packedsphere/GT_GEOPackedSphere.C

/*
 * Copyright (c) 2024
 *      Side Effects Software Inc.  All rights reserved.
 *
 * Redistribution and use of Houdini Development Kit samples in source and
 * binary forms, with or without modification, are permitted provided that the
 * following conditions are met:
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 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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#include "GT_GEOPackedSphere.h"
#include <GT/GT_GEOAttributeFilter.h>
#include <GT/GT_GEODetailList.h>
#include <GT/GT_GEOPrimCollectBoxes.h>
#include <GT/GT_GEOPrimPacked.h>
#include <GT/GT_GEOSupport.h>
#include <GT/GT_PrimCollect.h>
#include <GT/GT_PrimInstance.h>
#include <GT/GT_RefineParms.h>
#include <GT/GT_TransformArray.h>

#include <GU/GU_PrimPacked.h>


// Enable this to cause all the spheres to be instanced in the viewport.
// #define USE_INSTANCING

using namespace HDK_Sample;

namespace
{
    class PackedCollect : public GT_GEOPrimCollectData
    {
    public:
        PackedCollect(
            const GT_GEODetailListHandle &geometry,
            const GT_RefineParms *parms)
            : GT_GEOPrimCollectData()
            , myBoxes(geometry, true)
            , myUseLOD(GT_RefineParms::getPackedViewportLOD(parms))
        {
        }
        GEO_ViewportLOD         lod(const GU_PrimPacked *pack) const
        {
            if (myUseLOD)
            {
                return pack->viewportLOD();
            }
            return GEO_VIEWPORT_FULL;
        }

        GT_GEOPrimCollectBoxes  myBoxes;
        GT_GEOOffsetList        myPrimOffsets;
        bool                    myUseLOD;
    };
}

void
GT_GEOPackedSphere::registerPrimitive(const GA_PrimitiveTypeId &id)
{
    new GT_GEOPackedSphere(id);
}

GT_GEOPackedSphere::GT_GEOPackedSphere(const GA_PrimitiveTypeId &id)
{
    bind(id);
}

GT_GEOPackedSphere::~GT_GEOPackedSphere()
{
}

GT_GEOPrimCollectData *
GT_GEOPackedSphere::beginCollecting(const GT_GEODetailListHandle &g,
        const GT_RefineParms *parms) const
{
    return new PackedCollect(g, parms);
}

GT_PrimitiveHandle
GT_GEOPackedSphere::collect(const GT_GEODetailListHandle &g,
                            const GEO_Primitive *const* prim, int nseg,
                            GT_GEOPrimCollectData *data) const
{
    PackedCollect       *c = data->asPointer<PackedCollect>();
    const GU_PrimPacked *packed = UTverify_cast<const GU_PrimPacked *>(prim[0]);
    GEO_ViewportLOD      lod = c->lod(packed);

    switch (lod)
    {
        case GEO_VIEWPORT_HIDDEN:
            return GT_PrimitiveHandle();
        case GEO_VIEWPORT_CENTROID:
        case GEO_VIEWPORT_BOX:
        {
            UT_BoundingBox      box;
            UT_Matrix4D         m4d;

            packed->getUntransformedBounds(box);
            packed->getFullTransform4(m4d);
            if (lod == GEO_VIEWPORT_CENTROID)
                c->myBoxes.appendCentroid(box, m4d,
                           packed->getMapOffset(),
                           packed->getVertexOffset(0),
                           packed->getPointOffset(0));
            else
                c->myBoxes.appendBox(box, m4d,
                           packed->getMapOffset(),
                           packed->getVertexOffset(0),
                           packed->getPointOffset(0));
            return GT_PrimitiveHandle();
        }
        default:
            break;
    }
    
    // Full or point cloud LOD
    
#ifdef USE_INSTANCING
    // append prim offset for instancing in endCollecting()
    c->myPrimOffsets.append(packed->getMapOffset());
    return GT_PrimitiveHandle();
#else
    // Single prim per sphere.
    GT_GEOOffsetList offsets;
    offsets.append(packed->getMapOffset());
    return makeInstance(g, offsets);
#endif
}

GT_PrimitiveHandle
GT_GEOPackedSphere::endCollecting(const GT_GEODetailListHandle &g,
                                  GT_GEOPrimCollectData *data) const
{
    PackedCollect *c = data->asPointer<PackedCollect>();
    
#ifdef USE_INSTANCING
    // Both the spheres and bboxes are instanced.
    GT_PrimitiveHandle ph;
    
    if(c->myPrimOffsets.entries() > 0)
        ph = makeInstance(g, c->myPrimOffsets);

    if(c->myBoxes.getPrimitive())
    {
        if(ph)
        {
            auto collect = new GT_PrimCollect();
            collect->appendPrimitive(ph);
            collect->appendPrimitive(c->myBoxes.getPrimitive());
            ph = collect;
        }
        else
            ph = c->myBoxes.getPrimitive();
    }
    
    return ph;
#else
    // only boxes are instanced.
    return c->myBoxes.getPrimitive();
#endif
}


GT_PrimitiveHandle
GT_GEOPackedSphere::makeInstance(const GT_GEODetailListHandle &geometry,
                                 const GT_GEOOffsetList &offsets) const
{
    GU_ConstDetailHandle gdh = geometry->getGeometry(0);
    GU_DetailHandleAutoReadLock gdl(gdh);
    UT_Matrix4DArray transforms;
    GT_GEOOffsetList verts;
    GT_PrimitiveHandle geo;

    for(int i=0; i<offsets.entries(); i++)
    {
        const GU_PrimPacked *packed =
            UTverify_cast<const GU_PrimPacked *>(gdl->getPrimitive(offsets(i)));
        if(!geo)
            geo = new GT_GEOPrimPacked(gdh, packed);

        transforms.append();
        packed->getFullTransform4(transforms.last());
        verts.append(packed->getVertexOffset(0));
    }

    GT_TransformArrayHandle th = new GT_TransformArray();
    th->setTransforms(transforms);
    
    GT_GEOAttributeFilter filter;
    GT_AttributeListHandle uniform, detail;
    
    uniform = geometry->getPrimitiveVertexAttributes(
                filter,offsets, verts,
                GT_GEODetailList::GEO_INCLUDE_POINT,
                GT_GEODetailList::GEO_SKIP_DETAIL);
    detail  = geometry->getDetailAttributes(filter, true);

    return new GT_PrimInstance(geo, th, offsets, uniform, detail);
}