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  /*!
    \class SoTextureCombineElement Inventor/elements/SoTextureCombineElement.h
    \brief The SoTextureCombineElement class is yet to be documented.
  
    \ingroup elements
  
    FIXME: write doc.
  
    \COIN_CLASS_EXTENSION
  
    \since Coin 2.3
  */
  
  #include <Inventor/elements/SoTextureCombineElement.h>
  
  #include <cassert>
  #include <cstring>
  
  #include <Inventor/nodes/SoNode.h>
  #include <Inventor/lists/SbList.h>
  #include <Inventor/C/glue/gl.h>
  #include <Inventor/system/gl.h>
  
  #include "coindefs.h"
  #include "SbBasicP.h"
  
  #ifndef COIN_WORKAROUND_NO_USING_STD_FUNCS
  using std::memcpy;
  #endif // !COIN_WORKAROUND_NO_USING_STD_FUNCS
  
  class SoTextureCombineElementP {
  public:
    void ensureCapacity(int unit) const {
      while (unit >= this->unitdata.getLength()) {
        this->unitdata.append(SoTextureCombineElement::UnitData());
      }
    }
    mutable SbList<SoTextureCombineElement::UnitData> unitdata;
  };
  
  SO_ELEMENT_CUSTOM_CONSTRUCTOR_SOURCE(SoTextureCombineElement);
  
  #define PRIVATE(obj) obj->pimpl
  
  SoTextureCombineElement::SoTextureCombineElement(void)
  {
    PRIVATE(this) = new SoTextureCombineElementP;
  
    this->setTypeId(SoTextureCombineElement::classTypeId);
    this->setStackIndex(SoTextureCombineElement::classStackIndex);
  }
  
  /*!
    This static method initializes static data for the
    SoTextureCombineElement class.
  */
  
  void
  SoTextureCombineElement::initClass(void)
  {
    SO_ELEMENT_INIT_CLASS(SoTextureCombineElement, inherited);
  }
  
  /*!
    The destructor.
  */
  
  SoTextureCombineElement::~SoTextureCombineElement()
  {
    delete PRIVATE(this);
  }
  
  //! FIXME: write doc.
  
  void
  SoTextureCombineElement::init(SoState * state)
  {
    inherited::init(state);
  }
  
  //! FIXME: write doc.
  void
  SoTextureCombineElement::set(SoState * const state, SoNode * const node,
                               const int unit,
                               const Operation rgboperation,
                               const Operation alphaoperation,
                               const Source * rgbsource,
                               const Source * alphasource,
                               const Operand * rgboperand,
                               const Operand * alphaoperand,
                               const SbColor4f & constantcolor,
                               const float rgbscale,
                               const float alphascale)
  {
    SoTextureCombineElement * elem = coin_safe_cast<SoTextureCombineElement *>
      (state->getElement(classStackIndex));
    PRIVATE(elem)->ensureCapacity(unit);
    elem->setElt(unit, node->getNodeId(),
                 rgboperation,
                 alphaoperation,
                 rgbsource,
                 alphasource,
                 rgboperand,
                 alphaoperand,
                 constantcolor,
                 rgbscale,
                 alphascale);
  }
  
  
  //! FIXME: write doc.
  
  void
  SoTextureCombineElement::get(SoState * const state,
                               const int unit,
                               Operation & rgboperation,
                               Operation & alphaoperation,
                               Source * rgbsource,
                               Source * alphasource,
                               Operand * rgboperand,
                               Operand * alphaoperand,
                               SbColor4f & constantcolor,
                               float & rgbscale,
                               float & alphascale)
  {
    const SoTextureCombineElement * elem =
      coin_assert_cast<const SoTextureCombineElement *>
      (getConstElement(state, classStackIndex));
    
    assert(unit < PRIVATE(elem)->unitdata.getLength());
    const UnitData & ud = PRIVATE(elem)->unitdata[unit];
    
    rgboperation = ud.rgboperation;
    alphaoperation = ud.alphaoperation;
    memcpy(rgbsource, ud.rgbsource, 3*sizeof(Source));
    memcpy(alphasource, ud.alphasource, 3*sizeof(Source));
    memcpy(rgboperand, ud.rgboperand, 3*sizeof(Operand));
    memcpy(alphaoperand, ud.alphaoperand, 3*sizeof(Operand));
    constantcolor = ud.constantcolor;
    rgbscale = ud.rgbscale;
    alphascale = ud.alphascale;
  }
  
  
  SbBool
  SoTextureCombineElement::isDefault(SoState * const state,
                                     const int unit)
  {
    const SoTextureCombineElement * elem =
      coin_assert_cast<const SoTextureCombineElement *>
      (getConstElement(state, classStackIndex));
  
    if (unit < PRIVATE(elem)->unitdata.getLength()) {
      return PRIVATE(elem)->unitdata[unit].nodeid == 0;
    }
    return TRUE;
  }
  
  
  const SoTextureCombineElement::UnitData &
  SoTextureCombineElement::getUnitData(const int unit) const
  {
    assert(unit < PRIVATE(this)->unitdata.getLength());
    return PRIVATE(this)->unitdata[unit];
  }
  
  void
  SoTextureCombineElement::push(SoState * COIN_UNUSED_ARG(state))
  {
    const SoTextureCombineElement * prev = coin_assert_cast<SoTextureCombineElement *>
      (this->getNextInStack());
    PRIVATE(this)->unitdata = PRIVATE(prev)->unitdata;
  }
  
