From 322892bbaa600d6d9083a25f1458b570931c8e84 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bor=20Gro=C5=A1elj=20Simi=C4=87?=
 <bor.groseljsimic@telemach.net>
Date: Thu, 13 Jan 2022 02:32:51 +0100
Subject: [PATCH] "depth" "of" "field"

---
 camera.ha | 50 ++++++++++++++++++++++++++++++++++++++++----------
 main.ha   |  6 ++++--
 2 files changed, 44 insertions(+), 12 deletions(-)

diff --git a/camera.ha b/camera.ha
index b3dfd4a..b9e89b8 100644
--- a/camera.ha
+++ b/camera.ha
@@ -5,6 +5,10 @@ export type camera = struct {
 	plane_origin: vector,
 	horizontal: vector,
 	vertical: vector,
+	u: vector,
+	v: vector,
+	w: vector,
+	lens_r: f64,
 };
 
 export fn make_camera(
@@ -12,7 +16,9 @@ export fn make_camera(
 	to: vector,
 	vup: vector,
 	vfov: f64,
-	ar: f64
+	ar: f64,
+	ap: f64,
+	fdist: f64,
 ) camera = {
 	let height = 2.0 * math::tanf64(vfov * math::PI / 360.0);
 	let width = ar * height;
@@ -20,19 +26,43 @@ export fn make_camera(
 	let w = unit(diff(from, to)), u = unit(cross(vup, w)), v = cross(w, u);
 
 	let c = camera {
+		w = w,
+		u = u,
+		v = v,
 		origin = from,
-		horizontal = scale(u, width),
-		vertical = scale(v, height),
+		lens_r = ap / 2.0,
 		...
 	};
-	c.plane_origin = neg(sum(scale(sum(c.horizontal, c.vertical), 0.5), w));
+	c.horizontal = scale(c.u, width * fdist);
+	c.vertical = scale(c.v, height * fdist);
+	c.plane_origin = neg(sum(scale(sum(c.horizontal, c.vertical), 0.5), scale(w, fdist)));
 	return c;
 };
 
-export fn get_ray_for(c: *const camera, u: f64, v: f64) ray = ray {
-	origin = c.origin,
-	direction = sum(
-		sum(scale(c.horizontal, u), scale(c.vertical, v)),
-		c.plane_origin
-	),
+export fn random_in_circle() (f64, f64) = {
+	for (true) {
+		let x = random(-1.0, 1.0);
+		let y = random(-1.0, 1.0);
+		let l = x * x + y * y;
+		if (l < 1.0) {
+			let l = math::sqrtf64(l);
+			return (x / l, y / l);
+		};
+	};
+	abort();
+};
+
+export fn get_ray_for(c: *const camera, u: f64, v: f64) ray = {
+	let r = random_in_circle();
+	let offs = sum(scale(c.u, r.0 * c.lens_r), scale(c.v, r.1 * c.lens_r));
+	return ray {
+		origin = sum(c.origin, offs),
+		direction = diff(
+			sum(
+				sum(scale(c.horizontal, u), scale(c.vertical, v)),
+				c.plane_origin
+			),
+			offs
+		),
+	};
 };
diff --git a/main.ha b/main.ha
index a471407..d10d643 100644
--- a/main.ha
+++ b/main.ha
@@ -49,8 +49,10 @@ export fn main() void = {
 	let samples = 50u32;
 	let max_bounce = 50u;
 
-	let c = make_camera(V(-2.0, -2.0, 1.0), V(0.0, 0.0, -1.0), V(0.0, 1.0, 0.0),
-		20.0, 4.0/3.0);
+	let from = V(3.0, -3.0, 2.0);
+	let at = V(0.0, 0.0, -1.0);
+	let c = make_camera(from, at, V(0.0, 1.0, 0.0),
+		20.0, 4.0/3.0, 2.0, length(diff(from, at)));
 
 	let scene = init_scene();
 
-- 
2.45.2