Browse code
feat: add raytracer
Implemented up to: https://raytracing.github.io/books/RayTracingInOneWeekend.html#antialiasing
Edward authored on 20/03/2021 09:09:43Showing 1 changed files
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+(defpackage :fwoar.lisp-sandbox.1 |
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+ (:use :cl |
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+ ) |
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+ (:export )) |
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+(in-package :fwoar.lisp-sandbox.1) |
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+ |
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+(define-symbol-macro infinity |
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+ #.sb-ext:double-float-positive-infinity) |
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+(defun deg2rad (deg) |
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+ (/ (* deg pi) |
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+ 180.0d0)) |
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+ |
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+(defstruct (size (:type vector)) |
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+ width height) |
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+(defstruct (color (:type vector)) |
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+ r g b) |
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+(defstruct (vec3 (:type vector) |
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+ (:constructor vec3 (x y z)) |
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+ (:conc-name v3-)) |
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+ x y z) |
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+ |
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+(defun vec+ (vec1 vec2) |
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+ (declare (optimize (speed 3))) |
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+ (fw.lu:vector-destructuring-bind (a b c) vec1 |
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+ (fw.lu:vector-destructuring-bind (a1 b1 c1) vec2 |
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+ (vec3 (+ a a1) |
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+ (+ b b1) |
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+ (+ c c1))))) |
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+(define-compiler-macro vec+ (&whole whole vec1 vec2) |
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+ (cond ((and (vectorp vec1) |
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+ (vectorp vec2)) |
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+ (vec+ vec1 vec2)) |
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+ ((vectorp vec1) |
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+ (alexandria:once-only (vec2) |
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+ `(fw.lu:vector-destructuring-bind (a b c) ,vec1 |
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+ (vec3 |
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+ (+ a (aref ,vec2 0)) |
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+ (+ b (aref ,vec2 1)) |
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+ (+ c (aref ,vec2 2)))))) |
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+ ((vectorp vec2) |
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+ (alexandria:once-only (vec1) |
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+ `(fw.lu:vector-destructuring-bind (a b c) ,vec2 |
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+ (vec3 |
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+ (+ a (aref ,vec1 0)) |
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+ (+ b (aref ,vec1 1)) |
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+ (+ c (aref ,vec1 2)))))) |
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+ (t whole))) |
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+(defun vec- (vec1 vec2) |
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+ (declare (optimize (speed 3))) |
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+ (fw.lu:vector-destructuring-bind (a b c) vec1 |
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+ (fw.lu:vector-destructuring-bind (a1 b1 c1) vec2 |
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+ (vec3 (- a a1) |
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+ (- b b1) |
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+ (- c c1))))) |
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+(defun vec* (vec1 vec2) |
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+ (declare (optimize (speed 3))) |
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+ (etypecase vec1 |
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+ ((array * (3)) (fw.lu:vector-destructuring-bind (a b c) vec1 |
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+ (fw.lu:vector-destructuring-bind (a1 b1 c1) vec2 |
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+ (vec3 (* a a1) |
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+ (* b b1) |
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+ (* c c1))))) |
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+ (double-float (fw.lu:vector-destructuring-bind (a1 b1 c1) vec2 |
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+ (vec3 (* vec1 a1) |
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+ (* vec1 b1) |
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+ (* vec1 c1)))) |
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+ (single-float (fw.lu:vector-destructuring-bind (a1 b1 c1) vec2 |
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+ (vec3 (* vec1 a1) |
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+ (* vec1 b1) |
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+ (* vec1 c1)))) |
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+ (number (fw.lu:vector-destructuring-bind (a1 b1 c1) vec2 |
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+ (vec3 (* vec1 a1) |
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+ (* vec1 b1) |
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+ (* vec1 c1)))))) |
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+(defun vec/ (vec it) |
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+ (declare (optimize (speed 3))) |
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+ (vec* (/ 1.0 it) |
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+ vec)) |
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+(defun dot (u v) |
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+ (fw.lu:vector-destructuring-bind (a1 b1 c1) u |
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+ (fw.lu:vector-destructuring-bind (a2 b2 c2) v |
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+ (+ (* a1 a2) |
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+ (* b1 b2) |
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+ (* c1 c2))))) |
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+(defun cross (u v) |
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+ (fw.lu:vector-destructuring-bind (a1 b1 c1) u |
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+ (fw.lu:vector-destructuring-bind (a2 b2 c2) v |
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+ (vec3 (- (* b1 c2) |
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+ (* c1 b2)) |
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+ (- (* c1 a2) |
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+ (* a1 c2)) |
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+ (- (* a1 b2) |
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+ (* b1 a2)))))) |
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+ |
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+(defun length-squared (v) |
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+ (fw.lu:vector-destructuring-bind (x y z) v |
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+ (+ (* x x) |
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+ (* y y) |
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+ (* z z)))) |
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+(defun vec-length (v) |
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+ (sqrt (length-squared v))) |
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+(defun unit-vector (v) |
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+ (vec/ v |
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+ (vec-length v))) |
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+ |
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+(defun call-with-ppm-header (stream size callback &optional (colors 255)) |
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+ (format stream "P3~%~d ~d~%~d~%" |
