diff options
Diffstat (limited to 'src/rtw/hittable.zig')
| -rw-r--r-- | src/rtw/hittable.zig | 145 |
1 files changed, 128 insertions, 17 deletions
diff --git a/src/rtw/hittable.zig b/src/rtw/hittable.zig index c28ecb6..c73cfef 100644 --- a/src/rtw/hittable.zig +++ b/src/rtw/hittable.zig @@ -33,6 +33,7 @@ const HittableTag = enum { yzRect, box, translate, + rotateY, }; pub const Hittable = union(HittableTag) { @@ -45,11 +46,20 @@ pub const Hittable = union(HittableTag) { yzRect: YzRect, box: Box, translate: Translate, + rotateY: RotateY, pub fn makeBox(p0: Point3, p1: Point3, material: Rc(Material), allocator: anytype) !Hittable { return .{ .box = try Box.init(p0, p1, material, allocator) }; } + pub fn translate(obj: Rc(Hittable), offset: Vec3) Hittable { + return .{ .translate = .{ .object = obj, .offset = offset } }; + } + + pub fn rotateY(obj: Rc(Hittable), angle: f64) Hittable { + return .{ .rotateY = RotateY.init(obj, angle) }; + } + pub fn hit(h: Hittable, r: Ray, t_min: f64, t_max: f64, record: *HitRecord) bool { return switch (h) { HittableTag.sphere => |sphere| sphere.hit(r, t_min, t_max, record), @@ -61,11 +71,12 @@ pub const Hittable = union(HittableTag) { HittableTag.yzRect => |rect| rect.hit(r, t_min, t_max, record), HittableTag.box => |box| box.hit(r, t_min, t_max, record), HittableTag.translate => |tr| tr.hit(r, t_min, t_max, record), + HittableTag.rotateY => |rot| rot.hit(r, t_min, t_max, record), }; } fn boudingBox(h: Hittable, time0: f64, time1: f64, output_box: *Aabb) bool { - return switch (h.*) { + return switch (h) { HittableTag.sphere => |sphere| sphere.boudingBox(time0, time1, output_box), HittableTag.movingSphere => |movingSphere| movingSphere.boudingBox(time0, time1, output_box), HittableTag.list => |list| list.boudingBox(time0, time1, output_box), @@ -75,6 +86,7 @@ pub const Hittable = union(HittableTag) { HittableTag.yzRect => |rect| rect.boudingBox(time0, time1, output_box), HittableTag.box => |box| box.boudingBox(time0, time1, output_box), HittableTag.translate => |tr| tr.boudingBox(time0, time1, output_box), + HittableTag.rotateY => |rot| rot.boudingBox(time0, time1, output_box), }; } @@ -89,6 +101,7 @@ pub const Hittable = union(HittableTag) { HittableTag.yzRect => |rect| rect.deinit(), HittableTag.box => |box| box.deinit(), HittableTag.translate => |tr| tr.deinit(), + HittableTag.rotateY => |rot| rot.deinit(), }; } }; @@ -256,10 +269,10 @@ const HittableList = struct { var first_box = true; var tmp_box: Aabb = undefined; for (list.objects.items) |object| { - if (!object.boudingBox(time0, time1, tmp_box)) { + if (!object.boudingBox(time0, time1, &tmp_box)) { return false; } - output_box = if (first_box) tmp_box else Aabb.surroundingBox(output_box, tmp_box); + output_box.* = if (first_box) tmp_box else Aabb.surroundingBox(output_box.*, tmp_box); first_box = false; } return true; @@ -400,8 +413,8 @@ const XyRect = struct { // The bounding box must have non-zero width in each dimension, so pad the Z // dimension a small amount. output_box.* = .{ - .min = Point3.init(rect.x0, rect.y0, rect.k - 0.0001), - .max = Point3.init(rect.x1, rect.y1, rect.k + 0.0001), + .min = .{ .x = rect.x0, .y = rect.y0, .z = rect.k - 0.0001 }, + .max = .{ .x = rect.x1, .y = rect.y1, .z = rect.k + 0.0001 }, }; return true; } @@ -453,8 +466,8 @@ const XzRect = struct { // The bounding box must have non-zero width in each dimension, so pad the Y // dimension a small amount. output_box.* = .{ - .min = Point3.init(rect.x0, rect.k - 0.0001, rect.z0), - .max = Point3.init(rect.x1, rect.k + 0.0001, rect.z1), + .min = .{ .x = rect.x0, .y = rect.k - 0.0001, .z = rect.z0 }, + .max = .{ .x = rect.x1, .y = rect.k + 0.0001, .z = rect.z1 }, }; return true; } @@ -506,8 +519,8 @@ const YzRect = struct { // The bounding box must have non-zero width in each dimension, so pad the X // dimension a small amount. output_box.