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|
/* ScummVM - Graphic Adventure Engine
*
* ScummVM is the legal property of its developers, whose names
* are too numerous to list here. Please refer to the COPYRIGHT
* file distributed with this source distribution.
*
* 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 the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $URL$
* $Id$
*
*/
#include "sci/sci.h"
#include "sci/engine/state.h"
#include "sci/engine/kernel.h"
#include "sci/gfx/gfx_widgets.h"
#include "sci/gfx/gfx_state_internal.h" // required for GfxPort, GfxContainer
#include "common/list.h"
namespace Sci {
#define POLY_LAST_POINT 0x7777
#define POLY_POINT_SIZE 4
//#define DEBUG_AVOIDPATH //enable for avoidpath debugging
static void POLY_GET_POINT(const byte *p, int i, Common::Point &pt) {
pt.x = (int16)READ_LE_UINT16((p) + (i) * POLY_POINT_SIZE);
pt.y = (int16)READ_LE_UINT16((p) + (i) * POLY_POINT_SIZE + 2);
}
static void POLY_SET_POINT(byte *p, int i, const Common::Point &pt) {
WRITE_LE_UINT16((p) + (i) * POLY_POINT_SIZE, pt.x);
WRITE_LE_UINT16((p) + (i) * POLY_POINT_SIZE + 2, pt.y);
}
static void POLY_GET_POINT_REG_T(const reg_t *p, int i, Common::Point &pt) {
pt.x = (p)[(i) * 2].toUint16();
pt.y = (p)[(i) * 2 + 1].toUint16();
}
// SCI-defined polygon types
enum {
POLY_TOTAL_ACCESS = 0,
POLY_NEAREST_ACCESS = 1,
POLY_BARRED_ACCESS = 2,
POLY_CONTAINED_ACCESS = 3
};
// Polygon containment types
enum {
CONT_OUTSIDE = 0,
CONT_ON_EDGE = 1,
CONT_INSIDE = 2
};
#define HUGE_DISTANCE 0xFFFFFFFF
#define VERTEX_HAS_EDGES(V) ((V) != CLIST_NEXT(V))
// Error codes
enum {
PF_OK = 0,
PF_ERROR = -1,
PF_FATAL = -2
};
// Floating point struct
struct FloatPoint {
FloatPoint() : x(0), y(0) {}
FloatPoint(float x_, float y_) : x(x_), y(y_) {}
Common::Point toPoint() {
return Common::Point((int16)(x + 0.5), (int16)(y + 0.5));
}
float x, y;
};
struct Vertex {
// Location
Common::Point v;
// Vertex circular list entry
Vertex *_next; // next element
Vertex *_prev; // previous element
// Distance from starting vertex
uint32 dist;
// Previous vertex in shortest path
Vertex *path_prev;
public:
Vertex(const Common::Point &p) : v(p) {
dist = HUGE_DISTANCE;
path_prev = NULL;
}
};
typedef Common::List<Vertex *> VertexList;
/* Circular list definitions. */
#define CLIST_FOREACH(var, head) \
for ((var) = (head)->first(); \
(var); \
(var) = ((var)->_next == (head)->first() ? \
NULL : (var)->_next))
/* Circular list access methods. */
#define CLIST_NEXT(elm) ((elm)->_next)
#define CLIST_PREV(elm) ((elm)->_prev)
class CircularVertexList {
public:
Vertex *_head;
public:
CircularVertexList() : _head(0) {}
Vertex *first() const {
return _head;
}
void insertHead(Vertex *elm) {
if (_head == NULL) {
elm->_next = elm->_prev = elm;
} else {
elm->_next = _head;
elm->_prev = _head->_prev;
_head->_prev = elm;
elm->_prev->_next = elm;
}
_head = elm;
}
static void insertAfter(Vertex *listelm, Vertex *elm) {
elm->_prev = listelm;
elm->_next = listelm->_next;
listelm->_next->_prev = elm;
listelm->_next = elm;
}
void remove(Vertex *elm) {
if (elm->_next == elm) {
_head = NULL;
} else {
if (_head == elm)
_head = elm->_next;
elm->_prev->_next = elm->_next;
elm->_next->_prev = elm->_prev;
}
}
bool empty() const {
return _head == NULL;
}
uint size() const {
int n = 0;
Vertex *v;
CLIST_FOREACH(v, this)
++n;
return n;
}
/**
* Reverse the order of the elements in this circular list.
*/
void reverse() {
if (!_head)
return;
Vertex *elm = _head;
do {
SWAP(elm->_prev, elm->_next);
elm = elm->_next;
} while (elm != _head);
}
};
struct Polygon {
// SCI polygon type
int type;
// Circular list of vertices
CircularVertexList vertices;
public:
Polygon(int t) : type(t) {
}
~Polygon() {
while (!vertices.empty()) {
Vertex *vertex = vertices.first();
vertices.remove(vertex);
delete vertex;
}
}
};
typedef Common::List<Polygon *> PolygonList;
// Pathfinding state
struct PathfindingState {
// List of all polygons
PolygonList polygons;
// Start and end points for pathfinding
Vertex *vertex_start, *vertex_end;
// Array of all vertices, used for sorting
Vertex **vertex_index;
// Total number of vertices
int vertices;
// Point to prepend and append to final path
Common::Point *_prependPoint;
Common::Point *_appendPoint;
PathfindingState() {
vertex_start = NULL;
vertex_end = NULL;
vertex_index = NULL;
_prependPoint = NULL;
_appendPoint = NULL;
vertices = 0;
}
~PathfindingState() {
free(vertex_index);
delete _prependPoint;
delete _appendPoint;
for (PolygonList::iterator it = polygons.begin(); it != polygons.end(); ++it) {
delete *it;
}
}
};
static Vertex *s_vertex_cur; // FIXME: Avoid non-const global vars
// FIXME: Temporary hack to deal with points in reg_ts
static bool polygon_is_reg_t(const byte *list, int size) {
// Check the first three reg_ts
for (int i = 0; i < (size < 3 ? size : 3); i++)
if ((((reg_t *) list) + i)->segment)
// Non-zero segment, cannot be reg_ts
return false;
// First three segments were zero, assume reg_ts
return true;
}
static Common::Point read_point(const byte *list, int is_reg_t, int offset) {
Common::Point point;
if (!is_reg_t) {
POLY_GET_POINT(list, offset, point);
} else {
POLY_GET_POINT_REG_T((reg_t *)list, offset, point);
}
return point;
}
/**
* Checks whether two polygons are equal
*/
static bool polygons_equal(EngineState *s, reg_t p1, reg_t p2) {
// Check for same type
if (GET_SEL32(p1, type).toUint16() != GET_SEL32(p2, type).toUint16())
return false;
int size = GET_SEL32(p1, size).toUint16();
// Check for same number of points
if (size != GET_SEL32(p2, size).toUint16())
return false;
const byte *p1_points = kernel_dereference_bulk_pointer(s, GET_SEL32(p1, points), size * POLY_POINT_SIZE);
const byte *p2_points = kernel_dereference_bulk_pointer(s, GET_SEL32(p2, points), size * POLY_POINT_SIZE);
bool p1_is_reg_t = polygon_is_reg_t(p1_points, size);
bool p2_is_reg_t = polygon_is_reg_t(p2_points, size);
// Check for the same points
for (int i = 0; i < size; i++) {
if (read_point(p1_points, p1_is_reg_t, i) != read_point(p2_points, p2_is_reg_t, i))
return false;
}
return true;
}
#ifdef DEBUG_AVOIDPATH
static void draw_line(EngineState *s, Common::Point p1, Common::Point p2, int type) {
// Colors for polygon debugging.
