[capi] add visibility to capi

Oslandia · Sep 29, 2023 · 4150577 · 4150577
1 parent 04d6f32
commit 4150577
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diff --git a/src/capi/sfcgal_c.cpp b/src/capi/sfcgal_c.cpp
@@ -43,6 +43,7 @@
 #include <SFCGAL/algorithm/tesselate.h>
 #include <SFCGAL/algorithm/union.h>
 #include <SFCGAL/algorithm/volume.h>
+#include <SFCGAL/algorithm/visibility.h>
 #include <SFCGAL/triangulate/triangulate2DZ.h>
 
 #include <SFCGAL/detail/transform/ForceOrderPoints.h>
@@ -1334,3 +1335,76 @@ sfcgal_optimal_convex_partition_2(const sfcgal_geometry_t *geom)
 
   return result.release();
 }
+
+
+extern "C" sfcgal_geometry_t *
+sfcgal_visibility_point(const sfcgal_geometry_t *polygon, const sfcgal_geometry_t *point)
+{
+
+  const auto *poly = reinterpret_cast<const SFCGAL::Geometry *>(polygon);
+  const auto *pt = reinterpret_cast<const SFCGAL::Geometry *>(point);
+  std::unique_ptr<SFCGAL::Geometry> result;
+
+  if (poly->geometryTypeId() != SFCGAL::TYPE_POLYGON) {
+    SFCGAL_ERROR("visibility() only applies to polygons");
+    return result.release();
+  }
+
+  if (pt->geometryTypeId() != SFCGAL::TYPE_POINT) {
+    SFCGAL_ERROR("second argument must be a point");
+    return result.release();
+  }
+
+  try {
+    result = SFCGAL::algorithm::visibility(
+        poly->as<const SFCGAL::Polygon>(), pt->as<const SFCGAL::Point>());
+  } catch (std::exception &e) {
+    SFCGAL_WARNING("During visibility(A, B) :");
+    SFCGAL_WARNING("  with A: %s",
+                   poly->asText().c_str());
+    SFCGAL_WARNING("  and B: %s",
+                   pt->asText().c_str());
+    SFCGAL_ERROR("%s", e.what());
+    return result.release();
+  }
+
+  return result.release();
+}
+
+extern "C" sfcgal_geometry_t *
+sfcgal_visibility_segment(const sfcgal_geometry_t *polygon, const sfcgal_geometry_t *pointA, const sfcgal_geometry_t *pointB)
+{
+  const auto *poly = reinterpret_cast<const SFCGAL::Geometry *>(polygon);
+  const auto *ptA = reinterpret_cast<const SFCGAL::Geometry *>(pointA);
+  const auto *ptB = reinterpret_cast<const SFCGAL::Geometry *>(pointB);
+  std::unique_ptr<SFCGAL::Geometry> result;
+
+  if (poly->geometryTypeId() != SFCGAL::TYPE_POLYGON) {
+    SFCGAL_ERROR("visibility() only applies to polygons");
+    return result.release();
+  }
+
+  if ( (ptA->geometryTypeId() != SFCGAL::TYPE_POINT) || (ptB->geometryTypeId() != SFCGAL::TYPE_POINT) ) {
+    SFCGAL_ERROR("second and third argument must be a point");
+    return result.release();
+  }
+
+  try {
+    result = SFCGAL::algorithm::visibility(
+        poly->as<const SFCGAL::Polygon>(), ptA->as<const SFCGAL::Point>(), ptB->as<const SFCGAL::Point>());
+  } catch (std::exception &e) {
+    SFCGAL_WARNING("During visibility(A, B, C) :");
+    SFCGAL_WARNING("  with A: %s",
+                   poly->asText().c_str());
+    SFCGAL_WARNING("  and B: %s",
+                   ptA->asText().c_str());
+    SFCGAL_WARNING("  and C: %s",
+                   ptB->asText().c_str());
+    SFCGAL_ERROR("%s", e.what());
+    return result.release();
+  }
+
+  return result.release();
+}
+
+
diff --git a/src/capi/sfcgal_c.h b/src/capi/sfcgal_c.h
@@ -1081,6 +1081,31 @@ sfcgal_greene_approx_convex_partition_2(const sfcgal_geometry_t *geom);
 SFCGAL_API sfcgal_geometry_t *
 sfcgal_optimal_convex_partition_2(const sfcgal_geometry_t *geom);
 
+/**
+ * Returns the visibility polygon of a Point inside a Polygon
+ * @param polygon input geometry
+ * @param point input geometry
+ * @ingroup capi
+ * @pre polygon is a valid geometry
+ * @pre point must be inside polygon or on the boundary
+ */
+SFCGAL_API sfcgal_geometry_t *
+sfcgal_visibility_point(const sfcgal_geometry_t *polygon, const sfcgal_geometry_t *point);
+
+/**
+ * @brief build the visibility polygon of the segment [pointA ; pointB] on a
+ * Polygon
+ * @param polygon input geometry
+ * @param pointA input geometry
+ * @param pointB input geometry
+ * @ingroup public_api
+ * @pre polygon is a valid geometry
+ * @pre pointA and pointB must be vertices of poly, adjacents and respect the
+ * direction
+ */
+SFCGAL_API sfcgal_geometry_t *
+sfcgal_visibility_segment(const sfcgal_geometry_t *polygon, const sfcgal_geometry_t *pointA, const sfcgal_geometry_t *pointB);
+
 /*--------------------------------------------------------------------------------------*
  *
  * Error handling