hgi.h

//
// Copyright 2019 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_IMAGING_HGI_HGI_H
#define PXR_IMAGING_HGI_HGI_H

#include "pxr/pxr.h"
#include "pxr/base/tf/token.h"
#include "pxr/base/tf/type.h"

#include "pxr/imaging/hgi/api.h"
#include "pxr/imaging/hgi/blitCmds.h"
#include "pxr/imaging/hgi/buffer.h"
#include "pxr/imaging/hgi/computeCmds.h"
#include "pxr/imaging/hgi/computeCmdsDesc.h"
#include "pxr/imaging/hgi/graphicsCmds.h"
#include "pxr/imaging/hgi/graphicsCmdsDesc.h"
#include "pxr/imaging/hgi/graphicsPipeline.h"
#include "pxr/imaging/hgi/resourceBindings.h"
#include "pxr/imaging/hgi/sampler.h"
#include "pxr/imaging/hgi/shaderFunction.h"
#include "pxr/imaging/hgi/shaderProgram.h"
#include "pxr/imaging/hgi/texture.h"
#include "pxr/imaging/hgi/types.h"
#include "pxr/imaging/hgi/version.h"

#include <atomic>
#include <memory>

PXR_NAMESPACE_OPEN_SCOPE

class HgiCapabilities;
class HgiIndirectCommandEncoder;

using HgiUniquePtr = std::unique_ptr<class Hgi>;


class Hgi
{
public:
    HGI_API
    Hgi();

    HGI_API
    virtual ~Hgi();

    HGI_API
    void SubmitCmds(
        HgiCmds* cmds, 
        HgiSubmitWaitType wait = HgiSubmitWaitTypeNoWait);

    HGI_API
    static Hgi* GetPlatformDefaultHgi();

    HGI_API
    static HgiUniquePtr CreatePlatformDefaultHgi();

    HGI_API
    static HgiUniquePtr CreateNamedHgi(const TfToken& hgiToken);

    HGI_API
    virtual bool IsBackendSupported() const = 0;

    HGI_API
    static bool IsSupported(const TfToken& hgiToken = TfToken());

    HGI_API
    virtual HgiGraphicsCmdsUniquePtr CreateGraphicsCmds(
        HgiGraphicsCmdsDesc const& desc) = 0;

    HGI_API
    virtual HgiBlitCmdsUniquePtr CreateBlitCmds() = 0;

    HGI_API
    virtual HgiComputeCmdsUniquePtr CreateComputeCmds(
        HgiComputeCmdsDesc const& desc) = 0;

    HGI_API
    HgiTextureHandle CreateTexture(HgiTextureDesc const & desc);

    HGI_API
    virtual void DestroyTexture(HgiTextureHandle* texHandle) = 0;

    HGI_API
    HgiTextureViewHandle CreateTextureView(
        HgiTextureViewDesc const & desc);

    HGI_API
    virtual void DestroyTextureView(HgiTextureViewHandle* viewHandle) = 0;

    HGI_API
    virtual HgiSamplerHandle CreateSampler(HgiSamplerDesc const & desc) = 0;

    HGI_API
    virtual void DestroySampler(HgiSamplerHandle* smpHandle) = 0;

    HGI_API
    HgiBufferHandle CreateBuffer(HgiBufferDesc const & desc);

    HGI_API
    virtual void DestroyBuffer(HgiBufferHandle* bufHandle) = 0;

    HGI_API
    virtual HgiShaderFunctionHandle CreateShaderFunction(
        HgiShaderFunctionDesc const& desc) = 0;

    HGI_API
    virtual void DestroyShaderFunction(
        HgiShaderFunctionHandle* shaderFunctionHandle) = 0;

    HGI_API
    virtual HgiShaderProgramHandle CreateShaderProgram(
        HgiShaderProgramDesc const& desc) = 0;

    HGI_API
    virtual void DestroyShaderProgram(
        HgiShaderProgramHandle* shaderProgramHandle) = 0;

    HGI_API
    HgiResourceBindingsHandle CreateResourceBindings(
        HgiResourceBindingsDesc const& desc);

    HGI_API
    virtual void DestroyResourceBindings(
        HgiResourceBindingsHandle* resHandle) = 0;

    HGI_API
    virtual HgiGraphicsPipelineHandle CreateGraphicsPipeline(
        HgiGraphicsPipelineDesc const& pipeDesc) = 0;

    HGI_API
    virtual void DestroyGraphicsPipeline(
        HgiGraphicsPipelineHandle* pipeHandle) = 0;

    HGI_API
    virtual HgiComputePipelineHandle CreateComputePipeline(
        HgiComputePipelineDesc const& pipeDesc) = 0;

    HGI_API
    virtual void DestroyComputePipeline(HgiComputePipelineHandle* pipeHandle)=0;

    HGI_API
    virtual TfToken const& GetAPIName() const = 0;

    HGI_API
    virtual HgiCapabilities const* GetCapabilities() const = 0;

    HGI_API
    virtual HgiIndirectCommandEncoder* GetIndirectCommandEncoder() const = 0;

    HGI_API
    virtual void StartFrame() = 0;

    HGI_API
    virtual void EndFrame() = 0;

    HGI_API
    virtual void GarbageCollect() = 0;

protected:
    // Returns a unique id for handle creation.
    // Thread safety: Thread-safe atomic increment.
    HGI_API
    uint64_t GetUniqueId();

    // Calls Submit on provided Cmds.
    // Derived classes can override this function if they need customize the
    // command submission. The default implementation calls cmds->_Submit().
    HGI_API
    virtual bool _SubmitCmds(
        HgiCmds* cmds, HgiSubmitWaitType wait);

    HGI_API
    virtual HgiTextureHandle _CreateTexture(HgiTextureDesc const & desc) = 0;

    HGI_API
    virtual HgiTextureViewHandle _CreateTextureView(
        HgiTextureViewDesc const & desc) = 0;

    HGI_API
    virtual HgiBufferHandle _CreateBuffer(HgiBufferDesc const & desc) = 0;

    HGI_API
    virtual HgiResourceBindingsHandle _CreateResourceBindings(
        HgiResourceBindingsDesc const& desc) = 0;

private:
    Hgi & operator=(const Hgi&) = delete;
    Hgi(const Hgi&) = delete;

    std::atomic<uint64_t> _uniqueIdCounter;
};


class HgiFactoryBase : public TfType::FactoryBase {
public:
    virtual Hgi* New() const = 0;
};

template <class T>
class HgiFactory : public HgiFactoryBase {
public:
    Hgi* New() const {
        return new T;
    }
};


PXR_NAMESPACE_CLOSE_SCOPE

#endif