1 files changed, 88 insertions, 0 deletions
diff --git a/libdimension/model/objects/plane.c b/libdimension/model/objects/plane.c
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+++ b/libdimension/model/objects/plane.c
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+/*************************************************************************
+ * Copyright (C) 2010-2014 Tavian Barnes <tavianator@tavianator.com>     *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library 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  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+/**
+ * @file
+ * Planes.
+ */
+
+#include "dimension/model.h"
+#include <math.h>
+#include <stdlib.h>
+
+/// Plane type.
+typedef struct {
+  dmnsn_object object;
+  dmnsn_vector normal;
+} dmnsn_plane;
+
+/// Returns the closest intersection of `ray' with `plane'.
+static bool
+dmnsn_plane_intersection_fn(const dmnsn_object *object, dmnsn_ray ray,
+                            dmnsn_intersection *intersection)
+{
+  const dmnsn_plane *plane = (const dmnsn_plane *)object;
+  dmnsn_vector normal = plane->normal;
+
+  double den = dmnsn_vector_dot(ray.n, normal);
+  if (den != 0.0) {
+    double t = -dmnsn_vector_dot(ray.x0, normal)/den;
+    if (t >= 0.0) {
+      intersection->t      = t;
+      intersection->normal = normal;
+      return true;
+    }
+  }
+  return false;
+}
+
+/// Return whether a point is inside a plane.
+static bool
+dmnsn_plane_inside_fn(const dmnsn_object *object, dmnsn_vector point)
+{
+  const dmnsn_plane *plane = (const dmnsn_plane *)object;
+  return dmnsn_vector_dot(point, plane->normal) < 0.0;
+}
+
+/// Plane bounding callback.
+static dmnsn_aabb
+dmnsn_plane_bounding_fn(const dmnsn_object *object, dmnsn_matrix trans)
+{
+  return dmnsn_infinite_aabb();
+}
+
+/// Plane vtable.
+static const dmnsn_object_vtable dmnsn_plane_vtable = {
+  .intersection_fn = dmnsn_plane_intersection_fn,
+  .inside_fn = dmnsn_plane_inside_fn,
+  .bounding_fn = dmnsn_plane_bounding_fn,
+};
+
+dmnsn_object *
+dmnsn_new_plane(dmnsn_pool *pool, dmnsn_vector normal)
+{
+  dmnsn_plane *plane = DMNSN_PALLOC(pool, dmnsn_plane);
+  plane->normal = normal;
+
+  dmnsn_object *object = &plane->object;
+  dmnsn_init_object(object);
+  object->vtable = &dmnsn_plane_vtable;
+  return object;
+}