pickTask.h

//
// Copyright 2019 Pixar
//
// Licensed under the terms set forth in the LICENSE.txt file available at
// https://openusd.org/license.
//
#ifndef PXR_IMAGING_HDX_PICK_TASK_H
#define PXR_IMAGING_HDX_PICK_TASK_H
 
#include "pxr/pxr.h"
#include "pxr/imaging/hdx/api.h"
 
#include "pxr/imaging/hdSt/textureUtils.h"
#include "pxr/imaging/hd/dataSource.h"
#include "pxr/imaging/hd/enums.h"
#include "pxr/imaging/hd/primOriginSchema.h"
#include "pxr/imaging/hd/renderPass.h"
#include "pxr/imaging/hd/renderPassState.h"
#include "pxr/imaging/hd/rprimCollection.h"
#include "pxr/imaging/hd/task.h"
 
#include "pxr/base/arch/align.h"
#include "pxr/base/tf/declarePtrs.h"
#include "pxr/base/gf/matrix4d.h"
#include "pxr/base/gf/vec2i.h"
#include "pxr/base/gf/vec2f.h"
#include "pxr/base/gf/vec4i.h"
#include "pxr/base/gf/vec4d.h"
#include "pxr/usd/sdf/path.h"
 
#include <vector>
#include <memory>
 
PXR_NAMESPACE_OPEN_SCOPE
 
#define HDX_PICK_TOKENS              \
    /* Task context */               \
    (pickParams)                     \
                                     \
    /* Pick target */                \
    (pickPrimsAndInstances)          \
    (pickFaces)                      \
    (pickEdges)                      \
    (pickPoints)                     \
    (pickPointsAndInstances)         \
                                     \
    /* Resolve mode */               \
    (resolveNearestToCamera)         \
    (resolveNearestToCenter)         \
    (resolveUnique)                  \
    (resolveAll)                     \
    (resolveDeep)
 
TF_DECLARE_PUBLIC_TOKENS(HdxPickTokens, HDX_API, HDX_PICK_TOKENS);
 
class HdStRenderBuffer;
class HdStRenderPassState;
using HdStShaderCodeSharedPtr = std::shared_ptr<class HdStShaderCode>;
 
class Hgi;
 
struct HdxPickTaskParams
{
    HdxPickTaskParams()
        : cullStyle(HdCullStyleNothing)
    {}
 
    HdCullStyle cullStyle;
};
 
struct HdxPickHit
{
    SdfPath delegateId;
    SdfPath objectId;
    SdfPath instancerId;
    int instanceIndex;
    int elementIndex;
    int edgeIndex;
    int pointIndex;
    GfVec3d worldSpaceHitPoint;
    GfVec3f worldSpaceHitNormal;
    float normalizedDepth;
 
    inline bool IsValid() const {
        return !objectId.IsEmpty();
    }
 
    HDX_API
    size_t GetHash() const;
};
 
using HdxPickHitVector = std::vector<HdxPickHit>;
 
struct HdxInstancerContext
{
    SdfPath instancerSceneIndexPath;
    HdContainerDataSourceHandle instancerPrimOrigin;
 
    SdfPath instanceSceneIndexPath;
 
    HdContainerDataSourceHandle instancePrimOrigin;
    int instanceId;
};
 
struct HdxPrimOriginInfo
{
    HDX_API
    static HdxPrimOriginInfo
    FromPickHit(HdSceneIndexBaseRefPtr const &terminalSceneIndex,
                const HdxPickHit &hit);
 
    HDX_API
    static HdxPrimOriginInfo
    FromPickHit(HdRenderIndex * renderIndex,
                const HdxPickHit &hit);
 
    HDX_API
    static std::vector<HdxPrimOriginInfo>
    FromPickHits(HdSceneIndexBaseRefPtr const &terminalSceneIndex,
                 const std::vector<HdxPickHit> &hits);
 
    HDX_API
    static std::vector<HdxPrimOriginInfo>
    FromPickHits(HdRenderIndex * renderIndex,
                 const std::vector<HdxPickHit> &hits);
 
    HDX_API
    SdfPath GetFullPath(
        const TfToken &nameInPrimOrigin =
                    HdPrimOriginSchemaTokens->scenePath) const;
 
    HDX_API
    HdInstancerContext ComputeInstancerContext(
        const TfToken &nameInPrimOrigin =
                    HdPrimOriginSchemaTokens->scenePath) const;
 
    std::vector<HdxInstancerContext> instancerContexts;
    HdContainerDataSourceHandle primOrigin;
};
 
struct HdxPickTaskContextParams
{
    using DepthMaskCallback = std::function<void(void)>;
 
