From 4c15ab4bddcc2650ffb34be40f3fb8190e9572dc Mon Sep 17 00:00:00 2001
From: chairmanpow <chairmanpow@codeberg.org>
Date: Sat, 3 Oct 2026 16:37:38 +0100
Subject: [PATCH] shadow: skin the character caster on the GPU, so a crowd
 costs no CPU skin
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The character shadow lane CPU-skinned every admitted unit into one merged
Mesh asset and re-uploaded it each rebuild — the documented expensive half
of the lane's ~3 ms, and the part that scales with players. Replace it with
one GPU-skinned caster per admitted creature part: the part's own skinned
mesh and MeshTag, drawn through a new SkinnedShadowCasterMaterial whose
prepass vertex skins from the shared rig palette (the same rows wow_model
reads). Pose changes are free; only membership is reconciled per frame.

Palette region offsets are pushed as shader defs, so the caster shader reads
the shared light buffer's tail as a flat array and needs no copy of the
WowLight layout.
---
 crates/benilla-app/src/character_shadow.rs    | 208 +++++++++---------
 crates/benilla-app/src/shaders.rs             |   3 +-
 .../src/shaders/shadow_caster_skinned.wgsl    |  84 +++++++
 crates/benilla-app/src/shadow_core.rs         | 100 ++++++++-
 crates/benilla-world/src/rig_palette.rs       |   6 +-
 5 files changed, 286 insertions(+), 115 deletions(-)
 create mode 100644 crates/benilla-app/src/shaders/shadow_caster_skinned.wgsl

diff --git a/crates/benilla-app/src/character_shadow.rs b/crates/benilla-app/src/character_shadow.rs
index cdb5452f..b0477447 100644
--- a/crates/benilla-app/src/character_shadow.rs
+++ b/crates/benilla-app/src/character_shadow.rs
@@ -1,24 +1,27 @@
 //! The CHARACTER shadow lane — a thin plug-in on top of [`super::shadow_core`].
 //!
-//! It owns nothing but its own per-frame caster (players, NPCs, creatures, mounts). When
-//! `characterShadows` is on it declares demand to the shared rig ([`ShadowDemand`]); while the rig
-//! is live it collects the CREATURE entity parts into its caster using the rig's shared material and
-//! the per-frame facts the rig publishes ([`ShadowFrame`]). It does not know [`super::world_shadow`]
-//! exists — remove either lane and the other is untouched.
+//! It owns the per-unit caster for players, NPCs, creatures and mounts. When `characterShadows` is
+//! on it declares demand to the shared rig ([`ShadowDemand`]); while the rig is live it keeps one
+//! GPU-skinned caster per admitted creature part, drawn through [`SkinnedShadowCasterMaterial`].
+//!
+//! The caster carries the part's own skinned mesh and `MeshTag`, so it skins in the shadow pass's
+//! VERTEX stage from the shared rig palette the forward model already uploads — no per-frame CPU
+//! skinning, no merged mesh, no re-upload. Pose changes are free: only membership (spawn/despawn,
+//! range, occluder) is reconciled here. It does not know [`super::world_shadow`] exists.
 
 use bevy::ecs::entity::EntityHashSet;
-use bevy::pbr::MeshMaterial3d;
+use bevy::mesh::MeshTag;
+use bevy::platform::collections::HashMap;
 use bevy::prelude::*;
 
-use benilla_assets::materials::WowModelMaterial;
 use benilla_world::billboard::BillboardCard;
-use benilla_world::interact::PickMesh;
+use benilla_world::lighting::SharedLightBuffer;
 use benilla_world::model_render::{ModelPart, ShadowOccluder};
-use benilla_world::rig_palette::{RigPalettes, RigPart, RigSkin};
+use benilla_world::rig_palette::RigPart;
 
 use crate::shadow_core::{
-    collect_entity_geometry, empty_shadow_mesh, restore_mesh_buffers, shadow_trace,
-    spawn_solid_caster, take_mesh_buffers, RebuildRate, ShadowDemand, ShadowFrame, ShadowSet,
+    casts_realtime_shadow, shadow_trace, spawn_skinned_caster, ShadowDemand, ShadowFrame,
+    ShadowSet, SkinnedShadowCasterMaterial,
 };
 use crate::video::VideoConfig;
 
