hgi.h

//
// Copyright 2019 Pixar
//
// Licensed under the Apache License, Version 2.0 (the "Apache License")
// with the following modification; you may not use this file except in
// compliance with the Apache License and the following modification to it:
// Section 6. Trademarks. is deleted and replaced with:
//
// 6. Trademarks. This License does not grant permission to use the trade
//    names, trademarks, service marks, or product names of the Licensor
//    and its affiliates, except as required to comply with Section 4(c) of
//    the License and to reproduce the content of the NOTICE file.
//
// You may obtain a copy of the Apache License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the Apache License with the above modification is
// distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the Apache License for the specific
// language governing permissions and limitations under the Apache 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 <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
    virtual bool IsBackendSupported() const = 0;

    HGI_API
    static bool IsSupported();

    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
    virtual HgiTextureHandle CreateTexture(HgiTextureDesc const & desc) = 0;

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

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

    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
    virtual HgiBufferHandle CreateBuffer(HgiBufferDesc const & desc) = 0;

    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
    virtual HgiResourceBindingsHandle CreateResourceBindings(
        HgiResourceBindingsDesc const& desc) = 0;

    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;

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);

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