* = .{ - .min = Point3.init(rect.k - 0.0001, rect.y0, rect.z0), - .max = Point3.init(rect.k + 0.0001, rect.y1, rect.z1), + .min = .{ .x = rect.k - 0.0001, .y = rect.y0, .z = rect.z0 }, + .max = .{ .x = rect.k + 0.0001, .y = rect.y1, .z = rect.z1 }, }; return true; } @@ -566,13 +579,6 @@ const Translate = struct { object: Rc(Hittable), offset: Vec3, - pub fn init(object: Rc(Hittable), offset: Vec3) !Self { - return .{ - .object = object, - .offset = offset, - }; - } - pub fn hit(self: Self, r: Ray, t_min: f64, t_max: f64, record: *HitRecord) bool { const offset_r: Ray = .{ .origin = r.origin.sub(self.offset), @@ -587,7 +593,7 @@ const Translate = struct { } pub fn boudingBox(self: Self, time0: f64, time1: f64, output_box: *Aabb) bool { - const result = self.object.boudingBox(time0, time1, output_box); + const result = self.object.get().boudingBox(time0, time1, output_box); output_box.* = .{ .min = output_box.min.add(self.offset), .max = output_box.max.add(self.offset), @@ -599,3 +605,108 @@ const Translate = struct { self.object.deinit(); } }; + +const RotateY = struct { + const Self = @This(); + + object: Rc(Hittable), + sin_t: f64, + cos_t: f64, + bbox: Aabb, + + pub fn init(object: Rc(Hittable), t: f64) Self { + const sin_t = math.sin(t); + const cos_t = math.cos(t); + var bbox: Aabb = undefined; + _ = object.get().boudingBox(0, 0, &bbox); + + var min: Point3 = .{ .x = math.inf(f64), .y = math.inf(f64), .z = math.inf(f64) }; + var max: Point3 = .{ .x = -math.inf(f64), .y = -math.inf(f64), .z = -math.inf(f64) }; + + var i: u32 = 0; + while (i < 2) : (i += 1) { + var j: u32 = 0; + while (j < 2) : (j += 1) { + var k: u32 = 0; + while (k < 2) : (k += 1) { + const i_f: f64 = @floatFromInt(i); + const j_f: f64 = @floatFromInt(j); + const k_f: f64 = @floatFromInt(k); + const x = i_f * bbox.max.x + (1.0 - i_f) * bbox.min.x; + const y = j_f * bbox.max.y + (1.0 - j_f) * bbox.min.y; + const z = k_f * bbox.max.z + (1.0 - k_f) * bbox.min.z; + + const nx = cos_t * x + sin_t * z; + const nz = -sin_t * x + cos_t * z; + + const tester: Vec3 = .{ .x = nx, .y = y, .z = nz }; + + min.x = @min(min.x, tester.x); + min.y = @min(min.y, tester.y); + min.z = @min(min.z, tester.z); + max.x = @max(max.x, tester.x); + max.y = @max(max.y, tester.y); + max.z = @max(max.z, tester.z); + } + } + } + + return .{ + .object = object, + .sin_t = sin_t, + .cos_t = cos_t, + .bbox = .{ .min = min, .max = max }, + }; + } + + pub fn hit(self: Self, r: Ray, t_min: f64, t_max: f64, record: *HitRecord) bool { + // Change the ray from world space to object space. + var origin = r.origin; + var dir = r.dir; + + origin.x = self.cos_t * r.origin.x - self.sin_t * r.origin.z; + origin.z = self.sin_t * r.origin.x + self.cos_t * r.origin.z; + + dir.x = self.cos_t * r.dir.x - self.sin_t * r.dir.z; + dir.z = self.sin_t * r.dir.x + self.cos_t * r.dir.z; + + const rotated_r: Ray = .{ + .origin = origin, + .dir = dir, + .time = r.time, + }; + + if (!self.object.get().hit(rotated_r, t_min, t_max, record)) { + return false; + } + + // Change the intersection point from object space to world space. + // Rotate -t around axis Y. + // cos(-t) = cos(t) + // sin(-t) = -sin(t) + var p = record.p; + p.x = self.cos_t * record.p.x + self.sin_t * record.p.z; + p.z = -self.sin_t * record.p.x + self.cos_t * record.p.z; + + // Change the normal from object space to world space. + var normal = record.normal; + normal.x = self.cos_t * record.normal.x + self.sin_t * record.normal.z; + normal.z = -self.sin_t * record.normal.x + self.cos_t * record.normal.z; + + record.p = p; + record.normal = normal; + + return true; + } + + pub fn boudingBox(self: Self, time0: f64, time1: f64, output_box: *Aabb) bool { + _ = time0; + _ = time1; + output_box.* = self.bbox; + return true; + } + + pub fn deinit(self: *const Self) void { + self.object.deinit(); + } +}; |