    HdxPickTaskContextParams()
        : resolution(128, 128)
        , maxNumDeepEntries(32000)
        , pickTarget(HdxPickTokens->pickPrimsAndInstances)
        , resolveMode(HdxPickTokens->resolveNearestToCamera)
        , doUnpickablesOcclude(false)
        , viewMatrix(1)
        , projectionMatrix(1)
        , clipPlanes()
        , depthMaskCallback(nullptr)
        , collection()
        , alphaThreshold(0.0001f)
        , outHits(nullptr)
    {}
 
    GfVec2i resolution;
    int maxNumDeepEntries;
    TfToken pickTarget;
    TfToken resolveMode;
    bool doUnpickablesOcclude;
    GfMatrix4d viewMatrix;
    GfMatrix4d projectionMatrix;
    std::vector<GfVec4d> clipPlanes;
    DepthMaskCallback depthMaskCallback;
    HdRprimCollection collection;
    float alphaThreshold;
    HdxPickHitVector *outHits;
};
 
class HdxPickTask : public HdTask
{
public:
    using TaskParams = HdxPickTaskParams;
 
    HDX_API
    HdxPickTask(HdSceneDelegate* delegate, SdfPath const& id);
 
    HDX_API
    ~HdxPickTask() override;
 
    HDX_API
    void Sync(HdSceneDelegate* delegate,
              HdTaskContext* ctx,
              HdDirtyBits* dirtyBits) override;
 
    HDX_API
    void Prepare(HdTaskContext* ctx,
                 HdRenderIndex* renderIndex) override;
 
    HDX_API
    void Execute(HdTaskContext* ctx) override;
 
    HDX_API
    const TfTokenVector &GetRenderTags() const override;
 
    static inline int DecodeIDRenderColor(unsigned char const idColor[4]) {
        return (int32_t(idColor[0] & 0xff) << 0)  |
               (int32_t(idColor[1] & 0xff) << 8)  |
               (int32_t(idColor[2] & 0xff) << 16) |
               (int32_t(idColor[3] & 0xff) << 24);
    }
 
private:
    HdxPickTaskParams _params;
    HdxPickTaskContextParams _contextParams;
    TfTokenVector _renderTags;
    bool _useOverlayPass;
 
    // We need to cache a pointer to the render index so Execute() can
    // map prim ID to paths.
    HdRenderIndex *_index;
 
    void _InitIfNeeded();
    void _CreateAovBindings();
    void _CleanupAovBindings();
    void _ResizeOrCreateBufferForAOV(
        const HdRenderPassAovBinding& aovBinding);
 
    void _ConditionStencilWithGLCallback(
            HdxPickTaskContextParams::DepthMaskCallback maskCallback,
            HdRenderBuffer const * depthStencilBuffer);
 
    bool _UseOcclusionPass() const;
    bool _UseOverlayPass() const;
    void _UpdateUseOverlayPass();
 
    void _ClearPickBuffer();
    void _ResolveDeep();
 
    template<typename T>
    HdStTextureUtils::AlignedBuffer<T>
    _ReadAovBuffer(TfToken const & aovName) const;
 
    HdRenderBuffer const * _FindAovBuffer(TfToken const & aovName) const;
 
    // Create a shared render pass each for pickables, unpickables, and 
    // items in overlay (which may draw on top even when occluded).
    HdRenderPassSharedPtr _pickableRenderPass;
    HdRenderPassSharedPtr _occluderRenderPass;
    HdRenderPassSharedPtr _overlayRenderPass;
 
    // Having separate render pass states allows us to use different
    // shader mixins if we choose to (we don't currently).
    HdRenderPassStateSharedPtr _pickableRenderPassState;
    HdRenderPassStateSharedPtr _occluderRenderPassState;
    HdRenderPassStateSharedPtr _overlayRenderPassState;
 
    Hgi* _hgi;
 
    std::vector<std::unique_ptr<HdStRenderBuffer>> _pickableAovBuffers;
    HdRenderPassAovBindingVector _pickableAovBindings;
    HdRenderPassAovBinding _occluderAovBinding;
    size_t _pickableDepthIndex;
    TfToken _depthToken;
    std::unique_ptr<HdStRenderBuffer> _overlayDepthStencilBuffer;
    HdRenderPassAovBindingVector _overlayAovBindings;
 
    // pick buffer used for deep selection
    HdBufferArrayRangeSharedPtr _pickBuffer;
 
    HdxPickTask() = delete;
    HdxPickTask(const HdxPickTask &) = delete;
    HdxPickTask &operator =(const HdxPickTask &) = delete;
};
 
class HdxPickResult {
public:
 