// Green: Total access
// Red : Barred access
// Blue: Near-point access
// Yellow: Contained access
int poly_colors[][3] = {{0, 255, 0}, {0, 0, 255}, {255, 0, 0}, {255, 255, 0}};
gfx_color_t col;
GfxList *decorations = s->picture_port->_decorations;
GfxPrimitive *line;
col.visual = PaletteEntry(poly_colors[type][0], poly_colors[type][1], poly_colors[type][2]);
col.alpha = 0;
col.priority = -1;
col.control = 0;
col.mask = GFX_MASK_VISUAL | GFX_MASK_PRIORITY;
p1.y += 10;
p2.y += 10;
line = gfxw_new_line(p1, p2, col, GFX_LINE_MODE_CORRECT, GFX_LINE_STYLE_NORMAL);
decorations->add((GfxContainer *)decorations, (GfxWidget *)line);
}
static void draw_point(EngineState *s, Common::Point p, int start) {
// Colors for starting and end point
// Green: End point
// Blue: Starting point
int point_colors[][3] = {{0, 255, 0}, {0, 0, 255}};
gfx_color_t col;
GfxList *decorations = s->picture_port->_decorations;
GfxBox *box;
col.visual = PaletteEntry(point_colors[start][0], point_colors[start][1], point_colors[start][2]);
col.alpha = 0;
col.priority = -1;
col.control = 0;
col.mask = GFX_MASK_VISUAL | GFX_MASK_PRIORITY;
box = gfxw_new_box(s->gfx_state, gfx_rect(p.x - 1, p.y - 1 + 10, 3, 3), col, col, GFX_BOX_SHADE_FLAT);
decorations->add((GfxContainer *)decorations, (GfxWidget *)box);
}
static void draw_polygon(EngineState *s, reg_t polygon) {
reg_t points = GET_SEL32(polygon, points);
int size = GET_SEL32(polygon, size).toUint16();
int type = GET_SEL32(polygon, type).toUint16();
Common::Point first, prev;
const byte *list = kernel_dereference_bulk_pointer(s, points, size * POLY_POINT_SIZE);
int is_reg_t = polygon_is_reg_t(list, size);
int i;
prev = first = read_point(list, is_reg_t, 0);
for (i = 1; i < size; i++) {
Common::Point point = read_point(list, is_reg_t, i);
draw_line(s, prev, point, type);
prev = point;
}
draw_line(s, prev, first, type % 3);
}
static void draw_input(EngineState *s, reg_t poly_list, Common::Point start, Common::Point end, int opt) {
List *list;
Node *node;
draw_point(s, start, 1);
draw_point(s, end, 0);
if (!poly_list.segment)
return;
list = lookup_list(s, poly_list);
if (!list) {
warning("[avoidpath] Could not obtain polygon list");
return;
}
node = lookup_node(s, list->first);
while (node) {
draw_polygon(s, node->value);
node = lookup_node(s, node->succ);
}
}
#endif // DEBUG_AVOIDPATH
static void print_polygon(EngineState *s, reg_t polygon) {
reg_t points = GET_SEL32(polygon, points);
int size = GET_SEL32(polygon, size).toUint16();
int type = GET_SEL32(polygon, type).toUint16();
int i;
const byte *point_array = kernel_dereference_bulk_pointer(s, points, size * POLY_POINT_SIZE);
int is_reg_t = polygon_is_reg_t(point_array, size);
Common::Point point;
printf("%i:", type);
for (i = 0; i < size; i++) {
point = read_point(point_array, is_reg_t, i);
printf(" (%i, %i)", point.x, point.y);
}
point = read_point(point_array, is_reg_t, 0);
printf(" (%i, %i);\n", point.x, point.y);
}
static void print_input(EngineState *s, reg_t poly_list, Common::Point start, Common::Point end, int opt) {
List *list;
Node *node;
printf("Start point: (%i, %i)\n", start.x, start.y);
printf("End point: (%i, %i)\n", end.x, end.y);
printf("Optimization level: %i\n", opt);
if (!poly_list.segment)
return;
list = lookup_list(s, poly_list);
if (!list) {
warning("[avoidpath] Could not obtain polygon list");
return;
}
printf("Polygons:\n");
node = lookup_node(s, list->first);
while (node) {
print_polygon(s, node->value);
node = lookup_node(s, node->succ);
}
}
static int area(const Common::Point &a, const Common::Point &b, const Common::Point &c) {
// Computes the area of a triangle
// Parameters: (const Common::Point &) a, b, c: The points of the triangle
// Returns : (int) The area multiplied by two
return (b.x - a.x) * (a.y - c.y) - (c.x - a.x) * (a.y - b.y);
}
static bool left(const Common::Point &a, const Common::Point &b, const Common::Point &c) {
// Determines whether or not a point is to the left of a directed line
// Parameters: (const Common::Point &) a, b: The directed line (a, b)
// (const Common::Point &) c: The query point
// Returns : (int) true if c is to the left of (a, b), false otherwise
return area(a, b, c) > 0;
}
static bool left_on(const Common::Point &a, const Common::Point &b, const Common::Point &c) {
// Determines whether or not a point is to the left of or collinear with a
// directed line
// Parameters: (const Common::Point &) a, b: The directed line (a, b)
// (const Common::Point &) c: The query point
// Returns : (int) true if c is to the left of or collinear with (a, b), false
// otherwise
return area(a, b, c) >= 0;
}
static bool collinear(const Common::Point &a, const Common::Point &b, const Common::Point &c) {
// Determines whether or not three points are collinear
// Parameters: (const Common::Point &) a, b, c: The three points
// Returns : (int) true if a, b, and c are collinear, false otherwise
return area(a, b, c) == 0;
}
static bool between(const Common::Point &a, const Common::Point &b, const Common::Point &c) {
// Determines whether or not a point lies on a line segment
// Parameters: (const Common::Point &) a, b: The line segment (a, b)
// (const Common::Point &) c: The query point
// Returns : (int) true if c lies on (a, b), false otherwise
if (!collinear(a, b, c))
return false;
// Assumes a != b.
