From 39b57fa0729d16873193947b12e59a7da52695fa Mon Sep 17 00:00:00 2001
From: Tom Barrett <tom@tombarrett.xyz>
Date: Sat, 24 Dec 2022 18:31:35 +0100
Subject: more ziglike

---
 src/main.zig | 37 ++++++++++++++++++++-----------------
 src/vec.zig  | 16 ++++++++--------
 2 files changed, 28 insertions(+), 25 deletions(-)

diff --git a/src/main.zig b/src/main.zig
index e2b63d2..5f6ea29 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -2,28 +2,18 @@ const std = @import("std");
 const warn = @import("std").debug.print;
 const vec = @import("vec.zig");
 
-pub fn ray_color(r: ray) vec.vec {
-    if (hit_sphere(vec.init(0, 0, -1), 0.5, r)) |t| {
-        const n = vec.unit_vector(r.origin + vec.scalar(t) * r.direction - vec.init(0, 0, -1));
-        return vec.scalar(0.5) * vec.init(n[0] + 1, n[1] + 1, n[2] + 1);
-    }
-    const direction = vec.unit_vector(r.direction);
-    const t = 0.5 * (direction[1] + 1.0);
-    return vec.scalar(1.0 - t) * vec.init(1.0, 1.0, 1.0) + vec.scalar(t) * vec.init(0.5, 0.7, 1.0);
-}
-
-pub fn write_color(stdout: anytype, v: vec.vec) !void {
+pub fn writeColor(stdout: anytype, v: vec.Vec) !void {
     const r = @floatToInt(usize, v[0] * 255.999);
     const g = @floatToInt(usize, v[1] * 255.999);
     const b = @floatToInt(usize, v[2] * 255.999);
     try stdout.print("{} {} {}\n", .{ r, g, b });
 }
 
-pub fn hit_sphere(center: vec.vec, radius: f32, r: ray) ?f32 {
+pub fn hitSphere(center: vec.Vec, radius: f32, r: Ray) ?f32 {
     const oc = r.origin - center;
-    const a = vec.length_squared(r.direction);
+    const a = vec.lengthSquared(r.direction);
     const half_b = vec.dot(oc, r.direction);
-    const c = vec.length_squared(oc) - radius * radius;
+    const c = vec.lengthSquared(oc) - radius * radius;
     const discriminant = half_b * half_b - a * c;
     if (discriminant < 0) {
         return null;
@@ -32,7 +22,20 @@ pub fn hit_sphere(center: vec.vec, radius: f32, r: ray) ?f32 {
     }
 }
 
-const ray = struct { origin: vec.vec, direction: vec.vec };
+const Ray = struct {
+    origin: vec.Vec,
+    direction: vec.Vec,
+
+    pub fn color(self: Ray) vec.Vec {
+        if (hitSphere(vec.init(0, 0, -1), 0.5, self)) |t| {
+            const n = vec.unitVec(self.origin + vec.scalar(t) * self.direction - vec.init(0, 0, -1));
+            return vec.scalar(0.5) * vec.init(n[0] + 1, n[1] + 1, n[2] + 1);
+        }
+        const direction = vec.unitVec(self.direction);
+        const t = 0.5 * (direction[1] + 1.0);
+        return vec.scalar(1.0 - t) * vec.init(1.0, 1.0, 1.0) + vec.scalar(t) * vec.init(0.5, 0.7, 1.0);
+    }
+};
 
 pub fn main() !void {
     const aspect_ratio: f32 = 16.0 / 9.0;
@@ -59,9 +62,9 @@ pub fn main() !void {
         while (i < width) : (i += 1) {
             var u = vec.scalar(@intToFloat(f32, i) / @intToFloat(f32, width - 1));
             var v = vec.scalar(@intToFloat(f32, j) / @intToFloat(f32, height - 1));
-            var color = ray_color(ray{ .origin = origin, .direction = lower_left_corner + u * horizontal + v * vertical - origin });
+            var r = Ray{ .origin = origin, .direction = lower_left_corner + u * horizontal + v * vertical - origin };
 
-            try write_color(stdout, color);
+            try writeColor(stdout, r.color());
         }
     }
     try bw.flush();
diff --git a/src/vec.zig b/src/vec.zig
index cc245a4..b98f9f4 100644
--- a/src/vec.zig
+++ b/src/vec.zig
@@ -1,25 +1,25 @@
-pub const vec = @Vector(3, f32);
+pub const Vec = @Vector(3, f32);
 
-pub fn init(x: f32, y: f32, z: f32) vec {
+pub fn init(x: f32, y: f32, z: f32) Vec {
     return @Vector(3, f32){ x, y, z };
 }
 
-pub fn scalar(x: f32) vec {
+pub fn scalar(x: f32) Vec {
     return @splat(3, x);
 }
 
-pub fn unit_vector(v: vec) vec {
+pub fn unitVec(v: Vec) Vec {
     return v / scalar(length(v));
 }
 
-pub fn length_squared(v: vec) f32 {
+pub fn lengthSquared(v: Vec) f32 {
     return v[0] * v[0] + v[1] * v[1] + v[2] * v[2];
 }
 
-pub fn length(v: vec) f32 {
-    return @sqrt(length_squared(v));
+pub fn length(v: Vec) f32 {
+    return @sqrt(lengthSquared(v));
 }
 
-pub fn dot(x: vec, y: vec) f32 {
+pub fn dot(x: Vec, y: Vec) f32 {
     return x[0] * y[0] + x[1] * y[1] + x[2] * y[2];
 }
-- 
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