// Copyright (C) 2014 Klaralvdalens Datakonsult AB (KDAB).
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only

#include "qshaderprogram.h"
#include "qshaderprogram_p.h"
#include <Qt3DCore/private/qurlhelper_p.h>
#include <QDebug>
#include <QFile>
#include <QFileInfo>
#include <QUrl>
#include <QRegularExpression>

/*!
    \class Qt3DRender::QShaderProgram
    \inmodule Qt3DRender
    \brief Encapsulates a Shader Program.
    \inherits Qt3DCore::QNode
    \since 5.5

    A shader program consists of several different shaders, such as vertex and fragment shaders.

    Qt3D will automatically populate a set of default uniforms if they are
    encountered during the shader instrospection phase.

    \table
    \header
        \li Default Uniform
        \li Associated Qt3D Parameter name
        \li GLSL declaration

    \row
        \li ModelMatrix
        \li modelMatrix
        \li uniform mat4 modelMatrix;

    \row
        \li ViewMatrix
        \li viewMatrix
        \li uniform mat4 viewMatrix;

    \row
        \li ProjectionMatrix
        \li projectionMatrix
        \li uniform mat4 projectionMatrix;

    \row
        \li ModelViewMatrix
        \li modelView
        \li uniform mat4 modelView;

    \row
        \li ViewProjectionMatrix
        \li viewProjectionMatrix
        \li uniform mat4 viewProjectionMatrix;

    \row
        \li ModelViewProjectionMatrix
        \li modelViewProjection \br mvp
        \li uniform mat4 modelViewProjection; \br uniform mat4 mvp;

    \row
        \li InverseModelMatrix
        \li inverseModelMatrix
        \li uniform mat4 inverseModelMatrix;

    \row
        \li InverseViewMatrix
        \li inverseViewMatrix
        \li uniform mat4 inverseViewMatrix;

    \row
        \li InverseProjectionMatrix
        \li inverseProjectionMatrix
        \li uniform mat4 inverseProjectionMatrix;

    \row
        \li InverseModelViewMatrix
        \li inverseModelView
        \li uniform mat4 inverseModelView;

    \row
        \li InverseViewProjectionMatrix
        \li inverseViewProjectionMatrix
        \li uniform mat4 inverseViewProjectionMatrix;

    \row
        \li InverseModelViewProjectionMatrix
        \li inverseModelViewProjection
        \li uniform mat4 inverseModelViewProjection;

    \row
        \li ModelNormalMatrix
        \li modelNormalMatrix
        \li uniform mat3 modelNormalMatrix;

    \row
        \li ModelViewNormalMatrix
        \li modelViewNormal
        \li uniform mat3 modelViewNormal;

    \row
        \li ViewportMatrix
        \li viewportMatrix
        \li uniform mat4 viewportMatrix;

    \row
        \li InverseViewportMatrix
        \li inverseViewportMatrix
        \li uniform mat4 inverseViewportMatrix;

    \row
        \li AspectRatio \br (surface width / surface height)
        \li aspectRatio
        \li uniform float aspectRatio;

    \row
        \li Exposure
        \li exposure
        \li uniform float exposure;

    \row
        \li Gamma
        \li gamma
        \li uniform float gamma;

    \row
        \li Time \br (in nano seconds)
        \li time
        \li uniform float time;

    \row
        \li EyePosition
        \li eyePosition
        \li uniform vec3 eyePosition;

    \row
        \li SkinningPalette
        \li skinningPalette[0]
        \li const int maxJoints = 100; \br uniform mat4 skinningPalette[maxJoints];

    \endtable

    \section1 RHI Support

    When writing GLSL 450 shader code to use with Qt 3D's RHI backend,
    the default uniforms will be provided as 2 uniform buffer objects.

    The binding locations for these is set to bindings 0 for RenderView
    uniforms and 1 for Command uniforms.