  SbBool
  SoTextureCombineElement::matches(const SoElement * elem) const
  {
    const SoTextureCombineElement * e =
      coin_assert_cast<const SoTextureCombineElement *>(elem);
    const int n = PRIVATE(e)->unitdata.getLength();
    if (n != PRIVATE(this)->unitdata.getLength()) return FALSE;
  
    for (int i = 0; i < n; i++) {
      if (PRIVATE(e)->unitdata[i].nodeid != PRIVATE(this)->unitdata[i].nodeid) {
        return FALSE;
      }
    }
    return TRUE;
  }
  
  SoElement *
  SoTextureCombineElement::copyMatchInfo(void) const
  {
    SoTextureCombineElement * elem =
      static_cast<SoTextureCombineElement *>(getTypeId().createInstance());
    PRIVATE(elem)->unitdata = PRIVATE(this)->unitdata;
    return elem;
  }
  
  
  //! FIXME: write doc.
  
  void
  SoTextureCombineElement::setElt(const int unit,
                                  const SbUniqueId nodeid,
                                  const Operation rgboperation,
                                  const Operation alphaoperation,
                                  const Source * rgbsource,
                                  const Source * alphasource,
                                  const Operand * rgboperand,
                                  const Operand * alphaoperand,
                                  const SbColor4f & constantcolor,
                                  const float rgbscale,
                                  const float alphascale)
  
  {
    PRIVATE(this)->ensureCapacity(unit);
    UnitData & ud = PRIVATE(this)->unitdata[unit];
  
    ud.nodeid = nodeid;
    ud.rgboperation = rgboperation;
    ud.alphaoperation = alphaoperation;
    memcpy(ud.rgbsource, rgbsource, 3*sizeof(Source));
    memcpy(ud.alphasource, alphasource, 3*sizeof(Source));
    memcpy(ud.rgboperand, rgboperand, 3*sizeof(Operand));
    memcpy(ud.alphaoperand, alphaoperand, 3*sizeof(Operand));
    ud.constantcolor = constantcolor;
    ud.rgbscale = rgbscale;
    ud.alphascale = alphascale;
  }
  
  void
  SoTextureCombineElement::apply(SoState * state, const int unit)
  {
    const SoTextureCombineElement * elem =
      coin_assert_cast<const SoTextureCombineElement *>
      (getConstElement(state, classStackIndex));
  
    assert(unit < PRIVATE(elem)->unitdata.getLength());
    const UnitData & ud = PRIVATE(elem)->unitdata[unit];
    
    glTexEnvi(GL_TEXTURE_ENV, GL_TEXTURE_ENV_MODE, GL_COMBINE);
    glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_RGB, static_cast<GLenum>(ud.rgboperation));
    glTexEnvi(GL_TEXTURE_ENV, GL_COMBINE_ALPHA, static_cast<GLenum>(ud.alphaoperation));
  
    glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_RGB, static_cast<GLenum>(ud.rgbsource[0]));
    glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_RGB, static_cast<GLenum>(ud.rgbsource[1]));
    glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE2_RGB, static_cast<GLenum>(ud.rgbsource[2]));
  
    glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE0_ALPHA, static_cast<GLenum>(ud.alphasource[0]));
    glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE1_ALPHA, static_cast<GLenum>(ud.alphasource[1]));
    glTexEnvi(GL_TEXTURE_ENV, GL_SOURCE2_ALPHA, static_cast<GLenum>(ud.alphasource[2]));
  
    glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_RGB, static_cast<GLenum>(ud.rgboperand[0]));
    glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_RGB, static_cast<GLenum>(ud.rgboperand[1]));
    glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_RGB, static_cast<GLenum>(ud.rgboperand[2]));
  
    glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND0_ALPHA, static_cast<GLenum>(ud.alphaoperand[0]));
    glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND1_ALPHA, static_cast<GLenum>(ud.alphaoperand[1]));
    glTexEnvi(GL_TEXTURE_ENV, GL_OPERAND2_ALPHA, static_cast<GLenum>(ud.alphaoperand[2]));
  
    glTexEnvfv(GL_TEXTURE_ENV, GL_TEXTURE_ENV_COLOR,
               ud.constantcolor.getValue());
    glTexEnvf(GL_TEXTURE_ENV, GL_RGB_SCALE, ud.rgbscale);
    glTexEnvf(GL_TEXTURE_ENV, GL_ALPHA_SCALE, ud.alphascale);
  }
  
  SoTextureCombineElement::UnitData::UnitData()
    : nodeid(0),
      rgboperation(REPLACE),
      alphaoperation(REPLACE),
      constantcolor(0.0f, 0.0f, 0.0f, 0.0f),
      rgbscale(1.0f),
      alphascale(1.0f)
  {
    for (int i = 0; i < 3; i++) {
      rgbsource[i] = CONSTANT;
      alphasource[i] = CONSTANT;
      rgboperand[i] = SRC_COLOR;
      alphaoperand[i] = SRC_COLOR;
    }
  }
  
  SoTextureCombineElement::UnitData::UnitData(const UnitData & org)
  {
    memcpy(this, &org, sizeof(*this));
  }
  
  
  #undef PRIVATE
  