bounce rays around

in_one_weekend/src/vec3.zig

@@ -1,4 +1,7 @@
-const math = @import("std").math;
+const std = @import("std");
+const print = std.debug.print;
+const math = std.math;
+const Random = std.rand.Random;
 
 pub const Vec3 = packed struct {
     x: f32 = 0.0,
@@ -66,6 +69,24 @@ pub fn unitVector(vec: Vec3) Vec3 {
     return vec.div(vec.length());
 }
 
+pub fn random(rng: *Random, min: f32, max: f32) Vec3 {
+    const range = max - min;
+    return Vec3{
+        .x = rng.*.float(f32) * range + min,
+        .y = rng.*.float(f32) * range + min,
+        .z = rng.*.float(f32) * range + min,
+    };
+}
+
+pub fn random_in_unit_sphere(rng: *Random) Vec3 {
+    while (true) {
+        const v = random(rng, -1, 1);        
+        if (v.length_squared() < 1) {
+            return v;
+        }
+    }
+}
+
 pub const Point3 = Vec3;
 
 const assert = @import("std").debug.assert;