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SCI: Some cleanup; avoid taking square root unnecessarily

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svn-id: r39612
This commit is contained in:
Max Horn 2009-03-22 18:27:08 +00:00
parent 07cc19df38
commit 09ecda7ca4
1 changed files with 39 additions and 31 deletions
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70
engines/sci/engine/kpathing.cpp
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@ -254,20 +254,18 @@ struct PathfindingState {
}; };
static Vertex *vertex_cur; static Vertex *vertex_cur; // FIXME
// Temporary hack to deal with points in reg_ts // Temporary hack to deal with points in reg_ts
static int polygon_is_reg_t(unsigned char *list, int size) { static bool polygon_is_reg_t(unsigned char *list, int size) {
int i;
// Check the first three reg_ts // Check the first three reg_ts
for (i = 0; i < (size < 3 ? size : 3); i++) for (int i = 0; i < (size < 3 ? size : 3); i++)
if ((((reg_t *) list) + i)->segment) if ((((reg_t *) list) + i)->segment)
// Non-zero segment, cannot be reg_ts // Non-zero segment, cannot be reg_ts
return 0; return false;
// First three segments were zero, assume reg_ts // First three segments were zero, assume reg_ts
return 1; return true;
} }
static Common::Point read_point(unsigned char *list, int is_reg_t, int offset) { static Common::Point read_point(unsigned char *list, int is_reg_t, int offset) {
@ -424,38 +422,38 @@ static int area(Common::Point a, Common::Point b, Common::Point c) {
return (b.x - a.x) * (a.y - c.y) - (c.x - a.x) * (a.y - b.y); return (b.x - a.x) * (a.y - c.y) - (c.x - a.x) * (a.y - b.y);
} }
static int left(Common::Point a, Common::Point b, Common::Point c) { static bool left(Common::Point a, Common::Point b, Common::Point c) {
// Determines whether or not a point is to the left of a directed line // Determines whether or not a point is to the left of a directed line
// Parameters: (Common::Point) a, b: The directed line (a, b) // Parameters: (Common::Point) a, b: The directed line (a, b)
// (Common::Point) c: The query point // (Common::Point) c: The query point
// Returns : (int) 1 if c is to the left of (a, b), 0 otherwise // Returns : (int) true if c is to the left of (a, b), false otherwise
return area(a, b, c) > 0; return area(a, b, c) > 0;
} }
static int left_on(Common::Point a, Common::Point b, Common::Point c) { static bool left_on(Common::Point a, Common::Point b, Common::Point c) {
// Determines whether or not a point is to the left of or collinear with a // Determines whether or not a point is to the left of or collinear with a
// directed line // directed line
// Parameters: (Common::Point) a, b: The directed line (a, b) // Parameters: (Common::Point) a, b: The directed line (a, b)
// (Common::Point) c: The query point // (Common::Point) c: The query point
// Returns : (int) 1 if c is to the left of or collinear with (a, b), 0 // Returns : (int) true if c is to the left of or collinear with (a, b), false
// otherwise // otherwise
return area(a, b, c) >= 0; return area(a, b, c) >= 0;
} }
static int collinear(Common::Point a, Common::Point b, Common::Point c) { static bool collinear(Common::Point a, Common::Point b, Common::Point c) {
// Determines whether or not three points are collinear // Determines whether or not three points are collinear
// Parameters: (Common::Point) a, b, c: The three points // Parameters: (Common::Point) a, b, c: The three points
// Returns : (int) 1 if a, b, and c are collinear, 0 otherwise // Returns : (int) true if a, b, and c are collinear, false otherwise
return area(a, b, c) == 0; return area(a, b, c) == 0;
} }
static int between(Common::Point a, Common::Point b, Common::Point c) { static bool between(Common::Point a, Common::Point b, Common::Point c) {
// Determines whether or not a point lies on a line segment // Determines whether or not a point lies on a line segment
// Parameters: (Common::Point) a, b: The line segment (a, b) // Parameters: (Common::Point) a, b: The line segment (a, b)
// (Common::Point) c: The query point // (Common::Point) c: The query point
// Returns : (int) 1 if c lies on (a, b), 0 otherwise // Returns : (int) true if c lies on (a, b), false otherwise
if (!collinear(a, b, c)) if (!collinear(a, b, c))
return 0; return false;
// Assumes a != b. // Assumes a != b.
