/*
 * Copyright (C) 2005 Oliver Hunt <ojh16@student.canterbury.ac.nz>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public License
 * along with this library; see the file COPYING.LIB.  If not, write to
 * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA 02110-1301, USA.
 */

#include "config.h"
#include "SVGFESpotLightElement.h"

#include "GeometryUtilities.h"
#include "SVGFilterBuilder.h"
#include "SVGNames.h"
#include "SpotLightSource.h"
#include <wtf/MathExtras.h>

namespace WebCore {

inline SVGFESpotLightElement::SVGFESpotLightElement(const QualifiedName& tagName, Document& document)
    : SVGFELightElement(tagName, document)
{
    ASSERT(hasTagName(SVGNames::feSpotLightTag));
}

Ref<SVGFESpotLightElement> SVGFESpotLightElement::create(const QualifiedName& tagName, Document& document)
{
    return adoptRef(*new SVGFESpotLightElement(tagName, document));
}

Ref<LightSource> SVGFESpotLightElement::lightSource(SVGFilterBuilder& builder) const
{
    FloatPoint3D position;
    FloatPoint3D pointsAt;

    if (builder.primitiveUnits() == SVGUnitTypes::SVG_UNIT_TYPE_OBJECTBOUNDINGBOX) {
        FloatRect referenceBox = builder.targetBoundingBox();
        
        position.setX(referenceBox.x() + x() * referenceBox.width());
        position.setY(referenceBox.y() + y() * referenceBox.height());
        // https://www.w3.org/TR/SVG/filters.html#fePointLightZAttribute and https://www.w3.org/TR/SVG/coords.html#Units_viewport_percentage
        position.setZ(z() * euclidianDistance(referenceBox.minXMinYCorner(), referenceBox.maxXMaxYCorner()) / sqrtOfTwoFloat);

        pointsAt.setX(referenceBox.x() + pointsAtX() * referenceBox.width());
        pointsAt.setY(referenceBox.y() + pointsAtY() * referenceBox.height());
        // https://www.w3.org/TR/SVG/filters.html#fePointLightZAttribute and https://www.w3.org/TR/SVG/coords.html#Units_viewport_percentage
        pointsAt.setZ(pointsAtZ() * euclidianDistance(referenceBox.minXMinYCorner(), referenceBox.maxXMaxYCorner()) / sqrtOfTwoFloat);
    } else {
        position = FloatPoint3D(x(), y(), z());
        pointsAt = FloatPoint3D(pointsAtX(), pointsAtY(), pointsAtZ());
    }

    return SpotLightSource::create(position, pointsAt, specularExponent(), limitingConeAngle());
}

}