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Add point, spot, hemisphere lights and multi-light shading
Extends eido.ir.material with four light types inspired by 3ds Max: - directional: parallel rays (existing, enhanced with constructors) - omni: point light with position and distance decay - spot: cone light with hotspot/falloff angles and decay - hemisphere: sky/ground ambient blend by surface normal Adds multi-light support: shade-multi-light accumulates per-channel contributions from all lights. Light color tints diffuse and specular. Decay types: :none, :inverse, :inverse-square with configurable start. Updates scene3d render-mesh to pass face centroid to shading and accept :lights vector alongside :light for backward compatibility. Adds smoothstep to math3d. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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‎src/eido/ir/material.clj‎

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(ns eido.ir.material
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"Material descriptors for 3D rendering.
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"Material descriptors and multi-light shading for 3D rendering.
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Materials describe how surfaces respond to light — going beyond
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the existing diffuse-only shading in scene3d.
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Materials describe how surfaces respond to light using Blinn-Phong.
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Material types:
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:material/phong — Blinn-Phong shading with ambient, diffuse, and specular"
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Light types:
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:directional — parallel rays from a direction (default, existing)
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:omni — radiates in all directions from a position
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:spot — cone of light from a position with hotspot/falloff
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:hemisphere — sky/ground ambient blend by normal direction
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Inspired by 3ds Max Standard Lights."
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(:require
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[eido.color :as color]
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[eido.math3d :as m]))
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;; --- material constructors ---
@@ -22,54 +27,251 @@
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:material/shininess shininess
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:material/color color})
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;; --- shading ---
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;; --- light constructors ---
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(defn directional
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"Creates a directional light (parallel rays)."
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[direction & {:keys [color multiplier ambient]
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:or {multiplier 1.0 ambient 0.0}}]
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(cond-> {:light/type :directional
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:light/direction direction
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:light/multiplier multiplier}
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color (assoc :light/color color)
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(pos? ambient) (assoc :light/ambient ambient)))
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(defn omni
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"Creates an omni (point) light that radiates in all directions."
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[position & {:keys [color multiplier decay decay-start]
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:or {multiplier 1.0 decay :none decay-start 0.0}}]
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(cond-> {:light/type :omni
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:light/position position
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:light/multiplier multiplier
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:light/decay decay
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:light/decay-start decay-start}
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color (assoc :light/color color)))
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(defn spot
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"Creates a spot light with a cone defined by hotspot and falloff angles."
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[position direction & {:keys [color multiplier hotspot falloff decay decay-start]
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:or {multiplier 1.0 hotspot 43.0 falloff 45.0
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decay :none decay-start 0.0}}]
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(cond-> {:light/type :spot
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:light/position position
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:light/direction direction
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:light/multiplier multiplier
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:light/hotspot hotspot
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:light/falloff falloff
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:light/decay decay
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:light/decay-start decay-start}
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color (assoc :light/color color)))
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(defn hemisphere
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"Creates a hemisphere (sky) light with sky and ground colors."
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[sky-color ground-color & {:keys [up multiplier]
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:or {up [0 1 0] multiplier 0.3}}]
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{:light/type :hemisphere
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:light/sky-color sky-color
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:light/ground-color ground-color
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:light/up up
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:light/multiplier multiplier})
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;; --- decay ---
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(defn- apply-decay
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"Applies distance decay to light intensity."
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^double [^double intensity light ^double distance]
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(let [decay (get light :light/decay :none)
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decay-start (double (get light :light/decay-start 0.0))
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effective-dist (max 0.0 (- distance decay-start))]
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(if (or (= :none decay) (<= effective-dist 0.0))
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intensity
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(let [factor (case decay
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:inverse (/ 1.0 (+ 1.0 effective-dist))
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:inverse-square (/ 1.0 (+ 1.0 (* effective-dist effective-dist)))
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1.0)]
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(* intensity factor)))))
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;; --- per-light-type contribution ---
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(defn- clamp-byte ^long [^double v]
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(long (Math/max 0.0 (Math/min 255.0 v))))
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(defn shade-phong
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"Computes Blinn-Phong shading for a face.