@@ -32,141 +35,132 @@ impl Plugin for CharacterShadowPlugin {
     }
 }
 
-/// MONKEY (moon shadows): roots/ancestors with triangles in the LAST completed caster build.
-/// Blobs consume this in PostUpdate, before this frame's Last rebuild: a newly uploaded proxy
-/// gets a render frame before its oval yields. Cadence skips retain the same geometry/verdict.
+/// MONKEY (moon shadows): roots/ancestors with a live caster in the LAST completed reconciliation.
+/// Blobs consume this in PostUpdate, before this frame's Last pass: a newly spawned caster gets a
+/// render frame before its oval yields.
 #[derive(Resource, Default)]
 pub(crate) struct CharacterShadowReady(pub EntityHashSet);
 
-/// The character lane's retained per-frame caster.
+/// The character lane's retained casters: part entity → its shadow-caster entity.
 #[derive(Resource, Default)]
 struct CharacterLane {
-    caster: Option<Entity>,
-    mesh: Option<Handle<Mesh>>,
-    /// [`shadow_trace`]'s change detector: (tris, admitted, rejected).
+    casters: HashMap<Entity, Entity>,
+    material: Option<Handle<SkinnedShadowCasterMaterial>>,
+    /// [`shadow_trace`]'s change detector: (admitted, rejected, casters).
     traced: (u32, u32, u32),
-    /// MONKEY (sun shadow perf): the `characterShadowRate` cadence gate — see the rebuild comment
-    /// in [`collect_character_shadows`].
-    rate: RebuildRate,
+}
+
+/// Drop every caster and the shared material handle.
+fn teardown(commands: &mut Commands, lane: &mut CharacterLane) {
+    for (_, caster) in lane.casters.drain() {
+        commands.entity(caster).despawn();
+    }
+    lane.material = None;
 }
 
 #[allow(clippy::too_many_arguments)]
 fn collect_character_shadows(
     video: Res<VideoConfig>,
-    time: Res<Time>,
     mut demand: ResMut<ShadowDemand>,
     frame: Res<ShadowFrame>,
     mut lane: ResMut<CharacterLane>,
     mut ready: ResMut<CharacterShadowReady>,
     parents: Query<&ChildOf>,
     mut commands: Commands,
-    mut meshes: ResMut<Assets<Mesh>>,
+    light: Option<Res<SharedLightBuffer>>,
+    mut materials: ResMut<Assets<SkinnedShadowCasterMaterial>>,
     parts: Query<
         (
             Entity,
-            &PickMesh,
+            &Mesh3d,
+            &MeshTag,
             &ModelPart,
+            &ShadowOccluder,
             Option<&GlobalTransform>,
             Option<&RigPart>,
-            &ShadowOccluder,
-            Option<&MeshMaterial3d<WowModelMaterial>>,
         ),
         Without<BillboardCard>,
     >,
-    rigs: Query<&RigSkin>,
-    palettes: Res<RigPalettes>,
 ) {
     let on = video.character_shadows;
     // Declare demand so the shared rig stays up while this lane is on (the rig reads it next frame).
     demand.0 = demand.0 || on;
 
-    // Rig down or lane off → drop our caster so it stops casting.
-    if !(frame.active && on) {
+    // Rig down, lane off, or an off night → drop every caster so none keeps casting.
+    if !(frame.active && on) || frame.suspended {
         ready.0.clear();
-        if let Some(entity) = lane.caster.take() {
-            commands.entity(entity).despawn();
-        }
-        if let Some(handle) = lane.mesh.take() {
-            meshes.remove(handle.id());
-        }
-        // The mesh this gate was pacing is gone — re-arm so a re-enable builds on its first frame.
-        lane.rate.reset();
+        teardown(&mut commands, &mut lane);
         return;
     }
-    // MONKEY (moon shadows): keep the cache but suspend CPU skin/re-upload on feature-off nights.
-    if frame.suspended {
-        ready.0.clear();
-        lane.rate.reset();
-        return;
-    }
-    let Some(material) = frame.material.clone() else {
-        return;
+    let Some(light) = light else {
+        return; // the shared buffer is not up yet; the rig will still be live next frame
     };
+    if lane.material.is_none() {
+        lane.material = Some(materials.add(SkinnedShadowCasterMaterial {
+            light_buf: light.0.clone(),
+        }));
+    }
+    let material = lane
+        .material
+        .clone()
+        .expect("the material was inserted just above");
 
