1 files changed, 66 insertions, 0 deletions
diff --git a/src/display/nr-3dutils.cpp b/src/display/nr-3dutils.cpp
new file mode 100644
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+++ b/src/display/nr-3dutils.cpp
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 3D utils.
+ *
+ * Authors:
+ *   Jean-Rene Reinhard <jr@komite.net>
+ *
+ * Copyright (C) 2007 authors
+ *
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+
+#include <glib.h>
+
+#include "display/nr-3dutils.h"
+#include <cmath>
+#include <2geom/point.h>
+#include <2geom/affine.h>
+
+namespace NR {
+
+void convert_coord(gdouble &x, gdouble &y, gdouble &z, Geom::Affine const &trans) {
+    Geom::Point p = Geom::Point(x, y);
+    p *= trans;
+    x = p[Geom::X];
+    y = p[Geom::Y];
+    z *= trans[0];
+}
+
+gdouble norm(const Fvector &v) {
+    return sqrt(v[X_3D]*v[X_3D] + v[Y_3D]*v[Y_3D] + v[Z_3D]*v[Z_3D]);
+}
+
+void normalize_vector(Fvector &v) {
+    gdouble nv = norm(v);
+    //TODO test nv == 0
+    for (int j = 0; j < 3; j++) {
+        v[j] /= nv;
+    }
+}
+
+gdouble scalar_product(const Fvector &a, const Fvector &b) {
+    return  a[X_3D] * b[X_3D] +
+            a[Y_3D] * b[Y_3D] +
+            a[Z_3D] * b[Z_3D];
+}
+
+void normalized_sum(Fvector &r, const Fvector &a, const Fvector &b) {
+    r[X_3D] = a[X_3D] + b[X_3D];
+    r[Y_3D] = a[Y_3D] + b[Y_3D];
+    r[Z_3D] = a[Z_3D] + b[Z_3D];
+    normalize_vector(r);
+}
+
+}/* namespace NR */
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :