From b1a0552bf4dba462cd371ba369a40f4dcbf95a32 Mon Sep 17 00:00:00 2001
From: skyjake <skyjake@users.sf.net>
Date: Fri, 15 Nov 2013 19:53:53 +0200
Subject: [PATCH] Renderer: Added an interface for point light sources

---
 doomsday/client/client.pro                    |  1 +
 doomsday/client/include/render/ilightsource.h | 82 +++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 doomsday/client/include/render/ilightsource.h

diff --git a/doomsday/client/client.pro b/doomsday/client/client.pro
index ab76871ab2..3f87cb8e47 100644
--- a/doomsday/client/client.pro
+++ b/doomsday/client/client.pro
@@ -301,6 +301,7 @@ DENG_HEADERS += \
     include/render/fx/postprocessing.h \
     include/render/fx/vignette.h \
     include/render/huecirclevisual.h \
+    include/render/ilightsource.h \
     include/render/lightdecoration.h \
     include/render/lightgrid.h \
     include/render/lumobj.h \
diff --git a/doomsday/client/include/render/ilightsource.h b/doomsday/client/include/render/ilightsource.h
new file mode 100644
index 0000000000..51b40ece61
--- /dev/null
+++ b/doomsday/client/include/render/ilightsource.h
@@ -0,0 +1,82 @@
+/** @file ilightsource.h  Interface for a light source.
+ *
+ * @authors Copyright (c) 2013 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program 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 General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, see:
+ * http://www.gnu.org/licenses</small>
+ */
+
+#ifndef DENG_CLIENT_ILIGHTSOURCE_H
+#define DENG_CLIENT_ILIGHTSOURCE_H
+
+#include <de/libdeng2.h>
+#include <de/Vector>
+
+/**
+ * Interface for a light source.
+ *
+ * All sources of light should implement this interface. Through it, various
+ * parts of the rendering subsystem can know where and what kind of light this
+ * is.
+ *
+ * @ingroup render
+ */
+class ILightSource
+{
+public:
+    typedef de::Vector3d Origin;
+
+    /**
+     * Unique identifier of the source. This can be used to uniquely identify a
+     * source of light across multiple frames.
+     */
+    typedef de::duint32 LightId;
+
+    /**
+     * RGB color of the emitted light.
+     */
+    typedef de::Vector3f Color;
+
+public:
+    virtual ~ILightSource() {}
+
+    virtual LightId lightSourceId() const = 0;
+
+    /**
+     * Returns the position of the light source, in map units.
+     */
+    virtual Origin lightSourceOrigin() const = 0;
+
+    /**
+     * Returns the radius of the emitter itself, in map units. A radius of
+     * zero would mean that the light emitter is an infinitely small point.
+     */
+    virtual de::dfloat lightSourceRadius() const = 0;
+
+    /**
+     * Returns the color of the emitted light. The intensity of the light must
+     * not be factored into the color values, but is instead returned separately
+     * by lightSourceIntensity().
+     */
+    virtual Color lightSourceColor() const = 0;
+
+    /**
+     * Returns the intensity of the light.
+     *
+     * @param viewPoint  World point from where the light is being observed.
+     *                   Intensity may vary based on direction.
+     */
+    virtual de::dfloat lightSourceIntensity(de::Vector3d const &viewPoint) const = 0;
+};
+
+#endif // DENG_CLIENT_ILIGHTSOURCE_H