1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
|
/******************************************************************/
/* This file is part of the homework assignments for CSCI-427/527 */
/* at The College of William & Mary and authored by Pieter Peers. */
/* No part of this file, whether altered or in original form, can */
/* be distributed or used outside the context of CSCI-427/527 */
/* without consent of either the College of William & Mary or */
/* Pieter Peers. */
/******************************************************************/
#include <cmath>
#include "constants.h"
#include "camera.h"
/////////////////
// Constructor //
/////////////////
camera::camera(void)
{
_eye = vec3d();
_view = vec3d(0.0f, 0.0f, -1.0f);
_up = vec3d(0.0f, 1.0f, 0.0f);
_fov = 60.0f;
_width = _height = 256;
}
camera::camera(const vec3d& eye, const vec3d& viewDirection, const vec3d& up, float fov, size_t xres, size_t yres)
{
_eye = eye;
_view = normalize(viewDirection);
_up = normalize(up);
_fov = fov;
_width = xres;
_height = yres;
// fix up if needed
vec3d right = _view.cross(up).normalize();
_up = right.cross(_view).normalize();
}
camera::camera(const camera& cam)
{
_eye = cam._eye;
_view = cam._view;
_up = cam._up;
_fov = cam._fov;
_width = cam._width;
_height = cam._height;
}
///////////////
// Operators //
///////////////
camera& camera::operator=(const camera& cam)
{
_assign(cam);
return *this;
}
ray camera::operator()(float x, float y) const
{
vec3d right = _view.cross(_up).normalize();
// aspect ratio
float aspect = (float)(_height) / (float)(_width);
float tanFov = tan(_fov / 180.0f * PI);
// compute view plane center, and U and V unnormalized axes.
vec3d center = _eye + _view;
vec3d U = 2.0f * tanFov * right;
vec3d V = -2.0f * tanFov * aspect * _up; // y runs from top to bottom (opposite direction of up)
// get point on view plane
vec3d p = center + (x / (float)(_width) - 0.5f) * U + (y / (float)(_height) - 0.5f) * V;
// Done.
return ray(_eye, p - _eye);
}
//////////////
// Mutators //
//////////////
void camera::frameBoundingBox(const boundingBox& bb)
{
// determine the best eye location, given the other parameters and a bounding box such that the bounding box maximally occupies the view
vec3d right = _view.cross(_up).normalize();
_eye = 0.5f * (bb.corner(true,true,true) + bb.corner(false,false,false));
// => find max projection in up and right direction.
float maxRight=-LARGE, maxUp=-LARGE, maxDepth=-LARGE;
for(unsigned int i=0; i < 8; i++)
{
vec3d c = bb.corner( (i&1)==1, (i&2)==2, (i&4)==4 ) - _eye;
float r = fabs(c.dot(right));
float u = fabs(c.dot(_up));
float d = fabs(c.dot(_view));
maxRight = std::max(maxRight, r);
maxUp = std::max(maxUp, u);
maxDepth = std::max(maxDepth, d);
}
// => compute optimal distance for up and right
float aspect = (float)(_height) / (float)(_width);
float tanFov = tan(_fov / 180.0f * PI);
float optDistUp = fabs(maxUp / tanFov);
float optDistRight = fabs(maxRight / (tanFov * aspect));
// => move _eye back based on (max) optimal distance
_eye -= _view * (std::max(optDistUp, optDistRight) + maxDepth);
}
/////////////////////
// Private Methods //
/////////////////////
void camera::_swap(camera& cam)
{
// sanity check
if(&cam == this) return;
// swap
swap(_eye, cam._eye);
swap(_view, cam._view);
swap(_up, cam._up);
std::swap(_fov, cam._fov);
std::swap(_width, cam._width);
std::swap(_height, cam._height);
}
void camera::_assign(const camera& cam)
{
// sanity check
if(&cam == this) return;
// copy
_eye = cam._eye;
_view = cam._view;
_up = cam._up;
_fov = cam._fov;
_width = cam._width;
_height = cam._height;
}
|
