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#include "qsgflatcolormaterial.h"

#include <qopenglshaderprogram.h>

QT_BEGIN_NAMESPACE

class FlatColorMaterialShader : public QSGMaterialShader
{
public:
    virtual void updateState(const RenderState &state, QSGMaterial *newEffect, QSGMaterial *oldEffect);
    virtual char const *const *attributeNames() const;

    static QSGMaterialType type;

private:
    virtual void initialize();
    virtual const char *vertexShader() const;
    virtual const char *fragmentShader() const;

    int m_matrix_id;
    int m_color_id;
};

QSGMaterialType FlatColorMaterialShader::type;

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();
        QVector4D v(c.redF() * c.alphaF() * opacity,
                    c.greenF() * c.alphaF() * opacity,
                    c.blueF() * c.alphaF() * opacity,
                    c.alphaF() * 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");
}

const char *FlatColorMaterialShader::vertexShader() const {
    return
        "attribute highp vec4 vCoord;                   \n"
        "uniform highp mat4 matrix;                     \n"
        "void main() {                                  \n"
        "    gl_Position = matrix * vCoord;             \n"
        "}";
}

const char *FlatColorMaterialShader::fragmentShader() const {
    return
        "uniform lowp vec4 color;                       \n"
        "void main() {                                  \n"
        "    gl_FragColor = color;                      \n"
        "}";
}



/*!
    \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
