Split out vrect_t to its own file and add support functions.

The rest is cleanup after removing a wart from one of the field names.

include/QF/Makefile.am

@@ -8,8 +8,8 @@ nobase_pkginclude_HEADERS = \
 	pakfile.h pcx.h png.h plugin.h pr_comp.h pr_debug.h pr_obj.h progs.h \
 	qargs.h qdefs.h qendian.h qfplist.h qtypes.h quakefs.h quakeio.h render.h \
 	riff.h ruamoko.h screen.h script.h sizebuf.h skin.h sound.h spritegn.h \
-	sys.h teamplay.h tga.h uint32.h va.h ver_check.h vid.h view.h wad.h \
-	wadfile.h winding.h zone.h \
+	sys.h teamplay.h tga.h uint32.h va.h ver_check.h vid.h vrect.h view.h \
+	wad.h wadfile.h winding.h zone.h \
 	\
 	GL/ati.h GL/defines.h GL/extensions.h GL/funcs.h GL/qf_explosions.h \
 	GL/qf_funcs_list.h GL/qf_lightmap.h GL/qf_noisetextures.h \

include/QF/vid.h

@@ -30,6 +30,7 @@
 #define __vid_h_
 
 #include "QF/qtypes.h"
+#include "QF/vrect.h"
 
 #define VID_CBITS	6
 #define VID_GRADES	(1 << VID_CBITS)
@@ -44,11 +45,6 @@ extern struct cvar_s *vid_width;
 extern struct cvar_s *vid_height;
 extern struct cvar_s *vid_bitdepth;
 
-typedef struct vrect_s {
-	int				 x,y,width,height;
-	struct vrect_s	*pnext;
-} vrect_t;
-
 typedef struct {
 	qboolean		 initialized;
 	void			*buffer;		// invisible buffer

include/QF/vrect.h

@@ -0,0 +1,140 @@
+/*
+	vrect.h
+
+	Rectangle manipulation
+
+	Copyright (C) 2012 Bill Currie <bill@taniwha.org>
+
+	Author: Bill Currie <bill@taniwha.org>
+	Date: 2012/1/6
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program 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 General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to:
+
+		Free Software Foundation, Inc.
+		59 Temple Place - Suite 330
+		Boston, MA  02111-1307, USA
+
+	$Id$
+*/
+
+#ifndef __QF_vrect_h
+#define __QF_vrect_h
+
+typedef struct vrect_s {
+	int         x;
+	int         y;
+	int         width;
+	int         height;
+	struct vrect_s *next;
+} vrect_t;
+
+#define VRect_MinX(vr) ((vr)->x)
+#define VRect_MinY(vr) ((vr)->y)
+#define VRect_MaxX(vr) ((vr)->x + (vr)->width)
+#define VRect_MaxY(vr) ((vr)->y + (vr)->height)
+#define VRect_IsEmpty(vr) ((vr)->width <= 0 || (vr)->height <= 0)
+
+/** Create a new rectangle of the specified shape.
+
+	Other VRect functions will return a rectangle (or chain of rectangles)
+	created by this function.
+
+	\param x		The X coordinate of the top-left corner.
+	\param y		The Y coordinate of the top-left corner.
+	\param width	The width of the rectangle.
+	\param height	The height of the rectangle.
+	\return			The newly created rectangle.
+*/
+vrect_t *VRect_New (int x, int y, int width, int height);
+
+/** Free one rectangle.
+
+	This function will not free any other rectangles linked to the specified
+	rectangle.
+
+	\param rect		The rectangle to be freed.
+*/
+void VRect_Delete (vrect_t *rect);
+
+/** Return a rectangle representing the intersection of \a r1 and \a r2.
+
+	The returned rectangle may be empty. Use VRect_IsEmpty to check.
+
+	\param r1		The first rectangle.
+	\param r2		The second rectangle.
+	\return			The single (possibly empty) rectangle representing the
+					intersection of \a r1 and \a r2.
+	\note	It is the caller's responsibility to delete the returned rectangle.
+*/
+vrect_t *VRect_Intersect (const vrect_t *r1, const vrect_t *r2);
+
+/** Return two rectangles representing the portions of \a r above and below
+	\a y.
+
+	One of the returned rectangles may be empty. Use VRect_IsEmpty to check.
+	The first rectangle represents the portion of \a r that is above \a y, and
+	the second rectangle repesents the portion of \a r that is below \a y. The
+	second rectangle is linked to the first via the first's vrect_t::next
+	pointer.
+
+	\param r		The rectangle to split.
+	\param y		The horizontal line by which \r will be split.
+	\return			The two linked rectangles representing the portions above
+					and below \a y. The returned pointer points to the first
+					(above) rectangle, which links to the second (below)
+					rectangle.
+	\note	It is the caller's responsibility to delete the returned
+			rectangles.
+*/
+vrect_t *VRect_HSplit (const vrect_t *r, int y);
+
+/** Return two rectangles representing the portions of \a r to the left and
+	right of \a y.
+
+	One of the returned rectangles may be empty. Use VRect_IsEmpty to check.
+	The first rectangle represents the portion of \a r that is to the left of
+	\a y, and the second rectangle repesents the portion of \a r that is to
+	the right of \a y. The second rectangle is linked to the first via the
+	first's vrect_t::next pointer.
+
+	\param r		The rectangle to split.
+	\param x		The vertical line by which \r will be split.
+	\return			The two linked rectangles representing the portions to the
+					left and right of \a y. The returned pointer points to the
+					first (left) rectangle, which links to the second (right)
+					rectangle.
+	\note	It is the caller's responsibility to delete the returned
+			rectangles.
+*/
+vrect_t *VRect_VSplit (const vrect_t *r, int x);
+
+/** Return up to four rectangles representing the result of carving rectangle
+	\a s out of rectangle \a r.
+
+	None of the returned rectangles will be empty. If the difference is empty,
+	null will be returned.
+
+	\param r		The rectangle to be carved.
+	\param s		The rectangle used to carve \a r.
+	\return			Up to four linked rectangles representing the portions of
+					\a r after carving out the portion represented by \a s, or
+					null if the result is empty. A new rectangle that is a copy
+					of \a r will be returned if \a r and \a s do not intersect.
+	\note	It is the caller's responsibility to delete the returned
+			rectangles.
+*/
+vrect_t *VRect_Difference (const vrect_t *r, const vrect_t *s);
+
+#endif//__QF_vrect_h

