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
151
152
153
154
155
156
|
const std = @import("std");
const matrix = @import("matrix.zig");
const sdl = @import("sdl.zig");
const Cube = struct {
points: [8][3]f32,
};
pub fn draw_cube(instance: sdl.instance, cube: Cube) void {
var c = cube.points;
sdl.draw_color(instance, 255, 255, 255, 0);
sdl.draw_line(instance, &c[0], &c[1]);
sdl.draw_line(instance, &c[0], &c[2]);
sdl.draw_line(instance, &c[0], &c[4]);
sdl.draw_line(instance, &c[7], &c[6]);
sdl.draw_line(instance, &c[7], &c[5]);
sdl.draw_line(instance, &c[7], &c[3]);
sdl.draw_line(instance, &c[2], &c[3]);
sdl.draw_line(instance, &c[4], &c[5]);
sdl.draw_line(instance, &c[1], &c[5]);
sdl.draw_line(instance, &c[6], &c[2]);
sdl.draw_line(instance, &c[3], &c[1]);
sdl.draw_line(instance, &c[4], &c[6]);
}
pub fn get_shifted_cube(cube: Cube, x: f32, y: f32, z: f32) Cube {
var shifted_cube = Cube{ .points = undefined };
for (cube.points) |point, i| {
shifted_cube.points[i][0] = point[0] + x;
shifted_cube.points[i][1] = point[1] + y;
shifted_cube.points[i][2] = point[2] + z;
}
return shifted_cube;
}
pub fn get_centered_cube(cube: Cube, offset: f32) Cube {
var centered_cube = Cube{ .points = undefined };
for (cube.points) |point, i| {
for (point) |dimension, j| {
centered_cube.points[i][j] = dimension + offset;
}
}
return centered_cube;
}
pub fn get_projected_cube(cube: Cube, alpha: f32, beta: f32) Cube {
var projected_cube = Cube{ .points = undefined };
var ax = [_]f32{
1, 0, 0,
0, @cos(alpha), @sin(alpha),
0, -@sin(alpha), @cos(alpha),
};
var a = matrix.new(3, 3, &ax);
var bx = [_]f32{
@cos(beta), 0, -@sin(beta),
0, 1, 0,
@sin(beta), 0, @cos(beta),
};
var b = matrix.new(3, 3, &bx);
var cx = [_]f32{
1, 0, 0,
0, 1, 0,
0, 0, 0,
};
var c = matrix.new(3, 3, &cx);
for (cube.points) |point, i| {
var p = point;
var x = matrix.multiply(c, matrix.multiply(matrix.multiply(a, b), matrix.new(3, 1, &p))).x.items;
projected_cube.points[i][0] = x[0];
projected_cube.points[i][1] = x[1];
}
return projected_cube;
}
pub fn get_scaled_cube(cube: Cube, scale: f32) Cube {
var scaled_cube = Cube{ .points = undefined };
for (cube.points) |point, i| {
for (point) |dimension, j| {
scaled_cube.points[i][j] = dimension * scale;
}
}
return scaled_cube;
}
pub fn main() anyerror!void {
var instance = sdl.init();
const unit_cube = Cube{
.points = [8][3]f32{
[3]f32{ 01, 01, 01 },
[3]f32{ 01, 01, -1 },
[3]f32{ 01, -1, 01 },
[3]f32{ 01, -1, -1 },
[3]f32{ -1, 01, 01 },
[3]f32{ -1, 01, -1 },
[3]f32{ -1, -1, 01 },
[3]f32{ -1, -1, -1 },
},
};
var beta: f32 = 0;
var alpha: f32 = 0;
while (true) {
var event = sdl.get_event();
if (event.mode == sdl.modes.quit) {
break;
} else if (event.mode == sdl.modes.key) {
switch (event.key) {
sdl.keys.q => break,
else => continue,
}
}
sdl.draw_color(instance, 0, 0, 0, 0);
sdl.clear(instance);
var cube = get_projected_cube(unit_cube, alpha, beta);
cube = get_scaled_cube(cube, 50);
cube = get_centered_cube(cube, 250);
draw_cube(instance, cube);
cube = get_projected_cube(unit_cube, alpha + 90, beta + 90);
cube = get_scaled_cube(cube, 25);
cube = get_centered_cube(cube, 250);
draw_cube(instance, cube);
cube = get_shifted_cube(unit_cube, 5, 0, 0);
cube = get_projected_cube(cube, alpha, beta);
cube = get_scaled_cube(cube, 25);
cube = get_centered_cube(cube, 250);
draw_cube(instance, cube);
cube = get_shifted_cube(unit_cube, -5, 0, 0);
cube = get_projected_cube(cube, alpha, beta);
cube = get_scaled_cube(cube, 25);
cube = get_centered_cube(cube, 250);
draw_cube(instance, cube);
beta += 0.01;
alpha += 0.01;
sdl.present(instance);
sdl.delay(10);
}
sdl.quit(instance);
}
|
