/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtQuick module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL21$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 or version 3 as published by the Free
** Software Foundation and appearing in the file LICENSE.LGPLv21 and
** LICENSE.LGPLv3 included in the packaging of this file. Please review the
** following information to ensure the GNU Lesser General Public License
** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** As a special exception, The Qt Company gives you certain additional
** rights. These rights are described in The Qt Company LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qsgflatcolormaterial.h"
#include <private/qsgmaterialshader_p.h>

#include <qopenglshaderprogram.h>

QT_BEGIN_NAMESPACE

class FlatColorMaterialShader : public QSGMaterialShader
{
public:
    FlatColorMaterialShader();

    virtual void updateState(const RenderState &state, QSGMaterial *newEffect, QSGMaterial *oldEffect);
    virtual char const *const *attributeNames() const;

    static QSGMaterialType type;

private:
    virtual void initialize();

    int m_matrix_id;
    int m_color_id;
};

QSGMaterialType FlatColorMaterialShader::type;

FlatColorMaterialShader::FlatColorMaterialShader()
    : QSGMaterialShader(*new QSGMaterialShaderPrivate)
{
    setShaderSourceFile(QOpenGLShader::Vertex, QStringLiteral(":/qt-project.org/scenegraph/shaders/flatcolor.vert"));
    setShaderSourceFile(QOpenGLShader::Fragment, QStringLiteral(":/qt-project.org/scenegraph/shaders/flatcolor.frag"));
}

void FlatColorMaterialShader::updateState(const RenderState &state, QSGMaterial *newEffect, QSGMaterial *oldEffect)
{
    Q_ASSERT(oldEffect == 0 || newEffect->type() == oldEffect->type());

    QSGFlatColorMaterial *oldMaterial = static_cast<QSGFlatColorMaterial *>(oldEffect);
    QSGFlatColorMaterial *newMaterial = static_cast<QSGFlatColorMaterial *>(newEffect);

    const QColor &c = newMaterial->color();

    if (oldMaterial == 0 || c != oldMaterial->color() || state.isOpacityDirty()) {
        float opacity = state.opacity() * c.alphaF();
        QVector4D v(c.redF() * opacity,
                    c.greenF() *  opacity,
                    c.blueF() * opacity,
                    opacity);
        program()->setUniformValue(m_color_id, v);
    }

    if (state.isMatrixDirty())
        program()->setUniformValue(m_matrix_id, state.combinedMatrix());
}

char const *const *FlatColorMaterialShader::attributeNames() const
{
    static char const *const attr[] = { "vCoord", 0 };
    return attr;
}

void FlatColorMaterialShader::initialize()
{
    m_matrix_id = program()->uniformLocation("matrix");
    m_color_id = program()->uniformLocation("color");
}



/*!
    \class QSGFlatColorMaterial

    \brief The QSGFlatColorMaterial class provides a convenient way of rendering
    solid colored geometry in the scene graph.

    \inmodule QtQuick
    \ingroup qtquick-scenegraph-materials

    The flat color material will fill every pixel in a geometry using
    a solid color. The color can contain transparency.

    The geometry to be rendered with a flat color material requires
    vertices in attribute location 0 in the QSGGeometry object to render
    correctly. The QSGGeometry::defaultAttributes_Point2D() returns an attribute
    set compatible with this material.

    The flat color material respects both current opacity and current matrix
    when updating its rendering state.
 */


/*!
    Constructs a new flat color material.

    The default color is white.
 */

QSGFlatColorMaterial::QSGFlatColorMaterial() : m_color(QColor(255, 255, 255))
{
}



/*!
    \fn const QColor &QSGFlatColorMaterial::color() const

    Returns this flat color material's color.

    The default color is white.
 */



/*!
    Sets this flat color material's color to \a color.
 */

void QSGFlatColorMaterial::setColor(const QColor &color)
{
    m_color = color;
    setFlag(Blending, m_color.alpha() != 0xff);
}



/*!
    \internal
 */

QSGMaterialType *QSGFlatColorMaterial::type() const
{
    return &FlatColorMaterialShader::type;
}



/*!
    \internal
 */

QSGMaterialShader *QSGFlatColorMaterial::createShader() const
{
    return new FlatColorMaterialShader;
}


/*!
    \internal
 */

int QSGFlatColorMaterial::compare(const QSGMaterial *other) const
{
    const QSGFlatColorMaterial *flat = static_cast<const QSGFlatColorMaterial *>(other);
    return m_color.rgba() - flat->color().rgba();

}

QT_END_NAMESPACE
