diff options
| -rw-r--r-- | src/main.zig | 58 | ||||
| -rw-r--r-- | src/vec.zig | 25 |
2 files changed, 44 insertions, 39 deletions
diff --git a/src/main.zig b/src/main.zig index 1a8e14c..e2b63d2 100644 --- a/src/main.zig +++ b/src/main.zig @@ -1,40 +1,29 @@ const std = @import("std"); const warn = @import("std").debug.print; +const vec = @import("vec.zig"); -pub fn unit_vector(v: vec) vec { - return v / scalar(length(v)); -} - -pub fn length_squared(v: vec) f32 { - return v[0] * v[0] + v[1] * v[1] + v[2] * v[2]; -} - -pub fn length(v: vec) f32 { - return @sqrt(length_squared(v)); -} - -pub fn ray_color(r: ray) vec { - if (hit_sphere(vec{ 0, 0, -1 }, 0.5, r)) |t| { - const n = unit_vector(r.origin + scalar(t) * r.direction - vec{ 0, 0, -1 }); - return scalar(0.5) * vec{ n[0] + 1, n[1] + 1, n[2] + 1 }; +pub fn ray_color(r: ray) vec.vec { + if (hit_sphere(vec.init(0, 0, -1), 0.5, r)) |t| { + const n = vec.unit_vector(r.origin + vec.scalar(t) * r.direction - vec.init(0, 0, -1)); + return vec.scalar(0.5) * vec.init(n[0] + 1, n[1] + 1, n[2] + 1); } - const direction = unit_vector(r.direction); + const direction = vec.unit_vector(r.direction); const t = 0.5 * (direction[1] + 1.0); - return scalar(1.0 - t) * vec{ 1.0, 1.0, 1.0 } + scalar(t) * vec{ 0.5, 0.7, 1.0 }; + return vec.scalar(1.0 - t) * vec.init(1.0, 1.0, 1.0) + vec.scalar(t) * vec.init(0.5, 0.7, 1.0); } -pub fn write_color(stdout: anytype, v: vec) !void { +pub fn write_color(stdout: anytype, v: vec.vec) !void { const r = @floatToInt(usize, v[0] * 255.999); const g = @floatToInt(usize, v[1] * 255.999); const b = @floatToInt(usize, v[2] * 255.999); try stdout.print("{} {} {}\n", .{ r, g, b }); } -pub fn hit_sphere(center: vec, radius: f32, r: ray) ?f32 { +pub fn hit_sphere(center: vec.vec, radius: f32, r: ray) ?f32 { const oc = r.origin - center; - const a = length_squared(r.direction); - const half_b = dot(oc, r.direction); - const c = length_squared(oc) - radius * radius; + const a = vec.length_squared(r.direction); + const half_b = vec.dot(oc, r.direction); + const c = vec.length_squared(oc) - radius * radius; const discriminant = half_b * half_b - a * c; if (discriminant < 0) { return null; @@ -43,16 +32,7 @@ pub fn hit_sphere(center: vec, radius: f32, r: ray) ?f32 { } } -const vec = @Vector(3, f32); -pub fn scalar(x: f32) vec { - return @splat(3, x); -} - -pub fn dot(x: vec, y: vec) f32 { - return x[0] * y[0] + x[1] * y[1] + x[2] * y[2]; -} - -const ray = struct { origin: vec, direction: vec }; +const ray = struct { origin: vec.vec, direction: vec.vec }; pub fn main() !void { const aspect_ratio: f32 = 16.0 / 9.0; @@ -65,10 +45,10 @@ pub fn main() !void { const viewport_height = 2.0; const viewport_width = aspect_ratio * viewport_height; const focal_length = 1.0; - const origin = vec{ 0, 0, 0 }; - const horizontal = vec{ viewport_width, 0, 0 }; - const vertical = vec{ 0, viewport_height, 0 }; - const lower_left_corner = origin - (horizontal / scalar(2.0)) - (vertical / scalar(2.0)) - vec{ 0, 0, focal_length }; + const origin = vec.init(0, 0, 0); + const horizontal = vec.init(viewport_width, 0, 0); + const vertical = vec.init(0, viewport_height, 0); + const lower_left_corner = origin - (horizontal / vec.scalar(2.0)) - (vertical / vec.scalar(2.0)) - vec.init(0, 0, focal_length); try stdout.print("P3\n{} {}\n255\n", .{ width, height }); @@ -77,8 +57,8 @@ pub fn main() !void { warn("remaining: {}\n", .{j}); var i: usize = 0; while (i < width) : (i += 1) { - var u = scalar(@intToFloat(f32, i) / @intToFloat(f32, width - 1)); - var v = scalar(@intToFloat(f32, j) / @intToFloat(f32, height - 1)); + var u = vec.scalar(@intToFloat(f32, i) / @intToFloat(f32, width - 1)); + var v = vec.scalar(@intToFloat(f32, j) / @intToFloat(f32, height - 1)); var color = ray_color(ray{ .origin = origin, .direction = lower_left_corner + u * horizontal + v * vertical - origin }); try write_color(stdout, color); diff --git a/src/vec.zig b/src/vec.zig new file mode 100644 index 0000000..cc245a4 --- /dev/null +++ b/src/vec.zig @@ -0,0 +1,25 @@ +pub const vec = @Vector(3, f32); + +pub fn init(x: f32, y: f32, z: f32) vec { + return @Vector(3, f32){ x, y, z }; +} + +pub fn scalar(x: f32) vec { + return @splat(3, x); +} + +pub fn unit_vector(v: vec) vec { + return v / scalar(length(v)); +} + +pub fn length_squared(v: vec) f32 { + return v[0] * v[0] + v[1] * v[1] + v[2] * v[2]; +} + +pub fn length(v: vec) f32 { + return @sqrt(length_squared(v)); +} + +pub fn dot(x: vec, y: vec) f32 { + return x[0] * y[0] + x[1] * y[1] + x[2] * y[2]; +} |