Fix extended-region scene rendering and delivery

AGENTS.md

@@ -1,2 +1,3 @@
 All code and API mappings must be cross-platform; do not use macOS-only APIs unless equivalent Linux and Windows implementations are provided.
 Gitea Actions workflows must target only `ubuntu-latest`; do not add macOS or Windows Gitea jobs.
+Crates named `libremetaverse-*` are restricted to compatibility mappings of the C# LibreMetaverse libraries. New MetaCrate-native functionality must use a `metacrate-*` crate name; the reusable wgpu renderer is `metacrate-rendering-wgpu`.

Cargo.lock

@@ -2535,6 +2535,7 @@ dependencies = [
  "libremetaverse-types",
  "mentra",
  "metacrate-lsl-tools",
+ "metacrate-rendering-wgpu",
  "rustls",
  "serde",
  "serde_json",
@@ -2544,7 +2545,6 @@ dependencies = [
  "tokio-rustls",
  "unicode-width 0.2.2",
  "url",
- "wgpu",
 ]
 
 [[package]]
@@ -2572,6 +2572,13 @@ dependencies = [
  "stats_alloc",
 ]
 
+[[package]]
+name = "metacrate-rendering-wgpu"
+version = "0.0.1"
+dependencies = [
+ "wgpu",
+]
+
 [[package]]
 name = "minimal-lexical"
 version = "0.2.1"

Cargo.toml

@@ -11,6 +11,7 @@ members = [
     "crates/libremetaverse-rendering-simple",
     "crates/libremetaverse-rendering-mesh-foundry",
     "crates/metacrate-lsl-tools",
+    "crates/metacrate-rendering-wgpu",
     "crates/libremetaverse-rlv",
     "crates/libremetaverse-utilities",
     "crates/libremetaverse-voice-vivox",
@@ -36,6 +37,7 @@ default-members = [
     "crates/libremetaverse-rendering-simple",
     "crates/libremetaverse-rendering-mesh-foundry",
     "crates/metacrate-lsl-tools",
+    "crates/metacrate-rendering-wgpu",
     "crates/libremetaverse-rlv",
     "crates/libremetaverse-utilities",
     "crates/libremetaverse-voice-vivox",

