Mercurial > sdl-ios-xcode
annotate src/video/x11/SDL_x11render.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 | f7b03b6838cb |
rev | line source |
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2810
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
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1 /* |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
2 SDL - Simple DirectMedia Layer |
2859 | 3 Copyright (C) 1997-2009 Sam Lantinga |
2810
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
4 |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
5 This library is free software; you can redistribute it and/or |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
6 modify it under the terms of the GNU Lesser General Public |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
7 License as published by the Free Software Foundation; either |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
8 version 2.1 of the License, or (at your option) any later version. |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
9 |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
10 This library is distributed in the hope that it will be useful, |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
11 but WITHOUT ANY WARRANTY; without even the implied warranty of |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
13 Lesser General Public License for more details. |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
14 |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
15 You should have received a copy of the GNU Lesser General Public |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
16 License along with this library; if not, write to the Free Software |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
17 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
18 |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
19 Sam Lantinga |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
20 slouken@libsdl.org |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
21 */ |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
22 #include "SDL_config.h" |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
23 |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
24 /* SDL surface based renderer implementation */ |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
25 |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
26 #if SDL_VIDEO_RENDER_X11 |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
27 extern void X11_AddRenderDriver(_THIS); |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
28 #endif |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
29 |
27cb878a278e
Implemented the X11 (non-OpenGL) renderer, no alpha or scaling available.
Sam Lantinga <slouken@libsdl.org>
parents:
diff
changeset
|
30 /* vi: set ts=4 sw=4 expandtab: */ |