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Returns a shaded color vector [:color/rgb r g b].
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normal: normalized face normal (toward camera)
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light-dir: normalized light direction (toward light)
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cam-dir: normalized camera direction (toward camera)
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light: light map with :light/ambient, :light/intensity
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material: material descriptor with :material/* keys"
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[normal light-dir cam-dir light material]
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(let [base-color (:material/color material)
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[_ br bg bb] base-color
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ambient (double (:material/ambient material))
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(defn- get-multiplier ^double [light]
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(double (or (:light/multiplier light) 1.0)))
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(defn- directional-contribution
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"Computes diffuse + specular contribution from a directional light."
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[normal cam-dir material light]
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(let [light-dir (m/normalize (:light/direction light))
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multiplier (get-multiplier light)
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mat-diffuse (double (:material/diffuse material))
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mat-spec (double (:material/specular material))
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shininess (double (:material/shininess material))
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cos-angle (m/dot normal light-dir)
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diffuse (* mat-diffuse multiplier (max 0.0 cos-angle))
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half-vec (m/normalize (m/v+ light-dir cam-dir))
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n-dot-h (max 0.0 (m/dot normal half-vec))
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specular (if (pos? cos-angle)
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(* mat-spec multiplier (Math/pow n-dot-h shininess))
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0.0)]
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{:diffuse diffuse :specular specular}))
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(defn- omni-contribution
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"Computes diffuse + specular contribution from an omni (point) light."
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[normal cam-dir material light face-centroid]
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(let [light-pos (:light/position light)
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to-light (m/v- light-pos face-centroid)
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distance (m/magnitude to-light)
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light-dir (if (pos? distance) (m/v* to-light (/ 1.0 distance)) [0 0 0])
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multiplier (apply-decay (get-multiplier light) light distance)
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mat-diffuse (double (:material/diffuse material))
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mat-spec (double (:material/specular material))
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shininess (double (:material/shininess material))
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intensity (double (get light :light/intensity 0.7))
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;; Diffuse (Lambert)
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cos-angle (m/dot normal light-dir)
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diffuse (* mat-diffuse intensity (max 0.0 cos-angle))
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;; Specular (Blinn-Phong)
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diffuse (* mat-diffuse multiplier (max 0.0 cos-angle))
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half-vec (m/normalize (m/v+ light-dir cam-dir))
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n-dot-h (max 0.0 (m/dot normal half-vec))
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specular (if (pos? cos-angle)
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(* mat-spec intensity (Math/pow n-dot-h shininess))
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0.0)
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;; Combined brightness
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brightness (min 1.0 (+ ambient diffuse))
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;; Apply to color channels, add specular as white highlight
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r (clamp-byte (+ (* (double br) brightness) (* 255.0 specular)))
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g (clamp-byte (+ (* (double bg) brightness) (* 255.0 specular)))
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b (clamp-byte (+ (* (double bb) brightness) (* 255.0 specular)))]
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(* mat-spec multiplier (Math/pow n-dot-h shininess))
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0.0)]
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{:diffuse diffuse :specular specular}))
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(defn- spot-contribution
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"Computes diffuse + specular contribution from a spot light."