    \badcode
    #version 450 core

    layout(location = 0) in vec3 vertexPosition;

    layout(std140, binding = 0) uniform qt3d_render_view_uniforms {
      mat4 viewMatrix;
      mat4 projectionMatrix;
      mat4 uncorrectedProjectionMatrix;
      mat4 clipCorrectionMatrix;
      mat4 viewProjectionMatrix;
      mat4 inverseViewMatrix;
      mat4 inverseProjectionMatrix;
      mat4 inverseViewProjectionMatrix;
      mat4 viewportMatrix;
      mat4 inverseViewportMatrix;
      vec4 textureTransformMatrix;
      vec3 eyePosition;
      float aspectRatio;
      float gamma;
      float exposure;
      float time;
      float yUpInNDC;
      float yUpInFBO;
    };

    layout(std140, binding = 1) uniform qt3d_command_uniforms {
      mat4 modelMatrix;
      mat4 inverseModelMatrix;
      mat4 modelViewMatrix;
      mat3 modelNormalMatrix;
      mat4 inverseModelViewMatrix;
      mat4 modelViewProjection;
      mat4 inverseModelViewProjectionMatrix;
    };

    void main()
    {
        gl_Position = (projectionMatrix * viewMatrix * modelMatrix * vertexPosition);
    }
    \endcode

    For user defined uniform buffer object, use binding starting at 2 or auto
    to let Qt 3D work out the binding automatically. Make sure to remain
    consistent between the different shader stages.


    \badcode
    #version 450 core

    layout(std140, binding = auto) uniform my_uniforms {
      vec4 myColor;
    };

    layout(location=0) out vec4 fragColor;

    void main()
    {
        fragColor = myColor;
    }
    \endcode

    There is no change involved when it comes to feeding values to uniforms.

    For the above example, setting myColor could be done with:

    \badcode
    QParameter *parameter = new QParameter();
    parameter->setName("myColor");
    parameter->setValue(QVariant::fromValue(QColor(Qt::blue)));
    \endcode

    Textures still have to be defined as standalone uniforms.

    \badcode
    #version 450 core

    layout(binding=0) uniform sampler2D source;

    layout(location=0) out vec4 fragColor;

    void main()
    {
        fragColor = texture(source, vec2(0.5, 0.5));
    }
    \endcode
*/

/*!
    \qmltype ShaderProgram
    \instantiates Qt3DRender::QShaderProgram
    \inqmlmodule Qt3D.Render
    \brief Encapsulates a Shader Program.
    \since 5.5

    ShaderProgram class encapsulates a shader program. A shader program consists of several
    different shaders, such as vertex and fragment shaders.

    Qt3D will automatically populate a set of default uniforms if they are
    encountered during the shader instrospection phase.

    \table
    \header
        \li {1, 1} Default Uniform
        \li {2, 1} Associated Qt3D Parameter name
        \li {3, 1} GLSL declaration

    \row
        \li {1, 1} ModelMatrix
        \li {2, 1} modelMatrix
        \li {3, 1} uniform mat4 modelMatrix;

    \row
        \li {1, 1} ViewMatrix
        \li {2, 1} viewMatrix
        \li {3, 1} uniform mat4 viewMatrix;

    \row
        \li {1, 1} ProjectionMatrix
        \li {2, 1} projectionMatrix
        \li {3, 1} uniform mat4 projectionMatrix;

    \row
        \li {1, 1} ModelViewMatrix
        \li {2, 1} modelView
        \li {3, 1} uniform mat4 modelView;

    \row
        \li {1, 1} ViewProjectionMatrix
        \li {2, 1} viewProjectionMatrix
        \li {3, 1} uniform mat4 viewProjectionMatrix;

    \row
        \li {1, 1} ModelViewProjectionMatrix
        \li {2, 1} modelViewProjection \br mvp
        \li {3, 1} uniform mat4 modelViewProjection; \br uniform mat4 mvp;