    // Pick result takes a tuple of ID buffers:
    // - (primId, instanceId, elementId, edgeId, pointId)
    // along with some geometric buffers:
    // - (depth, Neye)
    // ... and resolves them into a series of hits, using one of the
    // algorithms specified below.
    //
    // index is used to fill in the HdxPickHit structure;
    // pickTarget is used to determine what a valid hit is;
    // viewMatrix, projectionMatrix, depthRange are used for unprojection
    // to calculate the worldSpaceHitPosition and worldSpaceHitNormal.
    // bufferSize is the size of the ID buffers, and subRect is the sub-region
    // of the id buffers to iterate over in the resolution algorithm.
    //
    // All buffers need to be the same size, if passed in.  It's legal for
    // only the depth and primId buffers to be provided; everything else is
    // optional but provides a richer picking result.
    HDX_API
    HdxPickResult(int const* primIds,
                  int const* instanceIds,
                  int const* elementIds,
                  int const* edgeIds,
                  int const* pointIds,
                  int const* neyes,
                  float const* depths,
                  HdRenderIndex const *index,
                  TfToken const& pickTarget,
                  GfMatrix4d const& viewMatrix,
                  GfMatrix4d const& projectionMatrix,
                  GfVec2f const& depthRange,
                  GfVec2i const& bufferSize,
                  GfVec4i const& subRect);
 
    HDX_API
    ~HdxPickResult();
 
    HDX_API
    HdxPickResult(HdxPickResult &&);
    HDX_API
    HdxPickResult& operator=(HdxPickResult &&);
 
    HDX_API
    bool IsValid() const;
 
    HDX_API
    void ResolveNearestToCamera(HdxPickHitVector* allHits) const;
 
    HDX_API
    void ResolveNearestToCenter(HdxPickHitVector* allHits) const;
 
    HDX_API
    void ResolveAll(HdxPickHitVector* allHits) const;
 
    HDX_API
    void ResolveUnique(HdxPickHitVector* allHits) const;
 
private:
    bool _ResolveHit(int index, int x, int y, float z, HdxPickHit* hit) const;
 
    size_t _GetHash(int index) const;
    bool _IsValidHit(int index) const;
 
    // Provide accessors for all of the ID buffers.  Since all but _primIds
    // are optional, if the buffer doesn't exist just return -1 (== no hit).
    int _GetPrimId(int index) const {
        return _primIds ? _primIds[index] : -1;
    }
    int _GetInstanceId(int index) const {
        return _instanceIds ? _instanceIds[index] : -1;
    }
    int _GetElementId(int index) const {
        return _elementIds ? _elementIds[index] : -1;
    }
    int _GetEdgeId(int index) const {
        return _edgeIds ? _edgeIds[index] : -1;
    }
    int _GetPointId(int index) const {
        return _pointIds ? _pointIds[index] : -1;
    }
 
    // Provide an accessor for the normal buffer.  If the normal buffer is
    // provided, this function will unpack the normal.  The fallback is
    // GfVec3f(0.0f).
    GfVec3f _GetNormal(int index) const;
 
    int const* _primIds;
    int const* _instanceIds;
    int const* _elementIds;
    int const* _edgeIds;
    int const* _pointIds;
    int const* _neyes;
    float const* _depths;
    HdRenderIndex const *_index;
    TfToken  _pickTarget;
    GfMatrix4d _ndcToWorld;
    GfMatrix4d _eyeToWorld;
    GfVec2f _depthRange;
    GfVec2i _bufferSize;
    GfVec4i _subRect;
};
 
// For sorting, order hits by ndc depth.
HDX_API
bool operator<(HdxPickHit const& lhs, HdxPickHit const& rhs);
 
// VtValue requirements
HDX_API
std::ostream& operator<<(std::ostream& out, const HdxPickHit& h);
HDX_API
bool operator==(const HdxPickHit& lhs,
                const HdxPickHit& rhs);
HDX_API
bool operator!=(const HdxPickHit& lhs,
                const HdxPickHit& rhs);
 
HDX_API
std::ostream& operator<<(std::ostream& out, const HdxPickTaskParams& pv);
HDX_API
bool operator==(const HdxPickTaskParams& lhs,
                const HdxPickTaskParams& rhs);
HDX_API
bool operator!=(const HdxPickTaskParams& lhs,
                const HdxPickTaskParams& rhs);
 
HDX_API
std::ostream& operator<<(std::ostream& out, const HdxPickTaskContextParams& pv);
HDX_API
bool operator==(const HdxPickTaskContextParams& lhs,
                const HdxPickTaskContextParams& rhs);
HDX_API
bool operator!=(const HdxPickTaskContextParams& lhs,
                const HdxPickTaskContextParams& rhs);
PXR_NAMESPACE_CLOSE_SCOPE
 
#endif // PXR_IMAGING_HDX_PICK_TASK_H