liblwgeom/lwgeom_sfcgal.c

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/**********************************************************************
 *
 * PostGIS - Spatial Types for PostgreSQL
 * http://postgis.net
 *
 * PostGIS 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.
 *
 * PostGIS 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 PostGIS.  If not, see <http://www.gnu.org/licenses/>.
 *
 **********************************************************************
 *
 * Copyright 2012-2013 Oslandia <infos@oslandia.com>
 *
 **********************************************************************/


#include "lwgeom_sfcgal.h"

static int SFCGAL_type_to_lwgeom_type(sfcgal_geometry_type_t type);
static POINTARRAY* ptarray_from_SFCGAL(const sfcgal_geometry_t* geom, int force3D);
static sfcgal_geometry_t* ptarray_to_SFCGAL(const POINTARRAY* pa, int type);



/* Return SFCGAL version string */
const char*
lwgeom_sfcgal_version()
{
        const char *version = sfcgal_version();
        return version;
}


/*
 * Mapping between SFCGAL and PostGIS types
 *
 * Throw an error if type is unsupported
 */
static int
SFCGAL_type_to_lwgeom_type(sfcgal_geometry_type_t type)
{
        switch (type)
        {
        case SFCGAL_TYPE_POINT:
                return POINTTYPE;

        case SFCGAL_TYPE_LINESTRING:
                return LINETYPE;

        case SFCGAL_TYPE_POLYGON:
                return POLYGONTYPE;

        case SFCGAL_TYPE_MULTIPOINT:
                return MULTIPOINTTYPE;

        case SFCGAL_TYPE_MULTILINESTRING:
                return MULTILINETYPE;

        case SFCGAL_TYPE_MULTIPOLYGON:
                return MULTIPOLYGONTYPE;

        case SFCGAL_TYPE_MULTISOLID:
                return COLLECTIONTYPE;  /* Nota: PolyhedralSurface closed inside
                                           aim is to use true solid type as soon
                                           as available in OGC SFS */

        case SFCGAL_TYPE_GEOMETRYCOLLECTION:
                return COLLECTIONTYPE;

#if 0
        case SFCGAL_TYPE_CIRCULARSTRING:
                return CIRCSTRINGTYPE;

        case SFCGAL_TYPE_COMPOUNDCURVE:
                return COMPOUNDTYPE;

        case SFCGAL_TYPE_CURVEPOLYGON:
                return CURVEPOLYTYPE;

        case SFCGAL_TYPE_MULTICURVE:
                return MULTICURVETYPE;

        case SFCGAL_TYPE_MULTISURFACE:
                return MULTISURFACETYPE;
#endif

        case SFCGAL_TYPE_POLYHEDRALSURFACE:
                return POLYHEDRALSURFACETYPE;

        case SFCGAL_TYPE_TRIANGULATEDSURFACE:
                return TINTYPE;

        case SFCGAL_TYPE_TRIANGLE:
                return TRIANGLETYPE;

        default:
                lwerror("SFCGAL_type_to_lwgeom_type: Unknown Type");
                return 0;
        }
}


/*
 * Return a PostGIS pointarray from a simple SFCGAL geometry:
 * POINT, LINESTRING or TRIANGLE
 *
 * Trought an error on others types
 */
static POINTARRAY*
ptarray_from_SFCGAL(const sfcgal_geometry_t* geom, int want3d)
{
        POINT4D point;
        uint32_t i, npoints;
        POINTARRAY* pa = NULL;

        assert(geom);

        switch (sfcgal_geometry_type_id(geom))
        {
        case SFCGAL_TYPE_POINT:
        {
                pa = ptarray_construct(want3d, 0, 1);
                point.x = sfcgal_point_x(geom);
                point.y = sfcgal_point_y(geom);

                if (sfcgal_geometry_is_3d(geom))
                        point.z = sfcgal_point_z(geom);
                else if (want3d)
                        point.z = 0.0;

                ptarray_set_point4d(pa, 0, &point);
        }
        break;

        case SFCGAL_TYPE_LINESTRING:
        {
                npoints = sfcgal_linestring_num_points(geom);
                pa = ptarray_construct(want3d, 0, npoints);

                for (i = 0; i < npoints; i++)
                {
                        const sfcgal_geometry_t* pt = sfcgal_linestring_point_n(geom, i);
                        point.x = sfcgal_point_x(pt);
                        point.y = sfcgal_point_y(pt);