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[normal cam-dir material light face-centroid]
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(let [light-pos (:light/position light)
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to-light (m/v- light-pos face-centroid)
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distance (m/magnitude to-light)
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light-dir (if (pos? distance) (m/v* to-light (/ 1.0 distance)) [0 0 0])
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;; Spot cone factor
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spot-dir (m/normalize (:light/direction light))
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cos-theta (m/dot (m/v* light-dir -1.0) spot-dir)
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hotspot-rad (* (/ (double (:light/hotspot light)) 2.0) (/ Math/PI 180.0))
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falloff-rad (* (/ (double (:light/falloff light)) 2.0) (/ Math/PI 180.0))
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cos-hotspot (Math/cos hotspot-rad)
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cos-falloff (Math/cos falloff-rad)
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spot-factor (m/smoothstep cos-falloff cos-hotspot cos-theta)]
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(if (zero? spot-factor)
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{:diffuse 0.0 :specular 0.0}
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(let [multiplier (* (apply-decay (get-multiplier light) light distance) spot-factor)
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mat-diffuse (double (:material/diffuse material))
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mat-spec (double (:material/specular material))
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shininess (double (:material/shininess material))
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cos-angle (m/dot normal light-dir)
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diffuse (* mat-diffuse multiplier (max 0.0 cos-angle))
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half-vec (m/normalize (m/v+ light-dir cam-dir))
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n-dot-h (max 0.0 (m/dot normal half-vec))
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specular (if (pos? cos-angle)
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(* mat-spec multiplier (Math/pow n-dot-h shininess))
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0.0)]
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{:diffuse diffuse :specular specular}))))
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(defn- hemisphere-contribution
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"Computes ambient contribution from a hemisphere light.
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Returns color contribution as [r g b] scaled 0-1."
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[normal light]
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(let [up (m/normalize (or (:light/up light) [0 1 0]))
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multiplier (get-multiplier light)
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factor (+ 0.5 (* 0.5 (m/dot normal up)))
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sky (color/resolve-color (:light/sky-color light))
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ground (color/resolve-color (:light/ground-color light))
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r (/ (+ (* factor (:r sky)) (* (- 1.0 factor) (:r ground))) 255.0)
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g (/ (+ (* factor (:g sky)) (* (- 1.0 factor) (:g ground))) 255.0)
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b (/ (+ (* factor (:b sky)) (* (- 1.0 factor) (:b ground))) 255.0)]
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{:ambient-r (* r multiplier)
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:ambient-g (* g multiplier)
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:ambient-b (* b multiplier)}))
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;; --- multi-light shading ---
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(defn- resolve-lights
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"Normalizes light input to a vector of light maps.
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Supports single :light map or :lights vector."
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[light lights]
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(cond
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(seq lights) lights
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light [light]
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:else []))
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(defn shade-multi-light
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"Shades a face using multiple lights and a Blinn-Phong material.
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Returns [:color/rgb r g b]."
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[normal cam-dir face-centroid material lights]
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(let [base-color (or (:material/color material) [:color/rgb 128 128 128])
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[_ br bg bb] base-color
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mat-ambient (double (:material/ambient material))
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;; Accumulate contributions from all lights
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;; Resolve light color to [0-1] RGB scale factors
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light-rgb (fn [light]
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(if-let [c (:light/color light)]
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(let [resolved (color/resolve-color c)]
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[(/ (double (:r resolved)) 255.0)
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(/ (double (:g resolved)) 255.0)
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(/ (double (:b resolved)) 255.0)])
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[1.0 1.0 1.0]))
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result (reduce
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(fn [{:keys [diff-r diff-g diff-b spec-r spec-g spec-b
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amb-r amb-g amb-b]} light]
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(let [light-type (get light :light/type :directional)
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[lr lg lb] (light-rgb light)]
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(case light-type
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:directional
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(let [{:keys [diffuse specular]} (directional-contribution normal cam-dir material light)]
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{:diff-r (+ diff-r (* diffuse lr)) :diff-g (+ diff-g (* diffuse lg)) :diff-b (+ diff-b (* diffuse lb))
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:spec-r (+ spec-r (* specular lr)) :spec-g (+ spec-g (* specular lg)) :spec-b (+ spec-b (* specular lb))