if (a.x != b.x)
return ((a.x <= c.x) && (c.x <= b.x)) || ((a.x >= c.x) && (c.x >= b.x));
else
return ((a.y <= c.y) && (c.y <= b.y)) || ((a.y >= c.y) && (c.y >= b.y));
}
static bool intersect_proper(const Common::Point &a, const Common::Point &b, const Common::Point &c, const Common::Point &d) {
// Determines whether or not two line segments properly intersect
// Parameters: (const Common::Point &) a, b: The line segment (a, b)
// (const Common::Point &) c, d: The line segment (c, d)
// Returns : (int) true if (a, b) properly intersects (c, d), false otherwise
int ab = (left(a, b, c) && left(b, a, d)) || (left(a, b, d) && left(b, a, c));
int cd = (left(c, d, a) && left(d, c, b)) || (left(c, d, b) && left(d, c, a));
return ab && cd;
}
static bool intersect(const Common::Point &a, const Common::Point &b, const Common::Point &c, const Common::Point &d) {
// Determines whether or not two line segments intersect
// Parameters: (const Common::Point &) a, b: The line segment (a, b)
// (const Common::Point &) c, d: The line segment (c, d)
// Returns : (int) true if (a, b) intersects (c, d), false otherwise
if (intersect_proper(a, b, c, d))
return true;
return between(a, b, c) || between(a, b, d) || between(c, d, a) || between(c, d, b);
}
static int contained(const Common::Point &p, Polygon *polygon) {
// Polygon containment test
// Parameters: (const Common::Point &) p: The point
// (Polygon *) polygon: The polygon
// Returns : (int) CONT_INSIDE if p is strictly contained in polygon,
// CONT_ON_EDGE if p lies on an edge of polygon,
// CONT_OUTSIDE otherwise
// Number of ray crossing left and right
int lcross = 0, rcross = 0;
Vertex *vertex;
// Iterate over edges
CLIST_FOREACH(vertex, &polygon->vertices) {
const Common::Point &v1 = vertex->v;
const Common::Point &v2 = CLIST_NEXT(vertex)->v;
// Flags for ray straddling left and right
int rstrad, lstrad;
// Check if p is a vertex
if (p == v1)
return CONT_ON_EDGE;
// Check if edge straddles the ray
rstrad = (v1.y < p.y) != (v2.y < p.y);
lstrad = (v1.y > p.y) != (v2.y > p.y);
if (lstrad || rstrad) {
// Compute intersection point x / xq
int x = v2.x * v1.y - v1.x * v2.y + (v1.x - v2.x) * p.y;
int xq = v1.y - v2.y;
// Multiply by -1 if xq is negative (for comparison that follows)
if (xq < 0) {
x = -x;
xq = -xq;
}
// Avoid floats by multiplying instead of dividing
if (rstrad && (x > xq * p.x))
rcross++;
else if (lstrad && (x < xq * p.x))
lcross++;
}
}
// If we counted an odd number of total crossings the point is on an edge
if ((lcross + rcross) % 2 == 1)
return CONT_ON_EDGE;
// If there are an odd number of crossings to one side the point is contained in the polygon
if (rcross % 2 == 1) {
// Invert result for contained access polygons.
if (polygon->type == POLY_CONTAINED_ACCESS)
return CONT_OUTSIDE;
return CONT_INSIDE;
}
// Point is outside polygon. Invert result for contained access polygons
if (polygon->type == POLY_CONTAINED_ACCESS)
return CONT_INSIDE;
return CONT_OUTSIDE;
}
static int polygon_area(Polygon *polygon) {
// Computes polygon area
// Parameters: (Polygon *) polygon: The polygon
// Returns : (int) The area multiplied by two
Vertex *first = polygon->vertices.first();
Vertex *v;
int size = 0;
v = CLIST_NEXT(first);
while (CLIST_NEXT(v) != first) {
size += area(first->v, v->v, CLIST_NEXT(v)->v);
v = CLIST_NEXT(v);
}
return size;
}
static void fix_vertex_order(Polygon *polygon) {
// Fixes the vertex order of a polygon if incorrect. Contained access
// polygons should have their vertices ordered clockwise, all other types
// anti-clockwise
// Parameters: (Polygon *) polygon: The polygon
int area = polygon_area(polygon);
// When the polygon area is positive the vertices are ordered
// anti-clockwise. When the area is negative the vertices are ordered
// clockwise
if (((area > 0) && (polygon->type == POLY_CONTAINED_ACCESS))
|| ((area < 0) && (polygon->type != POLY_CONTAINED_ACCESS))) {
polygon->vertices.reverse();
}
}
static int vertex_compare(const void *a, const void *b) {
// Compares two vertices by angle (first) and distance (second) in relation
// to s_vertex_cur. The angle is relative to the horizontal line extending
// right from s_vertex_cur, and increases clockwise
// Parameters: (const void *) a, b: The vertices
// Returns : (int) -1 if a is smaller than b, 1 if a is larger than b, and
// 0 if a and b are equal
const Common::Point &p0 = s_vertex_cur->v;
const Common::Point &p1 = (*(Vertex **) a)->v;
const Common::Point &p2 = (*(Vertex **) b)->v;
if (p1 == p2)
return 0;
// Points above p0 have larger angle than points below p0
if ((p1.y < p0.y) && (p2.y >= p0.y))
return 1;
if ((p2.y < p0.y) && (p1.y >= p0.y))
return -1;
// Handle case where all points have the same y coordinate
if ((p0.y == p1.y) && (p0.y == p2.y)) {
// Points left of p0 have larger angle than points right of p0
if ((p1.x < p0.x) && (p2.x >= p0.x))
return 1;
if ((p1.x >= p0.x) && (p2.x < p0.x))
return -1;
}
if (collinear(p0, p1, p2)) {
// At this point collinear points must have the same angle,
// so compare distance to p0
if (abs(p1.x - p0.x) < abs(p2.x - p0.x))
return -1;
if (abs(p1.y - p0.y) < abs(p2.y - p0.y))
return -1;
return 1;
}
// If p2 is left of the directed line (p0, p1) then p1 has greater angle
if (left(p0, p1, p2))
return 1;
return -1;
}
static void clockwise(const Vertex *vertex_cur, const Vertex *v, const Common::Point *&p1, const Common::Point *&p2) {
// Orders the points of an edge clockwise around vertex_cur. If all three
// points are collinear the original order is used
// Parameters: (const Vertex *) v: The first vertex of the edge
// Returns : (void)
// (const Common::Point *&) p1: The first point in clockwise order
// (const Common::Point *&) p2: The second point in clockwise order
Vertex *w = CLIST_NEXT(v);
if (left_on(vertex_cur->v, w->v, v->v)) {
p1 = &v->v;
p2 = &w->v;
} else {
p1 = &w->v;
p2 = &v->v;
}
}
/**
* Compares two edges that are intersected by the sweeping line by distance from vertex_cur
* @param a the first edge
* @param b the second edge
* @return true if a is closer to vertex_cur than b, false otherwise
*/
static bool edgeIsCloser(const Vertex *vertex_cur, const Vertex *a, const Vertex *b) {
const Common::Point *v1, *v2, *w1, *w2;
// Check for comparison of the same edge
if (a == b)
return false;
// We can assume that the sweeping line intersects both edges and
// that the edges do not properly intersect
// Order vertices clockwise so we know vertex_cur is to the right of
// directed edges (v1, v2) and (w1, w2)
clockwise(vertex_cur, a, v1, v2);
clockwise(vertex_cur, b, w1, w2);
// At this point we know that one edge must lie entirely to one side
// of the other, as the edges are not collinear and cannot intersect
// other than possibly sharing a vertex.
