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#ifndef QSSG_RENDER_MATERIAL_SHADER_GENERATOR_H
#define QSSG_RENDER_MATERIAL_SHADER_GENERATOR_H

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

#include <QtQuick3DRuntimeRender/private/qtquick3druntimerenderglobal_p.h>
#include <QtQuick3DUtils/private/qssgdataref_p.h>

#include <QtGui/QVector4D>
#include <QtGui/QMatrix4x4>

#include <QtQuick3DRuntimeRender/private/qssgrendershadercache_p.h>
#include <QtQuick3DRuntimeRender/private/qssgrendershaderkeys_p.h>

QT_BEGIN_NAMESPACE

// these are our current shader limits
#define QSSG_MAX_NUM_LIGHTS 16
#define QSSG_MAX_NUM_SHADOWS 8

// note this struct must exactly match the memory layout of the
// struct sampleLight.glsllib and sampleArea.glsllib. If you make changes here you need
// to adjust the code in sampleLight.glsllib and sampleArea.glsllib as well
struct QSSGLightSourceShader
{
    QVector4D position;
    QVector4D direction; // Specifies the light direction in world coordinates.
    QVector4D up;
    QVector4D right;
    QVector4D diffuse;
    QVector4D ambient;
    QVector4D specular;
    float spotExponent; // Specifies the intensity distribution of the light.
    float spotCutoff; // Specifies the maximum spread angle of the light.
    float constantAttenuation; // Specifies the constant light attenuation factor.
    float linearAttenuation; // Specifies the linear light attenuation factor.
    float quadraticAttenuation; // Specifies the quadratic light attenuation factor.
    float range; // Specifies the maximum distance of the light influence
    float width; // Specifies the width of the area light surface.
    float height; // Specifies the height of the area light surface;
    QVector4D shadowControls;
    float shadowView[16];
    qint32 shadowIdx;
    float padding1[3];
};

struct QSSGRenderLayer;
struct QSSGRenderCamera;
struct QSSGRenderLight;
class QSSGRenderShadowMap;
class QSSGRenderTexture2D;
struct QSSGRenderImage;
class QSSGShaderStageGeneratorInterface;
struct QSSGRenderableImage;
class QSSGRenderShaderProgram;
struct QSSGRenderGraphObject;
struct QSSGShaderDefaultMaterialKey;
class QSSGRenderContextInterface;
class QSSGShaderProgramGeneratorInterface;
class QSSGDefaultMaterialVertexPipelineInterface;
struct QSSGShaderGeneratorGeneratedShader;
class QSSGRenderConstantBuffer;

struct QSSGLayerGlobalRenderProperties
{
    const QSSGRenderLayer &layer;
    QSSGRenderCamera &camera;
    QVector3D cameraDirection;
    const QVector<QSSGRenderLight *> &lights;
    const QVector<QVector3D> &lightDirections;
    QSSGRef<QSSGRenderShadowMap> shadowMapManager;
    QSSGRef<QSSGRenderTexture2D> depthTexture;
    QSSGRef<QSSGRenderTexture2D> ssaoTexture;
    QSSGRenderImage *lightProbe;
    QSSGRenderImage *lightProbe2;
    float probeHorizon;
    float probeBright;
    float probe2Window;
    float probe2Pos;
    float probe2Fade;
    float probeFOV;
};

class QSSGMaterialShaderGeneratorInterface
{
    Q_DISABLE_COPY(QSSGMaterialShaderGeneratorInterface)
public:
    QAtomicInt ref;

protected:
    typedef QHash<QByteArray, QSSGRef<QSSGRenderConstantBuffer>> ConstanBufferMap;

    bool m_hasTransparency = false;
    QSSGRenderContextInterface *m_renderContext;
    const QSSGRef<QSSGShaderProgramGeneratorInterface> m_programGenerator;

    QSSGShaderDefaultMaterialKey *m_currentKey = nullptr;
    QSSGDefaultMaterialVertexPipelineInterface *m_currentPipeline = nullptr;
    ShaderFeatureSetList m_currentFeatureSet;
    QVector<QSSGRenderLight *> m_lights;
    QSSGRenderableImage *m_firstImage = nullptr;
    QSSGShaderDefaultMaterialKeyProperties m_defaultMaterialShaderKeyProperties;
    ConstanBufferMap m_constantBuffers; ///< store all constants buffers


protected:
    QSSGMaterialShaderGeneratorInterface(QSSGRenderContextInterface *renderContext);
public:
    virtual ~QSSGMaterialShaderGeneratorInterface();
    struct ImageVariableNames
    {
        QByteArray m_imageSampler;
        QByteArray m_imageFragCoords;
    };

    virtual ImageVariableNames getImageVariableNames(quint32 inIdx) = 0;
    virtual void generateImageUVCoordinates(QSSGShaderStageGeneratorInterface &inVertexPipeline,
                                            quint32 idx,
                                            quint32 uvSet,
                                            QSSGRenderableImage &image) = 0;

    // inPipelineName needs to be unique else the shader cache will just return shaders from
    // different pipelines.
    virtual QSSGRef<QSSGRenderShaderProgram> generateShader(const QSSGRenderGraphObject &inMaterial,
                                                                QSSGShaderDefaultMaterialKey inShaderDescription,
                                                                QSSGShaderStageGeneratorInterface &inVertexPipeline,
                                                                const ShaderFeatureSetList &inFeatureSet,
                                                                const QVector<QSSGRenderLight *> &inLights,
                                                                QSSGRenderableImage *inFirstImage,
                                                                bool inHasTransparency,
                                                                const QByteArray &inVertexPipelineName,
                                                                const QByteArray &inCustomMaterialName = QByteArray()) = 0;

    // Also sets the blend function on the render context.
    virtual void setMaterialProperties(const QSSGRef<QSSGRenderShaderProgram> &inProgram,
                                       const QSSGRenderGraphObject &inMaterial,
                                       const QVector2D &inCameraVec,
                                       const QMatrix4x4 &inModelViewProjection,
                                       const QMatrix3x3 &inNormalMatrix,
                                       const QMatrix4x4 &inGlobalTransform,
                                       QSSGRenderableImage *inFirstImage,
                                       float inOpacity,
                                       const QSSGLayerGlobalRenderProperties &inRenderProperties,
                                       bool receivesShadows = true) = 0;

    static QSSGRef<QSSGMaterialShaderGeneratorInterface> createCustomMaterialShaderGenerator(QSSGRenderContextInterface *inRenderContext);
};
QT_END_NAMESPACE

#endif