crates/libremetaverse/src/network_manager.rs

@@ -14,12 +14,15 @@
 
 use crate::interfaces::IMessage;
 use crate::packets::{
-    AgentPausePacket, AgentResumePacket, CloseCircuitPacket, CompleteAgentMovementPacket,
-    CompletePingCheckPacket, GenericStreamingMessagePacket, KickUserPacket, LogoutReplyPacket,
-    LogoutRequestPacket, Packet, PacketType, RegionHandshakePacket, RegionHandshakeReplyPacket,
-    SimStatsPacket, StartPingCheckPacket, UseCircuitCodePacket,
+    AgentPausePacket, AgentResumePacket, AgentThrottlePacket, CloseCircuitPacket,
+    CompleteAgentMovementPacket, CompletePingCheckPacket, GenericStreamingMessagePacket,
+    KickUserPacket, LogoutReplyPacket, LogoutRequestPacket, Packet, PacketType,
+    RegionHandshakePacket, RegionHandshakeReplyPacket, SimStatsPacket, StartPingCheckPacket,
+    UseCircuitCodePacket,
+};
+use crate::udp_transport::{
+    AgentThrottleSender, UDPBase, UDPPacketBuffer, UdpPacketHandler, UdpTransportConfig,
 };
-use crate::udp_transport::{UDPBase, UDPPacketBuffer, UdpPacketHandler, UdpTransportConfig};
 use crate::{
     AccountLevelBenefits, Avatar, Caps, Error, GenericStreamingMethod, GridClient, Helpers,
     LoginCredential, LoginParams, LoginProgressEventArgs, LoginResponseData, LoginStatus,
@@ -1509,17 +1512,10 @@ impl Simulator {
         patch: TerrainPatch,
         large_region: bool,
     ) -> Result<(), Error> {
-        let (width, height) = if large_region {
-            (
-                usize::try_from(self.size_x.max(16) / 16).map_err(|_| Error::Argument)?,
-                usize::try_from(self.size_y.max(16) / 16).map_err(|_| Error::Argument)?,
-            )
-        } else {
-            (16, 16)
-        };
+        let (width, height) = if large_region { (256, 256) } else { (16, 16) };
         let x = usize::try_from(patch.x).map_err(|_| Error::Argument)?;
         let y = usize::try_from(patch.y).map_err(|_| Error::Argument)?;
-        if x >= width || y >= height || width > 256 || height > 256 {
+        if x >= width || y >= height {
             return Err(Error::Argument);
         }
         let index = y
@@ -1528,6 +1524,23 @@ impl Simulator {
             .ok_or(Error::Argument)?;
         let patch_count = width.checked_mul(height).ok_or(Error::Argument)?;
         let mut terrain = write(&self.terrain);
+        if !terrain.is_empty() && terrain.len() != patch_count {
+            let previous = std::mem::take(&mut *terrain);
+            terrain.resize_with(patch_count, || TerrainPatch {
+                data: Vec::new(),
+                x: 0,
+                y: 0,
+            });
+            for old in previous.into_iter().filter(|old| !old.data.is_empty()) {
+                let (Ok(old_x), Ok(old_y)) = (usize::try_from(old.x), usize::try_from(old.y))
+                else {
+                    continue;
+                };
+                if old_x < width && old_y < height {
+                    terrain[old_y * width + old_x] = old;
+                }
+            }
+        }
         terrain.resize_with(patch_count, || TerrainPatch {
             data: Vec::new(),
             x: 0,
@@ -1622,14 +1635,21 @@ impl Simulator {
         let (Ok(x), Ok(y)) = (u32::try_from(x), u32::try_from(y)) else {
             return Ok(false);
         };
-        if x >= self.size_x || y >= self.size_y {
+        let terrain = read(&self.terrain);
+        let per_edge = if terrain.len() > 256 {
+            256
+        } else {
+            usize::try_from(self.size_x.max(16) / 16).map_err(|_| Error::Argument)?
+        };
+        if usize::try_from(x / 16).map_err(|_| Error::Argument)? >= per_edge
+            || usize::try_from(y / 16).map_err(|_| Error::Argument)?
+                >= terrain.len().div_ceil(per_edge)
+        {
             return Ok(false);
         }
-        let per_edge = usize::try_from(self.size_x.max(16) / 16).map_err(|_| Error::Argument)?;
         let patch_x = usize::try_from(x / 16).map_err(|_| Error::Argument)?;
         let patch_y = usize::try_from(y / 16).map_err(|_| Error::Argument)?;
         let point = usize::try_from((y % 16) * 16 + (x % 16)).map_err(|_| Error::Argument)?;
-        let terrain = read(&self.terrain);
         let Some(patch) = terrain.get(patch_y * per_edge + patch_x) else {
             return Ok(false);
         };
@@ -2927,6 +2947,36 @@ impl fmt::Debug for NetworkManager {
     }
 }
 
+struct NetworkAgentThrottleSender {
+    inner: Weak<NetworkManagerInner>,
+}
+
+impl AgentThrottleSender for NetworkAgentThrottleSender {
+    fn send_throttle(
+        &self,
+        throttle_bytes: &[u8],
+        simulator: Option<&Simulator>,
+    ) -> Result<(), Error> {
+        if throttle_bytes.len() != 28 {
+            return Err(Error::Argument);
+        }
+        let inner = self.inner.upgrade().ok_or(Error::InvalidOperation)?;
+        let manager = NetworkManager::native_from_inner(inner);
+        let simulator = simulator
+            .cloned()
+            .or_else(|| manager.native_current_sim())
+            .ok_or(Error::InvalidOperation)?;
+        let mut packet = AgentThrottlePacket::new_with_constructor()?;
+        packet.agent_data.agent_id = manager.native_agent_id();
+        packet.agent_data.session_id = manager.native_session_id();
+        packet.agent_data.circuit_code = manager.native_circuit_code();
+        packet.throttle.throttles = throttle_bytes.to_vec();
+        let data = packet.to_bytes_with_method()?;
+        let length = i32::try_from(data.len()).map_err(|_| Error::Argument)?;
+        simulator.native_send_packet_data(data, length, PacketType::AgentThrottle, true)
+    }
+}
+
 impl NetworkManager {
     pub(crate) fn native_from_inner(inner: Arc<NetworkManagerInner>) -> Self {
         Self {
@@ -3019,11 +3069,18 @@ impl NetworkManager {
                 }
             }),
         )?;
-        Ok(Self {
+        let manager = Self {
             login_response_data: Some(login_response),
             simulators,
             inner,
-        })
+        };
+        let mut client = manager.inner.client.clone();
+        client
+            .set_agent_throttle_sender(Arc::new(NetworkAgentThrottleSender {
+                inner: Arc::downgrade(&manager.inner),
+            }))
+            .map_err(|_| Error::InvalidOperation)?;
+        Ok(manager)
     }
 