return ((left_on(*v1, *v2, *w1) && left_on(*v1, *v2, *w2)) || (left_on(*w2, *w1, *v1) && left_on(*w2, *w1, *v2)));
}
static int inside(const Common::Point &p, Vertex *vertex) {
// Determines whether or not a line from a point to a vertex intersects the
// interior of the polygon, locally at that vertex
// Parameters: (Common::Point) p: The point
// (Vertex *) vertex: The vertex
// Returns : (int) 1 if the line (p, vertex->v) intersects the interior of
// the polygon, locally at the vertex. 0 otherwise
// Check that it's not a single-vertex polygon
if (VERTEX_HAS_EDGES(vertex)) {
const Common::Point &prev = CLIST_PREV(vertex)->v;
const Common::Point &next = CLIST_NEXT(vertex)->v;
const Common::Point &cur = vertex->v;
if (left(prev, cur, next)) {
// Convex vertex, line (p, cur) intersects the inside
// if p is located left of both edges
if (left(cur, next, p) && left(prev, cur, p))
return 1;
} else {
// Non-convex vertex, line (p, cur) intersects the
// inside if p is located left of either edge
if (left(cur, next, p) || left(prev, cur, p))
return 1;
}
}
return 0;
}
/**
* Determines whether or not a vertex is visible from vertex_cur.
* @param vertex_cur the base vertex
* @param vertex the vertex
* @param vertex_prev the previous vertex in the sort order, or NULL
* @param visible true if vertex_prev is visible, false otherwise
* @param intersected the list of edges intersected by the sweeping line
* @return true if vertex is visible from vertex_cur, false otherwise
*/
static bool visible(Vertex *vertex_cur, Vertex *vertex, Vertex *vertex_prev, bool visible, const VertexList &intersected) {
const Common::Point &p = vertex_cur->v;
const Common::Point &w = vertex->v;
// Check if sweeping line intersects the interior of the polygon
// locally at vertex
if (inside(p, vertex))
return false;
// If vertex_prev is on the sweeping line, then vertex is invisible
// if vertex_prev is invisible
if (vertex_prev && !visible && between(p, w, vertex_prev->v))
return false;
if (intersected.empty()) {
// No intersected edges
return true;
}
// Look for the intersected edge that is closest to vertex_cur
VertexList::const_iterator it = intersected.begin();
const Vertex *edge = *it++;
for (; it != intersected.end(); ++it) {
if (edgeIsCloser(vertex_cur, *it, edge))
edge = *it;
}
const Common::Point *p1, *p2;
// Check for intersection with sweeping line before vertex
clockwise(vertex_cur, edge, p1, p2);
if (left(*p2, *p1, p) && left(*p1, *p2, w))
return false;
return true;
}
/**
* Returns a list of all vertices that are visible from a particular vertex.
* @param s the pathfinding state
* @param vertex_cur the vertex
* @return list of vertices that are visible from vert
*/
static VertexList *visible_vertices(PathfindingState *s, Vertex *vertex_cur) {
// List of edges intersected by the sweeping line
VertexList intersected;
VertexList *visVerts = new VertexList();
const Common::Point &p = vertex_cur->v;
// Sort vertices by angle (first) and distance (second)
s_vertex_cur = vertex_cur;
qsort(s->vertex_index, s->vertices, sizeof(Vertex *), vertex_compare);
for (PolygonList::iterator it = s->polygons.begin(); it != s->polygons.end(); ++it) {
Polygon *polygon = *it;
Vertex *vertex;
vertex = polygon->vertices.first();
// Check that there is more than one vertex.
if (VERTEX_HAS_EDGES(vertex)) {
CLIST_FOREACH(vertex, &polygon->vertices) {
const Common::Point *high, *low;
// Add edges that intersect the initial position of the sweeping line
clockwise(vertex_cur, vertex, high, low);
if ((high->y < p.y) && (low->y >= p.y) && (*low != p))
intersected.push_front(vertex);
}
}
}
int is_visible = 1;
// The first vertex will be s_vertex_cur, so we skip it
for (int i = 1; i < s->vertices; i++) {
Vertex *v1;
// Compute visibility of vertex_index[i]
is_visible = visible(s_vertex_cur, s->vertex_index[i], s->vertex_index[i - 1], is_visible, intersected);
// Update visibility matrix
if (is_visible)
visVerts->push_front(s->vertex_index[i]);
// Delete anti-clockwise edges from list
v1 = CLIST_PREV(s->vertex_index[i]);
if (left(p, s->vertex_index[i]->v, v1->v))
intersected.remove(v1);
v1 = CLIST_NEXT(s->vertex_index[i]);
if (left(p, s->vertex_index[i]->v, v1->v))
intersected.remove(s->vertex_index[i]);
// Add clockwise edges of collinear vertices when sweeping line moves
if ((i < s->vertices - 1) && !collinear(p, s->vertex_index[i]->v, s->vertex_index[i + 1]->v)) {
int j;
for (j = i; (j >= 1) && collinear(p, s->vertex_index[i]->v, s->vertex_index[j]->v); j--) {
v1 = CLIST_PREV(s->vertex_index[j]);
if (left(s->vertex_index[j]->v, p, v1->v))
intersected.push_front(v1);
v1 = CLIST_NEXT(s->vertex_index[j]);
if (left(s->vertex_index[j]->v, p, v1->v))
intersected.push_front(s->vertex_index[j]);
}
}
}
return visVerts;
}
#if 0
static bool point_on_screen_border(const Common::Point &p) {
// Determines if a point lies on the screen border
// Parameters: (const Common::Point &) p: The point
// Returns : (int) true if p lies on the screen border, false otherwise
// FIXME get dimensions from somewhere?
return (p.x == 0) || (p.x == 319) || (p.y == 0) || (p.y == 189);
}
#endif
static bool edge_on_screen_border(const Common::Point &p, const Common::Point &q) {
// Determines if an edge lies on the screen border
// Parameters: (const Common::Point &) p, q: The edge (p, q)
// Returns : (int) true if (p, q) lies on the screen border, false otherwise
// FIXME get dimensions from somewhere?
