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#include "qsgflatcolormaterial.h"

#include <qglshaderprogram.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);
        m_program.setUniformValue(m_color_id, v);
    }

    if (state.isMatrixDirty())
        m_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 = m_program.uniformLocation("matrix");
    m_color_id = m_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"
        "}";
}


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

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


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

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

QT_END_NAMESPACE