/****************************************************************************
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** Copyright (C) 2014 Klaralvdalens Datakonsult AB (KDAB).
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** Alternatively, this file may be used under the terms of the GNU Lesser
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** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 3 requirements
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** Alternatively, this file may be used under the terms of the GNU
** General Public License version 2.0 or later as published by the Free
** Software Foundation and appearing in the file LICENSE.GPL included in
** the packaging of this file. Please review the following information to
** ensure the GNU General Public License version 2.0 requirements will be
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****************************************************************************/

#ifndef QT3DRENDER_RENDER_SHADER_H
#define QT3DRENDER_RENDER_SHADER_H

//
//  W A R N I N G
//  -------------
//
// This file is not part of the Qt API.  It exists for the convenience
// of other Qt classes.  This header file may change from version to
// version without notice, or even be removed.
//
// We mean it.
//

#include <QVector>
#include <Qt3DRender/private/quniformvalue_p.h>
#include <Qt3DRender/private/shadervariables_p.h>
#include <Qt3DCore/qbackendnode.h>

QT_BEGIN_NAMESPACE

class QOpenGLShaderProgram;
class QMutex;

namespace Qt3DRender {

class QShaderProgram;

namespace Render {

class ShaderManager;
class AttachmentPack;

typedef uint ProgramDNA;

class Q_AUTOTEST_EXPORT Shader : public Qt3DCore::QBackendNode
{
public:
    Shader();
    ~Shader();

    void cleanup();

    void updateFromPeer(Qt3DCore::QNode *peer) Q_DECL_OVERRIDE;
    void updateUniforms(GraphicsContext *ctx, const QUniformPack &pack);
    void setFragOutputs(const QHash<QString, int> &fragOutputs);

    QVector<QString> uniformsNames() const;
    QVector<QString> attributesNames() const;
    QVector<QString> uniformBlockNames() const;
    QVector<QByteArray> shaderCode() const;

    void sceneChangeEvent(const Qt3DCore::QSceneChangePtr &e) Q_DECL_OVERRIDE;
    bool isLoaded() const;
    ProgramDNA dna() const;

    QVector<ShaderUniform> uniforms() const;
    QVector<ShaderAttribute> attributes() const;
    QVector<ShaderUniformBlock> uniformBlocks() const;

    QHash<QString, ShaderUniform> activeUniformsForBlock(int blockIndex) const;
    ShaderUniformBlock uniformBlock(int blockIndex);
    ShaderUniformBlock uniformBlock(const QString &blockName);

private:
    QOpenGLShaderProgram *m_program;

    QOpenGLShaderProgram *createProgram(GraphicsContext *context);
    QOpenGLShaderProgram *createDefaultProgram();

    QVector<QString> m_uniformsNames;
    QVector<ShaderUniform> m_uniforms;

    QVector<QString> m_attributesNames;
    QVector<ShaderAttribute> m_attributes;

    QVector<QString> m_uniformBlockNames;
    QVector<ShaderUniformBlock> m_uniformBlocks;
    QHash<int, QHash<QString, ShaderUniform> > m_blockIndexToShaderUniforms;

    QHash<QString, int> m_fragOutputs;

    QVector<QByteArray> m_shaderCode;

    bool m_isLoaded;
    ProgramDNA m_dna;
    QMutex *m_mutex;

    void updateDNA();

    // Private so that only GraphicContext can call it
    void initializeUniforms(const QVector<ShaderUniform> &uniformsDescription);
    void initializeAttributes(const QVector<ShaderAttribute> &attributesDescription);
    void initializeUniformBlocks(const QVector<ShaderUniformBlock> &uniformBlockDescription);

    void initialize(const Shader &other);

    QOpenGLShaderProgram *getOrCreateProgram(GraphicsContext *ctx);
    friend class GraphicsContext;
};

} // namespace Render
} // namespace Qt3DRender

QT_END_NAMESPACE

#endif // QT3DRENDER_RENDER_SHADER_H