return ((p.x == 0 && q.x == 0) || (p.x == 319 && q.x == 319) || (p.y == 0 && q.y == 0) || (p.y == 189 && q.y == 189));
}
static int find_free_point(FloatPoint f, Polygon *polygon, Common::Point *ret) {
// Searches for a nearby point that is not contained in a polygon
// Parameters: (FloatPoint) f: The pointf to search nearby
// (Polygon *) polygon: The polygon
// Returns : (int) PF_OK on success, PF_FATAL otherwise
// (Common::Point) *ret: The non-contained point on success
Common::Point p;
// Try nearest point first
p = Common::Point((int)floor(f.x + 0.5), (int)floor(f.y + 0.5));
if (contained(p, polygon) != CONT_INSIDE) {
*ret = p;
return PF_OK;
}
p = Common::Point((int)floor(f.x), (int)floor(f.y));
// Try (x, y), (x + 1, y), (x , y + 1) and (x + 1, y + 1)
if (contained(p, polygon) == CONT_INSIDE) {
p.x++;
if (contained(p, polygon) == CONT_INSIDE) {
p.y++;
if (contained(p, polygon) == CONT_INSIDE) {
p.x--;
if (contained(p, polygon) == CONT_INSIDE)
return PF_FATAL;
}
}
}
*ret = p;
return PF_OK;
}
static int near_point(const Common::Point &p, Polygon *polygon, Common::Point *ret) {
// Computes the near point of a point contained in a polygon
// Parameters: (const Common::Point &) p: The point
// (Polygon *) polygon: The polygon
// Returns : (int) PF_OK on success, PF_FATAL otherwise
// (Common::Point) *ret: The near point of p in polygon on success
Vertex *vertex;
FloatPoint near_p;
uint32 dist = HUGE_DISTANCE;
CLIST_FOREACH(vertex, &polygon->vertices) {
const Common::Point &p1 = vertex->v;
const Common::Point &p2 = CLIST_NEXT(vertex)->v;
float u;
FloatPoint new_point;
uint32 new_dist;
// Ignore edges on the screen border, except for contained access polygons
if ((polygon->type != POLY_CONTAINED_ACCESS) && (edge_on_screen_border(p1, p2)))
continue;
// Compute near point
u = ((p.x - p1.x) * (p2.x - p1.x) + (p.y - p1.y) * (p2.y - p1.y)) / (float)p1.sqrDist(p2);
// Clip to edge
if (u < 0.0f)
u = 0.0f;
if (u > 1.0f)
u = 1.0f;
new_point.x = p1.x + u * (p2.x - p1.x);
new_point.y = p1.y + u * (p2.y - p1.y);
new_dist = p.sqrDist(new_point.toPoint());
if (new_dist < dist) {
near_p = new_point;
dist = new_dist;
}
}
// Find point not contained in polygon
return find_free_point(near_p, polygon, ret);
}
static int intersection(const Common::Point &a, const Common::Point &b, Vertex *vertex, FloatPoint *ret) {
// Computes the intersection point of a line segment and an edge (not
// including the vertices themselves)
// Parameters: (const Common::Point &) a, b: The line segment (a, b)
// (Vertex *) vertex: The first vertex of the edge
// Returns : (int) FP_OK on success, PF_ERROR otherwise
// (FloatPoint) *ret: The intersection point
// Parameters of parametric equations
float s, t;
// Numerator and denominator of equations
float num, denom;
const Common::Point &c = vertex->v;
const Common::Point &d = CLIST_NEXT(vertex)->v;
denom = a.x * (float)(d.y - c.y) + b.x * (float)(c.y - d.y) +
d.x * (float)(b.y - a.y) + c.x * (float)(a.y - b.y);
if (denom == 0.0)
// Segments are parallel, no intersection
return PF_ERROR;
num = a.x * (float)(d.y - c.y) + c.x * (float)(a.y - d.y) + d.x * (float)(c.y - a.y);
s = num / denom;
num = -(a.x * (float)(c.y - b.y) + b.x * (float)(a.y - c.y) + c.x * (float)(b.y - a.y));
t = num / denom;
if ((0.0 <= s) && (s <= 1.0) && (0.0 < t) && (t < 1.0)) {
// Intersection found
ret->x = a.x + s * (b.x - a.x);
ret->y = a.y + s * (b.y - a.y);
return PF_OK;
}
return PF_ERROR;
}
static int nearest_intersection(PathfindingState *s, const Common::Point &p, const Common::Point &q, Common::Point *ret) {
// Computes the nearest intersection point of a line segment and the polygon
// set. Intersection points that are reached from the inside of a polygon
// are ignored as are improper intersections which do not obstruct
// visibility
// Parameters: (PathfindingState *) s: The pathfinding state
// (const Common::Point &) p, q: The line segment (p, q)
// Returns : (int) PF_OK on success, PF_ERROR when no intersections were
// found, PF_FATAL otherwise
// (Common::Point) *ret: On success, the closest intersection point
Polygon *polygon = 0;
FloatPoint isec;
Polygon *ipolygon = 0;
uint32 dist = HUGE_DISTANCE;
for (PolygonList::iterator it = s->polygons.begin(); it != s->polygons.end(); ++it) {
polygon = *it;
Vertex *vertex;
CLIST_FOREACH(vertex, &polygon->vertices) {
uint32 new_dist;
FloatPoint new_isec;
// Check for intersection with vertex
if (between(p, q, vertex->v)) {
// Skip this vertex if we hit it from the
// inside of the polygon
if (inside(q, vertex)) {
new_isec.x = vertex->v.x;
new_isec.y = vertex->v.y;
} else
continue;
} else {
// Check for intersection with edges
// Skip this edge if we hit it from the
// inside of the polygon
if (!left(vertex->v, CLIST_NEXT(vertex)->v, q))
continue;
if (intersection(p, q, vertex, &new_isec) != PF_OK)
continue;
}
new_dist = p.sqrDist(new_isec.toPoint());
if (new_dist < dist) {
ipolygon = polygon;
isec = new_isec;
dist = new_dist;
}
}
}
if (dist == HUGE_DISTANCE)
return PF_ERROR;
// Find point not contained in polygon
return find_free_point(isec, ipolygon, ret);
}
/**
* Checks that the start point is in a valid position, and takes appropriate action if it's not.
