Panda3D
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00001 // Filename: cylindricalLens.cxx 00002 // Created by: drose (12Dec01) 00003 // 00004 //////////////////////////////////////////////////////////////////// 00005 // 00006 // PANDA 3D SOFTWARE 00007 // Copyright (c) Carnegie Mellon University. All rights reserved. 00008 // 00009 // All use of this software is subject to the terms of the revised BSD 00010 // license. You should have received a copy of this license along 00011 // with this source code in a file named "LICENSE." 00012 // 00013 //////////////////////////////////////////////////////////////////// 00014 00015 #include "cylindricalLens.h" 00016 #include "deg_2_rad.h" 00017 00018 TypeHandle CylindricalLens::_type_handle; 00019 00020 // This is the focal-length constant for fisheye lenses. See 00021 // fisheyeLens.cxx. 00022 static const PN_stdfloat cylindrical_k = 60.0f; 00023 // focal_length = film_size * cylindrical_k / fov; 00024 00025 00026 //////////////////////////////////////////////////////////////////// 00027 // Function: CylindricalLens::make_copy 00028 // Access: Public, Virtual 00029 // Description: Allocates a new Lens just like this one. 00030 //////////////////////////////////////////////////////////////////// 00031 PT(Lens) CylindricalLens:: 00032 make_copy() const { 00033 return new CylindricalLens(*this); 00034 } 00035 00036 //////////////////////////////////////////////////////////////////// 00037 // Function: CylindricalLens::do_extrude 00038 // Access: Protected, Virtual 00039 // Description: Given a 2-d point in the range (-1,1) in both 00040 // dimensions, where (0,0) is the center of the 00041 // lens and (-1,-1) is the lower-left corner, 00042 // compute the corresponding vector in space that maps 00043 // to this point, if such a vector can be determined. 00044 // The vector is returned by indicating the points on 00045 // the near plane and far plane that both map to the 00046 // indicated 2-d point. 00047 // 00048 // The z coordinate of the 2-d point is ignored. 00049 // 00050 // Returns true if the vector is defined, or false 00051 // otherwise. 00052 //////////////////////////////////////////////////////////////////// 00053 bool CylindricalLens:: 00054 do_extrude(const Lens::CData *lens_cdata, 00055 const LPoint3 &point2d, LPoint3 &near_point, LPoint3 &far_point) const { 00056 // Undo the shifting from film offsets, etc. This puts the point 00057 // into the range [-film_size/2, film_size/2] in x and y. 00058 LPoint3 f = point2d * do_get_film_mat_inv(lens_cdata); 00059 00060 PN_stdfloat focal_length = do_get_focal_length(lens_cdata); 00061 PN_stdfloat angle = f[0] * cylindrical_k / focal_length; 00062 PN_stdfloat sinAngle, cosAngle; 00063 csincos(deg_2_rad(angle), &sinAngle, &cosAngle); 00064 00065 // Define a unit vector (well, a unit vector in the XY plane, at 00066 // least) that represents the vector corresponding to this point. 00067 LPoint3 v(sinAngle, cosAngle, f[1] / focal_length); 00068 00069 // And we'll need to account for the lens's rotations, etc. at the 00070 // end of the day. 00071 const LMatrix4 &lens_mat = do_get_lens_mat(lens_cdata); 00072 00073 near_point = (v * do_get_near(lens_cdata)) * lens_mat; 00074 far_point = (v * do_get_far(lens_cdata)) * lens_mat; 00075 return true; 00076 } 00077 00078 //////////////////////////////////////////////////////////////////// 00079 // Function: CylindricalLens::do_extrude_vec 00080 // Access: Protected, Virtual 00081 // Description: Given a 2-d point in the range (-1,1) in both 00082 // dimensions, where (0,0) is the center of the 00083 // lens and (-1,-1) is the lower-left corner, 00084 // compute the vector that corresponds to the view 00085 // direction. This will be parallel to the normal on 00086 // the surface (the far plane) corresponding to the lens 00087 // shape at this point. 00088 // 00089 // See the comment block on Lens::extrude_vec_impl() for 00090 // a more in-depth comment on the meaning of this 00091 // vector. 00092 // 00093 // The z coordinate of the 2-d point is ignored. 00094 // 00095 // Returns true if the vector is defined, or false 00096 // otherwise. 00097 //////////////////////////////////////////////////////////////////// 00098 bool CylindricalLens:: 00099 do_extrude_vec(const Lens::CData *lens_cdata, const LPoint3 &point2d, LVector3 &vec) const { 00100 // Undo the shifting from film offsets, etc. This puts the point 00101 // into the range [-film_size/2, film_size/2] in x and y. 00102 LPoint3 f = point2d * do_get_film_mat_inv(lens_cdata); 00103 00104 PN_stdfloat focal_length = do_get_focal_length(lens_cdata); 00105 PN_stdfloat angle = f[0] * cylindrical_k / focal_length; 00106 PN_stdfloat sinAngle, cosAngle; 00107 csincos(deg_2_rad(angle), &sinAngle, &cosAngle); 00108 00109 vec = LVector3(sinAngle, cosAngle, 0.0f) * do_get_lens_mat(lens_cdata); 00110 00111 return true; 00112 } 00113 00114 //////////////////////////////////////////////////////////////////// 00115 // Function: CylindricalLens::do_project 00116 // Access: Protected, Virtual 00117 // Description: Given a 3-d point in space, determine the 2-d point 00118 // this maps to, in the range (-1,1) in both dimensions, 00119 // where (0,0) is the center of the lens and 00120 // (-1,-1) is the lower-left corner. 