--- /dev/null
+/* -*- C++ -*- ------------------------------------------------------------
+
+Copyright (c) 2007 Jesse Anders and Demian Nave http://cmldev.net/
+
+The Configurable Math Library (CML) is distributed under the terms of the
+Boost Software License, v1.0 (see cml/LICENSE for details).
+
+ *-----------------------------------------------------------------------*/
+/** @file
+ * @brief
+ */
+
+#ifndef picking_h
+#define picking_h
+
+#include <cml/mathlib/projection.h>
+
+/* Functions for picking with rays, volumes, and drag-enclosed volumes. */
+
+namespace cml {
+
+/* Support function for extracting the near and far depth range values from
+ * a viewport matrix.
+ */
+
+namespace detail {
+
+// NOTE: Changed 'near' and 'far' to 'n' and 'f' to work around windows.h
+// 'near' and 'far' macros.
+
+template < class MatT, typename Real > void
+depth_range_from_viewport_matrix(const MatT& viewport, Real& n, Real& f)
+{
+ detail::CheckMatHomogeneous3D(viewport);
+
+ n = viewport.basis_element(3,2);
+ f = viewport.basis_element(2,2) + n;
+}
+
+} // namespace detail
+
+/* Make a pick ray given screen coordinates and view, projection, and viewport
+ * matrices. The origin of the ray lies in the near plane of the frustum; the
+ * direction vector extends to the far plane if 'normalize' is false, and is
+ * made unit-length if 'normalize' is true (its default value).
+ *
+ * Note that the origin of the ray lies in the near plane rather than
+ * coinciding with the position of the virtual camera, as the latter gives
+ * incorrect results when the projection is orthographic.
+ *
+ * Note also that the screen y coordinate increases from bottom to top rather
+ * than top to bottom. If mouse coordinates are returned in window space where
+ * the y coordinate increases from top to bottom (as is often the case), the
+ * y value should be recomputed as 'y = <window height> - y' before being
+ * submitted to this function.
+ */
+
+template < class MatT_1, class MatT_2, class MatT_3, typename E, class A >
+void make_pick_ray(
+ E pick_x,
+ E pick_y,
+ const MatT_1& view,
+ const MatT_2& projection,
+ const MatT_3& viewport,
+ vector<E,A>& origin,
+ vector<E,A>& direction,
+ bool normalize = true)
+{
+ typedef vector<E,A> vector_type;
+ typedef typename vector_type::value_type value_type;
+
+ // NOTE: Changed 'near' and 'far' to 'n' and 'f' to work around
+ // windows.h 'near' and 'far' macros.
+ value_type n, f;
+ detail::depth_range_from_viewport_matrix(viewport, n, f);
+
+ origin =
+ unproject_point(
+ view,projection,viewport,vector_type(pick_x,pick_y,n)
+ );
+ direction =
+ unproject_point(
+ view,projection,viewport,vector_type(pick_x,pick_y,f)
+ ) - origin;
+ if (normalize) {
+ direction.normalize();
+ }
+}
+
+/* Make a pick volume given the screen coordinates of the center of the
+ * picking rect, the width and height of the picking rect, and view and
+ * projection matrices.
+ *
+ * The volume is loaded into the 'planes' array. The planes are of the form
+ * ax+by+cz+d = 0, and are in the order left, right, bottom, top, near, far.
+ *
+ * The z_clip argument should be either z_clip_neg_one or z_clip_zero, and
+ * should correspond to the near z-clipping range of the projection matrix
+ * argument.
+ *
+ * The 'normalize' argument indicates whether the output planes should be
+ * normalized; its default value is 'true'.
+ *
+ * Note that the screen y coordinate increases from bottom to top rather
+ * than top to bottom. If mouse coordinates are returned in window space where
+ * the y coordinate increases from top to bottom (as is often the case), the
+ * y value should be recomputed as 'y = <window height> - y' before being
+ * submitted to this function.
+ */
+
+template < class MatT_1, class MatT_2, typename Real >
+void make_pick_volume(
+ Real pick_x,
+ Real pick_y,
+ Real pick_width,
+ Real pick_height,
+ Real viewport_x,
+ Real viewport_y,
+ Real viewport_width,
+ Real viewport_height,
+ const MatT_1& view,
+ const MatT_2& projection,
+ Real planes[6][4],
+ ZClip z_clip,
+ bool normalize = true)
+{
+ // FIXME: Should be promoted type...
+ typedef matrix<
+ Real, fixed<4,4>,
+ typename MatT_1::basis_orient, typename MatT_1::layout >
+ matrix_type;
+
+ matrix_type pick;
+ matrix_pick(
+ pick, pick_x, pick_y, pick_width, pick_height,
+ viewport_x, viewport_y, viewport_width, viewport_height
+ );
+ cml::extract_frustum_planes(
+ view,detail::matrix_concat_transforms_4x4(projection,pick),
+ planes,z_clip,normalize);
+}
+
+/* Make a pick volume given two opposite corners of a rectangle in screen
+ * space, and view and projection matrices. The corners of the screen rect
+ * need not be in any particular 'order' with regard to the values of the
+ * coordinates.
+ *
+ * The volume is loaded into the 'planes' array. The planes are of the form
+ * ax+by+cz+d = 0, and are in the order left, right, bottom, top, near, far.
+ *
+ * The z_clip argument should be either z_clip_neg_one or z_clip_zero, and
+ * should correspond to the near z-clipping range of the projection matrix
+ * argument.
+ *
+ * The 'normalize' argument indicates whether the output planes should be
+ * normalized; its default value is 'true'.
+ *
+ * Note that the screen y coordinate increases from bottom to top rather
+ * than top to bottom. If mouse coordinates are returned in window space where
+ * the y coordinate increases from top to bottom (as is often the case), the
+ * y value should be recomputed as 'y = <window height> - y' before being
+ * submitted to this function.
+ */
+
+template < class MatT_1, class MatT_2, typename Real >
+void make_pick_drag_volume(
+ Real pick_x1,
+ Real pick_y1,
+ Real pick_x2,
+ Real pick_y2,
+ Real viewport_x,
+ Real viewport_y,
+ Real viewport_width,
+ Real viewport_height,
+ const MatT_1& view,
+ const MatT_2& projection,
+ Real planes[6][4],
+ ZClip z_clip,
+ bool normalize = true)
+{
+ typedef Real value_type;
+
+ make_pick_volume(
+ (pick_x1+pick_x2)*value_type(.5),
+ (pick_y1+pick_y2)*value_type(.5),
+ std::fabs(pick_x2-pick_x1),
+ std::fabs(pick_y2-pick_y1),
+ viewport_x, viewport_y, viewport_width, viewport_height,
+ view, projection, planes, z_clip, normalize
+ );
+}
+
+} // namespace cml
+
+#endif
projects / chaz / yoink / blobdiff