-    // Animated rigs re-skin every frame and creatures spawn/despawn under lifecycles this lane
-    // can't cheaply observe — so the caster is collected fresh, at a CAPPED cadence.
-    if lane.caster.is_none() {
-        let mesh = meshes.add(empty_shadow_mesh());
-        let entity = spawn_solid_caster(&mut commands, mesh.clone(), material);
-        lane.caster = Some(entity);
-        lane.mesh = Some(mesh);
-        // A brand-new caster is an EMPTY mesh; make sure this frame fills it.
-        lane.rate.reset();
+    ready.0.clear();
+    let mut wanted = EntityHashSet::default();
+    let (reach, light_pos) = (frame.entity_reach, frame.light_position);
+    let (mut admitted, mut rejected) = (0u32, 0u32);
+    for (part, mesh, tag, model_part, occluder, global, rig_part) in &parts {
+        if !casts_realtime_shadow(model_part.kind, model_part.blend, true, false) {
+            continue;
+        }
+        // The camera-independent content gate (toggles, far clip, distance fade, material alpha).
+        if !occluder.0 {
+            rejected += 1;
+            continue;
+        }
+        // GPU skinning needs the part's rig; a part with no palette would render in bind pose.
+        if rig_part.is_none() {
+            rejected += 1;
+            continue;
+        }
+        let anchor = global.map(GlobalTransform::translation).unwrap_or(Vec3::ZERO);
+        if anchor.distance_squared(light_pos) > reach * reach {
+            continue;
+        }
+        admitted += 1;
+        wanted.insert(part);
+        ready.0.insert(part);
+        // The unit root owns its blob; mounts and equipment can be nested below it.
+        ready.0.extend(parents.iter_ancestors(part));
+        if !lane.casters.contains_key(&part) {
+            let caster =
+                spawn_skinned_caster(&mut commands, mesh.0.clone(), material.clone(), tag.0);
+            lane.casters.insert(part, caster);
+        }
     }
-    // MONKEY (sun shadow perf): the `characterShadowRate` gate. This rebuild is the expensive half
-    // of the ~3 ms the character lane costs — it CPU-skins every admitted unit and then mutates the
-    // `Mesh` asset, and a mutated mesh is re-extracted and re-uploaded (vertices AND indices) to the
-    // GPU. Skipping it simply leaves the previous proxy in place: the shadow MAP is still rendered
-    // from that proxy every frame, so nothing flickers or disappears — a moving unit's silhouette
-    // merely lags by up to 1/rate second.
-    //
-    // Why a rate cap and not change detection: the obvious `Changed<GlobalTransform>` gate does not
-    // work here. A unit's shadow geometry comes from the RIG PALETTE (`append_skinned` reads
-    // `RigPalettes`, the per-frame skinning pose), not from the part's transform — so a standing NPC
-    // whose idle animation is breathing has an unchanged `GlobalTransform` and changed VERTICES.
-    // Gating on the transform would freeze exactly the poses this lane exists to draw. The rate cap
-    // is the honest saving, and it is bounded work rather than a guess about content.
-    if !lane
-        .rate
-        .due(time.elapsed_secs(), video.character_shadow_rate)
-    {
-        return;
+    // A part that left the admit set (destroyed, out of range, occluder off) loses its caster.
+    let stale: Vec<Entity> = lane
+        .casters
+        .keys()
+        .copied()
+        .filter(|part| !wanted.contains(part))
+        .collect();
+    for part in stale {
+        if let Some(caster) = lane.casters.remove(&part) {
+            commands.entity(caster).despawn();
+        }
     }
-    if let Some(handle) = lane.mesh.clone() {
-        if let Some(mesh) = meshes.get_mut(&handle) {
-            let (mut positions, mut indices) = take_mesh_buffers(mesh);
-            let mut built_parts = EntityHashSet::default();
