karma_procedurals/BRAY_HdSphere.C

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 *----------------------------------------------------------------------------
 * Karma Procedural Sphere Example
 */

#include "BRAY_HdSphere.h"
#include <BRAY/BRAY_Procedural.h>
#include <BRAY/BRAY_AttribList.h>
#include <UT/UT_StringHolder.h>
#include <UT/UT_Debug.h>
#include <UT/UT_DSOVersion.h>
#include <UT/UT_UniquePtr.h>
#include <UT/UT_JSONWriter.h>

using namespace UT::Literal;
using namespace HDK_Sample;

namespace
{
    // For now, replace point clouds with this primitive type
    static constexpr UT_StringLit       theToken("sphere");
    static constexpr UT_StringLit       theRadius("radius");
    static constexpr UT_StringLit       theColor("color");
    static constexpr UT_StringLit       theDisplayColor("displayColor");

    // Simple static factory
    static BRAY_HdSphere &
    getFactory()
    {
        static BRAY_HdSphere    theProc;
        return theProc;
    }

    // Simple class to build out params
    class ParamListBuilder
    {
    public:
        using Params = BRAY_AttribList::Attrib;
        ParamListBuilder()
        {
            Params      parms[] = {
                {
                    theRadius.asHolder(),
                    1,
                    BRAY_AttribList::ATTRIB_POINT,
                    GA_STORE_REAL32,
                    false
                },
                {
                    theColor.asHolder(),
                    3,
                    BRAY_AttribList::ATTRIB_POINT,
                    GA_STORE_REAL32,
                    false
                },
            };
            myParms = UTmakeUnique<BRAY_AttribList>(parms, SYSarraySize(parms), false);
        }
        UT_UniquePtr<BRAY_AttribList>       myParms;
    };

    // The actual class that is produced by the factory
    class CustomSphere final : public BRAY_Procedural
    {
    public:

        using Attribute = BRAY_AttribList::Attrib;

        CustomSphere()
            : BRAY_Procedural()
            , myDisplayColor(0, 0, 0)
            , myRadius(1.f)
        {
            BRAY_AttribList::Attrib     alist[] = {
                { theRadius.asHolder(),
                  1,
                  BRAY_AttribList::ATTRIB_CONSTANT,
                  GA_STORE_REAL32,
                  false,
                },
                { theColor.asHolder(),
                  3,
                  BRAY_AttribList::ATTRIB_CONSTANT,
                  GA_STORE_REAL32,
                  false
                },
                { theDisplayColor.asHolder(),
                  3,
                  BRAY_AttribList::ATTRIB_CONSTANT,
                  GA_STORE_REAL32,
                  false
                },
            };

            // This defines the primvars/attributes which can be bound to
            // shader arguments.  Note that we double up color and displayColor
            myAttribs = BRAY_AttribList::findList(alist, 3, 0);

            // Randomly generate the display color of the sphere
            myDisplayColor = 0;
            uint    seed = SYSpointerHash(this);
            while (myDisplayColor.maxComponent() < .7)
            {
                myDisplayColor = UT_Vector3(SYSfastRandom(seed),
                            SYSfastRandom(seed),
                            SYSfastRandom(seed));
            }
        }

        /// Default destructor
        ~CustomSphere() override
        {
        }

        /// Return the attribute list which can be bound to shader attributes
        /// These are attributes/primvars that are provided by the procedural
        /// for shading/rendering.
        const BRAY_AttribList *attribList() const override
        {
            return myAttribs;
        }

        /// Return the bounding box for the object at the given time
        void bounds(UT_BoundingBox &bounds, BRAYtime time) const override
        {
            bounds.initBounds(-myRadius, -myRadius, -myRadius);
            bounds.enlargeBounds(myRadius, myRadius, myRadius);
        }

        /// The intersect function of the sphere with a 32-bit ray
        HitPtr intersect(const Ray32 &ray) const override
        {
            return intersectSphere<fpreal32>(ray);
        }

        /// The intersect function of the sphere with a 64-bit ray
        HitPtr intersect(const Ray64 &ray) const override
        {
            return intersectSphere<fpreal64>(ray);
        }

        /// Return the display color which is used for low-quality rendering
        UT_Vector3 displayColor() const override
        {
            return myDisplayColor;
        }

        /// @{
        /// A set of virtual functions used by Karma to pass parameters to
        /// the procedural. This is implemented for int32, int64, fpreal32,
        /// fpreal64, and UT_StringHolder. The list of possible parameters
        /// for a procedural is given by it's factory's @c paramList() method.
        void doSetParameter(
                const UT_StringRef &key,
                const int32 *vals,
                int n) override
        {
        }

        void doSetParameter(
                const UT_StringRef &key,
                const int64 *vals,
                int n) override
        {
        }

        void doSetParameter(
                const UT_StringRef &key,
                const fpreal32 *vals,
                int n) override
        {
            if (key == theRadius.asRef())
            {
                // We are just expecting 1 value.
                UT_ASSERT(n == 1);
                myRadius = vals[0];
            }
            else if (key == theColor.asRef())
            {
                // If we have 1 value, r,g,b = val
                // else the three components
                // either way we need only 1 or 3 vals.
                if (n == 1)
                    myDisplayColor = UT_Vector3(vals[0]);
                else if (n >= 3)
                    myDisplayColor = UT_Vector3(vals[0], vals[1], vals[2]);
            }
        }

        void doSetParameter(
                const UT_StringRef &key,
                const fpreal64 *vals,
                int n) override
        {
        }

        void doSetParameter(
                const UT_StringRef &key,
                const UT_StringHolder *vals,
                int n) override
        {
        }
        /// @}

