0.0000000000000000e+00
> pow(9.9999999999999978e-01 4.5035996273704970e+15) = 3.6787944117144222e-01
> pow(-9.9999999999999978e-01 4.5035996273704970e+15) = 0.0000000000000000e+00
>
> which is incorrect for the negative arguments raised to an odd integer
> power.
>
> -----
> double pow (double, double);
>
> int
> main ()
> {
> double x, y, z;
>
> x = 1.0 + pow (2.0, -52.0);
> y = 1.0 + pow (2.0, 52.0);
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = -x;
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = 1.0 - pow (2.0, -52.0);
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = -x;
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> }
> -----
>
> Here is a patch for newlib/libm/math/epow.c:
Patch checked in and duplicated for ef_pow.c. Thanks.
-- Jeff J.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Mon, 15 Sep 2008 04:31:30 +0000 |
parents | c121d94672cb |
children | 99210400e8b9 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2006 Sam Lantinga This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Sam Lantinga slouken@libsdl.org */ #include "SDL_config.h" #ifndef _SDL_BView_h #define _SDL_BView_h /* This is the event handling and graphics update portion of SDL_BWin */ extern "C" { #include "../../events/SDL_events_c.h" }; class SDL_BView:public BView { public: SDL_BView(BRect frame):BView(frame, "SDL View", B_FOLLOW_ALL_SIDES, (B_WILL_DRAW | B_FRAME_EVENTS)) { image = NULL; xoff = yoff = 0; SetViewColor(0, 0, 0, 0); SetHighColor(0, 0, 0, 0); } virtual ~ SDL_BView() { SetBitmap(NULL); } /* Set drawing offsets for fullscreen mode */ virtual void SetXYOffset(int x, int y) { xoff = x; yoff = y; } virtual void GetXYOffset(int &x, int &y) { x = xoff; y = yoff; } /* The view changed size. If it means we're in fullscreen, we * draw a nice black box in the entire view to get black borders. */ virtual void FrameResized(float width, float height) { BRect bounds; bounds.top = bounds.left = 0; bounds.right = width; bounds.bottom = height; /* Fill the entire view with black */ FillRect(bounds, B_SOLID_HIGH); /* And if there's an image, redraw it. */ if (image) { bounds = image->Bounds(); Draw(bounds); } } /* Drawing portion of this complete breakfast. :) */ virtual void SetBitmap(BBitmap * bitmap) { if (image) { delete image; } image = bitmap; } virtual void Draw(BRect updateRect) { if (image) { if (xoff || yoff) { BRect dest; dest.top = updateRect.top + yoff; dest.left = updateRect.left + xoff; dest.bottom = updateRect.bottom + yoff; dest.right = updateRect.right + xoff; DrawBitmap(image, updateRect, dest); } else { DrawBitmap(image, updateRect, updateRect); } } } virtual void DrawAsync(BRect updateRect) { if (xoff || yoff) { BRect dest; dest.top = updateRect.top + yoff; dest.left = updateRect.left + xoff; dest.bottom = updateRect.bottom + yoff; dest.right = updateRect.right + xoff;; DrawBitmapAsync(image, updateRect, dest); } else { DrawBitmapAsync(image, updateRect, updateRect); } } private: BBitmap * image; int xoff, yoff; }; #endif /* _SDL_BView_h */ /* vi: set ts=4 sw=4 expandtab: */