params.h 13.5 KB
Newer Older
1 2
#pragma once

3 4 5 6 7 8 9 10
#include <string>
#include <map>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <cassert>
#include <iostream>

11 12
#include "common.h"

13
/*! \class params
14
 *  \ingroup core
15 16
 *  \brief a static class allowing to change from one parametrization
 *  to another.
17
 *
18 19
 *  Any function object or data object should have an associated
 *  parametrization.
20 21 22 23 24 25
 *
 *  We use the following convention to defined the tangent, normal and
 *  bi-normal of the surface:
 *   * The normal is the upper vector (0, 0, 1)
 *   * The tangent direction is along x direction (1, 0, 0)
 *   * The bi-normal is along the y direction (0, 1, 0)
26 27 28
 */
class params
{
29
    public: // data
30

31 32
		 //! \brief list of all supported parametrization for the input space.
		 //! An unsupported parametrization will go under the name
33 34 35 36 37
		 //! <em>unknown</em>. We use the following notations:
		 //!   * The view vector is \f$\vec{v}\f$
		 //!   * The light vector is \f$\vec{l}\f$
		 //!   * The normal vector is \f$\vec{n}\f$
		 //!   * The reflected vector is \f$\vec{r} = 2\mbox{dot}(\vec{v}, \vec{n})\vec{n} - \vec{v}\f$
38 39
		 enum input
		 {
40 41 42 43
             RUSIN_TH_PH_TD_PD,     /*!< Half-angle parametrization as described in [Rusinkiewicz'98] */
             RUSIN_TH_PH_TD,
             RUSIN_TH_TD_PD,
             RUSIN_TH_TD,           /*!< Half-angle parametrization with no azimutal information */
44 45 46 47 48 49
             RUSIN_VH_VD,           /*!< Half-angle parametrization in vector format. Coordinates are:
				                             [\f$\vec{h}_x, \vec{h}_y, \vec{h}_z, \vec{d}_x, \vec{d}_y, 
													  \vec{d}_z \f$].*/
             RUSIN_VH,              /*!< Half-angle parametrization with no difference direction in 
												     vector format. Coordinates are: [\f$\vec{h}_x, \vec{h}_y, 
													  \vec{h}_z\f$]. */
50 51 52
             COS_TH_TD,
             COS_TH,

53 54 55
             SCHLICK_TK_PK,         /*!< Schlick's back vector parametrization */
             SCHLICK_VK,            /*!< Schlick's back vector */
             COS_TK,                /*!< Schlick's back vector dot product with the normal */
56

57 58 59
             STEREOGRAPHIC,         /*!< Stereographic projection of the Light and View vectors */

             SPHERICAL_TL_PL_TV_PV, /*!< Light and View vectors represented in spherical coordinates */
60
             ISOTROPIC_TV_TL,       /*!< Light and View vectors represented in spherical coordinates, */
61 62
             ISOTROPIC_TV_TL_DPHI,  /*!< Light and View vectors represented in spherical coordinates,
                                         with the difference of azimutal coordinates in the last component  */
63 64 65
				 ISOTROPIC_TV_PROJ_DPHI,/*!< 2D Parametrization where the phi component is projected.
				                             Coordinates are: [\f$\theta_v \cos(\Delta\phi), \theta_v 
													  \sin(\Delta\phi).\f$]*/
66 67 68
				 ISOTROPIC_TL_TV_PROJ_DPHI,/*!< 3D Parametrization where the phi component is projected.
				                                Coordinates are: [\f$\theta_l, \theta_v \cos(\Delta\phi), 
														  \theta_v \sin(\Delta\phi).\f$]*/
69 70
             ISOTROPIC_TD_PD,       /*!< Difference between two directions such as R and H */

71 72 73
             CARTESIAN,             /*!< View and Light vectors represented in cartesian coordinates.
				                             We always pack the view vector first: \f$\vec{c} = [v.x, v.y, 
													  v.z, l.x, l.y, l.z] \f$*/
74

75
             UNKNOWN_INPUT          /*!< Default behaviour. Only use this is you do not fit BRDF data */
76 77 78 79 80 81 82
		 };

		 //! \brief list of all supported parametrization for the output space.
		 //! An unsupported parametrization will go under the name
		 //! <em>unknown</em>.
		 enum output
		 {
83 84 85 86 87
			 INV_STERADIAN,                /*!< Output values in inverse steradian (sr-1). 
														   This is the standard definition for a BRDF. */
			 INV_STERADIAN_COSINE_FACTOR,  /*!< Output values in inverse steradian (sr-1)
			                                    weighted by the cosine factor of the output
															direction. */
88 89 90 91 92
			 ENERGY,
			 RGB_COLOR,
			 XYZ_COLOR,
			 UNKNOWN_OUTPUT
		 };
93 94 95

    public: // methods

96
        //! \brief parse a string to provide a parametrization type.
97
        static params::input parse_input(const std::string& txt);
Laurent Belcour's avatar
Laurent Belcour committed
98

