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diff --git a/src/display/nr-light.h b/src/display/nr-light.h
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+// SPDX-License-Identifier: GPL-2.0-or-later
+/** @file
+ * TODO: insert short description here
+ *//*
+ * Authors: see git history
+ *
+ * Copyright (C) 2017 Authors
+ * Released under GNU GPL v2+, read the file 'COPYING' for more information.
+ */
+#ifndef SEEN_NR_LIGHT_H
+#define SEEN_NR_LIGHT_H
+
+/** \file
+ * These classes provide tools to compute interesting objects relative to light
+ * sources. Each class provides a constructor converting information contained
+ * in a sp light object into information useful in the current setting, a
+ * method to get the light vector (at a given point) and a method to get the
+ * light color components (at a given point).
+ */
+
+#include <2geom/forward.h>
+
+#include "display/nr-3dutils.h"
+#include "display/nr-light-types.h"
+
+class SPFeDistantLight;
+class SPFePointLight;
+class SPFeSpotLight;
+typedef unsigned int guint32;
+
+namespace Inkscape {
+namespace Filters {
+
+enum LightComponent {
+    LIGHT_RED = 0,
+    LIGHT_GREEN,
+    LIGHT_BLUE
+};
+
+class DistantLight {
+    public:
+        /**
+         * Constructor
+         *
+         * \param light the sp light object
+         * \param lighting_color the lighting_color used
+         */
+        DistantLight(DistantLightData const &light, guint32 lighting_color);
+        virtual ~DistantLight();
+
+        /**
+         * Computes the light vector of the distant light
+         *
+         * \param v a Fvector reference where we store the result
+         */
+        void light_vector(NR::Fvector &v);
+
+        /**
+         * Computes the light components of the distant light
+         *
+         * \param lc a Fvector reference where we store the result, X=R, Y=G, Z=B
+         */
+        void light_components(NR::Fvector &lc);
+
+    private:
+        guint32 color;
+        double azimuth; //azimuth in rad
+        double elevation; //elevation in rad
+};
+
+class PointLight {
+    public:
+        /**
+         * Constructor
+         *
+         * \param light the sp light object
+         * \param lighting_color the lighting_color used
+         * \param trans the transformation between absolute coordinate (those
+         * employed in the sp light object) and current coordinate (those
+         * employed in the rendering)
+         * \param device_scale for high DPI monitors.
+         */
+        PointLight(PointLightData const &light, guint32 lighting_color, const Geom::Affine &trans, int device_scale = 1);
+        virtual ~PointLight();
+        /**
+         * Computes the light vector of the distant light at point (x,y,z).
+         * x, y and z are given in the arena_item coordinate, they are used as
+         * is
+         *
+         * \param v a Fvector reference where we store the result
+         * \param x x coordinate of the current point
+         * \param y y coordinate of the current point
+         * \param z z coordinate of the current point
+         */
+        void light_vector(NR::Fvector &v, double x, double y, double z);
+
+        /**
+         * Computes the light components of the distant light
+         *
+         * \param lc a Fvector reference where we store the result, X=R, Y=G, Z=B
+         */
+        void light_components(NR::Fvector &lc);
+
+    private:
+        guint32 color;
+        //light position coordinates in render setting
+        double l_x;
+        double l_y;
+        double l_z;
+};
+
+class SpotLight {
+    public:
+        /**
+         * Constructor
+         *
+         * \param light the sp light object
+         * \param lighting_color the lighting_color used
+         * \param trans the transformation between absolute coordinate (those
+         * employed in the sp light object) and current coordinate (those
+         * employed in the rendering)
+         * \param device_scale for high DPI monitors.
+         */
+        SpotLight(SpotLightData const &light, guint32 lighting_color, const Geom::Affine &trans, int device_scale = 1);
+        virtual ~SpotLight();
+
+        /**
+         * Computes the light vector of the distant light at point (x,y,z).
+         * x, y and z are given in the arena_item coordinate, they are used as
+         * is
+         *
+         * \param v a Fvector reference where we store the result
+         * \param x x coordinate of the current point
+         * \param y y coordinate of the current point
+         * \param z z coordinate of the current point
+         */
+        void light_vector(NR::Fvector &v, double x, double y, double z);
+
+        /**
+         * Computes the light components of the distant light at the current
+         * point. We only need the light vector to compute these
+         *
+         * \param lc a Fvector reference where we store the result, X=R, Y=G, Z=B
+         * \param L the light vector of the current point
+         */
+        void light_components(NR::Fvector &lc, const NR::Fvector &L);
+
+    private:
+        guint32 color;
+        //light position coordinates in render setting
+        double l_x;
+        double l_y;
+        double l_z;
+        double cos_lca; //cos of the limiting cone angle
+        double speExp; //specular exponent;
+        NR::Fvector S; //unit vector from light position in the direction
+                   //the spot point at
+};
+
+
+} /* namespace Filters */
+} /* namespace Inkscape */
+
+#endif // __NR_LIGHT_H__
+/*
+  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 :