Use stub Vec3 / Color to implement gradient image.

zigrtiow/src/color.zig

@@ -0,0 +1,10 @@
+const std = @import("std");
+const Color = @import("./vec.zig").Color;
+
+pub fn write_color(c: Color) anyerror!void {
+    var ir = @floatToInt(u8, 255.999 * c.x());
+    var ig = @floatToInt(u8, 255.999 * c.y());
+    var ib = @floatToInt(u8, 255.999 * c.z());
+    const stdout = std.io.getStdOut();
+    try stdout.writer().print("{d} {d} {d}\n", .{ ir, ig, ib });
+}

zigrtiow/src/main.zig

@@ -1,5 +1,9 @@
 const std = @import("std");
 const info = std.log.info;
+const vec = @import("./vec.zig");
+const Vec3 = vec.Vec3;
+const Color = vec.Color;
+const write_color = @import("./color.zig").write_color;
 
 pub fn main() anyerror!void {
     const image_width: isize = 256;
@@ -16,15 +20,8 @@ pub fn main() anyerror!void {
 
         var i: isize = 0;
         while (i < image_width) : (i += 1) {
-            var r = @intToFloat(f32, i) / @intToFloat(f32, image_width - 1);
-            var g = @intToFloat(f32, j) / @intToFloat(f32, image_height - 1);
-            var b: f32 = 0.25;
-
-            var ir = @floatToInt(u8, 255.999 * r);
-            var ig = @floatToInt(u8, 255.999 * g);
-            var ib = @floatToInt(u8, 255.999 * b);
-
-            try stdout.writer().print("{d} {d} {d}\n", .{ ir, ig, ib });
+            const pixel_color = Color.init(@intToFloat(f32, i) / @intToFloat(f32, image_width - 1), @intToFloat(f32, j) / @intToFloat(f32, image_height - 1), 0.25);
+            try write_color(pixel_color);
         }
     }
 }

zigrtiow/src/vec.zig

@@ -0,0 +1,19 @@
+pub const Vec3 = struct {
+    v: @Vector(3, f32),
+    pub fn init(v0: f32, v1: f32, v2: f32) Vec3 {
+        return Vec3{
+            .v = .{ v0, v1, v2 },
+        };
+    }
+    pub fn x(vec: Vec3) f32 {
+        return vec.v[0];
+    }
+    pub fn y(vec: Vec3) f32 {
+        return vec.v[1];
+    }
+    pub fn z(vec: Vec3) f32 {
+        return vec.v[2];
+    }
+};
+pub const Color = Vec3;
+pub const Point3 = Vec3;