libs/util/Makefile.am

@@ -42,6 +42,6 @@ libQFutil_la_SOURCES= \
 	fendian.c hash.c idparse.c info.c link.c llist.c \
 	mathlib.c mdfour.c msg.c pakfile.c plugin.c qargs.c qendian.c \
 	qfplist.c quakefs.c quakeio.c riff.c script.c sizebuf.c string.c sys.c \
-	va.c ver_check.c wad.c wadfile.c zone.c $(fnmatch) $(getopt)
+	va.c ver_check.c vrect.c wad.c wadfile.c zone.c $(fnmatch) $(getopt)
 
 EXTRA_DIST= $(fnmatch_src) $(getopt_src)

libs/util/vrect.c

@@ -0,0 +1,178 @@
+/*
+	vrect.c
+
+	Rectangle manipulation
+
+	Copyright (C) 2012 Bill Currie <bill@taniwha.org>
+
+	Author: Bill Currie <bill@taniwha.org>
+	Date: 2012/1/6
+
+	This program is free software; you can redistribute it and/or
+	modify it under the terms of the GNU General Public License
+	as published by the Free Software Foundation; either version 2
+	of the License, or (at your option) any later version.
+
+	This program 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 General Public License for more details.
+
+	You should have received a copy of the GNU General Public License
+	along with this program; if not, write to:
+
+		Free Software Foundation, Inc.
+		59 Temple Place - Suite 330
+		Boston, MA  02111-1307, USA
+
+*/
+#ifdef HAVE_CONFIG_H
+# include "config.h"
+#endif
+
+static __attribute__ ((used)) const char rcsid[] = "$Id$";
+
+#include <stdlib.h>
+
+#include "QF/mathlib.h"
+#include "QF/vrect.h"
+
+#define RECT_BLOCK 128
+static vrect_t *free_rects;
+
+VISIBLE vrect_t *
+VRect_New (int x, int y, int width, int height)
+{
+	vrect_t    *r;
+
+	if (!free_rects) {
+		int         i;
+
+		free_rects = malloc (RECT_BLOCK * sizeof (vrect_t));
+		for (i = 0; i < RECT_BLOCK - 1; i++)
+			free_rects[i].next = &free_rects[i + 1];
+		free_rects[i].next = 0;
+	}
+	r = free_rects;
+	free_rects = free_rects->next;
+	r->next = 0;
+	r->x = x;
+	r->y = y;
+	r->width = width;
+	r->height = height;
+	return r;
+}
+
+VISIBLE void
+VRect_Delete (vrect_t *rect)
+{
+	rect->next = free_rects;
+	free_rects = rect;
+}
+
+VISIBLE vrect_t *
+VRect_Intersect (const vrect_t *r1, const vrect_t *r2)
+{
+	int         minx = max (VRect_MinX (r1), VRect_MinX (r2));
+	int         miny = max (VRect_MinY (r1), VRect_MinY (r2));
+	int         maxx = min (VRect_MaxX (r1), VRect_MaxX (r2));
+	int         maxy = min (VRect_MaxY (r1), VRect_MaxY (r2));
+	return VRect_New (minx, miny, maxx - minx, maxy - miny);
+}
+
+VISIBLE vrect_t *
+VRect_HSplit (const vrect_t *r, int y)
+{
+	vrect_t    *r1, *r2;
+	int         r1miny = VRect_MinY (r);
+	int         r1maxy = min (VRect_MaxY (r), y);
+	int         r2miny = max (VRect_MinY (r), y);
+	int         r2maxy = VRect_MaxY (r);
+	r1 = VRect_New (VRect_MinX (r), r1miny, r->width, r1maxy - r1miny);
+	r2 = VRect_New (VRect_MinX (r), r2miny, r->width, r2maxy - r2miny);
+	r1->next = r2;
+	return r1;
+}
+
+VISIBLE vrect_t *
+VRect_VSplit (const vrect_t *r, int x)
+{
+	vrect_t    *r1, *r2;
+	int         r1minx = VRect_MinX (r);
+	int         r1maxx = min (VRect_MaxX (r), x);
+	int         r2minx = max (VRect_MinX (r), x);