                        if (sfcgal_geometry_is_3d(geom))
                                point.z = sfcgal_point_z(pt);
                        else if (want3d)
                                point.z = 0.0;

                        ptarray_set_point4d(pa, i, &point);
                }
        }
        break;

        case SFCGAL_TYPE_TRIANGLE:
        {
                pa = ptarray_construct(want3d, 0, 4);

                for (i = 0; i < 4; i++)
                {
                        const sfcgal_geometry_t* pt = sfcgal_triangle_vertex(geom, (i%3));
                        point.x = sfcgal_point_x(pt);
                        point.y = sfcgal_point_y(pt);

                        if ( sfcgal_geometry_is_3d(geom))
                                point.z = sfcgal_point_z(pt);
                        else if (want3d)
                                point.z = 0.0;

                        ptarray_set_point4d(pa, i, &point);
                }
        }
        break;

        /* Other types should not be called directly ... */
        default:
                lwerror("ptarray_from_SFCGAL: Unknown Type");
                break;
        }
        return pa;
}


/*
 * Convert a PostGIS pointarray to SFCGAL structure
 *
 * Used for simple LWGEOM geometry POINT, LINESTRING, TRIANGLE
 * and POLYGON rings
 */
static sfcgal_geometry_t*
ptarray_to_SFCGAL(const POINTARRAY* pa, int type)
{
        POINT3DZ point;
        int is_3d;
        uint32_t i;

        assert(pa);

        is_3d = FLAGS_GET_Z(pa->flags) != 0;

        switch (type)
        {
        case POINTTYPE:
        {
                getPoint3dz_p(pa, 0, &point);
                if (is_3d) return sfcgal_point_create_from_xyz(point.x, point.y, point.z);
                else       return sfcgal_point_create_from_xy(point.x, point.y);
        }
        break;

        case LINETYPE:
        {
                sfcgal_geometry_t* line = sfcgal_linestring_create();

                for (i = 0; i < pa->npoints; i++)
                {
                        getPoint3dz_p(pa, i, &point);
                        if (is_3d)
                        {
                                sfcgal_linestring_add_point(line,
                                                            sfcgal_point_create_from_xyz(point.x, point.y, point.z));
                        }
                        else
                        {
                                sfcgal_linestring_add_point(line,
                                                            sfcgal_point_create_from_xy(point.x, point.y));
                        }
                }

                return line;
        }
        break;

        case TRIANGLETYPE:
        {
                sfcgal_geometry_t* triangle = sfcgal_triangle_create();

                getPoint3dz_p(pa, 0, &point);
                if (is_3d) sfcgal_triangle_set_vertex_from_xyz(triangle, 0, point.x, point.y, point.z);
                else       sfcgal_triangle_set_vertex_from_xy (triangle, 0, point.x, point.y);

                getPoint3dz_p(pa, 1, &point);
                if (is_3d) sfcgal_triangle_set_vertex_from_xyz(triangle, 1, point.x, point.y, point.z);
                else       sfcgal_triangle_set_vertex_from_xy (triangle, 1, point.x, point.y);

                getPoint3dz_p(pa, 2, &point);
                if (is_3d) sfcgal_triangle_set_vertex_from_xyz(triangle, 2, point.x, point.y, point.z);
                else       sfcgal_triangle_set_vertex_from_xy (triangle, 2, point.x, point.y);

                return triangle;
        }
        break;

        /* Other SFCGAL types should not be called directly ... */
        default:
                lwerror("ptarray_from_SFCGAL: Unknown Type");
                return NULL;
        }
}