00121 // 00122 // Some lens types also set the z coordinate of the 2-d 00123 // point to a value in the range (-1, 1), where 1 00124 // represents a point on the near plane, and -1 00125 // represents a point on the far plane. 00126 // 00127 // Returns true if the 3-d point is in front of the lens 00128 // and within the viewing frustum (in which case point2d 00129 // is filled in), or false otherwise. 00130 //////////////////////////////////////////////////////////////////// 00131 bool CylindricalLens:: 00132 do_project(const Lens::CData *lens_cdata, const LPoint3 &point3d, LPoint3 &point2d) const { 00133 // First, account for any rotations, etc. on the lens. 00134 LPoint3 p = point3d * do_get_lens_mat_inv(lens_cdata); 00135 00136 // To compute the x position on the frame, we only need to consider 00137 // the angle of the vector about the Z axis. Project the vector 00138 // into the XY plane to do this. 00139 LVector2 xy(p[0], p[1]); 00140 00141 // The perspective distance is the length of this vector in the XY 00142 // plane. 00143 PN_stdfloat pdist = xy.length(); 00144 if (pdist == 0.0f) { 00145 point2d.set(0.0f, 0.0f, 0.0f); 00146 return false; 00147 } 00148 00149 PN_stdfloat focal_length = do_get_focal_length(lens_cdata); 00150 00151 point2d.set 00152 ( 00153 // The x position is the angle about the Z axis. 00154 rad_2_deg(catan2(xy[0], xy[1])) * focal_length / cylindrical_k, 00155 // The y position is the Z height divided by the perspective 00156 // distance. 00157 p[2] * focal_length / pdist, 00158 // Z is the perspective distance scaled into the range (1, -1). 00159 (do_get_near(lens_cdata) - pdist) / (do_get_far(lens_cdata) - do_get_near(lens_cdata)) 00160 ); 00161 00162 // Now we have to transform the point according to the film 00163 // adjustments. 00164 point2d = point2d * do_get_film_mat(lens_cdata); 00165 00166 return 00167 point2d[0] >= -1.0f && point2d[0] <= 1.0f && 00168 point2d[1] >= -1.0f && point2d[1] <= 1.0f; 00169 } 00170 00171 //////////////////////////////////////////////////////////////////// 00172 // Function: CylindricalLens::fov_to_film 00173 // Access: Protected, Virtual 00174 // Description: Given a field of view in degrees and a focal length, 00175 // compute the correspdonding width (or height) on the 00176 // film. If horiz is true, this is in the horizontal 00177 // direction; otherwise, it is in the vertical direction 00178 // (some lenses behave differently in each direction). 00179 //////////////////////////////////////////////////////////////////// 00180 PN_stdfloat CylindricalLens:: 00181 fov_to_film(PN_stdfloat fov, PN_stdfloat focal_length, bool horiz) const { 00182 if (horiz) { 00183 return focal_length * fov / cylindrical_k; 00184 } else { 00185 return (ctan(deg_2_rad(fov * 0.5f)) * focal_length) * 2.0f; 00186 } 00187 } 00188 00189 //////////////////////////////////////////////////////////////////// 00190 // Function: CylindricalLens::fov_to_focal_length 00191 // Access: Protected, Virtual 00192 // Description: Given a field of view in degrees and a width (or 00193 // height) on the film, compute the focal length of the 00194 // lens. If horiz is true, this is in the horizontal 00195 // direction; otherwise, it is in the vertical direction 00196 // (some lenses behave differently in each direction). 00197 //////////////////////////////////////////////////////////////////// 00198 PN_stdfloat CylindricalLens:: 00199 fov_to_focal_length(PN_stdfloat fov, PN_stdfloat film_size, bool horiz) const { 00200 if (horiz) { 00201 return film_size * cylindrical_k / fov; 00202 } else { 00203 return film_size * 0.5f / ctan(deg_2_rad(fov * 0.5f)); 00204 } 00205 } 00206 00207 //////////////////////////////////////////////////////////////////// 00208 // Function: CylindricalLens::film_to_fov 00209 // Access: Protected, Virtual 00210 // Description: Given a width (or height) on the film and a focal 00211 // length, compute the field of view in degrees. If 00212 // horiz is true, this is in the horizontal direction; 00213 // otherwise, it is in the vertical direction (some 00214 // lenses behave differently in each direction). 00215 //////////////////////////////////////////////////////////////////// 00216 PN_stdfloat CylindricalLens:: 00217 film_to_fov(PN_stdfloat film_size, PN_stdfloat focal_length, bool horiz) const { 00218 if (horiz) { 00219 return film_size * cylindrical_k / focal_length; 00220 } else { 00221 return rad_2_deg(catan(film_size * 0.5f / focal_length)) * 2.0f; 00222 } 00223 }