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:amb-r amb-r :amb-g amb-g :amb-b amb-b})
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:omni
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(let [{:keys [diffuse specular]} (omni-contribution normal cam-dir material light face-centroid)]
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{:diff-r (+ diff-r (* diffuse lr)) :diff-g (+ diff-g (* diffuse lg)) :diff-b (+ diff-b (* diffuse lb))
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:spec-r (+ spec-r (* specular lr)) :spec-g (+ spec-g (* specular lg)) :spec-b (+ spec-b (* specular lb))
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:amb-r amb-r :amb-g amb-g :amb-b amb-b})
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:spot
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(let [{:keys [diffuse specular]} (spot-contribution normal cam-dir material light face-centroid)]
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{:diff-r (+ diff-r (* diffuse lr)) :diff-g (+ diff-g (* diffuse lg)) :diff-b (+ diff-b (* diffuse lb))
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:spec-r (+ spec-r (* specular lr)) :spec-g (+ spec-g (* specular lg)) :spec-b (+ spec-b (* specular lb))
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:amb-r amb-r :amb-g amb-g :amb-b amb-b})
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:hemisphere
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(let [{:keys [ambient-r ambient-g ambient-b]} (hemisphere-contribution normal light)]
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{:diff-r diff-r :diff-g diff-g :diff-b diff-b
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:spec-r spec-r :spec-g spec-g :spec-b spec-b
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:amb-r (+ amb-r ambient-r) :amb-g (+ amb-g ambient-g) :amb-b (+ amb-b ambient-b)})
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;; Unknown light type — skip
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{:diff-r diff-r :diff-g diff-g :diff-b diff-b
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:spec-r spec-r :spec-g spec-g :spec-b spec-b
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:amb-r amb-r :amb-g amb-g :amb-b amb-b})))
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{:diff-r 0.0 :diff-g 0.0 :diff-b 0.0
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:spec-r 0.0 :spec-g 0.0 :spec-b 0.0
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:amb-r mat-ambient :amb-g mat-ambient :amb-b mat-ambient}
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lights)
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{:keys [diff-r diff-g diff-b spec-r spec-g spec-b amb-r amb-g amb-b]} result
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r (clamp-byte (+ (* (double br) (min 1.0 (+ amb-r diff-r))) (* 255.0 spec-r)))
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g (clamp-byte (+ (* (double bg) (min 1.0 (+ amb-g diff-g))) (* 255.0 spec-g)))
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b (clamp-byte (+ (* (double bb) (min 1.0 (+ amb-b diff-b))) (* 255.0 spec-b)))]
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[:color/rgb r g b]))
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;; --- backward-compatible API ---
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(defn shade-phong
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"Computes Blinn-Phong shading for a face with a single directional light."
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[normal light-dir cam-dir light material]
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(shade-multi-light normal cam-dir [0 0 0] material
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[(assoc light :light/type :directional :light/direction light-dir)]))
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(defn shade-face
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"Shades a face style using a material descriptor.
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Falls back to the material's color if the face has no fill.
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Returns updated style map with shaded fill and stroke."
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[style normal light-dir cam-dir light material]
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(let [mat-color (or (:material/color material)
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(:style/fill style))
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material (assoc material :material/color mat-color)
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shaded-color (shade-phong normal light-dir cam-dir light material)]
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(cond-> (assoc style :style/fill shaded-color)
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(:style/stroke style)
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(assoc-in [:style/stroke :color] shaded-color))))
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"Shades a face style using a material and lights.
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Supports single light or lights vector."
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([style normal light-dir cam-dir light material]
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(shade-face style normal light-dir cam-dir light material nil nil))
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([style normal light-dir cam-dir light material lights face-centroid]
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(let [mat-color (or (:material/color material) (:style/fill style))
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material (assoc material :material/color mat-color)
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all-lights (resolve-lights light lights)
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centroid (or face-centroid [0 0 0])
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shaded-color (shade-multi-light normal cam-dir centroid material all-lights)]
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(cond-> (assoc style :style/fill shaded-color)
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(:style/stroke style)
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(assoc-in [:style/stroke :color] shaded-color)))))

‎src/eido/math3d.clj‎

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[0.0 0.0 0.0]
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(v* v (/ 1.0 m)))))
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(defn smoothstep
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"Hermite interpolation between edge0 and edge1.
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Returns 0 when x <= edge0, 1 when x >= edge1, smooth curve between."
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^double [^double edge0 ^double edge1 ^double x]
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(let [t (Math/max 0.0 (Math/min 1.0 (/ (- x edge0) (- edge1 edge0))))]
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(* t t (- 3.0 (* 2.0 t)))))
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;; --- rotations ---
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(defn rotate-x

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