src/video/SDL_rect.c
branchSDL-1.3
changeset 1735 8dd28c4ef746
child 2223 175754591a13
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/video/SDL_rect.c	Mon Jul 10 07:34:50 2006 +0000
@@ -0,0 +1,189 @@
+/*
+    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: */