1 files changed, 72 insertions, 0 deletions
diff --git a/src/rtw/texture.zig b/src/rtw/texture.zig
new file mode 100644
index 0000000..47c3c4f
--- /dev/null
+++ b/src/rtw/texture.zig
@@ -0,0 +1,72 @@
+const std = @import("std");
+
+const Color = @import("vec.zig").Color;
+const Vec3 = @import("vec.zig").Vec3;
+
+const TextureTag = enum {
+    solid,
+    checker,
+};
+
+pub const Texture = union(TextureTag) {
+    solid: SolidTexture,
+    checker: CheckerTexture,
+
+    pub fn makeSolid(color: Color) Texture {
+        return .{ .solid = .{ .color = color } };
+    }
+
+    pub fn makeChecker(allocator: std.mem.Allocator, odd: Color, even: Color) !Texture {
+        return .{ .checker = try CheckerTexture.init(
+            allocator,
+            Texture.makeSolid(odd),
+            Texture.makeSolid(even),
+        ) };
+    }
+
+    pub fn value(tx: Texture, u: f64, v: f64, p: Vec3) Color {
+        return switch (tx) {
+            TextureTag.solid => |solidTx| solidTx.value(u, v, p),
+            TextureTag.checker => |checkerTx| checkerTx.value(u, v, p),
+        };
+    }
+};
+
+pub const SolidTexture = struct {
+    color: Color,
+
+    fn value(tx: SolidTexture, u: f64, v: f64, p: Vec3) Color {
+        _ = u;
+        _ = v;
+        _ = p;
+        return tx.color;
+    }
+};
+
+pub const CheckerTexture = struct {
+    allocator: std.mem.Allocator,
+    odd: *const Texture,
+    even: *const Texture,
+
+    fn init(allocator: std.mem.Allocator, odd: Texture, even: Texture) !CheckerTexture {
+        var odd_ = try allocator.create(Texture);
+        var even_ = try allocator.create(Texture);
+        odd_.* = odd;
+        even_.* = even;
+        return .{
+            .allocator = allocator,
+            .odd = odd_,
+            .even = even_,
+        };
+    }
+
+    fn deinit(tx: CheckerTexture) void {
+        tx.allocator.destroy(tx.even);
+        tx.allocator.destroy(tx.odd);
+    }
+
+    fn value(tx: CheckerTexture, u: f64, v: f64, p: Vec3) Color {
+        const sines = @sin(10 * p.x) * @sin(10 * p.y) * @sin(10 * p.z);
+        return if (sines < 0) tx.odd.value(u, v, p) else tx.even.value(u, v, p);
+    }
+};