-            let (admitted, rejected) = collect_entity_geometry(
-                &parts,
-                &rigs,
-                &palettes,
-                true,  // want_creatures
-                false, // want_environment (the world lane's job)
-                frame.light_position,
-                frame.entity_reach,
-                frame.tall_reach,
-                &mut positions,
-                &mut indices,
-                Some(&mut built_parts),
+    if shadow_trace() {
+        let now = (admitted, rejected, lane.casters.len() as u32);
+        if lane.traced != now {
+            info!(
+                "shadow-trace: character gpu {} casters | creatures admitted {} / rejected {} (was {:?})",
+                lane.casters.len(),
+                admitted,
+                rejected,
+                lane.traced
             );
-            ready.0.clear();
-            for part in built_parts {
-                ready.0.insert(part);
-                // The unit root owns its blob; mounts and equipment can be nested below it.
-                ready.0.extend(parents.iter_ancestors(part));
-            }
-            let tris = (indices.len() / 3) as u32;
-            restore_mesh_buffers(mesh, positions, indices);
-            if shadow_trace() {
-                let now = (tris, admitted, rejected);
-                if lane.traced != now {
-                    info!(
-                        "shadow-trace: character {} tris | creatures admitted {} / rejected {} (was {:?})",
-                        tris, admitted, rejected, lane.traced
-                    );
-                    lane.traced = now;
-                }
-            }
+            lane.traced = now;
         }
     }
 }
diff --git a/crates/benilla-app/src/shaders.rs b/crates/benilla-app/src/shaders.rs
index 7c9df041..33e7ab0b 100644
--- a/crates/benilla-app/src/shaders.rs
+++ b/crates/benilla-app/src/shaders.rs
@@ -14,6 +14,7 @@ pub(crate) fn plugin(app: &mut App) {
     bevy::asset::embedded_asset!(app, "shaders/ui_slice_gamma.wgsl");
     bevy::asset::embedded_asset!(app, "shaders/shadow_caster.wgsl");
     bevy::asset::embedded_asset!(app, "shaders/shadow_caster_cutout_prepass.wgsl");
+    bevy::asset::embedded_asset!(app, "shaders/shadow_caster_skinned.wgsl");
     // MONKEY (ao): the contact-shadow pass.
     bevy::asset::embedded_asset!(app, "shaders/ssao.wgsl");
 }
@@ -50,6 +51,6 @@ mod tests {
                  `shaders::plugin`, or was registered from a file that is not directly under src/"
             );
         }
-        assert_eq!(found, 8, "the game's shader set changed size");
+        assert_eq!(found, 9, "the game's shader set changed size");
     }
 }
diff --git a/crates/benilla-app/src/shaders/shadow_caster_skinned.wgsl b/crates/benilla-app/src/shaders/shadow_caster_skinned.wgsl
new file mode 100644
index 00000000..3ff310dd
--- /dev/null
+++ b/crates/benilla-app/src/shaders/shadow_caster_skinned.wgsl
@@ -0,0 +1,84 @@
+// GPU-skinned shadow caster: one per animated unit part. It carries the part's own skinned mesh and
+// MeshTag and skins in the VERTEX stage from the shared light buffer's rig palette — the same rows
+// `wow_model.wgsl` reads — so the character shadow lane spends no per-frame CPU skinning and uploads
+// no merged mesh. The forward pass discards it (invisible to the camera); the prepass, which is the
+// directional-light shadow pass, writes depth from the skinned position.
+//
+// The palette region offsets are pushed as shader defs by
+// `shadow_core::SkinnedShadowCasterMaterial::specialize` from `benilla_world::rig_palette`, so this
+// file needs no copy of the huge `WowLight` layout: it reads the tail as a flat `array<f32>`.
+#import bevy_pbr::{
+    mesh_functions,
+    mesh_view_bindings::view,
+    prepass_io::{VertexOutput},
