1 files changed, 61 insertions, 0 deletions
diff --git a/src/rtw/aabb.zig b/src/rtw/aabb.zig
new file mode 100644
index 0000000..2c283c0
--- /dev/null
+++ b/src/rtw/aabb.zig
@@ -0,0 +1,61 @@
+const Ray = @import("ray.zig").Ray;
+const Point3 = @import("vec.zig").Point3;
+
+pub const Aabb = struct {
+    min: Point3,
+    max: Point3,
+
+    pub fn hit(aabb: Aabb, r: Ray, tMin: f64, tMax: f64) bool {
+        var tMin_ = tMin;
+        var tMax_ = tMax;
+        {
+            const s0 = (aabb.min.x - r.origin.x) / r.dir.x;
+            const s1 = (aabb.max.x - r.origin.x) / r.dir.x;
+            const t0 = @min(s0, s1);
+            const t1 = @max(s0, s1);
+            tMin_ = @max(t0, tMin_);
+            tMax_ = @min(t1, tMax_);
+            if (tMax_ <= tMin_) {
+                return false;
+            }
+        }
+        {
+            const s0 = (aabb.min.y - r.origin.y) / r.dir.y;
+            const s1 = (aabb.max.y - r.origin.y) / r.dir.y;
+            const t0 = @min(s0, s1);
+            const t1 = @max(s0, s1);
+            tMin_ = @max(t0, tMin_);
+            tMax_ = @min(t1, tMax_);
+            if (tMax_ <= tMin_) {
+                return false;
+            }
+        }
+        {
+            const s0 = (aabb.min.z - r.origin.z) / r.dir.z;
+            const s1 = (aabb.max.z - r.origin.z) / r.dir.z;
+            const t0 = @min(s0, s1);
+            const t1 = @max(s0, s1);
+            tMin_ = @max(t0, tMin_);
+            tMax_ = @min(t1, tMax_);
+            if (tMax_ <= tMin_) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    pub fn surroundingBox(box0: Aabb, box1: Aabb) Aabb {
+        return .{
+            .min = .{
+                .x = @min(box0.min.x, box1.min.x),
+                .y = @min(box0.min.y, box1.min.y),
+                .z = @min(box0.min.z, box1.min.z),
+            },
+            .max = .{
+                .x = @max(box0.max.x, box1.max.x),
+                .y = @max(box0.max.y, box1.max.y),
+                .z = @max(box0.max.z, box1.max.z),
+            },
+        };
+    }
+};