    \row
        \li {1, 1} InverseModelMatrix
        \li {2, 1} inverseModelMatrix
        \li {3, 1} uniform mat4 inverseModelMatrix;

    \row
        \li {1, 1} InverseViewMatrix
        \li {2, 1} inverseViewMatrix
        \li {3, 1} uniform mat4 inverseViewMatrix;

    \row
        \li {1, 1} InverseProjectionMatrix
        \li {2, 1} inverseProjectionMatrix
        \li {3, 1} uniform mat4 inverseProjectionMatrix;

    \row
        \li {1, 1} InverseModelViewMatrix
        \li {2, 1} inverseModelView
        \li {3, 1} uniform mat4 inverseModelView;

    \row
        \li {1, 1} InverseViewProjectionMatrix
        \li {2, 1} inverseViewProjectionMatrix
        \li {3, 1} uniform mat4 inverseViewProjectionMatrix;

    \row
        \li {1, 1} InverseModelViewProjectionMatrix
        \li {2, 1} inverseModelViewProjection
        \li {3, 1} uniform mat4 inverseModelViewProjection;

    \row
        \li {1, 1} ModelNormalMatrix
        \li {2, 1} modelNormalMatrix
        \li {3, 1} uniform mat3 modelNormalMatrix;

    \row
        \li {1, 1} ModelViewNormalMatrix
        \li {2, 1} modelViewNormal
        \li {3, 1} uniform mat3 modelViewNormal;

    \row
        \li {1, 1} ViewportMatrix
        \li {2, 1} viewportMatrix
        \li {3, 1} uniform mat4 viewportMatrix;

    \row
        \li {1, 1} InverseViewportMatrix
        \li {2, 1} inverseViewportMatrix
        \li {3, 1} uniform mat4 inverseViewportMatrix;

    \row
        \li {1, 1} AspectRatio \br (surface width / surface height)
        \li {2, 1} aspectRatio
        \li {3, 1} uniform float aspectRatio;

    \row
        \li {1, 1} Exposure
        \li {2, 1} exposure
        \li {3, 1} uniform float exposure;

    \row
        \li {1, 1} Gamma
        \li {2, 1} gamma
        \li {3, 1} uniform float gamma;

    \row
        \li {1, 1} Time \br (in nano seconds)
        \li {2, 1} time
        \li {3, 1} uniform float time;

    \row
        \li {1, 1} EyePosition
        \li {2, 1} eyePosition
        \li {3, 1} uniform vec3 eyePosition;

    \row
        \li {1, 1} SkinningPalette
        \li {2, 1} skinningPalette[0]
        \li {3, 1} const int maxJoints = 100; \br uniform mat4 skinningPalette[maxJoints];

    \endtable

    \section1 RHI Support

    When writing GLSL 450 shader code to use with Qt 3D's RHI backend,
    the default uniforms will be provided as 2 uniform buffer objects.

    The binding locations for these is set to bindings 0 for RenderView
    uniforms and 1 for Command uniforms.

    \badcode
    #version 450 core

    layout(location = 0) in vec3 vertexPosition;

    layout(std140, binding = 0) uniform qt3d_render_view_uniforms {
      mat4 viewMatrix;
      mat4 projectionMatrix;
      mat4 uncorrectedProjectionMatrix;
      mat4 clipCorrectionMatrix;
      mat4 viewProjectionMatrix;
      mat4 inverseViewMatrix;
      mat4 inverseProjectionMatrix;
      mat4 inverseViewProjectionMatrix;
      mat4 viewportMatrix;
      mat4 inverseViewportMatrix;
      vec4 textureTransformMatrix;
      vec3 eyePosition;
      float aspectRatio;
      float gamma;
      float exposure;
      float time;
      float yUpInNDC;
      float yUpInFBO;
    };

    layout(std140, binding = 1) uniform qt3d_command_uniforms {
      mat4 modelMatrix;
      mat4 inverseModelMatrix;
      mat4 modelViewMatrix;
      mat3 modelNormalMatrix;
      mat4 inverseModelViewMatrix;
      mat4 modelViewProjection;
      mat4 inverseModelViewProjectionMatrix;
    };

    void main()
    {
        gl_Position = (projectionMatrix * viewMatrix * modelMatrix * vertexPosition);
    }
    \endcode

    For user defined uniform buffer object, use binding starting at 2 or auto
    to let Qt 3D work out the binding automatically. Make sure to remain
    consistent between the different shader stages.


