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 * Copyright (C) 2011 University of Szeged
8 * Copyright (C) 2011 Renata Hodovan <reni@webkit.org>
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY UNIVERSITY OF SZEGED ``AS IS'' AND ANY
20 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL UNIVERSITY OF SZEGED OR
23 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
24 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
25 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
26 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
27 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
28 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
29 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
30 */
31
32#include "config.h"
33
34#if ENABLE(FILTERS)
35#include "SpotLightSource.h"
36
37#include "TextStream.h"
38
39namespace WebCore {
40
41// spot-light edge darkening depends on an absolute treshold
42// according to the SVG 1.1 SE light regression tests
43static const float antiAliasTreshold = 0.016f;
44
45void SpotLightSource::initPaintingData(PaintingData& paintingData)
46{
47    paintingData.privateColorVector = paintingData.colorVector;
48    paintingData.directionVector.setX(m_direction.x() - m_position.x());
49    paintingData.directionVector.setY(m_direction.y() - m_position.y());
50    paintingData.directionVector.setZ(m_direction.z() - m_position.z());
51    paintingData.directionVector.normalize();
52
53    if (!m_limitingConeAngle) {
54        paintingData.coneCutOffLimit = 0.0f;
55        paintingData.coneFullLight = -antiAliasTreshold;
56    } else {
57        float limitingConeAngle = m_limitingConeAngle;
58        if (limitingConeAngle < 0.0f)
59            limitingConeAngle = -limitingConeAngle;
60        if (limitingConeAngle > 90.0f)
61            limitingConeAngle = 90.0f;
62        paintingData.coneCutOffLimit = cosf(deg2rad(180.0f - limitingConeAngle));
63        paintingData.coneFullLight = paintingData.coneCutOffLimit - antiAliasTreshold;
64    }
65
66    // Optimization for common specularExponent values
67    if (!m_specularExponent)
68        paintingData.specularExponent = 0;
69    else if (m_specularExponent == 1.0f)
70        paintingData.specularExponent = 1;
71    else // It is neither 0.0f nor 1.0f
72        paintingData.specularExponent = 2;
73}
74
75void SpotLightSource::updatePaintingData(PaintingData& paintingData, int x, int y, float z)
76{
77    paintingData.lightVector.setX(m_position.x() - x);
78    paintingData.lightVector.setY(m_position.y() - y);
79    paintingData.lightVector.setZ(m_position.z() - z);
80    paintingData.lightVectorLength = paintingData.lightVector.length();
81
82    float cosineOfAngle = (paintingData.lightVector * paintingData.directionVector) / paintingData.lightVectorLength;
83    if (cosineOfAngle > paintingData.coneCutOffLimit) {
84        // No light is produced, scanlines are not updated
85        paintingData.colorVector.setX(0.0f);
86        paintingData.colorVector.setY(0.0f);
87        paintingData.colorVector.setZ(0.0f);
88        return;
89    }
90
91    // Set the color of the pixel
92    float lightStrength;
93    switch (paintingData.specularExponent) {
94    case 0:
95        lightStrength = 1.0f; // -cosineOfAngle ^ 0 == 1
96        break;
97    case 1:
98        lightStrength = -cosineOfAngle; // -cosineOfAngle ^ 1 == -cosineOfAngle
99        break;
100    default:
101        lightStrength = powf(-cosineOfAngle, m_specularExponent);
102        break;
103    }
104
105    if (cosineOfAngle > paintingData.coneFullLight)
106        lightStrength *= (paintingData.coneCutOffLimit - cosineOfAngle) / (paintingData.coneCutOffLimit - paintingData.coneFullLight);
107
108    if (lightStrength > 1.0f)
109        lightStrength = 1.0f;
110
111    paintingData.colorVector.setX(paintingData.privateColorVector.x() * lightStrength);
112    paintingData.colorVector.setY(paintingData.privateColorVector.y() * lightStrength);
113    paintingData.colorVector.setZ(paintingData.privateColorVector.z() * lightStrength);
114}
115
116bool SpotLightSource::setX(float x)
117{
118    if (m_position.x() == x)
119        return false;
120    m_position.setX(x);
121    return true;
122}
123
124bool SpotLightSource::setY(float y)
125{
126    if (m_position.y() == y)
127        return false;
128    m_position.setY(y);
129    return true;
130}
131
132bool SpotLightSource::setZ(float z)
133{
134    if (m_position.z() == z)
135        return false;
136    m_position.setZ(z);
137    return true;
138}
139
140bool SpotLightSource::setPointsAtX(float pointsAtX)
141{
142    if (m_direction.x() == pointsAtX)
143        return false;
144    m_direction.setX(pointsAtX);
145    return true;
146}
147
148bool SpotLightSource::setPointsAtY(float pointsAtY)
149{
150    if (m_direction.y() == pointsAtY)
151        return false;
152    m_direction.setY(pointsAtY);
153    return true;
154}
155
156bool SpotLightSource::setPointsAtZ(float pointsAtZ)
157{
158    if (m_direction.z() == pointsAtZ)
159        return false;
160    m_direction.setZ(pointsAtZ);
161    return true;
162}
163
164bool SpotLightSource::setSpecularExponent(float specularExponent)
165{
166    if (m_specularExponent == specularExponent)
167        return false;
168    m_specularExponent = specularExponent;
169    return true;
170}
171
172bool SpotLightSource::setLimitingConeAngle(float limitingConeAngle)
173{
174    if (m_limitingConeAngle == limitingConeAngle)
175        return false;
176    m_limitingConeAngle = limitingConeAngle;
177    return true;
178}
179
180static TextStream& operator<<(TextStream& ts, const FloatPoint3D& p)
181{
182    ts << "x=" << p.x() << " y=" << p.y() << " z=" << p.z();
183    return ts;
184}
185
186TextStream& SpotLightSource::externalRepresentation(TextStream& ts) const
187{
188    ts << "[type=SPOT-LIGHT] ";
189    ts << "[position=\"" << position() << "\"]";
190    ts << "[direction=\"" << direction() << "\"]";
191    ts << "[specularExponent=\"" << specularExponent() << "\"]";
192    ts << "[limitingConeAngle=\"" << limitingConeAngle() << "\"]";
193    return ts;
194}
195
196}; // namespace WebCore
197
198#endif // ENABLE(FILTERS)
199