+    view_transformations::position_world_to_clip,
+}
+
+// Bevy's standard vertex locations (position @0) plus the owned-palette joints at 10/11, exactly
+// the layout `SkinnedShadowCasterMaterial::specialize` binds.
+struct CasterVertex {
+    @builtin(instance_index) instance_index: u32,
+    @location(0) position: vec3<f32>,
+    @location(10) joint_indices: vec4<u32>,
+    @location(11) joint_weights: vec4<f32>,
+}
+
+@group(#{MATERIAL_BIND_GROUP}) @binding(90) var<storage, read> rig_buf: array<f32>;
+
+// Byte offsets of the slot-keyed regions, divided by 4 to index the flat f32 array.
+const RIG_TABLE_F: u32 = #{WOW_RIG_TABLE_OFF} / 4u;
+const RIG_ORIGIN_F: u32 = #{WOW_RIG_ORIGIN_OFF} / 4u;
+const PALETTE_F: u32 = #{WOW_PALETTE_OFF} / 4u;
+
+fn rig_slot(instance_index: u32) -> u32 {
+    return (mesh_functions::get_tag(instance_index) >> 19u) & 0x7ffu;
+}
+
+// Palette row `row` (0..2) of bone `bone`, as the model shader's `palettes[3*bone + row]`.
+fn palette_row(bone: u32, row: u32) -> vec4<f32> {
+    let o = PALETTE_F + 4u * (3u * bone + row);
+    return vec4<f32>(rig_buf[o], rig_buf[o + 1u], rig_buf[o + 2u], rig_buf[o + 3u]);
+}
+
+@vertex
+fn vertex(v: CasterVertex) -> VertexOutput {
+    var out: VertexOutput;
+    let slot = rig_slot(v.instance_index);
+    let base = u32(rig_buf[RIG_TABLE_F + slot]);
+    let w = v.joint_weights;
+    let b0 = base + v.joint_indices.x;
+    let b1 = base + v.joint_indices.y;
+    let b2 = base + v.joint_indices.z;
+    let b3 = base + v.joint_indices.w;
+    let r0 = w.x * palette_row(b0, 0u) + w.y * palette_row(b1, 0u)
+        + w.z * palette_row(b2, 0u) + w.w * palette_row(b3, 0u);
+    let r1 = w.x * palette_row(b0, 1u) + w.y * palette_row(b1, 1u)
+        + w.z * palette_row(b2, 1u) + w.w * palette_row(b3, 1u);
+    let r2 = w.x * palette_row(b0, 2u) + w.y * palette_row(b1, 2u)
+        + w.z * palette_row(b2, 2u) + w.w * palette_row(b3, 2u);
+    // r0/r1/r2 are the affine's rows; a WGSL matrix is column-major (as in `wow_skin_model`).
+    let frame = mat4x4<f32>(
+        vec4<f32>(r0.x, r1.x, r2.x, 0.0),
+        vec4<f32>(r0.y, r1.y, r2.y, 0.0),
+        vec4<f32>(r0.z, r1.z, r2.z, 0.0),
+        vec4<f32>(r0.w, r1.w, r2.w, 1.0),
+    );
+    let origin = vec3<f32>(
+        rig_buf[RIG_ORIGIN_F + 4u * slot],
+        rig_buf[RIG_ORIGIN_F + 4u * slot + 1u],
+        rig_buf[RIG_ORIGIN_F + 4u * slot + 2u],
+    );
+    // Camera-relative like `wow_model.wgsl`, so no f32 product mixes the ~9 k yd origin with a
+    // local position.
+    let p_cam = (frame * vec4<f32>(v.position, 1.0)).xyz + (origin - view.world_position);
+    out.world_position = vec4<f32>(p_cam + view.world_position, 1.0);
+    out.position = position_world_to_clip(out.world_position.xyz);
+    return out;
+}
+
+// Invisible to the camera's forward pass; the shadow map renders through the prepass instead.
+@fragment
+fn fragment() -> @location(0) vec4<f32> {
+    discard;
+    return vec4<f32>(0.0);
+}
diff --git a/crates/benilla-app/src/shadow_core.rs b/crates/benilla-app/src/shadow_core.rs
index 56312344..dd5839a8 100644
--- a/crates/benilla-app/src/shadow_core.rs
+++ b/crates/benilla-app/src/shadow_core.rs
@@ -32,17 +32,18 @@ use bevy::light::{
     CascadeShadowConfigBuilder, DirectionalLight, DirectionalLightShadowMap, NotShadowReceiver,
     ShadowFilteringMethod,
 };
-use bevy::mesh::{Indices, PrimitiveTopology};
+use bevy::mesh::{Indices, Mesh, PrimitiveTopology};
 use bevy::pbr::{Material, MaterialPipeline, MaterialPlugin, MeshMaterial3d};
 use bevy::prelude::*;
 use bevy::reflect::TypePath;
 use bevy::render::render_resource::{
-    AsBindGroup, RenderPipelineDescriptor, SpecializedMeshPipelineError,
+    AsBindGroup, Buffer, RenderPipelineDescriptor, SpecializedMeshPipelineError,
 };
-use bevy::shader::ShaderRef;
+use bevy::shader::{ShaderDefVal, ShaderRef};
 