+	int         r2maxx = VRect_MaxX (r);
+	r1 = VRect_New (r1minx, VRect_MinY (r), r1maxx - r1minx, r->height);
+	r2 = VRect_New (r2minx, VRect_MinY (r), r2maxx - r2minx, r->height);
+	r1->next = r2;
+	return r1;
+}
+
+VISIBLE vrect_t *
+VRect_Difference (const vrect_t *r, const vrect_t *s)
+{
+	vrect_t    *i, *t, *_r;
+	vrect_t    *rects = 0;
+#define STASH(t)					\
+	do {							\
+		if (!VRect_IsEmpty (t)) {	\
+			t->next = rects;		\
+			rects = t;				\
+		} else {					\
+			VRect_Delete (t);		\
+		}							\
+	} while (0)
+
+	// Find the intersection of r (original rect) and s (the rect being
+	// subtracted from r). The intersection rect is used to carve the original
+	// rect. If there is no intersection (the intersection rect is empty),
+	// then there is nothing to subtract and the original rect (actually, a
+	// copy of it) is returned.
+	i = VRect_Intersect (r, s);
+	if (VRect_IsEmpty (i)) {
+		// copy r's shape to i, and return i.
+		i->x = r->x;
+		i->y = r->y;
+		i->width = r->width;
+		i->height = r->height;
+		return i;
+	}
+
+	// Split r along the top of the intersection rect and stash the top
+	// section if it is not empty.
+	t = VRect_HSplit (r, VRect_MinY (i));
+	// can't delete r: we don't own it
+	_r = t->next;
+	STASH (t);			// maybe stash the top section
+	// r now represents the portion of the original rect below the top of
+	// the intersection rect.
+
+	// Split r along the bottom of the intersection rect and stash the bottom
+	// section if it is not empty.
+	t = VRect_HSplit (_r, VRect_MaxY (i));
+	VRect_Delete (_r);	// finished with that copy of _r
+	_r = t;
+	STASH (t->next);	// maybe stash the bottom section
+	// r now represents the horizontal section that is common with the
+	// intersection rect.
+
+	// Split r along the left side of tht intersection rect and stash the
+	// left section if it is not empty.
+	t = VRect_VSplit (_r, VRect_MinX (i));
+	VRect_Delete (_r);	// finished with that copy of _r
+	_r = t->next;
+	STASH (t);			// maybe stash the left section
+	// r now represets the section of the original rect that is between the
+	// top and bottom, and to the right of the left side of the intersection
+	// rect.
+
+	// Split r along the right side of the intersection rect and stash the
+	// right section if it is not empty. The left section is discarded.
+	t = VRect_VSplit (_r, VRect_MaxX (i));
+	VRect_Delete (_r);	// finished with that copy of _r
+	STASH (t->next);	// maybe stash the right section
+	VRect_Delete (t);	// discard the left section
+
+	return rects;
+}

libs/video/renderer/sw/screen.c

@@ -286,7 +286,7 @@ SCR_UpdateScreen (double realtime, SCR_Func *scr_funcs)
 		vrect.y = 0;
 		vrect.width = vid.width;
 		vrect.height = vid.height;
-		vrect.pnext = 0;
+		vrect.next = 0;
 
 		VID_Update (&vrect);
 	} else if (scr_copytop) {
@@ -294,7 +294,7 @@ SCR_UpdateScreen (double realtime, SCR_Func *scr_funcs)
 		vrect.y = 0;
 		vrect.width = vid.width;
 		vrect.height = vid.height - r_lineadj;
-		vrect.pnext = 0;
+		vrect.next = 0;
 