     pub fn native_subscribe_login_progress(
@@ -4324,4 +4381,28 @@ mod tests {
             ("UpdateAgentLanguage".to_owned(), true, 11)
         );
     }
+
+    #[test]
+    fn extended_terrain_patch_is_stored_outside_the_legacy_region_extent() {
+        let client = GridClient::new().expect("client");
+        let simulator =
+            Simulator::new(client, "127.0.0.1:14002".parse().unwrap(), 12, None, None).unwrap();
+        simulator
+            .native_store_terrain_patch(
+                TerrainPatch {
+                    data: vec![27.0; 256],
+                    x: 42,
+                    y: 33,
+                },
+                true,
+            )
+            .unwrap();
+        let mut height = 0.0;
+        assert!(
+            simulator
+                .native_terrain_height_at_point(675, 538, &mut height)
+                .unwrap()
+        );
+        assert!((height - 27.0).abs() < f32::EPSILON);
+    }
 }

crates/libremetaverse/src/terrain_manager.rs

@@ -428,7 +428,7 @@ mod tests {
     }
 
     #[test]
-    fn rectangular_large_region_uses_independent_patch_dimensions() {
+    fn large_region_packets_can_extend_stale_declared_dimensions() {
         let client = GridClient::new().unwrap();
         let sim = Simulator::new(
             client,
@@ -450,16 +450,16 @@ mod tests {
         let mut height = 0.0;
         assert!(sim.terrain_height_at_point(511, 255, &mut height).unwrap());
         assert_eq!(height, 41.5);
-        assert!(
-            sim.native_store_terrain_patch(
-                TerrainPatch {
-                    data: vec![0.0; 256],
-                    x: 0,
-                    y: 16,
-                },
-                true,
-            )
-            .is_err()
-        );
+        sim.native_store_terrain_patch(
+            TerrainPatch {
+                data: vec![42.5; 256],
+                x: 0,
+                y: 16,
+            },
+            true,
+        )
+        .unwrap();
+        assert!(sim.terrain_height_at_point(0, 256, &mut height).unwrap());
+        assert_eq!(height, 42.5);
     }
 }

crates/libremetaverse/tests/network_manager.rs

@@ -9,15 +9,16 @@ use libremetaverse::messages::linden::{
     EnableSimulatorMessage, EnableSimulatorMessageSimulatorInfoBlock,
 };
 use libremetaverse::packets::{
-    CompleteAgentMovementPacket, DisableSimulatorPacket, LogoutReplyPacket,
+    AgentThrottlePacket, CompleteAgentMovementPacket, DisableSimulatorPacket, LogoutReplyPacket,
     LogoutReplyPacketInventoryDataBlock, LogoutRequestPacket, Packet, PacketAckPacket,
     PacketAckPacketPacketsBlock, PacketType, RegionHandshakePacket, RegionHandshakeReplyPacket,
     SimStatsPacket, SimStatsPacketStatBlock, StartPingCheckPacket, UseCircuitCodePacket,
 };
 use libremetaverse::{
-    CapsEventDictionary, CapsEventQueueCallback, GridClient, Helpers, HttpCapsClient,
-    InventoryItem, LoginState, LoginStatus, NetworkManager, NetworkManagerDisconnectType,
-    NetworkManagerLoginResponseCallback, PacketEventDictionary, Simulator,
+    AgentThrottle, CapsEventDictionary, CapsEventQueueCallback, GridClient, Helpers,
+    HttpCapsClient, InventoryItem, LoginState, LoginStatus, NetworkManager,
+    NetworkManagerDisconnectType, NetworkManagerLoginResponseCallback, PacketEventDictionary,
+    Simulator,
 };
 use libremetaverse_structured_data::{OSD, OSDMap, OSDParser};
 use libremetaverse_types::compat::{
@@ -417,6 +418,7 @@ enum ServerCommand {
     Disable,
     ExpectEconomy,
     Handoff,
+    ExpectThrottle,
     ExpectLogout,
     LogoutReply(Vec<UUID>),
     Stop,
@@ -431,6 +433,7 @@ enum ServerReport {
     Logout(UUID, UUID),
     Movement(u32),
     Ping(u8),
+    Throttle(u32, Vec<u8>),
 }
 