        /// If the procedural had computation to do due to set
        /// parameters it would do so here
        void doBeginUpdate() override
        {
        }

        void doEndUpdate() override
        {
        }

        /// Validate the state of the attributes and parameters here
        bool checkIsValid() const override { return true; }

        /// @{
        /// Functions to evaluate the procedural's attributes, these functions
        /// are called by Karma when shading and rendering. The attributes are
        /// indexed by the value attrib, in the order of the @c attribList().
        using BRAY_Procedural::attribVal;

        const int32 *
        attribVal(
                int attrib,
                BRAYtime time,
                const Hit &hit_info,
                int32 *buf,
                int size) const override
        {
            return evalAttribute(attrib, time, hit_info, buf, size);
        }

        const int64 *
        attribVal(
                int attrib,
                BRAYtime time,
                const Hit &hit_info,
                int64 *buf,
                int size) const override
        {
            return evalAttribute(attrib, time, hit_info, buf, size);
        }

        const fpreal32 *
        attribVal(
                int attrib,
                BRAYtime time,
                const Hit &hit_info,
                fpreal32 *buf,
                int size) const override
        {
            // Return attributes based on their the attrib index
            switch (attrib)
            {
                case 0:
                    return &myRadius;
                case 1:
                case 2:
                    return myDisplayColor.data();
                default:
                    UT_ASSERT(0);
            }
            return buf;
        }

        const fpreal64 *
        attribVal(
                int attrib,
                BRAYtime time,
                const Hit &hit_info,
                fpreal64 *buf,
                int size) const override
        {
            // Return attributes based on their the attrib index
            // note that it accounts for the 32 -> 64 bit conversion
            switch (attrib)
            {
                case 0:
                    buf[0] = myRadius;
                    return buf;
                case 1:
                case 2:
                    std::copy(myDisplayColor.data(), myDisplayColor.data()+3, buf);
                    return buf;
                default:
                    UT_ASSERT(0);
            }
            return buf;
        }

        const UT_StringHolder *
        attribVal(
                int attrib,
                BRAYtime time,
                const Hit &hit_info,
                UT_StringHolder *buf,
                int size) const override
        {
            return evalAttribute(attrib, time, hit_info, buf, size);
        }
        /// @}

        template <typename T>
        const T *
        evalAttribute(
                int attrib,
                BRAYtime time,
                const Hit &hit,
                T *buf,
                int size) const
        {
            return buf;
        }

        void update(BRAY_EventType event) override
        {
            UTdebugFormat("Update {}", className());
        }

        void dumpInfo(UT_JSONWriter &w) const override
        {
            w.jsonBeginMap();
            w.jsonKeyValue("radius", myRadius);
            w.jsonEndMap();
        }

    protected:
        // Templated intersect function for either ray precision
        template <typename T> HitPtr
        intersectSphere(const Ray<T> &ray) const
        {
            // Simple spherical intersection
            T   a = ray.dir.length2();
            T   b = 2 * dot(ray.org, ray.dir);
            T   c = ray.org.length2() - myRadius * myRadius;
            T   d = b*b - 4*a*c;
            // No intersection (no real solution to quadratic)
            if (d < 0)
                return HitPtr();

            a = 1.0f / (2.0f * a);
            d = SYSsqrt(d);

            // Intersection distances
            T       t0 = a*(-b - d);
            T       t1 = a*(-b + d);
            // If these intersections are smaller than the current
            // hit distance, update the hit
            T       dist = ray.tfar;
            if (t0 > 0 && t0 < dist)
                dist = t0;
            else if (t1 > 0 && t1 < dist)
                dist = t1;
            else
                return HitPtr();

            // Update the hit
            HitPtr      hit = getHit();
            hit->distance = dist;
            hit->Ng = ray.org + dist * ray.dir;
            hit->Ng.normalize();

            return hit;
        }

        private:
            const BRAY_AttribList        *myAttribs;
            float                         myRadius;
            UT_Vector3                    myDisplayColor;
        };
    }

/// Call procedural factory constructor, and name the procedural
BRAY_HdSphere::BRAY_HdSphere()
    : BRAY_ProceduralFactory(theToken.asHolder())
{
}

BRAY_HdSphere::~BRAY_HdSphere()
{
}

BRAY_Procedural *
BRAY_HdSphere::create() const
{
    return new CustomSphere;
}

/// Return the list of parameters, which are attributes of the procedural that
/// can be set by Karma. These parameters can control the behaviour of the
/// procedural.
/// In this example, the parameters are the radius and the color of the sphere.
const BRAY_AttribList *
BRAY_HdSphere::paramList() const
{
    // Thread safe static initialization
    static ParamListBuilder builder;
    return builder.myParms.get();
}

void
BRAYregisterProcedural()
{
    getFactory();       // Instantiate
}