* @param s the pathfinding state
* @param start the start point
* @return a valid start point on success, NULL otherwise
*/
static Common::Point *fixup_start_point(PathfindingState *s, const Common::Point &start) {
PolygonList::iterator it = s->polygons.begin();
Common::Point *new_start = new Common::Point(start);
while (it != s->polygons.end()) {
int cont = contained(start, *it);
int type = (*it)->type;
switch (type) {
case POLY_TOTAL_ACCESS:
// Remove totally accessible polygons that contain the start point
if (cont != CONT_OUTSIDE) {
delete *it;
it = s->polygons.erase(it);
continue;
}
break;
case POLY_CONTAINED_ACCESS:
// Remove contained access polygons that do not contain
// the start point (containment test is inverted here).
if (cont == CONT_INSIDE) {
delete *it;
it = s->polygons.erase(it);
continue;
}
break;
case POLY_BARRED_ACCESS:
case POLY_NEAREST_ACCESS:
if (cont == CONT_INSIDE) {
if (s->_prependPoint != NULL) {
// We shouldn't get here twice
warning("AvoidPath: start point is contained in multiple polygons");
continue;
}
if (near_point(start, (*it), new_start) != PF_OK) {
delete new_start;
return NULL;
}
if (type == POLY_BARRED_ACCESS)
warning("AvoidPath: start position at unreachable location");
// The original start position is in an invalid location, so we
// use the moved point and add the original one to the final path
// later on.
s->_prependPoint = new Common::Point(start);
}
}
++it;
}
return new_start;
}
/**
* Checks that the end point is in a valid position, and takes appropriate action if it's not.
* @param s the pathfinding state
* @param end the end point
* @return a valid end point on success, NULL otherwise
*/
static Common::Point *fixup_end_point(PathfindingState *s, const Common::Point &end) {
PolygonList::iterator it = s->polygons.begin();
Common::Point *new_end = new Common::Point(end);
while (it != s->polygons.end()) {
int cont = contained(end, *it);
int type = (*it)->type;
switch (type) {
case POLY_TOTAL_ACCESS:
// Remove totally accessible polygons that contain the end point
if (cont != CONT_OUTSIDE) {
delete *it;
it = s->polygons.erase(it);
continue;
}
break;
case POLY_CONTAINED_ACCESS:
case POLY_BARRED_ACCESS:
case POLY_NEAREST_ACCESS:
if (cont != CONT_OUTSIDE) {
if (s->_appendPoint != NULL) {
// We shouldn't get here twice
warning("AvoidPath: end point is contained in multiple polygons");
continue;
}
// The original end position is in an invalid location, so we move the point
if (near_point(end, (*it), new_end) != PF_OK) {
delete new_end;
return NULL;
}
// For near-point access polygons we need to add the original end point
// to the path after pathfinding.
if (type == POLY_NEAREST_ACCESS)
s->_appendPoint = new Common::Point(end);
}
}
++it;
}
return new_end;
}
static Vertex *merge_point(PathfindingState *s, const Common::Point &v) {
// Merges a point into the polygon set. A new vertex is allocated for this
// point, unless a matching vertex already exists. If the point is on an
// already existing edge that edge is split up into two edges connected by
// the new vertex
// Parameters: (PathfindingState *) s: The pathfinding state
// (const Common::Point &) v: The point to merge
// Returns : (Vertex *) The vertex corresponding to v
Vertex *vertex;
Vertex *v_new;
Polygon *polygon;
// Check for already existing vertex
for (PolygonList::iterator it = s->polygons.begin(); it != s->polygons.end(); ++it) {
polygon = *it;
CLIST_FOREACH(vertex, &polygon->vertices) {
if (vertex->v == v)
return vertex;
}
}
v_new = new Vertex(v);
// Check for point being on an edge
for (PolygonList::iterator it = s->polygons.begin(); it != s->polygons.end(); ++it) {
polygon = *it;
// Skip single-vertex polygons
if (VERTEX_HAS_EDGES(polygon->vertices.first())) {
CLIST_FOREACH(vertex, &polygon->vertices) {
Vertex *next = CLIST_NEXT(vertex);
if (between(vertex->v, next->v, v)) {
// Split edge by adding vertex
polygon->vertices.insertAfter(vertex, v_new);
return v_new;
}
}
}
}
// Add point as single-vertex polygon
polygon = new Polygon(POLY_BARRED_ACCESS);
polygon->vertices.insertHead(v_new);
s->polygons.push_front(polygon);
return v_new;
}
static Polygon *convert_polygon(EngineState *s, reg_t polygon) {
// Converts an SCI polygon into a Polygon
// Parameters: (EngineState *) s: The game state
// (reg_t) polygon: The SCI polygon to convert
// Returns : (Polygon *) The converted polygon
int i;
reg_t points = GET_SEL32(polygon, points);
int size = GET_SEL32(polygon, size).toUint16();
const byte *list = kernel_dereference_bulk_pointer(s, points, size * POLY_POINT_SIZE);
Polygon *poly = new Polygon(GET_SEL32(polygon, type).toUint16());
int is_reg_t = polygon_is_reg_t(list, size);
// WORKAROUND: broken polygon in LSL1VGA, room 350, after opening elevator
// Polygon has 17 points but size is set to 19
if ((size == 19) && (s->_gameName == "LSL1")) {
if ((s->currentRoomNumber() == 350)
&& (read_point(list, is_reg_t, 18) == Common::Point(108, 137))) {
debug(1, "Applying fix for broken polygon in LSL1VGA, room 350");
size = 17;
}
}
// WORKAROUND: self-intersecting polygons in ECO, rooms 221, 280 and 300
if ((size == 11) && (s->_gameName == "eco")) {
if ((s->currentRoomNumber() == 300)
&& (read_point(list, is_reg_t, 10) == Common::Point(221, 0))) {
debug(1, "Applying fix for self-intersecting polygon in ECO, room 300");
size = 10;
}
}
if ((size == 12) && (s->_gameName == "eco")) {
if ((s->currentRoomNumber() == 280)
&& (read_point(list, is_reg_t, 11) == Common::Point(238, 189))) {
debug(1, "Applying fix for self-intersecting polygon in ECO, room 280");
size = 10;
}
}
if ((size == 16) && (s->_gameName == "eco")) {
if ((s->currentRoomNumber() == 221)
&& (read_point(list, is_reg_t, 1) == Common::Point(419, 175))) {
debug(1, "Applying fix for self-intersecting polygon in ECO, room 221");
// Swap the first two points
poly->vertices.insertHead(new Vertex(read_point(list, is_reg_t, 1)));
poly->vertices.insertHead(new Vertex(read_point(list, is_reg_t, 0)));
size = 14;
assert(!is_reg_t);
list += 2 * POLY_POINT_SIZE;
}
}
for (i = 0; i < size; i++) {
Vertex *vertex = new Vertex(read_point(list, is_reg_t, i));
poly->vertices.insertHead(vertex);
}
fix_vertex_order(poly);
return poly;
}
// WORKAROUND: intersecting polygons in Longbow, room 210.