99 100 101
		  //! \brief look for the string associated with a parametrization
		  //! type.
		  static std::string get_name(const params::input param);
Laurent Belcour's avatar
Laurent Belcour committed
102

103 104 105 106 107 108 109 110 111 112 113 114 115
        //! \brief parse a string to provide a parametrization type.
        static params::output parse_output(const std::string& txt)
        {
            if(txt == std::string("ENERGY"))
            {
                return params::ENERGY;
            }
            else
            {
                return params::UNKNOWN_OUTPUT;
            }
        }

116 117
        //! \brief static function for input type convertion. This
        //! function allocate the resulting vector.
118 119
        static double* convert(const double* invec, params::input intype,
                               params::input outtype)
120
        {
121 122 123 124 125
            int dim = dimension(outtype); // Get the size of the output vector

            if(dim > 0)
            {
                double* outvec = new double[dim];
126
                double  temvec[6] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0}; // Temp CARTESIAN vectors
127 128 129 130 131 132 133 134 135 136 137
                to_cartesian(invec, intype, temvec);
                from_cartesian(temvec, outtype, outvec);

                return outvec;
            }
            else
            {
                return NULL;
            }
        }

138 139
        //! \brief static function for input type convertion. The outvec
        //! resulting vector should be allocated with the correct
140
        //! output size.
141 142
        static void convert(const double* invec, params::input intype,
                            params::input outtype, double* outvec)
143
        {
144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171
			  // The convertion is done using the cartesian parametrization as
			  // an intermediate one. If the two parametrizations are equals
			  // there is no need to perform the conversion.
			  if(intype == outtype)
			  {
				  int dim = dimension(outtype);
				  for(int i=0; i<dim; ++i) { outvec[i] = invec[i]; }
			  }
			  // If the input parametrization is the CARTESIAN param, then 
			  // there is no need to transform the input data.
			  if(intype == params::CARTESIAN)
			  {
				  from_cartesian(invec, outtype, outvec);
			  }
			  // If the output parametrization is the CARTESIAN param, then
			  // there is no need to convert back to another param.
			  else if(outtype == params::CARTESIAN)
			  {
				  to_cartesian(invec, intype, outvec);
			  }
			  else
			  {
				  // temporary CARTESIAN vector
				  double  temvec[6] = {0.0, 0.0, 0.0, 0.0, 0.0, 0.0};

				  to_cartesian(invec, intype, temvec);
				  from_cartesian(temvec, outtype, outvec);
			  }
172 173 174 175 176
        }

        //! \brief convert a input vector in a given parametrization to an
        //! output vector in a cartesian parametrization, that is two 3d
        //! vectors concatenated.
177
        static void to_cartesian(const double* invec, params::input intype,
178
                                 double* outvec);
179 180 181

        //! \brief convert a input CARTESIAN vector, that is two 3d vectors
        //! concatenated  to an output vector in a given parametrization.
182
        static void from_cartesian(const double* invec, params::input outtype,
183
                                   double* outvec);
184 185

        //! \brief provide a dimension associated with a parametrization
186
        static int  dimension(params::input t);
187

188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205
        //! \brief provide a dimension associated with a parametrization
        static int  dimension(params::output t)
        {
            switch(t)
            {
                // 1D Parametrizations
                case params::INV_STERADIAN:
                case params::ENERGY:
                    return 1;
                    break;

                // 3D Parametrization
                case params::RGB_COLOR:
                case params::XYZ_COLOR:
                    return 3;
                    break;

                default:
206
                    assert(false);
207 208 209 210 211
                    return -1;
                    break;
            }
        }

212 213 214 215 216 217 218
        //! \brief from the 4D definition of a half vector parametrization,
        //! export the cartesian coordinates.
        static void half_to_cartesian(double theta_h, double phi_h,
                                      double theta_d, double phi_d, double* out)
        {
            // Calculate the half vector
            double half[3];
219 220
            half[0] = sin(theta_h)*cos(phi_h);
            half[1] = sin(theta_h)*sin(phi_h);
221 222 223
            half[2] = cos(theta_h);

            // Compute the light vector using the rotation formula.
224 225
            out[0] = sin(theta_d)*cos(phi_d);
            out[1] = sin(theta_d)*sin(phi_d);
226
            out[2] = cos(theta_d);
227

228
				// Rotate the diff vector to get the output vector
229
            rotate_binormal(out, theta_h);
230
            rotate_normal(out, phi_h);
231 232 233 234

            // Compute the out vector from the in vector and the half
            // vector.
            const double dot = out[0]*half[0] + out[1]*half[1] + out[2]*half[2];
235 236 237
            out[3] = -out[0] + 2.0*dot * half[0];
            out[4] = -out[1] + 2.0*dot * half[1];
            out[5] = -out[2] + 2.0*dot * half[2];
238