 struct FakeServer {
@@ -650,6 +653,35 @@ fn spawn_fake_server() -> FakeServer {
                         break;
                     }
                 }
+                ServerCommand::ExpectThrottle => loop {
+                    let (length, _) = socket.recv_from(&mut buffer).expect("AgentThrottle");
+                    if packet_type(&buffer[..length]) != Some(PacketType::AgentThrottle) {
+                        continue;
+                    }
+                    let mut bytes = buffer[..length].to_vec();
+                    if bytes[0] & Helpers::MSG_ZEROCODED != 0 {
+                        let mut decoded = vec![0; 8192];
+                        let decoded_length = Helpers::zero_decode(
+                            Some(&bytes),
+                            i32::try_from(bytes.len()).unwrap(),
+                            Some(&mut decoded),
+                        )
+                        .unwrap();
+                        decoded.truncate(usize::try_from(decoded_length).unwrap());
+                        decoded[0] &= !Helpers::MSG_ZEROCODED;
+                        bytes = decoded;
+                    }
+                    let mut position = 0;
+                    let packet =
+                        AgentThrottlePacket::new_with_bytes_int32(bytes, &mut position).unwrap();
+                    report_sender
+                        .send(ServerReport::Throttle(
+                            packet.agent_data.circuit_code,
+                            packet.throttle.throttles,
+                        ))
+                        .unwrap();
+                    break;
+                },
                 ServerCommand::ExpectLogout => loop {
                     let (length, _) = socket.recv_from(&mut buffer).expect("LogoutRequest");
                     if packet_type(&buffer[..length]) != Some(PacketType::LogoutRequest) {
@@ -772,6 +804,46 @@ fn assert_reuse_preserves_connected_override(
     manager.set_connected(true);
 }
 
+#[test]
+fn grid_client_throttle_sender_writes_agent_throttle_to_the_simulator() {
+    let _network_guard = network_test_guard();
+    let server = spawn_fake_server();
+    let client = GridClient::new().expect("client");
+    let mut manager = NetworkManager::new(client.clone()).expect("manager");
+    manager.set_circuit_code(0x4455_6677);
+    let simulator = manager
+        .connect_with_ip_end_point_u_int64_boolean_uri_u_int32_u_int32(
+            server.endpoint,
+            0x1234,
+            true,
+            None,
+            256,
+            256,
+        )
+        .unwrap()
+        .expect("simulator");
+    assert_eq!(
+        server.reports.recv_timeout(Duration::from_secs(1)).unwrap(),
+        ServerReport::Circuit(0x4455_6677)
+    );
+    assert_eq!(
+        server.reports.recv_timeout(Duration::from_secs(1)).unwrap(),
+        ServerReport::HandshakeReply(0x1 | 0x2 | 0x4)
+    );
+
+    let throttle = AgentThrottle::new_with_grid_client(client).unwrap();
+    server.commands.send(ServerCommand::ExpectThrottle).unwrap();
+    throttle.set_with_simulator(Some(simulator)).unwrap();
+    assert_eq!(
+        server.reports.recv_timeout(Duration::from_secs(1)).unwrap(),
+        ServerReport::Throttle(0x4455_6677, throttle.to_bytes().unwrap())
+    );
+
+    manager
+        .shutdown_with_disconnect_type(NetworkManagerDisconnectType::ClientInitiated)
+        .unwrap();
+}
+
 #[test]
 fn fake_server_drives_circuit_handshake_ping_disable_and_disconnect_reasons() {
     let _network_guard = network_test_guard();

crates/metacrate-grid-agent/Cargo.toml

@@ -17,6 +17,7 @@ libremetaverse-imaging = { version = "0.0.1", path = "../libremetaverse-imaging"
 libremetaverse-rendering-simple = { version = "0.0.1", path = "../libremetaverse-rendering-simple", optional = true }
 libremetaverse-types = { version = "0.0.1", path = "../libremetaverse-types" }
 metacrate-lsl-tools = { version = "0.0.1", path = "../metacrate-lsl-tools" }
+metacrate-rendering-wgpu = { version = "0.0.1", path = "../metacrate-rendering-wgpu" }
 mentra = { version = "0.18.3", default-features = false }
 jpeg-encoder = "0.6.1"
 rustls = { version = "0.23.43", default-features = false, features = ["aws_lc_rs", "std", "tls12"] }
@@ -28,7 +29,6 @@ tokio = { version = "1.53.1", features = ["macros", "rt", "sync", "time"] }
 tokio-rustls = { version = "0.26.4", default-features = false, features = ["aws_lc_rs", "tls12"] }
 url = "2.5.8"
 unicode-width = "0.2"
-wgpu = { version = "30.0.1", default-features = false, features = ["std", "dx12", "metal", "gles", "vulkan", "wgsl"], optional = true }
 