    \badcode
    #version 450 core

    layout(std140, binding = auto) uniform my_uniforms {
      vec4 myColor;
    };

    layout(location=0) out vec4 fragColor;

    void main()
    {
        fragColor = myColor;
    }
    \endcode

    There is no change involved when it comes to feeding values to uniforms.

    For the above example, setting myColor could be done with:

    \badcode
    Parameter { name: "myColor"; value: "blue" }
    \endcode

    Textures still have to be defined as standalone uniforms.

    \badcode
    #version 450 core

    layout(binding=0) uniform sampler2D source;

    layout(location=0) out vec4 fragColor;

    void main()
    {
        fragColor = texture(source, vec2(0.5, 0.5));
    }
    \endcode
*/

/*!
    \enum QShaderProgram::ShaderType

    This enum identifies the type of shader used.

    \value Vertex                  Vertex shader
    \value Fragment                Fragment shader
    \value TessellationControl     Tesselation control shader
    \value TessellationEvaluation  Tesselation evaluation shader
    \value Geometry                Geometry shader
    \value Compute                 Compute shader
*/

/*!
    \enum QShaderProgram::Status

    This enum identifies the status of shader used.

    \value NotReady              The shader hasn't been compiled and linked yet
    \value Ready                 The shader was successfully compiled
    \value Error                 An error occurred while compiling the shader
*/

/*!
    \enum QShaderProgram::Format

    This enum identifies the format of the shader code used.

    \value GLSL              OpenGL
    \value SPIRV             Vulkan, OpenGL 5

    \since 5.15
*/

QT_BEGIN_NAMESPACE

namespace Qt3DRender {

QShaderProgramPrivate::QShaderProgramPrivate()
    : QNodePrivate()
    , m_status(QShaderProgram::NotReady)
    , m_format(QShaderProgram::GLSL)
{
}

void QShaderProgramPrivate::setLog(const QString &log)
{
    Q_Q(QShaderProgram);
    if (log != m_log) {
        m_log = log;
        const bool blocked = q->blockNotifications(true);
        emit q->logChanged(m_log);
        q->blockNotifications(blocked);
    }
}

void QShaderProgramPrivate::setStatus(QShaderProgram::Status status)
{
    Q_Q(QShaderProgram);
    if (status != m_status) {
        m_status = status;
        const bool blocked = q->blockNotifications(true);
        emit q->statusChanged(m_status);
        q->blockNotifications(blocked);
    }
}

QShaderProgram::QShaderProgram(QNode *parent)
    : QNode(*new QShaderProgramPrivate, parent)
{
}

QShaderProgram::~QShaderProgram()
{
}

/*! \internal */
QShaderProgram::QShaderProgram(QShaderProgramPrivate &dd, QNode *parent)
    : QNode(dd, parent)
{
}

/*!
    \qmlproperty string ShaderProgram::vertexShaderCode

    Holds the vertex shader code used by this shader program.
*/
/*!
    \property QShaderProgram::vertexShaderCode

    Holds the vertex shader code used by this shader program.
*/
void QShaderProgram::setVertexShaderCode(const QByteArray &vertexShaderCode)
{
    Q_D(QShaderProgram);
    if (vertexShaderCode != d->m_vertexShaderCode) {
        d->m_vertexShaderCode = vertexShaderCode;
        emit vertexShaderCodeChanged(vertexShaderCode);
    }
}