/*
 * Convert a SFCGAL structure to PostGIS LWGEOM
 *
 * Throws an error on unsupported type
 */
LWGEOM*
SFCGAL2LWGEOM(const sfcgal_geometry_t* geom, int force3D, int srid)
{
        uint32_t ngeoms, nshells, nsolids;
        uint32_t i, j, k;
        int want3d;

        assert(geom);

        want3d = force3D || sfcgal_geometry_is_3d(geom);

        switch (sfcgal_geometry_type_id(geom))
        {
        case SFCGAL_TYPE_POINT:
        {
                if (sfcgal_geometry_is_empty(geom))
                        return (LWGEOM*) lwpoint_construct_empty(srid, want3d, 0);

                POINTARRAY* pa = ptarray_from_SFCGAL(geom, want3d);
                return (LWGEOM*) lwpoint_construct(srid, NULL, pa);
        }

        case SFCGAL_TYPE_LINESTRING:
        {
                if (sfcgal_geometry_is_empty(geom))
                        return (LWGEOM*) lwline_construct_empty(srid, want3d, 0);

                POINTARRAY* pa = ptarray_from_SFCGAL(geom, want3d);
                return (LWGEOM*) lwline_construct(srid, NULL, pa);
        }

        case SFCGAL_TYPE_TRIANGLE:
        {
                if (sfcgal_geometry_is_empty(geom))
                        return (LWGEOM*) lwtriangle_construct_empty(srid, want3d, 0);

                POINTARRAY* pa = ptarray_from_SFCGAL(geom, want3d);
                return (LWGEOM*) lwtriangle_construct(srid, NULL, pa);
        }

        case SFCGAL_TYPE_POLYGON:
        {
                if (sfcgal_geometry_is_empty(geom))
                        return (LWGEOM*) lwpoly_construct_empty(srid, want3d, 0);

                uint32_t nrings = sfcgal_polygon_num_interior_rings(geom) + 1;
                POINTARRAY** pa = (POINTARRAY**) lwalloc(sizeof(POINTARRAY*) * nrings);

                pa[0] = ptarray_from_SFCGAL(sfcgal_polygon_exterior_ring(geom), want3d);
                for (i = 1; i < nrings; i++)
                        pa[i] = ptarray_from_SFCGAL(sfcgal_polygon_interior_ring_n(geom, i-1), want3d);

                return (LWGEOM*) lwpoly_construct(srid, NULL, nrings, pa);
        }

        case SFCGAL_TYPE_MULTIPOINT:
        case SFCGAL_TYPE_MULTILINESTRING:
        case SFCGAL_TYPE_MULTIPOLYGON:
        case SFCGAL_TYPE_MULTISOLID:
        case SFCGAL_TYPE_GEOMETRYCOLLECTION:
        {
                ngeoms = sfcgal_geometry_collection_num_geometries(geom);
                LWGEOM** geoms = NULL;
                if (ngeoms)
                {
                        nsolids = 0;
                        geoms = (LWGEOM**) lwalloc(sizeof(LWGEOM*) * ngeoms);
                        for (i = 0; i < ngeoms; i++)
                        {
                                const sfcgal_geometry_t* g = sfcgal_geometry_collection_geometry_n(geom, i);
                                geoms[i] = SFCGAL2LWGEOM(g, 0, srid);
                                if ( FLAGS_GET_SOLID( geoms[i]->flags ) ) ++nsolids;
                        }
                        geoms = (LWGEOM**) lwrealloc(geoms, sizeof(LWGEOM*) * ngeoms);
                }
                LWGEOM* rgeom = (LWGEOM*) lwcollection_construct(SFCGAL_type_to_lwgeom_type(
                                sfcgal_geometry_type_id(geom)), srid, NULL, ngeoms, geoms);
                if ( ngeoms )
                {
                        if ( ngeoms == nsolids ) FLAGS_SET_SOLID( rgeom->flags, 1);
                        else if ( nsolids ) lwnotice("SFCGAL2LWGEOM: SOLID in heterogeneous collection will be treated as a POLYHEDRALSURFACETYPE");
                }
                return rgeom;
        }