 [dev-dependencies]
 jpeg-decoder = { version = "0.3.2", default-features = false }
@@ -39,7 +39,7 @@ tokio = { version = "1.53.1", features = ["io-util", "net", "rt-multi-thread", "
 
 [features]
 default = []
-live-grid = ["dep:libremetaverse", "dep:libremetaverse-imaging", "dep:libremetaverse-rendering-simple", "dep:wgpu"]
+live-grid = ["dep:libremetaverse", "dep:libremetaverse-imaging", "dep:libremetaverse-rendering-simple", "metacrate-rendering-wgpu/wgpu"]
 
 [lints]
 workspace = true

crates/metacrate-grid-agent/src/backend.rs

@@ -94,6 +94,7 @@ impl OfflineGridBackend {
 #[cfg(feature = "live-grid")]
 pub struct LibremetaverseClientOwner {
     client: libremetaverse::GridClient,
+    network: libremetaverse::NetworkManager,
     agent: Arc<libremetaverse::AgentManager>,
     delivery_generation: Arc<std::sync::RwLock<Option<u64>>>,
 }
@@ -132,6 +133,7 @@ impl fmt::Debug for LibremetaverseClientOwner {
 pub struct LibremetaverseSessionBackend {
     network: libremetaverse::NetworkManager,
     agent: Arc<libremetaverse::AgentManager>,
+    throttle: libremetaverse::AgentThrottle,
     login_url: String,
     first_name: String,
     last_name: String,
@@ -168,7 +170,11 @@ impl LibremetaverseClientOwner {
             .map_err(|_| BackendError::Configuration {
                 component: "libremetaverse client defaults",
             })?;
+        // The compatibility client caches its network manager weakly. Retain the
+        // composition root before managers register packet subscriptions on it.
+        let network = client.network();
         let _grid = client.grid();
+        let _terrain = client.terrain();
         let agent = Arc::new(
             libremetaverse::AgentManager::new(Some(Arc::new(client.clone()))).map_err(|_| {
                 BackendError::Configuration {
@@ -178,6 +184,7 @@ impl LibremetaverseClientOwner {
         );
         Ok(Self {
             client,
+            network,
             agent,
             delivery_generation: Arc::new(std::sync::RwLock::new(None)),
         })
@@ -273,8 +280,12 @@ impl LibremetaverseClientOwner {
             });
         }
         Ok(LibremetaverseSessionBackend {
-            network: self.client.network(),
+            network: self.network.clone(),
             agent: Arc::clone(&self.agent),
+            throttle: libremetaverse::AgentThrottle::new_with_grid_client(self.client.clone())
+                .map_err(|_| BackendError::Configuration {
+                    component: "libremetaverse agent throttle",
+                })?,
             login_url: connection.login_url.expose_url().to_owned(),
             first_name: first_name.to_owned(),
             last_name: last_name.to_owned(),
@@ -794,30 +805,7 @@ impl crate::behavior::EmbodimentSink for LibremetaverseEmbodimentSink {
                 return Err(crate::behavior::BehaviorError::Cancelled);
             }
             self.ensure_generation(generation)?;
-            let avatar = self.agent.sim_position();
-            let forward = libremetaverse_types::Vector3::mul_with_vector3_quaternion(
-                libremetaverse_types::Vector3::unit_x(),
-                self.agent.sim_rotation(),
-            );
-            let position = libremetaverse_types::Vector3 {
-                x: avatar.x,
-                y: avatar.y,
-                z: avatar.z + 1.6,
-            };
-            let target = libremetaverse_types::Vector3 {
-                x: position.x + forward.x * 4.0,
-                y: position.y + forward.y * 4.0,
-                z: position.z + forward.z * 4.0,
-            };
-            self.agent
-                .movement
-                .camera
-                .look_at_with_vector3_vector3(position, target)
-                .and_then(|()| {
-                    self.agent
-                        .movement
-                        .set_fov_vertical_angle(60.0_f32.to_radians())
-                })
+            native_reset_camera(&self.agent)
                 .and_then(|()| self.agent.movement.send_update_with_boolean(Some(true)))
                 .map_err(|_| crate::behavior::BehaviorError::NativeOperation)
         })
@@ -847,6 +835,30 @@ fn native_position(value: libremetaverse_types::Vector3) -> crate::perception::W
     }
 }
 