static void fixLongbowRoom210(PathfindingState *s, const Common::Point &start, const Common::Point &end) {
Polygon *barred = NULL;
Polygon *total = NULL;
// Find the intersecting polygons
for (PolygonList::iterator it = s->polygons.begin(); it != s->polygons.end(); ++it) {
Polygon *polygon = *it;
assert(polygon);
if ((polygon->type == POLY_BARRED_ACCESS) && (polygon->vertices.size() == 11)
&& (polygon->vertices.first()->v == Common::Point(319, 161)))
barred = polygon;
else if ((polygon->type == POLY_TOTAL_ACCESS) && (polygon->vertices.size() == 8)
&& (polygon->vertices.first()->v == Common::Point(313, 58)))
total = polygon;
}
if (!barred || !total)
return;
debug(1, "[avoidpath] Applying fix for intersecting polygons in Longbow, room 210");
// If the start or end point is contained in the total access polygon, removing that
// polygon is sufficient. Otherwise we merge the total and barred access polygons.
bool both_outside = (contained(start, total) == CONT_OUTSIDE) && (contained(end, total) == CONT_OUTSIDE);
s->polygons.remove(total);
delete total;
if (both_outside) {
int points[28] = {
224, 159, 223, 162 ,194, 173 ,107, 173, 74, 162, 67, 156, 2, 58,
63, 160, 0, 160, 0, 0, 319, 0, 319, 161, 228, 161, 313, 58
};
s->polygons.remove(barred);
delete barred;
barred = new Polygon(POLY_BARRED_ACCESS);
for (int i = 0; i < 14; i++) {
Vertex *vertex = new Vertex(Common::Point(points[i * 2], points[i * 2 + 1]));
barred->vertices.insertHead(vertex);
}
s->polygons.push_front(barred);
}
}
static void change_polygons_opt_0(PathfindingState *s) {
// Changes the polygon list for optimization level 0 (used for keyboard
// support). Totally accessible polygons are removed and near-point
// accessible polygons are changed into totally accessible polygons.
// Parameters: (PathfindingState *) s: The pathfinding state
PolygonList::iterator it = s->polygons.begin();
while (it != s->polygons.end()) {
Polygon *polygon = *it;
assert(polygon);
if (polygon->type == POLY_TOTAL_ACCESS) {
delete polygon;
it = s->polygons.erase(it);
} else {
if (polygon->type == POLY_NEAREST_ACCESS)
polygon->type = POLY_TOTAL_ACCESS;
++it;
}
}
}
static PathfindingState *convert_polygon_set(EngineState *s, reg_t poly_list, Common::Point start, Common::Point end, int opt) {
// Converts the SCI input data for pathfinding
// Parameters: (EngineState *) s: The game state
// (reg_t) poly_list: Polygon list
// (Common::Point) start: The start point
// (Common::Point) end: The end point
// (int) opt: Optimization level (0, 1 or 2)
// Returns : (PathfindingState *) On success a newly allocated pathfinding state,
// NULL otherwise
Polygon *polygon;
int err;
int count = 0;
PathfindingState *pf_s = new PathfindingState();
// Convert all polygons
if (poly_list.segment) {
List *list = lookup_list(s, poly_list);
Node *node = lookup_node(s, list->first);
while (node) {
Node *dup = lookup_node(s, list->first);
// Workaround for game bugs that put a polygon in the list more than once
while (dup != node) {
if (polygons_equal(s, node->value, dup->value)) {
warning("[avoidpath] Ignoring duplicate polygon");
break;
}
dup = lookup_node(s, dup->succ);
}
if (dup == node) {
// Polygon is not a duplicate, so convert it
polygon = convert_polygon(s, node->value);
pf_s->polygons.push_back(polygon);
count += GET_SEL32(node->value, size).toUint16();
}
node = lookup_node(s, node->succ);
}
}
if (opt == 0) {
Common::Point intersection;
// Keyboard support
// FIXME: We don't need to dijkstra for keyboard support as we currently do
change_polygons_opt_0(pf_s);
// Find nearest intersection
err = nearest_intersection(pf_s, start, end, &intersection);
if (err == PF_FATAL) {
warning("AvoidPath: fatal error finding nearest intersection");
delete pf_s;
return NULL;
}
if (err == PF_OK) {
// Intersection was found, prepend original start position after pathfinding
pf_s->_prependPoint = new Common::Point(start);
// Merge new start point into polygon set
pf_s->vertex_start = merge_point(pf_s, intersection);
} else {
// Otherwise we proceed with the original start point
pf_s->vertex_start = merge_point(pf_s, start);
}
// Merge end point into polygon set
pf_s->vertex_end = merge_point(pf_s, end);
} else {
Common::Point *new_start = fixup_start_point(pf_s, start);
if (!new_start) {
warning("AvoidPath: Couldn't fixup start position for pathfinding");
delete pf_s;
return NULL;
}
Common::Point *new_end = fixup_end_point(pf_s, end);
if (!new_end) {
warning("AvoidPath: Couldn't fixup end position for pathfinding");
delete pf_s;
return NULL;
}
if (s->_gameName == "Longbow" && s->currentRoomNumber() == 210)
fixLongbowRoom210(pf_s, *new_start, *new_end);
// Merge start and end points into polygon set
pf_s->vertex_start = merge_point(pf_s, *new_start);
pf_s->vertex_end = merge_point(pf_s, *new_end);
delete new_start;
delete new_end;
}
// Allocate and build vertex index
pf_s->vertex_index = (Vertex**)malloc(sizeof(Vertex *) * (count + 2));
count = 0;
for (PolygonList::iterator it = pf_s->polygons.begin(); it != pf_s->polygons.end(); ++it) {
polygon = *it;
Vertex *vertex;
CLIST_FOREACH(vertex, &polygon->vertices) {
pf_s->vertex_index[count++] = vertex;
}
}
pf_s->vertices = count;
return pf_s;
}
static int intersecting_polygons(PathfindingState *s) {
// Detects (self-)intersecting polygons
// Parameters: (PathfindingState *) s: The pathfinding state
// Returns : (int) 1 if s contains (self-)intersecting polygons, 0 otherwise
int i, j;
for (i = 0; i < s->vertices; i++) {
Vertex *v1 = s->vertex_index[i];
if (!VERTEX_HAS_EDGES(v1))
continue;
for (j = i + 1; j < s->vertices; j++) {
Vertex *v2 = s->vertex_index[j];
if (!VERTEX_HAS_EDGES(v2))
continue;
// Skip neighbouring edges
if ((CLIST_NEXT(v1) == v2) || CLIST_PREV(v1) == v2)
continue;
if (intersect(v1->v, CLIST_NEXT(v1)->v,
v2->v, CLIST_NEXT(v2)->v))
return 1;
}
}
return 0;
}
static void dijkstra(PathfindingState *s) {
// Computes a shortest path from vertex_start to vertex_end. The caller can
// construct the resulting path by following the path_prev links from
// vertex_end back to vertex_start. If no path exists vertex_end->path_prev
// will be NULL
// Parameters: (PathfindingState *) s: The pathfinding state
Polygon *polygon;
// Vertices of which the shortest path is known
VertexList done;
// The remaining vertices
VertexList remain;
// Start out with all vertices in set remain
for (PolygonList::iterator it = s->polygons.begin(); it != s->polygons.end(); ++it) {
polygon = *it;
Vertex *vertex;
CLIST_FOREACH(vertex, &polygon->vertices) {
remain.push_front(vertex);
}
}
s->vertex_start->dist = 0;
// Loop until we find vertex_end
while (1) {
// Find vertex at shortest distance from set done
VertexList::iterator vertex_min_it = remain.end();
Vertex *vertex_min = 0;
uint32 min = HUGE_DISTANCE;
for (VertexList::iterator it = remain.begin(); it != remain.end(); ++it) {
Vertex *vertex = *it;
if (vertex->dist < min) {
vertex_min_it = it;
vertex_min = *vertex_min_it;
min = vertex->dist;
}
}
if (min == HUGE_DISTANCE) {
warning("[avoidpath] End point (%i, %i) is unreachable", s->vertex_end->v.x, s->vertex_end->v.y);
return;
}
// If vertex_end is at shortest distance we can stop
if (vertex_min == s->vertex_end)
return;
// Move vertex from set remain to set done
done.push_front(vertex_min);
remain.erase(vertex_min_it);
VertexList *visVerts = visible_vertices(s, vertex_min);
for (VertexList::iterator it = visVerts->begin(); it != visVerts->end(); ++it) {
uint32 new_dist;
Vertex *vertex = *it;
// Early pathfinding-enabled games exclude edges on screen borders.
