New cube object.

1 files changed, 113 insertions, 0 deletions

diff --git a/libdimension/cube.c b/libdimension/cube.c
new file mode 100644
index 0000000..197a0f8
--- /dev/null
+++ b/libdimension/cube.c
@@ -0,0 +1,113 @@
+/*************************************************************************
+ * Copyright (C) 2008 Tavian Barnes <tavianator@gmail.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/>.                                       *
+ *************************************************************************/
+
+#include "dimension.h"
+#include <stdlib.h> /* For malloc */
+#include <math.h>   /* For sqrt   */
+
+static dmnsn_array *dmnsn_cube_intersections_fn(const dmnsn_object *cube,
+                                                  dmnsn_line line);
+static int dmnsn_cube_inside_fn(const dmnsn_object *cube,
+                                  dmnsn_vector point);
+
+dmnsn_object *
+dmnsn_new_cube()
+{
+  dmnsn_object *cube = dmnsn_new_object();
+  if (cube) {
+    cube->intersections_fn = &dmnsn_cube_intersections_fn;
+    cube->inside_fn        = &dmnsn_cube_inside_fn;
+  }
+  return cube;
+}
+
+void
+dmnsn_delete_cube(dmnsn_object *cube)
+{
+  dmnsn_delete_object(cube);
+}
+
+static dmnsn_array *
+dmnsn_cube_intersections_fn(const dmnsn_object *cube, dmnsn_line line)
+{
+  double t;
+  dmnsn_vector p;
+  dmnsn_array *array = dmnsn_new_array(sizeof(double));
+
+  /* Six ray-plane intersection tests (x, y, z) = +/- 1.0 */
+
+  if (line.n.x != 0.0) {
+    /* x = -1.0 */
+    t = (-1.0 - line.x0.x)/line.n.x;
+    p = dmnsn_line_point(line, t);
+    if (p.y >= -1.0 && p.y <= 1.0 && p.z >= -1.0 && p.z <= 1.0) {
+      dmnsn_array_push(array, &t);
+    }
+
+    /* x = 1.0 */
+    t = (1.0 - line.x0.x)/line.n.x;
+    p = dmnsn_line_point(line, t);
+    if (p.y >= -1.0 && p.y <= 1.0 && p.z >= -1.0 && p.z <= 1.0) {
+      dmnsn_array_push(array, &t);
+    }
+  }
+
+  if (line.n.y != 0.0) {
+    /* y = -1.0 */
+    t = (-1.0 - line.x0.y)/line.n.y;
+    p = dmnsn_line_point(line, t);
+    if (p.x >= -1.0 && p.x <= 1.0 && p.z >= -1.0 && p.z <= 1.0) {
+      dmnsn_array_push(array, &t);
+    }
+
+    /* y = 1.0 */
+    t = (1.0 - line.x0.y)/line.n.y;
+    p = dmnsn_line_point(line, t);
+    if (p.x >= -1.0 && p.x <= 1.0 && p.z >= -1.0 && p.z <= 1.0) {
+      dmnsn_array_push(array, &t);
+    }
+  }
+
+  if (line.n.z != 0.0) {
+    /* z = -1.0 */
+    t = (-1.0 - line.x0.z)/line.n.z;
+    p = dmnsn_line_point(line, t);
+    if (p.x >= -1.0 && p.x <= 1.0 && p.y >= -1.0 && p.y <= 1.0) {
+      dmnsn_array_push(array, &t);
+    }
+
+    /* z = 1.0 */
+    t = (1.0 - line.x0.z)/line.n.z;
+    p = dmnsn_line_point(line, t);
+    if (p.x >= -1.0 && p.x <= 1.0 && p.y >= -1.0 && p.y <= 1.0) {
+      dmnsn_array_push(array, &t);
+    }
+  }
+
+  return array;
+}
+
+static int
+dmnsn_cube_inside_fn(const dmnsn_object *cube, dmnsn_vector point)
+{
+  return point.x > -1.0 && point.x < 1.0
+      && point.y > -1.0 && point.y < 1.0
+      && point.z > -1.0 && point.z < 1.0; 
+}