 use benilla_assets::coords::wow_to_bevy;
 use benilla_assets::materials::WowModelMaterial;
+use benilla_assets::{ATTRIBUTE_WOW_JOINT_INDEX, ATTRIBUTE_WOW_JOINT_WEIGHT};
 use benilla_formats::ModelBlend;
 use benilla_world::billboard::BillboardCard;
 use benilla_world::interact::PickMesh;
@@ -354,6 +355,72 @@ impl Material for ShadowCasterMaterial {
     }
 }
 
+/// The per-unit GPU-skinned shadow caster: the character lane's replacement for the CPU-skinned
+/// merged proxy. It carries a part's own skinned `Mesh3d` and `MeshTag` and skins in the vertex
+/// stage from the shared light buffer's rig palette (the same rows `wow_model.wgsl` reads), so a
+/// crowd costs no per-frame CPU skin and no full-mesh re-upload. The forward pass discards it; the
+/// prepass (the directional shadow pass) writes depth from the skinned position.
+#[derive(Asset, AsBindGroup, TypePath, Debug, Clone)]
+pub(crate) struct SkinnedShadowCasterMaterial {
+    /// The shared light buffer (`lighting::SharedLightBuffer`), whose slot-keyed tail holds
+    /// `rig_table`, `rig_origin` and `palettes`. Bound at the same binding the model material uses.
+    #[storage(90, read_only, buffer, visibility(vertex))]
+    pub light_buf: Buffer,
+}
+
+impl Material for SkinnedShadowCasterMaterial {
+    fn vertex_shader() -> ShaderRef {
+        "embedded://benilla_app/shaders/shadow_caster_skinned.wgsl".into()
+    }
+
+    fn fragment_shader() -> ShaderRef {
+        "embedded://benilla_app/shaders/shadow_caster_skinned.wgsl".into()
+    }
+
+    fn prepass_vertex_shader() -> ShaderRef {
+        "embedded://benilla_app/shaders/shadow_caster_skinned.wgsl".into()
+    }
+
+    fn specialize(
+        _pipeline: &MaterialPipeline,
+        descriptor: &mut RenderPipelineDescriptor,
+        layout: &bevy::mesh::MeshVertexBufferLayoutRef,
+        _key: bevy::pbr::MaterialPipelineKey<Self>,
+    ) -> Result<(), SpecializedMeshPipelineError> {
+        // Two-sided, like the solid proxy: a mixed-winding batch's silhouette must have no holes.
+        descriptor.primitive.cull_mode = None;
+        // The palette region byte offsets, substituted into the shader's flat `array<f32>` reads.
+        // (`benilla_world::rig_palette` owns them; the buffer's prefix is irrelevant to the tail.)
+        for (name, offset) in [
+            (
+                "WOW_RIG_TABLE_OFF",
+                benilla_world::rig_palette::rig_table_region_offset(),
+            ),
+            (
+                "WOW_RIG_ORIGIN_OFF",
+                benilla_world::rig_palette::rig_origin_region_offset(),
+            ),
+            (
+                "WOW_PALETTE_OFF",
+                benilla_world::rig_palette::palette_region_offset(),
+            ),
+        ] {
+            descriptor
+                .vertex
+                .shader_defs
+                .push(ShaderDefVal::UInt(name.into(), offset as u32));
+        }
+        // The owned-palette joint attributes at 10/11, matching `WowModelExt::specialize`.
+        let attrs = [
+            Mesh::ATTRIBUTE_POSITION.at_shader_location(0),
+            ATTRIBUTE_WOW_JOINT_INDEX.at_shader_location(10),
+            ATTRIBUTE_WOW_JOINT_WEIGHT.at_shader_location(11),
+        ];
+        descriptor.vertex.buffers = vec![layout.0.get_layout(&attrs)?];
+        Ok(())
+    }
+}
+
 impl Plugin for ShadowCorePlugin {
     fn build(&self, app: &mut App) {
         // MONKEY (sun shadow perf): the shipped edge is now 2048, and it is a LIVE cvar
@@ -364,6 +431,7 @@ impl Plugin for ShadowCorePlugin {
             size: DEFAULT_SHADOW_MAP_SIZE as usize,
         })
         .add_plugins(MaterialPlugin::<ShadowCasterMaterial>::default())
+        .add_plugins(MaterialPlugin::<SkinnedShadowCasterMaterial>::default())
         .init_resource::<ShadowRigState>()
         .init_resource::<ShadowDemand>()
         .init_resource::<ShadowFrame>()
@@ -687,6 +755,30 @@ pub(crate) fn spawn_solid_caster(
         .id()
 }
 
