nonlinear_transform.h

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#ifndef NONLINEAR_TRANSFORM_H_
#define NONLINEAR_TRANSFORM_H_
#include "macosx_math.h"
#include <math.h>
#ifndef M_PI
#define M_PI (3.1415926536)
#endif

class IdentityTransform
{
public:
    virtual QVector Transform( const QVector &v ) const
    {
        return v;
    }
    virtual QVector TransformNormal( const QVector &v, const QVector &n ) const
    {
        return n;
    }
    virtual QVector InvTransform( const QVector &v ) const
    {
        return v;
    }
    virtual CLIPSTATE BoxInFrustum( Vector &min, Vector &max, const Vector &campos ) const
    {
        return GFXBoxInFrustum( min, max );
    }
    float TransformS( float x, float scale ) const
    {
        return x*scale;
    }
    float TransformT( float y, float scale ) const
    {
        return y*scale;
    }
};

extern float SphereTransformRenderlevel;
class SphericalTransform : public IdentityTransform
{
protected:
    float scalex, scalez, r;
public: SphericalTransform( float a, float b, float c ) : IdentityTransform()
    {
        SetXZ( a, c );
        SetR( b );
    }
    void SetXZ( float x, float z )
    {
        this->scalex = 2*M_PI/x;
        this->scalez = M_PI/z;
    }                                                                         //x ranges from 0 to 2PI x ranges from -PI/2 to PI/2
    void SetR( float rr )
    {
        r = rr;
    }
    float GetR() const
    {
        return r;
    }
    float GetX() const
    {
        return 2*M_PI/scalex;
    }
    float GetZ() const
    {
        return M_PI/scalez;
    }
    QVector Transform( const QVector &v ) const
    {
        Vector T( v.i*scalex, r+v.j, v.k*scalez-.5*M_PI );
        float  cosphi = cos( T.k );
        return QVector( T.j*cosphi*cos( T.i ), T.j*sin( T.k ), T.j*cosphi*sin( T.i ) );
    }
    QVector TransformNormal( const QVector &point, const QVector &n ) const
    {
        return SphericalTransform::Transform( n+point )-Transform( point );
    }
    QVector InvTransform( const QVector &v ) const
    {
        float rplusy = v.Magnitude();
        //float lengthxypln = sqrtf (rplusy*rplusy-v.j*v.j);//pythagorus
        return QVector( (atan2( -v.k, -v.i )+M_PI)/scalex, rplusy-r, (asin( v.j/rplusy )+M_PI*.5)/scalez );
    }
    CLIPSTATE BoxInFrustum( Vector &min, Vector &max, const Vector &campos ) const
    {
        const float rendermin = 3;
        /*
         *  float tmpx = fabs(campos.i-min.i);float maxx = fabs(campos.i-max.i);
         *  if (tmpx>.35*GetX()&&tmpx<.65*GetX()&&maxx>.25*GetX()&&maxx<.75*GetX()) {return GFX_NOT_VISIBLE;}
         *  tmpx = fabs(campos.k-min.k); maxx = fabs(campos.k-max.k);
         *  if (tmpx>.25*GetZ()&&tmpx<.75*GetZ()&&maxx>.25*GetZ()&&maxx<.75*GetZ()) {      return GFX_NOT_VISIBLE;//i/f it's on the other side of the hemisphere} */
        if (SphereTransformRenderlevel < rendermin)
            return GFX_PARTIALLY_VISIBLE;
        Vector tmin = SphericalTransform::Transform( min );
        Vector tmax = SphericalTransform::Transform( max );
        tmax = .5*(tmax+tmin);   //center
        float  rad  = 1.8*(tmax-tmin).Magnitude();

        return GFXSpherePartiallyInFrustum( tmax, rad );
    }
};
/*
 *  class PlanetaryTransform:public SphericalTransform {
 *  Vector Origin;
 *  public:
 *  PlanetaryTransform (Vector loc, float r, float scalex, float scaley): SphericalTransform (float r,float scalex, float scaley), origin(loc) {}
 *  void SetOrigin (const Vector &t) {Origin = t;}
 *  ~PlanetaryTransform () {while (1);}
 *  Vector Transform (const Vector & v) {return Origin+SphericalTransform::Transform(v);}
 *  Vector TransformNormal (const Vector &p, const vector & n){return SphericalTransform::TransformNormal (p,n);}
 *  Vector InvTransform (const Vector &v) {return SphericalTransform::InvTransform (v-Origin);}
 *  void GrabPerpendicularOrigin (const Vector &m, Matrix trans){
 *   Vector norm (m-Origin);
 *   Normalize(norm);
 *   Vector Intersection (norm*r);
 *
 *
 *
 *  }
 *  CLIPSTATE BoxInFrustum (Vector &min, Vector &max, const Vector & campos) {
 *   min = min-Origin;
 *   max = max-Origin;
 *   return SphericalTransform::BoxInFrustum(min,max,campos-Origin);
 *  }
 *  };
 */
#endif