QByteArray QShaderProgram::vertexShaderCode() const
{
    Q_D(const QShaderProgram);
    return d->m_vertexShaderCode;
}

/*!
    \qmlproperty string ShaderProgram::tessellationControlShaderCode

    Holds the tesselation control shader code used by this shader program.
*/
/*!
    \property QShaderProgram::tessellationControlShaderCode

    Holds the tesselation control shader code used by this shader program.
*/
void QShaderProgram::setTessellationControlShaderCode(const QByteArray &tessellationControlShaderCode)
{
    Q_D(QShaderProgram);
    if (tessellationControlShaderCode != d->m_tessControlShaderCode) {
        d->m_tessControlShaderCode = tessellationControlShaderCode;
        emit tessellationControlShaderCodeChanged(tessellationControlShaderCode);
    }
}

QByteArray QShaderProgram::tessellationControlShaderCode() const
{
    Q_D(const QShaderProgram);
    return d->m_tessControlShaderCode;
}

/*!
    \qmlproperty string ShaderProgram::tessellationEvaluationShaderCode

    Holds the tesselation evaluation shader code used by this shader program.
*/
/*!
    \property QShaderProgram::tessellationEvaluationShaderCode

    Holds the tesselation evaluation shader code used by this shader program.
*/
void QShaderProgram::setTessellationEvaluationShaderCode(const QByteArray &tessellationEvaluationShaderCode)
{
    Q_D(QShaderProgram);
    if (tessellationEvaluationShaderCode != d->m_tessEvalShaderCode) {
        d->m_tessEvalShaderCode = tessellationEvaluationShaderCode;
        emit tessellationEvaluationShaderCodeChanged(tessellationEvaluationShaderCode);
    }
}

QByteArray QShaderProgram::tessellationEvaluationShaderCode() const
{
    Q_D(const QShaderProgram);
    return d->m_tessEvalShaderCode;
}

/*!
    \qmlproperty string ShaderProgram::geometryShaderCode

    Holds the geometry shader code used by this shader program.
*/
/*!
    \property QShaderProgram::geometryShaderCode

    Holds the geometry shader code used by this shader program.
*/
void QShaderProgram::setGeometryShaderCode(const QByteArray &geometryShaderCode)
{
    Q_D(QShaderProgram);
    if (geometryShaderCode != d->m_geometryShaderCode) {
        d->m_geometryShaderCode = geometryShaderCode;
        emit geometryShaderCodeChanged(geometryShaderCode);
    }
}

QByteArray QShaderProgram::geometryShaderCode() const
{
    Q_D(const QShaderProgram);
    return d->m_geometryShaderCode;
}

/*!
    \qmlproperty string ShaderProgram::fragmentShaderCode

    Holds the fragment shader code used by this shader program.
*/
/*!
    \property QShaderProgram::fragmentShaderCode

    Holds the fragment shader code used by this shader program.
*/
void QShaderProgram::setFragmentShaderCode(const QByteArray &fragmentShaderCode)
{
    Q_D(QShaderProgram);
    if (fragmentShaderCode != d->m_fragmentShaderCode) {
        d->m_fragmentShaderCode = fragmentShaderCode;
        emit fragmentShaderCodeChanged(fragmentShaderCode);
    }
}

QByteArray QShaderProgram::fragmentShaderCode() const
{
    Q_D(const QShaderProgram);
    return d->m_fragmentShaderCode;
}

/*!
    \qmlproperty string ShaderProgram::computeShaderCode

    Holds the compute shader code used by this shader program.
*/
/*!
    \property QShaderProgram::computeShaderCode

    Holds the compute shader code used by this shader program.
*/
void QShaderProgram::setComputeShaderCode(const QByteArray &computeShaderCode)
{
    Q_D(QShaderProgram);
    if (computeShaderCode != d->m_computeShaderCode) {
        d->m_computeShaderCode = computeShaderCode;
        emit computeShaderCodeChanged(computeShaderCode);
    }
}