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+ (size-width size) |
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+ (size-height size) |
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+ colors) |
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+ (funcall callback stream)) |
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+ |
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+#.(progn (defmacro ig (&rest syms) `'(declare (ignore ,@syms))) |
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+ nil) |
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+ |
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+(defvar *color-depth* 255) |
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+(defun format-color (s v _ __) |
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+ #.(ig _ __) |
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+ (fwoar.lisputils:vector-destructuring-bind (r g b) v |
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+ (format s "~4d ~4d ~4d" |
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+ (round (* *color-depth* r)) |
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+ (round (* *color-depth* g)) |
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+ (round (* *color-depth* b))))) |
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+ |
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+(defun write-colors (stream colors columns) |
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+ (let ((intermediate ()) |
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+ (idx 0)) |
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+ (funcall colors |
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+ (lambda (color) |
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+ (push color intermediate) |
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+ (when (= (1- columns) |
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+ (mod idx columns)) |
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+ (format stream "~{~/fwoar.lisp-sandbox.1::format-color/~^ ~}~&" intermediate)
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+ (setf intermediate ())) |
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+ (incf idx))) |
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+ (when intermediate |
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+ (format stream "~{~/fwoar.lisp-sandbox.1::format-color/~^ ~}~&" intermediate))))
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+ |
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+(fw.lu:defclass+ ray () |
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+ ((origin :initarg :origin) |
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+ (direction :initarg :direction))) |
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+ |
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+(defgeneric at (self it) |
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+ (:method ((ray ray) (it number)) |
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+ (with-slots (origin direction) ray |
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+ (vec+ origin |
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+ (vec* it direction))))) |
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+ |
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+(fw.lu:defclass+ hit-record () |
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+ ((p :initarg :p :reader .p) |
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+ (time :initarg :time :reader .time) |
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+ (normal :initarg :normal :accessor .normal :initform ()) |
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+ (front-face :initarg :front-face :accessor .front-face :initform ()))) |
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+(defun set-face-normal (hit-record r outward-normal) |
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+ (prog1 hit-record |
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+ (with-slots (direction) r |
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+ (let ((front-face (< (dot direction outward-normal) |
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+ 0))) |
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+ (setf (.front-face hit-record) front-face |
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+ (.normal hit-record) (if front-face |
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+ outward-normal |
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+ (vec* -1 outward-normal))))))) |
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+ |
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+(defclass hittable () |
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+ ()) |
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+(fw.lu:defclass+ sphere (hittable) |
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+ ((center :initarg :center) |
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+ (radius :initarg :radius))) |
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+(defgeneric hit (thing ray t-min t-max) |
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+ (:method ((things list) (r ray) (t-min real) (t-max real)) |
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+ (let (temp-rec |
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+ (hit-anything nil) |
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+ (closest-so-far t-max)) |
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+ (loop for thing in things |
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+ for (hit-p hit-rec) = (multiple-value-list |
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+ (hit thing r t-min closest-so-far)) |
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+ when hit-p do |
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+ (setf hit-anything t |
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+ closest-so-far (.time hit-rec) |
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+ temp-rec hit-rec)) |
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+ (when hit-anything |
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+ (values hit-anything |
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+ temp-rec)))) |
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+ (:method ((sphere sphere) (r ray) (t-min real) (t-max real)) |
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+ (uiop:nest (with-slots ((%center center) (%radius radius)) sphere) |
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+ (let ((center %center) (radius %radius))) |
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+ (with-slots ((%origin origin) (%direction direction)) r) |
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+ (let ((origin %origin) (direction %direction))) |
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+ (let* ((oc (vec- origin center)) |
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+ (a (length-squared direction)) |
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+ (half-b (dot oc direction)) |
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+ (c (- (length-squared oc) |
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+ (* radius radius))) |
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+ (discriminant (- (* half-b half-b) |
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+ (* a c)))) |
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+ (if (< discriminant 0) |
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+ (return-from hit nil) |
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+ (let* ((sqrtd (sqrt discriminant)) |
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+ (root (/ (- (- half-b) |
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+ sqrtd) |
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+ a))) |
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+ (when (or (< root t-min) |
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+ (< t-max root)) |
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+ (setf root (/ (- sqrtd half-b) |
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+ a)) |
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+ (when (or (< root t-min) |
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+ (< t-max root)) |
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+ (return-from hit nil))) |
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+ (let* ((p (at r root)) |
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+ (outward-normal (vec/ (vec- p center) |
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+ radius))) |
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+ |
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+ (values t |