// FIXME: Enable this selectively for those games that need it.
#if 0
// Avoid plotting path along screen edge
if ((vertex != s->vertex_end) && point_on_screen_border(vertex->v))
continue;
#endif
new_dist = vertex_min->dist + (uint32)sqrt((float)vertex_min->v.sqrDist(vertex->v));
if (new_dist < vertex->dist) {
vertex->dist = new_dist;
vertex->path_prev = vertex_min;
}
}
delete visVerts;
}
}
static reg_t output_path(PathfindingState *p, EngineState *s) {
// Stores the final path in newly allocated dynmem
// Parameters: (PathfindingState *) p: The pathfinding state
// (EngineState *) s: The game state
// Returns : (reg_t) Pointer to dynmem containing path
int path_len = 0;
byte *oref;
reg_t output;
Vertex *vertex = p->vertex_end;
int unreachable = vertex->path_prev == NULL;
if (unreachable) {
// If pathfinding failed we only return the path up to vertex_start
oref = s->seg_manager->allocDynmem(POLY_POINT_SIZE * 3, AVOIDPATH_DYNMEM_STRING, &output);
if (p->_prependPoint)
POLY_SET_POINT(oref, 0, *p->_prependPoint);
else
POLY_SET_POINT(oref, 0, p->vertex_start->v);
POLY_SET_POINT(oref, 1, p->vertex_start->v);
POLY_SET_POINT(oref, 2, Common::Point(POLY_LAST_POINT, POLY_LAST_POINT));
return output;
}
while (vertex) {
// Compute path length
path_len++;
vertex = vertex->path_prev;
}
// Allocate memory for path, plus 3 extra for appended point, prepended point and sentinel
oref = s->seg_manager->allocDynmem(POLY_POINT_SIZE * (path_len + 3), AVOIDPATH_DYNMEM_STRING, &output);
int offset = 0;
if (p->_prependPoint)
POLY_SET_POINT(oref, offset++, *p->_prependPoint);
vertex = p->vertex_end;
for (int i = path_len - 1; i >= 0; i--) {
POLY_SET_POINT(oref, offset + i, vertex->v);
vertex = vertex->path_prev;
}
offset += path_len;
if (p->_appendPoint)
POLY_SET_POINT(oref, offset++, *p->_appendPoint);
// Sentinel
POLY_SET_POINT(oref, offset, Common::Point(POLY_LAST_POINT, POLY_LAST_POINT));
#ifdef DEBUG_AVOIDPATH
printf("[avoidpath] Returning path:");
for (int i = 0; i < offset; i++) {
Common::Point pt;
POLY_GET_POINT(oref, i, pt);
printf(" (%i, %i)", pt.x, pt.y);
}
printf("\n");
#endif
return output;
}
reg_t kAvoidPath(EngineState *s, int funct_nr, int argc, reg_t *argv) {
Common::Point start = Common::Point(argv[0].toSint16(), argv[1].toSint16());
#ifdef DEBUG_AVOIDPATH
GfxPort *port = s->picture_port;
if (!port->_decorations) {
port->_decorations = gfxw_new_list(gfx_rect(0, 0, 320, 200), 0);
port->_decorations->setVisual(port->_visual);
} else {
port->_decorations->free_contents(port->_decorations);
}
#endif
switch (argc) {
case 3 : {
reg_t retval;
Polygon *polygon = convert_polygon(s, argv[2]);
// Override polygon type to prevent inverted result for contained access polygons
polygon->type = POLY_BARRED_ACCESS;
retval = make_reg(0, contained(start, polygon) != CONT_OUTSIDE);
delete polygon;
return retval;
}
case 6 :
case 7 : {
Common::Point end = Common::Point(argv[2].toSint16(), argv[3].toSint16());
reg_t poly_list = argv[4];
//int poly_list_size = argv[5].toUint16();
int opt = (argc > 6) ? argv[6].toUint16() : 1;
reg_t output;
PathfindingState *p;
#ifdef DEBUG_AVOIDPATH
printf("[avoidpath] Pathfinding input:\n");
draw_point(s, start, 1);
draw_point(s, end, 0);
if (poly_list.segment) {
print_input(s, poly_list, start, end, opt);
draw_input(s, poly_list, start, end, opt);
}
#endif
p = convert_polygon_set(s, poly_list, start, end, opt);
if (p && intersecting_polygons(p)) {
warning("[avoidpath] input set contains (self-)intersecting polygons");
delete p;
p = NULL;
}
if (!p) {
byte *oref;
printf("[avoidpath] Error: pathfinding failed for following input:\n");
print_input(s, poly_list, start, end, opt);
printf("[avoidpath] Returning direct path from start point to end point\n");
oref = s->seg_manager->allocDynmem(POLY_POINT_SIZE * 3,
AVOIDPATH_DYNMEM_STRING, &output);
POLY_SET_POINT(oref, 0, start);
POLY_SET_POINT(oref, 1, end);
POLY_SET_POINT(oref, 2, Common::Point(POLY_LAST_POINT, POLY_LAST_POINT));
return output;
}
dijkstra(p);
output = output_path(p, s);
delete p;
// Memory is freed by explicit calls to Memory
return output;
}
default:
warning("Unknown AvoidPath subfunction %d", argc);
return NULL_REG;
break;
}
}
} // End of namespace Sci
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