#if 0
        case SFCGAL_TYPE_CIRCULARSTRING:
        case SFCGAL_TYPE_COMPOUNDCURVE:
        case SFCGAL_TYPE_CURVEPOLYGON:
        case SFCGAL_TYPE_MULTICURVE:
        case SFCGAL_TYPE_MULTISURFACE:
        case SFCGAL_TYPE_CURVE:
        case SFCGAL_TYPE_SURFACE:

        /* TODO curve types handling */
#endif

        case SFCGAL_TYPE_POLYHEDRALSURFACE:
        {
                ngeoms = sfcgal_polyhedral_surface_num_polygons(geom);

                LWGEOM** geoms = NULL;
                if (ngeoms)
                {
                        geoms = (LWGEOM**) lwalloc(sizeof(LWGEOM*) * ngeoms);
                        for (i = 0; i < ngeoms; i++)
                        {
                                const sfcgal_geometry_t* g = sfcgal_polyhedral_surface_polygon_n( geom, i );
                                geoms[i] = SFCGAL2LWGEOM(g, 0, srid);
                        }
                }
                return (LWGEOM*)lwcollection_construct(POLYHEDRALSURFACETYPE, srid, NULL, ngeoms, geoms);
        }

        /* Solid is map as a closed PolyhedralSurface (for now) */
        case SFCGAL_TYPE_SOLID:
        {
                nshells = sfcgal_solid_num_shells(geom);

                for (ngeoms = 0, i = 0; i < nshells; i++)
                        ngeoms += sfcgal_polyhedral_surface_num_polygons(sfcgal_solid_shell_n(geom, i));

                LWGEOM** geoms = 0;
                if (ngeoms)
                {
                        geoms = (LWGEOM**) lwalloc( sizeof(LWGEOM*) * ngeoms);
                        for (i = 0, k =0 ; i < nshells; i++)
                        {
                                const sfcgal_geometry_t* shell = sfcgal_solid_shell_n(geom, i);
                                ngeoms = sfcgal_polyhedral_surface_num_polygons(shell);

                                for (j = 0; j < ngeoms; j++)
                                {
                                        const sfcgal_geometry_t* g = sfcgal_polyhedral_surface_polygon_n(shell, j);
                                        geoms[k] = SFCGAL2LWGEOM(g, 1, srid);
                                        k++;
                                }
                        }
                }
                LWGEOM* rgeom =  (LWGEOM*) lwcollection_construct(POLYHEDRALSURFACETYPE, srid, NULL, ngeoms, geoms);
                if (ngeoms) FLAGS_SET_SOLID( rgeom->flags, 1);
                return rgeom;
        }

        case SFCGAL_TYPE_TRIANGULATEDSURFACE:
        {
                ngeoms = sfcgal_triangulated_surface_num_triangles(geom);
                LWGEOM** geoms = NULL;
                if (ngeoms)
                {
                        geoms = (LWGEOM**) lwalloc(sizeof(LWGEOM*) * ngeoms);
                        for (i = 0; i < ngeoms; i++)
                        {
                                const sfcgal_geometry_t* g = sfcgal_triangulated_surface_triangle_n(geom, i);
                                geoms[i] = SFCGAL2LWGEOM(g, 0, srid);
                        }
                }
                return (LWGEOM*) lwcollection_construct(TINTYPE, srid, NULL, ngeoms, geoms);
        }

        default:
                lwerror("SFCGAL2LWGEOM: Unknown Type");
                return NULL;
        }
}


sfcgal_geometry_t*
LWGEOM2SFCGAL(const LWGEOM* geom)
{
        uint32_t i;
        sfcgal_geometry_t* ret_geom = NULL;

        assert(geom);

        switch (geom->type)
        {
        case POINTTYPE:
        {
                const LWPOINT* lwp = (const LWPOINT*) geom;
                if (lwgeom_is_empty(geom)) return sfcgal_point_create();

                return ptarray_to_SFCGAL(lwp->point, POINTTYPE);
        }
        break;

        case LINETYPE:
        {
                const LWLINE* line = (const LWLINE*) geom;
                if (lwgeom_is_empty(geom)) return sfcgal_linestring_create();

                return ptarray_to_SFCGAL(line->points, LINETYPE);
        }
        break;

