Mercurial > sdl-ios-xcode
view src/video/SDL_rect.c @ 2042:3908e1f808e1
Fixed bug #292
I might be on crack here.
It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and
right channels of a stereo stream together, and clamps the new mono channel if
it would overflow.
Shouldn't it be dividing by 2 to average the two sample points instead of
clamping? Otherwise the mono sample point's volume doubles in the conversion.
This would also make the conversion faster, as it replaces two branches per
sample frame with a bitwise shift.
--ryan.
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Sun, 24 Sep 2006 15:56:36 +0000 |
parents | c121d94672cb |
children | 175754591a13 |
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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" #include "SDL_video.h" #include "SDL_rect_c.h" SDL_bool SDL_HasIntersection(const SDL_Rect * A, const SDL_Rect * B) { int Amin, Amax, Bmin, Bmax; /* Horizontal intersection */ Amin = A->x; Amax = Amin + A->w; Bmin = B->x; Bmax = Bmin + B->w; if (Bmin > Amin) Amin = Bmin; if (Bmax < Amax) Amax = Bmax; if (Amax <= Amin) return SDL_FALSE; /* Vertical intersection */ Amin = A->y; Amax = Amin + A->h; Bmin = B->y; Bmax = Bmin + B->h; if (Bmin > Amin) Amin = Bmin; if (Bmax < Amax) Amax = Bmax; if (Amax <= Amin) return SDL_FALSE; return SDL_TRUE; } SDL_bool SDL_IntersectRect(const SDL_Rect * A, const SDL_Rect * B, SDL_Rect * result) { int Amin, Amax, Bmin, Bmax; /* Horizontal intersection */ Amin = A->x; Amax = Amin + A->w; Bmin = B->x; Bmax = Bmin + B->w; if (Bmin > Amin) Amin = Bmin; result->x = Amin; if (Bmax < Amax) Amax = Bmax; result->w = Amax - Amin; /* Vertical intersection */ Amin = A->y; Amax = Amin + A->h; Bmin = B->y; Bmax = Bmin + B->h; if (Bmin > Amin) Amin = Bmin; result->y = Amin; if (Bmax < Amax) Amax = Bmax; result->h = Amax - Amin; return !SDL_RectEmpty(result); } void SDL_UnionRect(const SDL_Rect * A, const SDL_Rect * B, SDL_Rect * result) { int Amin, Amax, Bmin, Bmax; /* Horizontal union */ Amin = A->x; Amax = Amin + A->w; Bmin = B->x; Bmax = Bmin + B->w; if (Bmin < Amin) Amin = Bmin; result->x = Amin; if (Bmax > Amax) Amax = Bmax; result->w = Amax - Amin; /* Vertical intersection */ Amin = A->y; Amax = Amin + A->h; Bmin = B->y; Bmax = Bmin + B->h; if (Bmin < Amin) Amin = Bmin; result->y = Amin; if (Bmax > Amax) Amax = Bmax; result->h = Amax - Amin; } void SDL_AddDirtyRect(SDL_DirtyRectList * list, const SDL_Rect * rect) { SDL_DirtyRect *dirty; SDL_DirtyRect *check, *prev, *next; if (list->free) { dirty = list->free; list->free = dirty->next; } else { dirty = (SDL_DirtyRect *) SDL_malloc(sizeof(*dirty)); if (!dirty) { return; } } dirty->rect = *rect; /* FIXME: At what point is this optimization too expensive? */ for (prev = NULL, check = list->list; check; check = next) { next = check->next; if (SDL_HasIntersection(&dirty->rect, &check->rect)) { SDL_UnionRect(&dirty->rect, &check->rect, &dirty->rect); if (prev) { prev->next = next; } else { list->list = next; } check->next = list->free; list->free = check; --list->count; } else { prev = check; } } dirty->next = list->list; list->list = dirty; ++list->count; } void SDL_ClearDirtyRects(SDL_DirtyRectList * list) { while (list->list) { SDL_DirtyRect *elem = list->list; list->list = elem->next; elem->next = list->free; list->free = elem; } list->count = 0; } void SDL_FreeDirtyRects(SDL_DirtyRectList * list) { while (list->list) { SDL_DirtyRect *elem = list->list; list->list = elem->next; SDL_free(elem); } while (list->free) { SDL_DirtyRect *elem = list->free; list->free = elem->next; SDL_free(elem); } } /* vi: set ts=4 sw=4 expandtab: */