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
 *
 * Throw 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, int32_t 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;
}