1 files changed, 109 insertions, 0 deletions
diff --git a/src/rtw/vec.zig b/src/rtw/vec.zig
new file mode 100644
index 0000000..9b2c3f0
--- /dev/null
+++ b/src/rtw/vec.zig
@@ -0,0 +1,109 @@
+const std = @import("std");
+
+const rand = @import("rand.zig");
+const Random = rand.Random;
+const randomReal = rand.randomReal;
+const randomReal01 = rand.randomReal01;
+
+pub const Vec3 = struct {
+    x: f64,
+    y: f64,
+    z: f64,
+
+    pub fn norm(v: Vec3) f64 {
+        return @sqrt(v.normSquared());
+    }
+
+    pub fn normSquared(v: Vec3) f64 {
+        return v.x * v.x + v.y * v.y + v.z * v.z;
+    }
+
+    pub fn dot(u: Vec3, v: Vec3) f64 {
+        return u.x * v.x + u.y * v.y + u.z * v.z;
+    }
+
+    pub fn cross(u: Vec3, v: Vec3) Vec3 {
+        return Vec3{
+            .x = u.y * v.z - u.z * v.y,
+            .y = u.z * v.x - u.x * v.z,
+            .z = u.x * v.y - u.y * v.x,
+        };
+    }
+
+    pub fn normalized(v: Vec3) Vec3 {
+        const n = v.norm();
+        if (n == 0.0) {
+            return v;
+        } else {
+            return v.div(n);
+        }
+    }
+
+    pub fn add(u: Vec3, v: Vec3) Vec3 {
+        return Vec3{
+            .x = u.x + v.x,
+            .y = u.y + v.y,
+            .z = u.z + v.z,
+        };
+    }
+
+    pub fn sub(u: Vec3, v: Vec3) Vec3 {
+        return Vec3{
+            .x = u.x - v.x,
+            .y = u.y - v.y,
+            .z = u.z - v.z,
+        };
+    }
+
+    pub fn mul(v: Vec3, t: f64) Vec3 {
+        return Vec3{
+            .x = v.x * t,
+            .y = v.y * t,
+            .z = v.z * t,
+        };
+    }
+
+    pub fn mulV(u: Vec3, v: Vec3) Vec3 {
+        return Vec3{
+            .x = u.x * v.x,
+            .y = u.y * v.y,
+            .z = u.z * v.z,
+        };
+    }
+
+    pub fn div(v: Vec3, t: f64) Vec3 {
+        return Vec3{
+            .x = v.x / t,
+            .y = v.y / t,
+            .z = v.z / t,
+        };
+    }
+
+    pub fn random01(rng: Random) Vec3 {
+        return Vec3{
+            .x = randomReal01(rng),
+            .y = randomReal01(rng),
+            .z = randomReal01(rng),
+        };
+    }
+
+    pub fn random(rng: Random, min: f64, max: f64) Vec3 {
+        return Vec3{
+            .x = randomReal(rng, min, max),
+            .y = randomReal(rng, min, max),
+            .z = randomReal(rng, min, max),
+        };
+    }
+
+    pub fn near_zero(v: Vec3) bool {
+        const epsilon = 1e-8;
+        return @fabs(v.x) < epsilon and @fabs(v.y) < epsilon and @fabs(v.z) < epsilon;
+    }
+};
+
+pub const Point3 = Vec3;
+pub const Color = Vec3;
+
+pub fn rgb(r: f64, g: f64, b: f64) Color {
+    return .{ .x = r, .y = g, .z = b };
+}