RixIES.h

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#ifndef RixIES_h
#define RixIES_h

#include <cstddef>                      // for NULL
#include <string>                       // for string
#include "RixInterfaces.h"              // for RixInterface, etc
#include "prmanapi.h"                   // for PRMAN_INLINE
#include "RiTypesHelper.h"              // for RtUString

/*
 * RixIES interface -- Rix Light Emission Profile interface
 *
 * Each RixLight optionally has an emission profile
 * accessable via "RixIES* profile = light->GetRixIES();".
 *
 * profile->EvaluateIESProfile, profile->EvaluateConeAngle()
 * are methods to evaluate emission.
 *
 * profile->ReadIESProfile reads all the params/settings of a IES profile.
 *
 */

class RixIES : public RixInterface
{
public:
    struct IESProfile
    {
        IESProfile()
            : mapName(US_NULL),
              profile(NULL),
              nu(0),
              nv(0),
              isColor(false),
              isExr(false),
              profileScale(1.0f)
        {
        }

        ~IESProfile() { clearProfile(); }

        void clearProfile()
        {
            delete[] profile;
            profile = NULL;
        }
        void clear()
        {
            clearProfile();
            mapName = US_NULL;
            nu      = 0;
            nv      = 0;
            isExr   = false;
            isColor = false;
        }

        RtUString mapName;
        float* profile;
        // RtMatrix    profileSpace;
        int nu, nv;
        bool isColor;
        bool isExr;
        float profileScale;
    };

    RixIES()
        : RixInterface(1),
          m_coneAngle(-1.0f),
          m_coneOffset(0.0f),
          m_hasNegativeDeterminant(false),
          m_normalizationFactor(1.0f)
    {
        // FIXME: do we need to support a profileSpace?
        // MxIdentity(m_profileSpace);
    }

    PRMAN_INLINE void EvaluateIESProfile(
        RtFloat3 const& P,
        RtColorRGB* emission) const;

    PRMAN_INLINE bool ReadIESProfile(
        RixContext const& rixCtx,
        RtUString const iesProfile);

    PRMAN_INLINE float EvaluateConeAngle(RtFloat3 const& P) const;

    PRMAN_INLINE float EvaluateConeAngle(RtPoint3 const& lightP, RtVector3& lightN,
                                         RtPoint3 const& offsetP, RtVector3 const& segmentDir,
                                         float& minT, float& maxT) const;

    // clang-format off
    // get/set funcs
    IESProfile& GetIESProfile()                   { return m_iesProfile; }

    float GetConeAngle() const                    { return m_coneAngle; }
    float GetConeOffset() const                   { return m_coneOffset; }
    bool GetHasNegativeDeterminant() const        { return m_hasNegativeDeterminant; }
    float GetNormalizationFactor() const          { return m_normalizationFactor; }

    void SetConeAngle(float v)                    { m_coneAngle = v; m_cosConeAngle = cosf(m_coneAngle); }
    void SetConeOffset(float v)                   { m_coneOffset = v; }
    void SetHasNegativeDeterminant(float v)       { m_hasNegativeDeterminant = v; }
    // clang-format on

private:
    // Utility routines
    PRMAN_INLINE float calcLongitude(float x, float y, bool isExr) const;

    PRMAN_INLINE void calcLatLongParam(
        int n,               // number of points in BOP
        float* dir,          // array of reflection directions
        bool openEXR,        // Is this an EXR latlong?
        float* s,           // output s array pointer
        float* t) const;    // output t array pointer

private:
    IESProfile m_iesProfile; // only the read func accesses its members

    float m_coneAngle;
    float m_cosConeAngle;
    float m_coneOffset;

    bool m_hasNegativeDeterminant;

    // The factor that scales the profile data to sum to unit intensity over the
    // entire sphere.
    float m_normalizationFactor;
};

#include "RixIESInline.h" // IWYU pragma: export

#endif