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#pragma once
#ifndef QT3DS_RENDER_SHADER_CACHE_H
#define QT3DS_RENDER_SHADER_CACHE_H
#include "Qt3DSRender.h"
#include "foundation/Qt3DSRefCounted.h"
#include "foundation/Qt3DSFlags.h"
#include "foundation/StringTable.h"

namespace qt3ds {
namespace render {
    struct ShaderCacheProgramFlagValues
    {
        enum Enum {
            TessellationEnabled = 1 << 0, // tessellation enabled
            GeometryShaderEnabled = 1 << 1, // geometry shader enabled
        };
    };
    struct SShaderCacheProgramFlags : public NVFlags<ShaderCacheProgramFlagValues::Enum, QT3DSU32>
    {
        // tessellation enabled
        void SetTessellationEnabled(bool inValue)
        {
            clearOrSet(inValue, ShaderCacheProgramFlagValues::TessellationEnabled);
        }
        bool IsTessellationEnabled() const
        {
            return this->operator&(ShaderCacheProgramFlagValues::TessellationEnabled);
        }
        // geometry shader enabled
        void SetGeometryShaderEnabled(bool inValue)
        {
            clearOrSet(inValue, ShaderCacheProgramFlagValues::GeometryShaderEnabled);
        }
        bool IsGeometryShaderEnabled() const
        {
            return this->operator&(ShaderCacheProgramFlagValues::GeometryShaderEnabled);
        }
    };
    // There are a number of macros used to turn on or off various features.  This allows those
    // features
    // to be propagated into the shader cache's caching mechanism.  They will be translated into
    //#define name value where value is 1 or zero depending on if the feature is enabled or not.
    struct SShaderPreprocessorFeature
    {
        CRegisteredString m_Name;
        bool m_Enabled;
        SShaderPreprocessorFeature()
            : m_Enabled(false)
        {
        }
        SShaderPreprocessorFeature(CRegisteredString name, bool val)
            : m_Name(name)
            , m_Enabled(val)
        {
        }
        bool operator<(const SShaderPreprocessorFeature &inOther) const;
        bool operator==(const SShaderPreprocessorFeature &inOther) const;
    };

    typedef NVConstDataRef<SShaderPreprocessorFeature> TShaderFeatureSet;

    inline TShaderFeatureSet ShaderCacheNoFeatures() { return TShaderFeatureSet(); }

    // Hash is dependent on the order of the keys; so make sure their order is consistent!!
    size_t HashShaderFeatureSet(NVConstDataRef<SShaderPreprocessorFeature> inFeatureSet);

    class IShaderCache : public NVRefCounted
    {
    protected:
        virtual ~IShaderCache() {}
    public:
        // If directory is nonnull, then we attempt to load any shaders from shadercache.xml in
        // inDirectory
        // and save any new ones out to the same file.  The shaders are marked by the gl version
        // used when saving.
        // If we can't open shadercache.xml from inDirectory for writing (at least), then we still
        // consider the
        // shadercache to be disabled.
        // This call immediately blocks and attempts to load all applicable shaders from the
        // shadercache.xml file in
        // the given directory.
        virtual void SetShaderCachePersistenceEnabled(const char8_t *inDirectory) = 0;
        virtual bool IsShaderCachePersistenceEnabled() const = 0;
        // It is up to the caller to ensure that inFeatures contains unique keys.
        // It is also up the the caller to ensure the keys are ordered in some way.
        virtual NVRenderShaderProgram *
        GetProgram(CRegisteredString inKey,
                   NVConstDataRef<SShaderPreprocessorFeature> inFeatures) = 0;

        // Replace an existing program in the cache for the same key with this program.
        // The shaders returned by *CompileProgram functions can be released by this object
        // due to ForceCompileProgram or SetProjectDirectory, so clients need to either not
        // hold on to them or they need to addref/release them to ensure they still have
        // access to them.
        // The flags just tell us under what gl state to compile the program in order to hopefully
        // reduce program compilations.
        // It is up to the caller to ensure that inFeatures contains unique keys.
        // It is also up the the caller to ensure the keys are ordered in some way.
        virtual NVRenderShaderProgram *
        ForceCompileProgram(CRegisteredString inKey, const char8_t *inVert, const char8_t *inFrag,
                            const char8_t *inTessCtrl, const char8_t *inTessEval,
                            const char8_t *inGeom, const SShaderCacheProgramFlags &inFlags,
                            TShaderFeatureSet inFeatures, bool separableProgram,
                            bool fromDisk = false) = 0;

        // It is up to the caller to ensure that inFeatures contains unique keys.
        // It is also up the the caller to ensure the keys are ordered in some way.
        virtual NVRenderShaderProgram *
        CompileProgram(CRegisteredString inKey, const char8_t *inVert, const char8_t *inFrag,
                       const char8_t *inTessCtrl, const char8_t *inTessEval, const char8_t *inGeom,
                       const SShaderCacheProgramFlags &inFlags, TShaderFeatureSet inFeatures,
                       bool separableProgram = false) = 0;

        // Used to disable any shader compilation during loading.  This is used when we are just
        // interested in going from uia->binary
        // and we expect to run on a headless server of sorts.  See the UICCompiler project for its
        // only current use case.
        virtual void SetShaderCompilationEnabled(bool inEnableShaderCompilation) = 0;

        // Upping the shader version invalidates all previous cache files.
        static QT3DSU32 GetShaderVersion() { return 4; }
        static const char8_t *GetShaderCacheFileName() { return "shadercache.xml"; }

        static IShaderCache &CreateShaderCache(NVRenderContext &inContext,
                                               IInputStreamFactory &inInputStreamFactory,
                                               IPerfTimer &inPerfTimer);
    };
}
}

#endif