 		VID_Update (&vrect);
 	} else {
@@ -302,7 +302,7 @@ SCR_UpdateScreen (double realtime, SCR_Func *scr_funcs)
 		vrect.y = scr_vrect.y;
 		vrect.width = scr_vrect.width;
 		vrect.height = scr_vrect.height;
-		vrect.pnext = 0;
+		vrect.next = 0;
 
 		VID_Update (&vrect);
 	}

libs/video/renderer/sw/sw_rmisc.c

@@ -75,7 +75,7 @@ R_TimeRefresh_f (void)
 		vr.y = r_refdef.vrect.y;
 		vr.width = r_refdef.vrect.width;
 		vr.height = r_refdef.vrect.height;
-		vr.pnext = NULL;
+		vr.next = NULL;
 		VID_Update (&vr);
 	}
 	stop = Sys_DoubleTime ();

libs/video/renderer/sw32/screen.c

@@ -307,7 +307,7 @@ SCR_UpdateScreen (double realtime, SCR_Func *scr_funcs)
 		vrect.y = 0;
 		vrect.width = vid.width;
 		vrect.height = vid.height;
-		vrect.pnext = 0;
+		vrect.next = 0;
 
 		VID_Update (&vrect);
 	} else if (scr_copytop) {
@@ -315,7 +315,7 @@ SCR_UpdateScreen (double realtime, SCR_Func *scr_funcs)
 		vrect.y = 0;
 		vrect.width = vid.width;
 		vrect.height = vid.height - r_lineadj;
-		vrect.pnext = 0;
+		vrect.next = 0;
 
 		VID_Update (&vrect);
 	} else {
@@ -323,7 +323,7 @@ SCR_UpdateScreen (double realtime, SCR_Func *scr_funcs)
 		vrect.y = scr_vrect.y;
 		vrect.width = scr_vrect.width;
 		vrect.height = scr_vrect.height;
-		vrect.pnext = 0;
+		vrect.next = 0;
 
 		VID_Update (&vrect);
 	}

libs/video/renderer/sw32/sw32_rmisc.c

@@ -75,7 +75,7 @@ R_TimeRefresh_f (void)
 		vr.y = r_refdef.vrect.y;
 		vr.width = r_refdef.vrect.width;
 		vr.height = r_refdef.vrect.height;
-		vr.pnext = NULL;
+		vr.next = NULL;
 		VID_Update (&vr);
 	}
 	stop = Sys_DoubleTime ();

libs/video/targets/vid_fbdev.c

@@ -518,7 +518,7 @@ VID_Update (vrect_t *rects)
 				d += lineskip;
 				s += lineskip;
 			}
-			rects = rects->pnext;
+			rects = rects->next;
 		}
 	}
 }

libs/video/targets/vid_sdl.c

@@ -147,14 +147,14 @@ VID_Update (vrect_t *rects)
 
 	// First, count the number of rectangles
 	n = 0;
-	for (rect = rects; rect; rect = rect->pnext)
+	for (rect = rects; rect; rect = rect->next)
 		++n;
 
 	// Second, copy them to SDL rectangles and update
 	if (!(sdlrects = (SDL_Rect *) calloc (1, n * sizeof (SDL_Rect))))
 		Sys_Error ("Out of memory!");
 	i = 0;
-	for (rect = rects; rect; rect = rect->pnext) {
+	for (rect = rects; rect; rect = rect->next) {
 		sdlrects[i].x = rect->x;
 		sdlrects[i].y = rect->y;
 		sdlrects[i].w = rect->width;

libs/video/targets/vid_sdl32.c

@@ -197,7 +197,7 @@ VID_Update (vrect_t *rects)
 		// update display
 		SDL_UpdateRect (screen, rects->x, rects->y, rects->width,
 						rects->height);
-		rects = rects->pnext;
+		rects = rects->next;
 	}
 }
 

libs/video/targets/vid_svgalib.c

@@ -457,7 +457,7 @@ VID_Update (vrect_t *rects)
 				}
 				offset += vid.rowbytes;
 			}
-			rects = rects->pnext;
+			rects = rects->next;
 		}
 	}
 }

libs/video/targets/vid_x11.c

@@ -615,7 +615,7 @@ VID_Update (vrect_t *rects)
 			oktodraw = false;
 			while (!oktodraw)
 				X11_ProcessEvent ();
-			rects = rects->pnext;
+			rects = rects->next;
 
 			current_framebuffer = !current_framebuffer;
 		} else {
@@ -624,7 +624,7 @@ VID_Update (vrect_t *rects)
 							rects->width, rects->height)) {
 				Sys_Error ("VID_Update: XPutImage failed");
 			}
-			rects = rects->pnext;
+			rects = rects->next;
 		}
 	}
 	XSync (x_disp, False);