        case TRIANGLETYPE:
        {
                const LWTRIANGLE* triangle = (const LWTRIANGLE*) geom;
                if (lwgeom_is_empty(geom)) return sfcgal_triangle_create();
                return ptarray_to_SFCGAL(triangle->points, TRIANGLETYPE);
        }
        break;

        case POLYGONTYPE:
        {
                const LWPOLY* poly = (const LWPOLY*) geom;
                uint32_t nrings = poly->nrings - 1;

                if (lwgeom_is_empty(geom)) return sfcgal_polygon_create();

                sfcgal_geometry_t* exterior_ring = ptarray_to_SFCGAL(poly->rings[0], LINETYPE);
                ret_geom = sfcgal_polygon_create_from_exterior_ring(exterior_ring);

                for (i = 0; i < nrings; i++)
                {
                        sfcgal_geometry_t* ring = ptarray_to_SFCGAL(poly->rings[i + 1], LINETYPE);
                        sfcgal_polygon_add_interior_ring(ret_geom, ring);
                }
                return ret_geom;
        }
        break;

        case MULTIPOINTTYPE:
        case MULTILINETYPE:
        case MULTIPOLYGONTYPE:
        case COLLECTIONTYPE:
        {
                if (geom->type == MULTIPOINTTYPE)        ret_geom = sfcgal_multi_point_create();
                else if (geom->type == MULTILINETYPE)    ret_geom = sfcgal_multi_linestring_create();
                else if (geom->type == MULTIPOLYGONTYPE) ret_geom = sfcgal_multi_polygon_create();
                else                                     ret_geom = sfcgal_geometry_collection_create();

                const LWCOLLECTION* lwc = (const LWCOLLECTION*)geom;
                for (i = 0; i < lwc->ngeoms; i++)
                {
                        sfcgal_geometry_t* g = LWGEOM2SFCGAL(lwc->geoms[i]);
                        sfcgal_geometry_collection_add_geometry(ret_geom, g);
                }

                return ret_geom;
        }
        break;

        case POLYHEDRALSURFACETYPE:
        {
                const LWPSURFACE* lwp = (const LWPSURFACE*) geom;
                ret_geom = sfcgal_polyhedral_surface_create();

                for (i = 0; i < lwp->ngeoms; i++)
                {
                        sfcgal_geometry_t* g = LWGEOM2SFCGAL((const LWGEOM*) lwp->geoms[i]);
                        sfcgal_polyhedral_surface_add_polygon(ret_geom, g);
                }
                /* We treat polyhedral surface as the only exterior shell,
                   since we can't distinguish exterior from interior shells ... */
                if (FLAGS_GET_SOLID(lwp->flags))
                {
                        return sfcgal_solid_create_from_exterior_shell(ret_geom);
                }

                return ret_geom;
        }
        break;

        case TINTYPE:
        {
                const LWTIN* lwp = (const LWTIN*) geom;
                ret_geom = sfcgal_triangulated_surface_create();

                for (i = 0; i < lwp->ngeoms; i++)
                {
                        sfcgal_geometry_t* g = LWGEOM2SFCGAL((const LWGEOM*) lwp->geoms[i]);
                        sfcgal_triangulated_surface_add_triangle(ret_geom, g);
                }

                return ret_geom;
        }
        break;

        default:
                lwerror("LWGEOM2SFCGAL: Unknown geometry type !");
                return NULL;
        }
}


/*
 * No Operation SFCGAL function, used (only) for cunit tests
 * Take a PostGIS geometry, send it to SFCGAL and return it unchanged (in theory)
 */
LWGEOM* lwgeom_sfcgal_noop(const LWGEOM* geom_in)
{
        sfcgal_geometry_t* converted;

        assert(geom_in);

        converted = LWGEOM2SFCGAL(geom_in);
        assert(converted);

        LWGEOM* geom_out = SFCGAL2LWGEOM(converted, 0, SRID_UNKNOWN);
        sfcgal_geometry_delete(converted);

        /* copy SRID (SFCGAL does not store the SRID) */
        geom_out->srid = geom_in->srid;
        return geom_out;
}