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1const zm = @import("zmath");
2
3pub const Texture = union(enum) {
4 solid_color: SolidColor,
5 checker_texture: CheckerTexture,
6
7 pub fn value(self: *Texture, u: f32, v: f32, p: zm.Vec) zm.Vec {
8 switch (self.*) {
9 inline else => |*n| return n.value(u, v, p),
10 }
11 }
12};
13
14pub const SolidColor = struct {
15 albedo: zm.Vec,
16
17 pub fn init(albedo: zm.Vec) SolidColor {
18 return SolidColor{ .albedo = albedo };
19 }
20
21 pub fn rgb(r: f32, g: f32, b: f32) SolidColor {
22 return init(zm.f32x4(r, g, b, 1.0));
23 }
24
25 pub fn value(self: *SolidColor, _: f32, _: f32, _: zm.Vec) zm.Vec {
26 return self.albedo;
27 }
28};
29
30pub const CheckerTexture = struct {
31 inv_scale: f32,
32 even: *Texture,
33 odd: *Texture,
34
35 pub fn init(scale: f32, even: *Texture, odd: *Texture) CheckerTexture {
36 return CheckerTexture{ .inv_scale = 1 / scale, .even = even, .odd = odd };
37 }
38
39 pub fn value(self: *CheckerTexture, u: f32, v: f32, p: zm.Vec) zm.Vec {
40 const x = @as(i32, @intFromFloat(@floor(self.inv_scale * p[0])));
41 const y = @as(i32, @intFromFloat(@floor(self.inv_scale * p[1])));
42 const z = @as(i32, @intFromFloat(@floor(self.inv_scale * p[2])));
43
44 const is_even = @rem(x + y + z, 2) == 0;
45
46 if (is_even) {
47 return self.even.value(u, v, p);
48 } else {
49 return self.odd.value(u, v, p);
50 }
51 }
52};