comp20003-project02/dcel.h

#ifndef TOWERS_HEADER
#include "towers.h"
#endif

#ifndef DCEL_HEADER
#define DCEL_HEADER

/* Here is the Base Code from Grady, with some alterations by me */

enum intersectType {
    DOESNT_INTERSECT  = 0, // Doesn't intersect
    INTERSECT         = 1, // Intersects
    SAME_LINE_OVERLAP = 2, // Lines are the same
    ENDS_OVERLAP      = 3  // Intersects at exactly one point (endpoint)
};

typedef struct vertex {
    double x;
    double y;
} vertex_t;

typedef struct bisector {
    double startX;
    double startY;
    double endX;
    double endY;

    /* This refers to the midpoint of the line segment AB, not the midpoint
     * of the bisector itself.
     */
    double midX;
    double midY;

    int isSlopeInfinite;
    double slope;
} bisector_t;

typedef struct halfEdgeLabel {
    struct halfEdgeLabel *previous;
    struct halfEdgeLabel *next;
    struct halfEdgeLabel *twin;
    int face;
    int edge;
    int startVertex;
    int endVertex;
} halfEdge_t;

typedef struct edge {
    halfEdge_t *halfEdge;
} edge_t;

typedef struct face {
    halfEdge_t *start;
    tower_t *tower;
} face_t;

typedef struct split {
    int startEdge;
    int endEdge;
    int verticesSpecified;
    vertex_t startPoint;
    vertex_t endPoint;
} split_t;

typedef struct intersection {
    vertex_t intersectionPoint;
} intersection_t;

typedef struct DCEL {
    edge_t *edges;
    int edgesUsed;
    int edgesAllocated;

    face_t *faces;
    int facesUsed;
    int facesAllocated;

    vertex_t *vertices;
    int verticesUsed;
    int verticesAllocated;
} DCEL_t;

/* Allocate a new DCEL and return it. */
DCEL_t *newDCEL();

/* Allocate a new halfEdge and return it. */
halfEdge_t *newHalfEdge();

/* Returns INSIDE if the points is on the INSIDE of the vector twin by the CW 
 * winding order, OUTSIDE if it is OUTSIDE by the CW winding order, and 
 * DIR_UNDECIDED if the point lies on the vector between the points v1 and v2. 
 */
int getRelativeDir(double x, double y, vertex_t *v1, vertex_t *v2);

/* Takes an established direction and a new direction, and returns 1 if the 
 * direction matches the decidedDirection or if the direction is undecided.
 */
int directionOrUndecided(int decidedDirection, int direction);

/* Check there's space for another vertex in the DCEL, 
 * or increase the allocated space. 
 */
void ensureSpaceForVertex(DCEL_t *dcel);

/* Check there's space for another edge in the DCEL, 
 * or increase the allocated space. 
 */
void ensureSpaceForEdge(DCEL_t *dcel);

/* Check there's space for another face in the DCEL, 
 * or increase the allocated space. 
 */
void ensureSpaceForFace(DCEL_t *dcel);

/* Add an edge from the startVertex index vertex to the endVertex index. 
 * Only fills one half-edge as other half-edges will always be added 
 * through geometry construction.
 */
void addEdge(DCEL_t *dcel, int startVertex, int endVertex);

/* Add a face to the DCEL given using the given halfEdge and sets the face. */
void addFace(DCEL_t *dcel, halfEdge_t *he);

/* Reads the polygon from the given file. */
DCEL_t *readPolygonFile(char *polygonfileName);

/* Reads the next split from the given file. */
split_t *readNextSplit(FILE *splitfile);

/* Frees a given split.  */
void freeSplit(split_t *split);

/* Returns 1 if vertices are sufficiently close, 0 otherwise. */
int vertexMatch(vertex_t *v1, vertex_t *v2);

/* Gets the string for the given bisector equation. */
char *getBisectorEquation(bisector_t *b);

/* Frees the given bisector. */
void freeBisector(bisector_t *bisector);

/* Representation of no face */
#define NOFACE (-1)

/* Default face for intersections. */
#define DEFAULT_FACE 0

/* Default minimum length for bisector in each direction */
#define DEFAULTMINLENGTH (200)

