diff options
Diffstat (limited to 'fennel-raytracer.fnl')
| -rw-r--r-- | fennel-raytracer.fnl | 127 |
1 files changed, 112 insertions, 15 deletions
diff --git a/fennel-raytracer.fnl b/fennel-raytracer.fnl index d8606df..804667e 100644 --- a/fennel-raytracer.fnl +++ b/fennel-raytracer.fnl @@ -192,7 +192,7 @@ multiplication." :intersect intersect-plane :normal (fn [] (vec3-normalize n)) - }) + }) (fn intersect-sphere [r shape t-min t-max] (let [{ :origin origin :direction direction } r @@ -218,22 +218,117 @@ multiplication." :intersect intersect-sphere :normal (fn [position] (vec3-normalize (vec3- position center))) + }) + + +;;; +;;; Lights, and generic procedures for working with them. +;;; + +(fn light-sample [intensity position direction] + { + :intensity intensity + :position position + :direction direction }) +(fn spot-light-at [light point] + (let [{ :from position :to target + :intensity intensity :exponent exponent + :cutoff-angle cutoff} light + direction (vec3- position point) + pf (vec3-normalize (vec3- point position)) + intensity (if (< (vec3-dot pf (vec3-normalize (vec3- target position))) + (math.cos (degrees->radians cutoff))) + (vec3 0.00 0.00 0.00) + (vec3* (* (/ 1 (square (vec3-magnitude direction))) + (math.pow (vec3-dot pf (vec3-normalize (vec3- target position))) + exponent)) + intensity))] + (light-sample intensity position (vec3-normalize direction)))) + +(fn spot-light [from to intensity exponent cutoff-angle] + { + :from from + :to to + :intensity intensity + :exponent exponent + :cutoff-angle cutoff-angle + + :sample-at spot-light-at + }) + + +;;; +;;; Materials. +;;; + +(fn diffuse-material [ka kd] { :ka ka :kd kd}) +(fn phong-material [ka kd ks p] { :ka ka :kd kd :ks ks :p p}) + +(fn reflect [l n] + "Compute reflected vector, by mirroring l around n." + (vec3- (vec3* (* 2.00 (vec3-dot n l)) n) l)) + +(fn max [a b] (if (>= a b) a b)) +(fn min [a b] (if (< a b) a b)) + +(global ambient-light (vec3 0.01 0.01 0.01)) +(global lights [(spot-light (vec3 10.00 10.00 5.00) + (vec3 0.00 0.00 0.00) + (vec3 100.00 96.00 88.00) + 50 + 15)]) (global shapes [(sphere (vec3 -0.25 0.00 0.25) 1.25 - nil - ;; (phong-material (make-vec3 1.0 0.2 0.2) - ;; (make-vec3 1.0 0.2 0.2) - ;; (make-vec3 2.0 2.0 2.0) - ;; 20) - ) + (phong-material (vec3 1.0 0.2 0.2) + (vec3 1.0 0.2 0.2) + (vec3 2.0 2.0 2.0) + 20)) (plane (vec3 0.00 -1.25 0.00) (vec3 0.00 1.00 0.00) - nil - ;; (diffuse-material (make-vec3 1.0 1.0 0.2) - ;; (make-vec3 1.0 1.0 0.2)) - )]) + (diffuse-material (vec3 1.0 1.0 0.2) + (vec3 1.0 1.0 0.2)))]) + +(fn shade-pixel [shape position origin] + (let [{:ka ka :kd kd :ks ks :p p} shape.material + normal (shape.normal position) + Ia (let [{:x α :y β :z γ} ka + {:x x :y y :z z} ambient-light] + (vec3 (* α x) (* β y) (* γ z))) + Id (vec3+ + (unpack + (map (fn [light] + (let [sample (light.sample-at light position) + { :direction direction :intensity intensity } sample + scalar (max (vec3-dot normal direction) 0) + {:x α :y β :z γ} kd + {:x x :y y :z z} intensity] + (vec3 (* α x scalar) + (* β y scalar) + (* γ z scalar)))) + lights))) + Is (if ks + (vec3+ + (unpack + (map (fn [light] + (let [sample (light.sample-at light position) + { :position point :intensity intensity } sample + l (vec3-normalize (vec3- point position)) + v (vec3-normalize (vec3- origin position)) + r (reflect l normal) + scalar (math.pow (max 0 (vec3-dot v r)) p) + {:x α :y β :z γ} ks + {:x x :y y :z z} intensity] + (vec3 (* α x scalar) + (* β y scalar) + (* γ z scalar)))) + lights))) + (vec3 0.00 0.00 0.00)) + {:x x :y y :z z} (vec3+ Ia Id Is)] + [(math.floor (* 255 (min 1.0 x))) + (math.floor (* 255 (min 1.0 y))) + (math.floor (* 255 (min 1.0 z)))])) (fn ray-intersect-scene [r] "Return the nearest shape with which RAY intersects, with the point, if any. @@ -252,7 +347,7 @@ Otherwise, return nil." { :shape shape :intersection intersection } :none))) shapes)) - { :shape shape :intersection t} (let [] { :shape shape :point (point-at r t)}))) + { :shape shape :intersection t } { :shape shape :point (point-at r t)})) ;;; @@ -281,9 +376,11 @@ Otherwise, return nil." (var output (image image-width image-height)) (for [x 0 image-width] (for [y 0 image-height] - (let [r (coordinate->ray (screen->viewport x y))] - (if (ray-intersect-scene r) - (set-pixel output x y [0 0 0]) + (let [r (coordinate->ray (screen->viewport x y)) + intersection (ray-intersect-scene r)] + (if intersection + (let [{ :shape shape :point point } intersection] + (set-pixel output x y (shade-pixel shape point camera-position))) (set-pixel output x y (ray-color r)))))) (write-ppm output)) |