QByteArray QShaderProgram::computeShaderCode() const
{
    Q_D(const QShaderProgram);
    return d->m_computeShaderCode;
}


/*!
    Sets the shader code for \a type of shader to the \a shaderCode.
*/
void QShaderProgram::setShaderCode(ShaderType type, const QByteArray &shaderCode)
{
    switch (type) {
    case Vertex:
        setVertexShaderCode(shaderCode);
        break;
    case TessellationControl:
        setTessellationControlShaderCode(shaderCode);
        break;
    case TessellationEvaluation:
        setTessellationEvaluationShaderCode(shaderCode);
        break;
    case Geometry:
        setGeometryShaderCode(shaderCode);
        break;
    case Fragment:
        setFragmentShaderCode(shaderCode);
        break;
    case Compute:
        setComputeShaderCode(shaderCode);
        break;
    default:
        Q_UNREACHABLE();
    }
}

/*!
    Returns the shader code for \a type.
*/
QByteArray QShaderProgram::shaderCode(ShaderType type) const
{
    Q_D(const QShaderProgram);
    switch (type) {
    case Vertex:
        return d->m_vertexShaderCode;
    case TessellationControl:
        return d->m_tessControlShaderCode;
    case TessellationEvaluation:
        return d->m_tessEvalShaderCode;
    case Geometry:
        return d->m_geometryShaderCode;
    case Fragment:
        return d->m_fragmentShaderCode;
    case Compute:
        return d->m_computeShaderCode;
    default:
        Q_UNREACHABLE();
    }
}

/*!
    \qmlproperty string ShaderProgram::log

    Holds the log of the current shader program. This is useful to diagnose a
    compilation failure of the shader program.
*/
/*!
    \property QShaderProgram::log

    Holds the log of the current shader program. This is useful to diagnose a
    compilation failure of the shader program.
*/
QString QShaderProgram::log() const
{
    Q_D(const QShaderProgram);
    return d->m_log;
}

/*!
    \qmlproperty enumeration ShaderProgram::status

    Holds the status of the current shader program.
*/
/*!
    \property QShaderProgram::status

    Holds the status of the current shader program.
*/
/*!
    Returns the status of the current shader program.
*/
QShaderProgram::Status QShaderProgram::status() const
{
    Q_D(const QShaderProgram);
    return d->m_status;
}

void QShaderProgram::setFormat(QShaderProgram::Format format)
{
    Q_D(QShaderProgram);
    if (format != d->m_format) {
        d->m_format = format;
        emit formatChanged(format);
    }
}

/*!
    \qmlproperty enumeration ShaderProgram::format
    \since 5.15

    Holds the format of the code provided on the ShaderProgram.
    The default is ShaderProgram.GLSL
*/
/*!
    \property QShaderProgram::format
    \since 5.15

    Holds the format of the code provided on the ShaderProgram.
    The default is ShaderProgram.GLSL
*/
QShaderProgram::Format QShaderProgram::format() const
{
    Q_D(const QShaderProgram);
    return d->m_format;
}

QByteArray QShaderProgramPrivate::deincludify(const QString &filePath)
{
    QFile f(filePath);
    if (!f.open(QIODevice::ReadOnly | QIODevice::Text)) {
        qWarning() << "Could not read shader source file:" << f.fileName();
        return QByteArray();
    }

    QByteArray contents = f.readAll();
    return deincludify(contents, filePath);
}

QByteArray QShaderProgramPrivate::resolveAutoBindingIndices(const QByteArray &content,
                                                            int &currentBinding,
                                                            int &currentInputLocation,
                                                            int &currentOutputLocation)
{
    QString shaderCode = QString::fromUtf8(content);