if (a.x != b.x) if (a.x != b.x)
@ -464,24 +462,24 @@ static int between(Common::Point a, Common::Point b, Common::Point c) {
return ((a.y <= c.y) && (c.y <= b.y)) || ((a.y >= c.y) && (c.y >= b.y)); return ((a.y <= c.y) && (c.y <= b.y)) || ((a.y >= c.y) && (c.y >= b.y));
} }
static int intersect_proper(Common::Point a, Common::Point b, Common::Point c, Common::Point d) { static bool intersect_proper(Common::Point a, Common::Point b, Common::Point c, Common::Point d) {
// Determines whether or not two line segments properly intersect // Determines whether or not two line segments properly intersect
// Parameters: (Common::Point) a, b: The line segment (a, b) // Parameters: (Common::Point) a, b: The line segment (a, b)
// (Common::Point) c, d: The line segment (c, d) // (Common::Point) c, d: The line segment (c, d)
// Returns : (int) 1 if (a, b) properly intersects (c, d), 0 otherwise // 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 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)); int cd = (left(c, d, a) && left(d, c, b)) || (left(c, d, b) && left(d, c, a));
return ab && cd; return ab && cd;
} }
static int intersect(Common::Point a, Common::Point b, Common::Point c, Common::Point d) { static bool intersect(Common::Point a, Common::Point b, Common::Point c, Common::Point d) {
// Determines whether or not two line segments intersect // Determines whether or not two line segments intersect
// Parameters: (Common::Point) a, b: The line segment (a, b) // Parameters: (Common::Point) a, b: The line segment (a, b)
// (Common::Point) c, d: The line segment (c, d) // (Common::Point) c, d: The line segment (c, d)
// Returns : (int) 1 if (a, b) intersects (c, d), 0 otherwise // Returns : (int) true if (a, b) intersects (c, d), false otherwise
if (intersect_proper(a, b, c, d)) if (intersect_proper(a, b, c, d))
return 1; return true;
return between(a, b, c) || between(a, b, d) || between(c, d, a) || between(c, d, b); return between(a, b, c) || between(a, b, d) || between(c, d, a) || between(c, d, b);
} }
@ -837,28 +835,38 @@ static void visible_vertices(PathfindingState *s, Vertex *vert) {
free(vert_sorted); free(vert_sorted);
} }
static float distance(FloatPoint a, FloatPoint b) { /**
// Computes the distance between two pointfs * Computes the distance between two FloatPoints.
// Parameters: (Common::Point) a, b: The two pointfs */
// Returns : (int) The distance between a and b, rounded to int static float distance(const FloatPoint &a, const FloatPoint &b) {
float w = a.x - b.x; float w = a.x - b.x;
float h = a.y - b.y; float h = a.y - b.y;
return sqrt(w * w + h * h); return sqrt(w * w + h * h);
} }
static int point_on_screen_border(Common::Point p) { /**
* Computes the square of the distance between two FloatPoints.
*/
static float distanceSqr(const FloatPoint &a, const FloatPoint &b) {
float w = a.x - b.x;
float h = a.y - b.y;
return w * w + h * h;
}
static bool point_on_screen_border(const Common::Point &p) {
// Determines if a point lies on the screen border // Determines if a point lies on the screen border
// Parameters: (Common::Point) p: The point // Parameters: (Common::Point) p: The point
// Returns : (int) 1 if p lies on the screen border, 0 otherwise // Returns : (int) true if p lies on the screen border, false otherwise
// FIXME get dimensions from somewhere? // FIXME get dimensions from somewhere?
return (p.x == 0) || (p.x == 319) || (p.y == 0) || (p.y == 189); return (p.x == 0) || (p.x == 319) || (p.y == 0) || (p.y == 189);
} }
static int edge_on_screen_border(Common::Point p, Common::Point q) { static bool edge_on_screen_border(const Common::Point &p, const Common::Point &q) {
// Determines if an edge lies on the screen border // Determines if an edge lies on the screen border
// Parameters: (Common::Point) p, q: The edge (p, q) // Parameters: (Common::Point) p, q: The edge (p, q)
// Returns : (int) 1 if (p, q) lies on the screen border, 0 otherwise // Returns : (int) true if (p, q) lies on the screen border, false otherwise
// FIXME get dimensions from somewhere? // 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)); 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));
} }
@ -934,7 +942,7 @@ static int near_point(Common::Point p, Polygon *polygon, Common::Point *ret) {
new_point.x = p1.x + u * (p2.x - p1.x); new_point.x = p1.x + u * (p2.x - p1.x);
new_point.y = p1.y + u * (p2.y - p1.y); new_point.y = p1.y + u * (p2.y - p1.y);
new_dist = distance(toFloatPoint(p), new_point); new_dist = distanceSqr(toFloatPoint(p), new_point);
if (new_dist < dist) { if (new_dist < dist) {
near_p = new_point; near_p = new_point;
@ -1029,7 +1037,7 @@ static int nearest_intersection(PathfindingState *s, Common::Point p, Common::Po
continue; continue;
} }
new_dist = distance(toFloatPoint(p), new_isec); new_dist = distanceSqr(toFloatPoint(p), new_isec);
if (new_dist < dist) { if (new_dist < dist) {
ipolygon = polygon; ipolygon = polygon;
isec = new_isec; isec = new_isec;