239 240 241
#ifdef DEBUG
				assert(out[2] >= 0.0 && out[5] >= 0.0);
#endif
242
        }
243 244 245 246 247 248 249 250 251 252 253 254 255
			
        //! \brief from the 4D definition of a classical vector parametrization,
        //! export the cartesian coordinates.
		  static void classical_to_cartesian(double theta_l, double phi_l, 
		                                     double theta_v, double phi_v, double* out)
		  {
			  out[0] = cos(phi_l)*sin(theta_l);
			  out[1] = sin(phi_l)*sin(theta_l);
			  out[2] = cos(theta_l);
			  out[3] = cos(phi_v)*sin(theta_v);
			  out[4] = sin(phi_v)*sin(theta_v);
			  out[5] = cos(theta_v);
		  }
256

257 258 259 260 261 262
		  //! \brief rotate a cartesian vector with respect to the normal of
		  //! theta degrees.
		  static void rotate_normal(double* vec, double theta)
		  {
			  const double cost = cos(theta);
			  const double sint = sin(theta);
263

264
			  const double temp = cost * vec[0] + sint * vec[1];
265

266 267 268
			  vec[1] = cost * vec[1] - sint * vec[0];
			  vec[0] = temp;
		  }
269

270 271 272 273 274 275
		  //! \brief rotate a cartesian vector with respect to the bi-normal of
		  //! theta degrees.
		  static void rotate_binormal(double* vec, double theta)
		  {
			  const double cost = cos(theta);
			  const double sint = sin(theta);
276

277
			  const double temp = cost * vec[0] + sint * vec[2];
278

279 280 281
			  vec[2] = cost * vec[2] - sint * vec[0];
			  vec[0] = temp;
		  }
282

283
		  static void print_input_params();
284

285
};
286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331

/*! \brief A parametrized object. Allow to define function object (either data
 *  or functions that are defined over an input space and output space. This
 *  Object allowas to change the parametrization of the input or output space.
 */
class parametrized
{
	public:
		parametrized() : _in_param(params::UNKNOWN_INPUT), 
		                 _out_param(params::UNKNOWN_OUTPUT) { }

		//! \brief provide the input parametrization of the object.
		virtual params::input parametrization() const
		{
			return _in_param;
		}
		
		//! \brief provide the input parametrization of the object.
		virtual params::input input_parametrization() const
		{
			return _in_param;
		}
		
		//! \brief provide the outout parametrization of the object.
		virtual params::output output_parametrization() const
		{
			return _out_param;
		}

		//! \brief can set the input parametrization of a non-parametrized
		//! object. Print an error if it is already defined.
		virtual void setParametrization(params::input new_param)
		{
			//! \todo Here is something strange happening. The equality between
			//! those enums is not correct for UNKNOWN_INPUT
			if(_in_param == new_param)
			{
				return;
			}
			else if(_in_param == params::UNKNOWN_INPUT)
			{
				_in_param = new_param;
			}
			else
			{
				std::cout << "<<ERROR>> an input parametrization is already defined: " << params::get_name(_in_param) << std::endl;
332 333
				std::cout << "<<ERROR>> changing to: " << params::get_name(new_param) << std::endl;
				_in_param = new_param;
334 335 336 337 338 339 340 341 342 343 344 345
			}
		}
		
		//! \brief can set the output parametrization of a non-parametrized
		//! function. Throw an exception if it tries to erase a previously
		//! defined one.
		virtual void setParametrization(params::output new_param)
		{
			if(_out_param == new_param)
			{
				return;
			}
346
            else if(_out_param == params::UNKNOWN_OUTPUT)
347 348 349 350 351 352 353 354 355
			{
				_out_param = new_param;
			}
			else
			{
				std::cout << "<<ERROR>> an output parametrization is already defined: " << std::endl;
			}
		}

356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378

		/* DIMENSION OF THE INPUT AND OUTPUT DOMAIN */

		//! Provide the dimension of the input space of the function
		virtual int dimX() const { return _nX ; }
		//! Provide the dimension of the output space of the function
		virtual int dimY() const { return _nY ; }

		//! Set the dimension of the input space of the function
		virtual void setDimX(int nX) { _nX = nX ; }
		//! Set the dimension of the output space of the function
		virtual void setDimY(int nY) { _nY = nY ; }


		/* DEFINITION DOMAIN OF THE FUNCTION */

		//! \brief Set the minimum value the input can take
		virtual void setMin(const vec& min) ;

		//! \brief Set the maximum value the input can take
		virtual void setMax(const vec& max) ;

		//! \brief Get the minimum value the input can take
379
		virtual vec min() const ;
380 381

		//! \brief Get the maximum value the input can take
382
		virtual vec max() const ;
383 384


385 386 387 388
	protected:
		// Input and output parametrization
		params::input  _in_param ;
		params::output _out_param ;
389 390 391 392

		// Dimension of the function & domain of definition.
		int _nX, _nY ;
		vec _min, _max ;
393
};