    // This lambda will replace all occurrences of a string (e.g. "binding = auto") by another,
    // with the incremented int passed as argument (e.g. "binding = 1", "binding = 2" ...)
    const auto replaceAndIncrement = [&](const QRegularExpression &regexp,
            int &variable,
            const QString &replacement) noexcept {
        int matchStart = 0;
        do {
            matchStart = shaderCode.indexOf(regexp, matchStart);
            if (matchStart != -1) {
#if QT_VERSION >= QT_VERSION_CHECK(6, 0, 0)
                const auto match = regexp.match(QStringView{shaderCode}.mid(matchStart));
#else
                const auto match = regexp.match(shaderCode.mid(matchStart));
#endif
                const auto length = match.capturedLength(0);
                shaderCode.replace(matchStart, length, replacement.arg(variable++));
            }
        } while (matchStart != -1);
    };

    // 1. Handle uniforms
    {
        thread_local const QRegularExpression bindings(
                    QStringLiteral("binding\\s*=\\s*auto"));

        replaceAndIncrement(bindings, currentBinding, QStringLiteral("binding = %1"));
    }

    // 2. Handle inputs
    {
        thread_local const QRegularExpression inLocations(
                    QStringLiteral("location\\s*=\\s*auto\\s*\\)\\s*in\\s+"));

        replaceAndIncrement(inLocations, currentInputLocation,
                            QStringLiteral("location = %1) in "));
    }

    // 3. Handle outputs
    {
        thread_local const QRegularExpression outLocations(
                    QStringLiteral("location\\s*=\\s*auto\\s*\\)\\s*out\\s+"));

        replaceAndIncrement(outLocations, currentOutputLocation,
                            QStringLiteral("location = %1) out "));
    }

    return shaderCode.toUtf8();
}

QByteArray QShaderProgramPrivate::resolveAutoBindingIndices(const QByteArray &content)
{
    int currentBinding = 2; // Qt3D default uniforms are 0 and 1
    int currentInputLocation = 0;
    int currentOutputLocation = 0;

    return QShaderProgramPrivate::resolveAutoBindingIndices(content,
                                                            currentBinding,
                                                            currentInputLocation,
                                                            currentOutputLocation);
}

QByteArray QShaderProgramPrivate::deincludify(const QByteArray &contents, const QString &filePath)
{
    QByteArrayList lines = contents.split('\n');
    const QByteArray includeDirective = QByteArrayLiteral("#pragma include");
    for (int i = 0; i < lines.count(); ++i) {
        const auto line = lines[i].simplified();
        if (line.startsWith(includeDirective)) {
            const QString includePartialPath = QString::fromUtf8(line.mid(includeDirective.size() + 1));

            QString includePath = QFileInfo(includePartialPath).isAbsolute() ? includePartialPath
                                : QFileInfo(filePath).absolutePath() + QLatin1Char('/') + includePartialPath;
            if (qEnvironmentVariableIsSet("QT3D_GLSL100_WORKAROUND")) {
                QString candidate = includePath + QLatin1String("100");
                if (QFile::exists(candidate))
                    includePath = candidate;
            }
            lines.removeAt(i);
            QByteArray includedContents = deincludify(includePath);
            lines.insert(i, includedContents);
            QString lineDirective = QString(QStringLiteral("#line %1")).arg(i + 2);
            lines.insert(i + 1, lineDirective.toUtf8());
        }
    }

    return lines.join('\n');
}

/*!
    \qmlmethod string ShaderProgram::loadSource(url sourceUrl)

    Returns the shader code loaded from \a sourceUrl.
*/
/*!
    Returns the shader code loaded from \a sourceUrl.
*/
QByteArray QShaderProgram::loadSource(const QUrl &sourceUrl)
{
    // TO DO: Handle remote path
    const QByteArray deincluded = QShaderProgramPrivate::deincludify(Qt3DCore::QUrlHelper::urlToLocalFileOrQrc(sourceUrl));
    return QShaderProgramPrivate::resolveAutoBindingIndices(deincluded);
}

} // of namespace Qt3DRender

QT_END_NAMESPACE

#include "moc_qshaderprogram.cpp"
