-
Notifications
You must be signed in to change notification settings - Fork 0
/
projection.cpp
136 lines (115 loc) · 3.13 KB
/
projection.cpp
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
#include "projection.h"
#include "effect.h"
#include "QRgb"
#include <cmath>
projection::projection()
{
// Initialize framebuffer
framebuffer = QImage(320, 240, QImage::Format_RGB16);
framebuffer.fill(qRgb(0,0,0));
}
void projection::update()
{
framebuffer.fill(qRgb(0,0,0));
rotateX(bl);
rotateX(br);
rotateX(tl);
rotateX(tr);
rotateX(blz);
rotateX(brz);
rotateX(tlz);
rotateX(trz);
rotateY(bl);
rotateY(br);
rotateY(tl);
rotateY(tr);
rotateY(blz);
rotateY(brz);
rotateY(tlz);
rotateY(trz);
rotateZ(bl);
rotateZ(br);
rotateZ(tl);
rotateZ(tr);
rotateZ(blz);
rotateZ(brz);
rotateZ(tlz);
rotateZ(trz);
point2 blr, brr, tlr, trr;
point2 blrz, brrz, tlrz, trrz;
blr = worldToScreen(bl);
brr = worldToScreen(br);
tlr = worldToScreen(tl);
trr = worldToScreen(tr);
blrz = worldToScreen(blz);
brrz = worldToScreen(brz);
tlrz = worldToScreen(tlz);
trrz = worldToScreen(trz);
framebuffer.setPixel(blr.x, blr.y, qRgb(255, 255, 255));
framebuffer.setPixel(brr.x, brr.y, qRgb(255, 255, 255));
framebuffer.setPixel(tlr.x, tlr.y, qRgb(255, 255, 255));
framebuffer.setPixel(trr.x, trr.y, qRgb(255, 255, 255));
framebuffer.setPixel(blrz.x, blrz.y, qRgb(255, 255, 255));
framebuffer.setPixel(brrz.x, brrz.y, qRgb(255, 255, 255));
framebuffer.setPixel(tlrz.x, tlrz.y, qRgb(255, 255, 255));
framebuffer.setPixel(trrz.x, trrz.y, qRgb(255, 255, 255));
// frontmost square
drawLine(blr, brr);
drawLine(blr, tlr);
drawLine(tlr, trr);
drawLine(brr, trr);
// z square
drawLine(blrz, brrz);
drawLine(blrz, tlrz);
drawLine(tlrz, trrz);
drawLine(brrz, trrz);
// connect the squares
drawLine(blr, blrz);
drawLine(brr, brrz);
drawLine(tlr, tlrz);
drawLine(trr, trrz);
}
point2 projection::worldToScreen(point3 &p) {
float factor = 320.0;
return {p.x / p.z * factor + 160, p.y / p.z * factor + 120};
}
// cos(angle) = 1
// sin(angle) = angle
void projection::rotateX(point3 &p, float angle) {
p.z -= 6.0f;
p.y = p.y - p.z*angle;
p.z = p.y*angle + p.z;
p.z += 6.0f;
}
void projection::rotateY(point3 &p, float angle) {
p.z -= 6.0f;
p.x = p.x + p.z*angle;
p.z = -p.x*angle + p.z;
p.z += 6.0f;
}
void projection::rotateZ(point3 &p, float angle) {
p.x = p.x - p.y*angle;
p.y = p.y + p.x*angle;
}
void projection::drawLine(const point2& p0, const point2& p1, const uint color) {
drawLine(p0.x, p0.y, p1.x, p1.y, color);
}
void projection::drawLine(int x0, int y0, const int x1, const int y1, const uint color) {
const auto dx = abs(x1 - x0);
const auto dy = abs(y1 - y0);
const auto sx = (x0 < x1) ? 1 : -1;
const auto sy = (y0 < y1) ? 1 : -1;
auto err = dx - dy;
while (true) {
if (x0 >= 0 &&
y0 >= 0 &&
x0 < 320 &&
y0 < 240) {
framebuffer.setPixel(x0, y0, color);
}
if ((x0 == x1) && (y0 == y1)) break;
const auto e2 = 2 * err;
if (e2 > -dy) { err -= dy; x0 += sx; }
if (e2 < dx) { err += dx; y0 += sy; }
}
}