1/*
2 * Copyright (C) 2008 Alex Mathews <possessedpenguinbob@gmail.com>
3 * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
4 * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
5 * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
6 * Copyright (C) 2010 Zoltan Herczeg <zherczeg@webkit.org>
7 *
8 * This library is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Library General Public
10 * License as published by the Free Software Foundation; either
11 * version 2 of the License, or (at your option) any later version.
12 *
13 * This library is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Library General Public License for more details.
17 *
18 * You should have received a copy of the GNU Library General Public License
19 * along with this library; see the file COPYING.LIB.  If not, write to
20 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
21 * Boston, MA 02110-1301, USA.
22 */
23
24#ifndef LightSource_h
25#define LightSource_h
26
27#include "platform/PlatformExport.h"
28#include "platform/geometry/FloatPoint3D.h"
29#include "wtf/PassRefPtr.h"
30#include "wtf/RefCounted.h"
31
32namespace blink {
33
34enum LightType {
35    LS_DISTANT,
36    LS_POINT,
37    LS_SPOT
38};
39
40class TextStream;
41
42class PLATFORM_EXPORT LightSource : public RefCounted<LightSource> {
43public:
44
45    // Light vectors must be calculated for every pixel during
46    // painting. It is expensive to pass all these arguments to
47    // a frequently called function, especially because not all
48    // light sources require all of them. Instead, we just pass
49    // a reference to the following structure
50    struct PaintingData {
51        // SVGFELighting also use them
52        FloatPoint3D lightVector;
53        FloatPoint3D colorVector;
54        float lightVectorLength;
55        // Private members
56        FloatPoint3D directionVector;
57        FloatPoint3D privateColorVector;
58        float coneCutOffLimit;
59        float coneFullLight;
60    };
61
62    LightSource(LightType type)
63        : m_type(type)
64    { }
65
66    virtual ~LightSource();
67
68    LightType type() const { return m_type; }
69    virtual TextStream& externalRepresentation(TextStream&) const = 0;
70
71    virtual PassRefPtr<LightSource> create(const FloatPoint3D& scale, const FloatSize& offset) const = 0;
72
73    virtual void initPaintingData(PaintingData&) const = 0;
74    // z is a float number, since it is the alpha value scaled by a user
75    // specified "surfaceScale" constant, which type is <number> in the SVG standard
76    virtual void updatePaintingData(PaintingData&, int x, int y, float z) const = 0;
77
78    virtual bool setAzimuth(float) { return false; }
79    virtual bool setElevation(float) { return false; }
80    virtual bool setPosition(const FloatPoint3D&) { return false; }
81    virtual bool setPointsAt(const FloatPoint3D&) { return false; }
82    virtual bool setSpecularExponent(float) { return false; }
83    virtual bool setLimitingConeAngle(float) { return false; }
84
85private:
86    LightType m_type;
87};
88
89} // namespace blink
90
91#endif // LightSource_h
92