/* Gets the intersection between the given bisector and the given DCEL
 * for the given face. 
 */
intersection_t *getIntersection(bisector_t *b, DCEL_t *dcel, \
    int face, double minLength);

/* Gets the string for the given intersection. */
char *getIntersectionString(intersection_t *intersection);

/* Frees a given intersection. */
void freeIntersection(intersection_t *intersection);

/* Applies a given split to the DCEL. */
void applySplit(split_t *split, DCEL_t *dcel);

/* Frees the given DCEL */
void freeDCEL(DCEL_t *dcel);

/* Gets the number of faces in the DCEL. */
int getFaceCount(DCEL_t *dcel);

/* Returns 1 if the given x,y point is inside the given face. */
int inFace(DCEL_t *dcel, double x, double y, int faceIndex);

/* Gets the diameter of the given face. */
double getDiameter(DCEL_t *dcel, int faceIndex);

/* Adds the watchtower to the Voronoi diagram represented by the given DCEL, 
 * applying required splits and setting the watchtower as required.
 */
void incrementalVoronoi(DCEL_t *dcel, tower_t *watchTower);

/* Returns the number of vertices in the DCEL. */
int getDCELPointCount(DCEL_t *dcel);

/* Get x value of given vertex in DCEL. */
double getDCELVertexX(DCEL_t *dcel, int vertex);

/* Get y value of given vertex in DCEL. */
double getDCELVertexY(DCEL_t *dcel, int vertex);

/* Returns the number of edges in the DCEL. */
int getDCELEdgeCount(DCEL_t *dcel);

/* Get start vertex of given edge in DCEL. */
int getDCELEdgeVertexStart(DCEL_t *dcel, int edge);

/* Get end vertex of given edge in DCEL. */
int getDCELEdgeVertexEnd(DCEL_t *dcel, int edge);

/* Get start vertex of paired given edge in DCEL. */
int getDCELEdgeVertexPairStart(DCEL_t *dcel, int edge);

/* Get end vertex of paired given edge in DCEL. */
int getDCELEdgeVertexPairEnd(DCEL_t *dcel, int edge);

/* Check if the DCEL has the given edge. */
int DCELhasEdge(DCEL_t *dcel, int edge);

/* Check if the DCEL has a pair for the given edge. */
int DCELhasEdgePair(DCEL_t *dcel, int edge);

/* My own functions */

/* Reads the polygon file and stores the information in the vertices array */
vertex_t **readPolygon(vertex_t **vertices, FILE *polygonFile, \
    int *numVertices);

/* Frees an array of vertices */
void freeVertices(vertex_t **vertices, int numVertices);

/* Calculates and returns the equation of a bisector of two points */
bisector_t *getBisector(vertex_t *pointA, vertex_t *pointB);

/* Euclidian distance between two 2D points */
double dist_2D(double x1, double y1, double x2, double y2);

/* Returns a value for x that ensures the point (x, y) is at least d (distance) 
 * away from (x1, y1) whilst ensuring (x, y) is on the line y = mx + c1.
 */
double inv_dist_2D(double x1, double y1, double m, double c, double d);

/* Returns a point at least distance away from the midpoint of the bisector given */
vertex_t *getBisectorPoint(double distance, bisector_t *b);

/* O'Rourke's functions */
/* Returns -1, 0 or 1, based on the area enclosed by the three points. 0 corresponds
    to no area enclosed.
*/
int areaSign(double sx, double sy, double ex, double ey, double x, double y);

/* Returns 1 if point (x, y) is between (sx, sy) and (ex, ey) */
int between(double sx, double sy, double ex, double ey, double x, double y);

/* Returns 1 if the point (x, y) is in the line from s(x, y) to e(x, y),
 * 0 otherwise.
 */
int collinear(double sx, double sy, double ex, double ey, double x, double y);

/* Tests if the half edge and bisector are parallel and overlapping, or not
 * intersecting.
 */
enum intersectType parallelIntersects(double heSx, double heSy, \
    double heEx, double heEy, double bSx, double bSy, \
    double bEx, double bEy, double *x, double *y);

/* Tests if  */
enum intersectType intersects(halfEdge_t *he, bisector_t *b, \
    DCEL_t *dcel, double minLength, double *x, double *y);

#endif