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
|
#include <u.h>
#include <libc.h>
#include <draw.h>
#include <geometry.h>
#include <graphics.h>
static Point2
flatten(Camera *c, Point3 p)
{
Point2 p2;
Matrix S = {
Dx(c->viewport->r)/2, 0, 0,
0, Dy(c->viewport->r)/2, 0,
0, 0, 1,
}, T = {
1, 0, 1,
0, 1, 1,
0, 0, 1,
};
p2 = Pt2(p.x, p.y, p.w);
if(p2.w != 0)
p2 = divpt2(p2, p2.w);
mulm(S, T);
p2 = xform(p2, S);
return p2;
}
Point3
world2vcs(Camera *c, Point3 p)
{
return rframexform3(p, *c);
}
Point3
vcs2ndc(Camera *c, Point3 p)
{
return xform3(p, c->proj);
}
Point3
world2ndc(Camera *c, Point3 p)
{
return vcs2ndc(c, world2vcs(c, p));
}
/* requires p to be in NDC */
int
isclipping(Point3 p)
{
if(p.x > p.w || p.x < -p.w ||
p.y > p.w || p.y < -p.w ||
p.z > p.w || p.z < 0)
return 1;
return 0;
}
Point
toviewport(Camera *c, Point3 p)
{
Point2 p2;
RFrame rf = {
c->viewport->r.min.x, c->viewport->r.max.y, 1,
1, 0, 0,
0, -1, 0
};
p2 = invrframexform(flatten(c, p), rf);
return Pt(p2.x, p2.y);
}
Point2
fromviewport(Camera *c, Point p)
{
RFrame rf = {
c->viewport->r.min.x, c->viewport->r.max.y, 1,
1, 0, 0,
0, -1, 0
};
return rframexform(Pt2(p.x,p.y,1), rf);
}
void
perspective(Matrix3 m, double fov, double a, double n, double f)
{
double cotan;
cotan = 1/tan(fov/2);
identity3(m);
m[0][0] = cotan/a;
m[1][1] = cotan;
m[2][2] = -(f+n)/(f-n);
m[2][3] = -2*f*n/(f-n);
m[3][2] = -1;
}
void
orthographic(Matrix3 m, double l, double r, double b, double t, double n, double f)
{
identity3(m);
m[0][0] = 2/(r - l);
m[1][1] = 2/(t - b);
m[2][2] = -2/(f - n);
m[0][3] = -(r + l)/(r - l);
m[1][3] = -(t + b)/(t - b);
m[2][3] = -(f + n)/(f - n);
}
void
line3(Camera *c, Point3 p0, Point3 p1, int end0, int end1, Image *src)
{
p0 = world2ndc(c, p0);
p1 = world2ndc(c, p1);
if(isclipping(p0) || isclipping(p1))
return;
line(c->viewport, toviewport(c, p0), toviewport(c, p1), end0, end1, 0, src, ZP);
}
Point
string3(Camera *c, Point3 p, Image *src, Font *f, char *s)
{
p = world2ndc(c, p);
if(isclipping(p))
return Pt(-1,-1);
return string(c->viewport, toviewport(c, p), src, ZP, f, s);
}
|