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+ (set-face-normal (hit-record p root) |
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+ r |
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+ outward-normal))))))))) |
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+ |
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+(defun hit-sphere (center radius r) |
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+ (with-slots (origin direction) r |
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+ (let* ((oc (vec- origin center)) |
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+ (a (length-squared direction)) |
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+ (half-b (dot oc direction)) |
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+ (c (- (length-squared oc) |
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+ (expt radius 2))) |
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+ (discriminant (- (* half-b half-b) |
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+ (* a c)))) |
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+ (if (< discriminant 0) |
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+ -1.0d0 |
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+ (/ (- (- half-b) (sqrt discriminant)) |
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+ a))))) |
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+ |
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+(defgeneric ray-color (ray world) |
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+ (:method ((ray ray) world) |
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+ (multiple-value-bind (hit-p rec) |
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+ (hit world ray 0 infinity) |
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+ (when hit-p |
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+ (return-from ray-color |
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+ (vec* 0.5 |
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+ (vec+ #(1 1 1) |
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+ (.normal rec))))) |
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+ (with-slots (direction) ray |
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+ (let* ((unit-direction (unit-vector direction)) |
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+ (it (+ (* 0.5 (v3-y unit-direction)) |
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+ 1.0d0))) |
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+ (vec+ (vec* (- 1.0d0 it) |
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+ #(1.0d0 1.0d0 1.0d0)) |
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+ (vec* it |
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+ #(0.5d0 0.7d0 1.0d0)))))))) |
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+ |
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+(defun raytrace (out) |
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+ (let* ((world (list (sphere #(0 0 -1) 0.5) |
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+ (sphere #(0 -100.5 -1) 100))) |
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+ (aspect-ratio (/ 16.0d0 9.0d0)) |
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+ (image-width 400) |
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+ (image-height (* (floor (/ image-width aspect-ratio)))) |
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+ |
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+ (viewport-height 2.0d0) |
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+ (viewport-width (* aspect-ratio viewport-height)) |
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+ (focal-length 1.0d0) |
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+ |
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+ (origin (vec3 0 0 0)) |
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+ (horizontal (vec3 viewport-width 0 0)) |
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+ (vertical (vec3 0 viewport-height 0)) |
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+ (lower-left-corner (vec- (vec- (vec- origin |
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+ (vec/ horizontal 2)) |
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+ (vec/ vertical 2)) |
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+ (vec3 0 0 focal-length)))) |
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+ (alexandria:with-output-to-file (s out :if-exists :supersede) |
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+ (call-with-ppm-header s (make-size :width image-width :height image-height) |
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+ (lambda (s) |
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+ (write-colors s |
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+ (lambda (c) |
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+ (loop for j from (1- image-height) downto 0 |
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+ do (format *trace-output* |
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+ "~&Scanlines remaining: ~d ~s~%" |
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+ j |
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+ (local-time:now)) |
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+ do |
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+ (loop for i from 0 below image-width |
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+ for u = (/ (* 1.0d0 i) |
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+ (1- image-width)) |
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+ for v = (/ (* 1.0d0 j) |
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+ (1- image-height)) |
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+ for r = (ray origin |
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+ (vec- (vec+ (vec+ lower-left-corner |
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+ (vec* u |
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+ horizontal)) |
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+ (vec* v |
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+ vertical)) |
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+ origin)) |
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+ for color = (ray-color r world) |
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+ collect |
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+ (funcall c color)))) |
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+ image-width)) |
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+ (round *color-depth*))))) |
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+ |
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+(defun sample-image (out) |
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+ (let ((image-width 256) |
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+ (image-height 256)) |
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+ (alexandria:with-output-to-file (s out :if-exists :supersede) |
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+ (call-with-ppm-header s (make-size :width image-width :height image-height) |
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+ (lambda (s) |
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+ (write-colors s |
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+ (lambda (c) |
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+ (loop for j from (1- image-height) downto 0 |
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+ do (format *trace-output* |
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+ "~&Scanlines remaining: ~d ~s~%" |
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+ j |
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+ (local-time:now)) |
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+ do |
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+ (loop for i from 0 below image-width |
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+ collect |
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+ (let* ((r (/ (* i 1.0d0) |
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+ (1- image-width))) |
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+ (g (/ (* j 1.0d0) |
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+ (1- image-height))) |
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+ (b 0.15d0)) |
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+ (funcall c (make-color :r r |
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+ :g g |
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+ :b b)))))) |
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+ image-width)) |
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+ (1- #.(expt 2 8)))))) |