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zigrtiow: shoot child rays for diffuse shading.

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This commit is contained in:
Bill Thiede 2022-08-04 21:43:47 -07:00
parent f4d3129d5a
commit 94b0f8355e
2 changed files with 39 additions and 13 deletions
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27
zigrtiow/src/main.zig
View File

@ -15,18 +15,18 @@ const Point3 = vec.Point3;
const Ray = ray.Ray;
const Sphere = sphere.Sphere;
const Vec3 = vec.Vec3;
const random_in_unit_sphere = vec.random_in_unit_sphere;
const info = std.log.info;
const write_color = color.write_color;
fn ray_color(r: Ray, world: Hittable) Color {
fn ray_color(r: Ray, world: Hittable, depth: isize) Color {
// If we've exceeded the ray bounce limit, no more light is gathered.
if (depth <= 0) return Color.init(0, 0, 0);
var hit = world.hit(r, 0, std.math.inf(f32));
if (hit) |rec| {
const n = rec.normal;
return Color.init(
n.x() + 1,
n.y() + 1,
n.z() + 1,
).scale(0.5);
const target = rec.p.add(rec.normal.add(random_in_unit_sphere()));
return ray_color(Ray.init(rec.p, target.sub(rec.p)), world, depth - 1);
}
var unit_direction = r.direction().unit();
const t = 0.5 * (unit_direction.y() + 1);
@ -39,11 +39,13 @@ pub fn main() anyerror!void {
const image_width = 400;
const image_height = @floatToInt(isize, @intToFloat(f32, image_width) / aspect_ratio);
const samples_per_pixel = 100;
const max_depth = 50;
// World
var world = HittableList.init();
try world.add(Hittable{ .sphere = Sphere.init(Point3.init(0, 0, -1), 0.5) });
try world.add(Hittable{ .sphere = Sphere.init(Point3.init(0, -100.5, -1), 100) });
var tmp_world = HittableList.init();
try tmp_world.add(Hittable{ .sphere = Sphere.init(Point3.init(0, 0, -1), 0.5) });
try tmp_world.add(Hittable{ .sphere = Sphere.init(Point3.init(0, -100.5, -1), 100) });
const world = Hittable{ .hittable_list = tmp_world };
// Camera
const cam = Camera.init();
@ -58,7 +60,7 @@ pub fn main() anyerror!void {
const rand = prng.random();
var j: isize = image_height - 1;
while (j >= 0) : (j -= 1) {
//info("Scanlines remaining: {d}", .{j});
info("Scanlines remaining: {d}", .{j});
var i: isize = 0;
while (i < image_width) : (i += 1) {
@ -68,8 +70,7 @@ pub fn main() anyerror!void {
const u = (@intToFloat(f32, i) + rand.float(f32)) / @intToFloat(f32, image_width - 1);
const v = (@intToFloat(f32, j) + rand.float(f32)) / @intToFloat(f32, image_height - 1);
const r = cam.get_ray(u, v);
//Ray.init(origin, lower_left_corner.add(horizontal.scale(u)).add(vertical.scale(v)).sub(origin));
pixel_color = pixel_color.add(ray_color(r, Hittable{ .hittable_list = world }));
pixel_color = pixel_color.add(ray_color(r, world, max_depth));
}
try write_color(pixel_color, samples_per_pixel);
}

25
zigrtiow/src/vec.zig
View File

@ -1,5 +1,13 @@
const std = @import("std");
const info = std.log.info;
var prng = std.rand.DefaultPrng.init(0);
const rand = prng.random();
pub const Vec3 = struct {
v: @Vector(3, f32),
pub fn init(v0: f32, v1: f32, v2: f32) Vec3 {
return Vec3{
.v = .{ v0, v1, v2 },
@ -36,6 +44,23 @@ pub const Vec3 = struct {
const t = u.v * v.v;
return t[0] + t[1] + t[2];
}
/// Return value in unit cube from -1, 1
pub fn random() Vec3 {
return Vec3.init(
rand.float(f32) * 2 - 0.5,
rand.float(f32) * 2 - 0.5,
rand.float(f32) * 2 - 0.5,
);
}
};
pub fn random_in_unit_sphere() Vec3 {
while (true) {
const p = Vec3.random();
if (p.length_squared() > 1) continue;
return p;
}
}
pub const Color = Vec3;
pub const Point3 = Vec3;