+/// Spawn a GPU-skinned caster: a part's own skinned mesh and `MeshTag`, drawn through
+/// [`SkinnedShadowCasterMaterial`] on the private shadow layer. Its `Transform` is unused (the
+/// palette carries the world pose), so it is the identity.
+pub(crate) fn spawn_skinned_caster(
+    commands: &mut Commands,
+    mesh: Handle<Mesh>,
+    material: Handle<SkinnedShadowCasterMaterial>,
+    tag: u32,
+) -> Entity {
+    commands
+        .spawn((
+            Mesh3d(mesh),
+            MeshMaterial3d(material),
+            bevy::mesh::MeshTag(tag),
+            Transform::IDENTITY,
+            Visibility::Visible,
+            RenderLayers::layer(PLAYER_SHADOW_LAYER),
+            NoFrustumCulling,
+            NotShadowReceiver,
+            ShadowCaster,
+        ))
+        .id()
+}
+
 /// Append a triangle list, dropping WHOLE triangles whose indices exceed the vertex range (filtering
 /// single indices out of a `TriangleList` rewires the rest of the submesh into garbage).
 pub(crate) fn append_triangles(
@@ -835,7 +927,7 @@ pub(crate) fn collect_entity_geometry(
 /// ENVIRONMENT (gameobjects, faded doodads, WMO props) is OPAQUE only — a foliage leaf-card cast
 /// solid becomes a box; retained-world cutout is cast leaf-shaped by the world lane's alpha-tested
 /// material instead. Additive/transparent geometry never casts a solid shadow.
-fn casts_realtime_shadow(
+pub(crate) fn casts_realtime_shadow(
     kind: ModelKind,
     blend: ModelBlend,
     want_creatures: bool,
diff --git a/crates/benilla-world/src/rig_palette.rs b/crates/benilla-world/src/rig_palette.rs
index 36df4050..03b3f17e 100644
--- a/crates/benilla-world/src/rig_palette.rs
+++ b/crates/benilla-world/src/rig_palette.rs
@@ -27,12 +27,12 @@ pub(crate) const MAX_PALETTE_BONES: usize = 131_072;
 const BONE_BYTES: u64 = 48;
 
 /// Byte offset of the rig slot table (a base bone index a slot), after the prop-probe region.
-pub(crate) fn rig_table_region_offset() -> u64 {
+pub fn rig_table_region_offset() -> u64 {
     crate::lighting::prop_probe_region_offset() + (7 * crate::lighting::MAX_PROP_PROBES * 16) as u64
 }
 
 /// Byte offset of the rig origin table (a `vec4` a slot), after the tint table, as in the shader.
-pub(crate) fn rig_origin_region_offset() -> u64 {
+pub fn rig_origin_region_offset() -> u64 {
     crate::instance_tint::region_offset() + crate::instance_tint::region_bytes()
 }
 
@@ -43,7 +43,7 @@ pub(crate) fn rig_origin_region_bytes() -> u64 {
 
 /// Byte offset of the palette rows, after the slot, tint, origin, mat-anim and straddle-clip
 /// tables: last, because `wow_model.wgsl` declares them as the struct's one runtime-sized array.
-pub(crate) fn palette_region_offset() -> u64 {
+pub fn palette_region_offset() -> u64 {
     crate::straddle::region_offset() + crate::straddle::region_bytes()
 }