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pSphereLens.cxx
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1/**
2 * PANDA 3D SOFTWARE
3 * Copyright (c) Carnegie Mellon University. All rights reserved.
4 *
5 * All use of this software is subject to the terms of the revised BSD
6 * license. You should have received a copy of this license along
7 * with this source code in a file named "LICENSE."
8 *
9 * @file pSphereLens.cxx
10 * @author drose
11 * @date 2001-12-12
12 */
13
14#include "pSphereLens.h"
15#include "deg_2_rad.h"
16
17 TypeHandle PSphereLens::_type_handle;
18
19// This is the focal-length constant for fisheye lenses. See fisheyeLens.cxx.
20 static const PN_stdfloat pspherical_k = 60.0f;
21
22
23/**
24 * Allocates a new Lens just like this one.
25 */
26PT(Lens) PSphereLens::
27make_copy() const {
28 return new PSphereLens(*this);
29}
30
31/**
32 * Given a 2-d point in the range (-1,1) in both dimensions, where (0,0) is
33 * the center of the lens and (-1,-1) is the lower-left corner, compute the
34 * corresponding vector in space that maps to this point, if such a vector can
35 * be determined. The vector is returned by indicating the points on the near
36 * plane and far plane that both map to the indicated 2-d point.
37 *
38 * The z coordinate of the 2-d point is ignored.
39 *
40 * Returns true if the vector is defined, or false otherwise.
41 */
42 bool PSphereLens::
43do_extrude(const Lens::CData *lens_cdata,
44 const LPoint3 &point2d, LPoint3 &near_point, LPoint3 &far_point) const {
45 // Undo the shifting from film offsets, etc. This puts the point into the
46 // range [-film_size2, film_size2] in x and y.
47 LPoint3 f = point2d * do_get_film_mat_inv(lens_cdata);
48
49 PN_stdfloat focal_length = do_get_focal_length(lens_cdata);
50
51 // Rotate the forward vector through the rotation angles corresponding to
52 // this point.
53 LPoint3 v = LPoint3(0.0f, 1.0f, 0.0f) *
54 LMatrix3::rotate_mat(f[1] * pspherical_k / focal_length, LVector3(1.0f, 0.0f, 0.0f)) *
55 LMatrix3::rotate_mat(f[0] * pspherical_k / focal_length, LVector3(0.0f, 0.0f, -1.0f));
56
57 // And we'll need to account for the lens's rotations, etc. at the end of
58 // the day.
59 const LMatrix4 &lens_mat = do_get_lens_mat(lens_cdata);
60 const LMatrix4 &proj_inv_mat = do_get_projection_mat_inv(lens_cdata);
61
62 near_point = (v * do_get_near(lens_cdata)) * proj_inv_mat * lens_mat;
63 far_point = (v * do_get_far(lens_cdata)) * proj_inv_mat * lens_mat;
64 return true;
65}
66
67/**
68 * Given a 3-d point in space, determine the 2-d point this maps to, in the
69 * range (-1,1) in both dimensions, where (0,0) is the center of the lens and
70 * (-1,-1) is the lower-left corner.
71 *
72 * Some lens types also set the z coordinate of the 2-d point to a value in
73 * the range (-1, 1), where -1 represents a point on the near plane, and 1
74 * represents a point on the far plane.
75 *
76 * Returns true if the 3-d point is in front of the lens and within the
77 * viewing frustum (in which case point2d is filled in), or false otherwise.
78 */
79 bool PSphereLens::
80do_project(const Lens::CData *lens_cdata, const LPoint3 &point3d, LPoint3 &point2d) const {
81 // First, account for any rotations, etc. on the lens.
82 LVector3 v3 = point3d * do_get_lens_mat_inv(lens_cdata) * do_get_projection_mat(lens_cdata);
83 PN_stdfloat dist = v3.length();
84 if (dist == 0.0f) {
85 point2d.set(0.0f, 0.0f, 0.0f);
86 return false;
87 }
88
89 v3 /= dist;
90
91 PN_stdfloat focal_length = do_get_focal_length(lens_cdata);
92
93 // To compute the x position on the frame, we only need to consider the
94 // angle of the vector about the Z axis. Project the vector into the XY
95 // plane to do this.
96 LVector2 xy(v3[0], v3[1]);
97
98 // Unroll the Z angle, and the y position is the angle about the X axis.
99 xy.normalize();
100 LVector2d yz(v3[0]*xy[0] + v3[1]*xy[1], v3[2]);
101
102 // Compute the depth as a linear distance in the range 0 .. 1.
103 PN_stdfloat z = (dist - do_get_near(lens_cdata)) / (do_get_far(lens_cdata) - do_get_near(lens_cdata));
104
105 point2d.set
106 (
107 // The x position is the angle about the Z axis.
108 rad_2_deg(catan2(xy[0], xy[1])) * focal_length / pspherical_k,
109 // The y position is the angle about the X axis.
110 rad_2_deg(catan2(yz[1], yz[0])) * focal_length / pspherical_k,
111 // Z is the distance scaled into the range -1 .. 1.
112 2.0 * z - 1.0
113 );
114
115 // Now we have to transform the point according to the film adjustments.
116 point2d = point2d * do_get_film_mat(lens_cdata);
117
118 return
119 point2d[0] >= -1.0f && point2d[0] <= 1.0f &&
120 point2d[1] >= -1.0f && point2d[1] <= 1.0f;
121}
122
123/**
124 * Given a field of view in degrees and a focal length, compute the
125 * correspdonding width (or height) on the film. If horiz is true, this is in
126 * the horizontal direction; otherwise, it is in the vertical direction (some
127 * lenses behave differently in each direction).
128 */
129PN_stdfloat PSphereLens::
130fov_to_film(PN_stdfloat fov, PN_stdfloat focal_length, bool) const {
131 return focal_length * fov / pspherical_k;
132}
133
134/**
135 * Given a field of view in degrees and a width (or height) on the film,
136 * compute the focal length of the lens. If horiz is true, this is in the
137 * horizontal direction; otherwise, it is in the vertical direction (some
138 * lenses behave differently in each direction).
139 */
140PN_stdfloat PSphereLens::
141fov_to_focal_length(PN_stdfloat fov, PN_stdfloat film_size, bool) const {
142 return film_size * pspherical_k / fov;
143}
144
145/**
146 * Given a width (or height) on the film and a focal length, compute the field
147 * of view in degrees. If horiz is true, this is in the horizontal direction;
148 * otherwise, it is in the vertical direction (some lenses behave differently
149 * in each direction).
150 */
151PN_stdfloat PSphereLens::
152film_to_fov(PN_stdfloat film_size, PN_stdfloat focal_length, bool) const {
153 return film_size * pspherical_k / focal_length;
154}
Lens
A base class for any number of different kinds of lenses, linear and otherwise.
Definition lens.h:41
TypeHandle
TypeHandle is the identifier used to differentiate C++ class types.
Definition typeHandle.h:81
deg_2_rad.h
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.
pSphereLens.h
PANDA 3D SOFTWARE Copyright (c) Carnegie Mellon University.