+#[cfg(feature = "live-grid")]
+fn native_reset_camera(agent: &libremetaverse::AgentManager) -> Result<(), libremetaverse::Error> {
+    let avatar = agent.sim_position();
+    let forward = libremetaverse_types::Vector3::mul_with_vector3_quaternion(
+        libremetaverse_types::Vector3::unit_x(),
+        agent.sim_rotation(),
+    );
+    let position = libremetaverse_types::Vector3 {
+        x: avatar.x,
+        y: avatar.y,
+        z: avatar.z + 1.6,
+    };
+    let target = libremetaverse_types::Vector3 {
+        x: position.x + forward.x * 4.0,
+        y: position.y + forward.y * 4.0,
+        z: position.z + forward.z * 4.0,
+    };
+    agent
+        .movement
+        .camera
+        .look_at_with_vector3_vector3(position, target)?;
+    agent.movement.set_fov_vertical_angle(60.0_f32.to_radians())
+}
+
 #[cfg(feature = "live-grid")]
 fn native_inventory_metadata(
     client: &libremetaverse::GridClient,
@@ -1089,6 +1101,23 @@ impl crate::session::GridSessionBackend for LibremetaverseSessionBackend {
                         )
                     })?;
                 if logged_in {
+                    let simulator = self.network.current_sim().ok_or_else(|| {
+                        crate::session::SessionFailure::new(
+                            crate::session::SessionFailureKind::TransientTransport,
+                        )
+                    })?;
+                    self.throttle
+                        .set_with_simulator(Some(simulator))
+                        .map_err(|_| {
+                            crate::session::SessionFailure::new(
+                                crate::session::SessionFailureKind::TransientTransport,
+                            )
+                        })?;
+                    native_reset_camera(&self.agent).map_err(|_| {
+                        crate::session::SessionFailure::new(
+                            crate::session::SessionFailureKind::TransientTransport,
+                        )
+                    })?;
                     break;
                 }
                 let error_key = self.network.native_login_error_key();

crates/metacrate-grid-agent/src/vision_tests.rs

@@ -35,9 +35,76 @@ fn uuid(value: u32) -> UUID {
 fn triangle(z: f32, color: [u8; 4]) -> SceneTriangle {
     SceneTriangle {
         vertices: [[-1.0, -1.0, z], [1.0, -1.0, z], [0.0, 1.0, z]],
-        color_srgb: color,
+        colors_srgb: [color; 3],
     }
 }
+
+#[cfg(feature = "live-grid")]
+#[test]
+fn extended_terrain_layout_uses_received_patch_coordinates() {
+    let mut terrain = (0..65_536)
+        .map(|_| libremetaverse::TerrainPatch {
+            data: Vec::new(),
+            x: 0,
+            y: 0,
+        })
+        .collect::<Vec<_>>();
+    terrain[33 * 256 + 42] = libremetaverse::TerrainPatch {
+        data: vec![20.0; 256],
+        x: 42,
+        y: 33,
+    };
+    assert_eq!(terrain_layout(&terrain, (256.0, 256.0)), (688, 544, 256));
+    assert_eq!(terrain_height(&terrain, 256, 675, 538), Some(20.0));
+}
+
+#[cfg(feature = "live-grid")]
+#[test]
+fn renderer_uses_the_camera_axis_that_points_at_the_requested_target() {
+    let camera = libremetaverse::AgentManagerAgentMovementAgentCamera::new().unwrap();
+    camera
+        .look_at_with_vector3_vector3(
+            libremetaverse_types::Vector3::zero(),
+            libremetaverse_types::Vector3::unit_y(),
+        )
+        .unwrap();
+    assert_eq!(
+        native_camera_forward(&camera),
+        libremetaverse_types::Vector3::unit_y()
+    );
+}
+
+#[cfg(feature = "live-grid")]
+#[test]
+fn scene_faces_are_shaded_without_changing_alpha() {
+    let shade = triangle_shade([[0.0, 0.0, 0.0], [1.0, 0.0, 0.0], [0.0, 1.0, 0.0]]);
+    let color = shade_color([200, 160, 120, 77], shade);
+    assert!(color[0] < 200);
+    assert_eq!(color[3], 77);
+}
+
+#[cfg(feature = "live-grid")]
+#[test]
+fn scene_broad_phase_rejects_object_centers_behind_the_camera() {
+    assert!(scene_center_in_front(
+        libremetaverse_types::Vector3 {
+            x: 4.0,
+            y: 0.0,
+            z: 0.0
+        },
+        [0.0; 3],
+        [1.0, 0.0, 0.0]
+    ));
+    assert!(!scene_center_in_front(
+        libremetaverse_types::Vector3 {
+            x: -4.0,
+            y: 0.0,
+            z: 0.0
+        },
+        [0.0; 3],
+        [1.0, 0.0, 0.0]
+    ));
+}
 fn scene() -> SceneSnapshot {
     SceneSnapshot {
         generation: 7,
@@ -123,7 +190,7 @@ async fn golden_scene_is_deterministic_depth_ordered_and_privacy_marked() {
 #[cfg(feature = "live-grid")]
 #[tokio::test(flavor = "multi_thread")]
 async fn offscreen_wgpu_renders_depth_ordered_scene_when_an_adapter_is_available() {
-    let Ok(renderer) = WgpuRenderer::new().await else {
+    let Ok(renderer) = metacrate_rendering_wgpu::Renderer::new().await else {
         return;
     };
     let limits = VisionLimits {
@@ -132,10 +199,28 @@ async fn offscreen_wgpu_renders_depth_ordered_scene_when_an_adapter_is_available
         minimum_interval: std::time::Duration::ZERO,
         ..VisionLimits::default()
     };
-    let rgba = tokio::task::spawn_blocking(move || renderer.render(&scene(), limits))
-        .await
-        .expect("render worker")
-        .expect("offscreen render");
+    let scene = scene();
+    let triangles = scene
+        .entities
+        .iter()
+        .flat_map(|entity| entity.triangles.iter().cloned())
+        .collect::<Vec<_>>();
+    let rgba = tokio::task::spawn_blocking(move || {
+        renderer.render(
+            scene.camera,
+            &triangles,
+            [72, 96, 120, 255],
+            metacrate_rendering_wgpu::RenderLimits {
+                width: limits.width,
+                height: limits.height,
+                max_triangles: limits.max_triangles,
+                far_distance: 512,
+            },
+        )
+    })
+    .await
+    .expect("render worker")
+    .expect("offscreen render");
     assert_eq!(rgba.len(), 64 * 64 * 4);
     let center = (32 * 64 + 32) * 4;
     assert!(rgba[center + 1] > 180 && rgba[center] < 80 && rgba[center + 2] < 80);

crates/metacrate-grid-agent/tests/dependency_policy.rs

@@ -10,6 +10,7 @@ const ALLOWED_DEPENDENCIES: [&str; 20] = [
     "libremetaverse-imaging",
     "libremetaverse-rendering-simple",
     "metacrate-lsl-tools",
+    "metacrate-rendering-wgpu",
     "mentra",
     "jpeg-encoder",
     "libremetaverse-types",
@@ -22,7 +23,6 @@ const ALLOWED_DEPENDENCIES: [&str; 20] = [
     "tokio-rustls",
     "url",
     "unicode-width",
-    "wgpu",
 ];
 
 #[test]
@@ -101,7 +101,10 @@ fn vision_path_selects_only_reviewed_rust_renderers_and_codec() {
         .expect("simple renderer manifest");
     assert!(!renderer.contains("imaging-skia"));
     assert!(!renderer.contains("openjpeg"));
-    assert!(manifest.contains("wgpu = { version = \"30.0.1\""));
+    assert!(manifest.contains("metacrate-rendering-wgpu ="));
+    let renderer = fs::read_to_string(root.join("../metacrate-rendering-wgpu/Cargo.toml"))
+        .expect("wgpu renderer manifest");
+    assert!(renderer.contains("wgpu = { version = \"30.0.1\""));
 }
 
 #[test]

crates/metacrate-rendering-wgpu/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "metacrate-rendering-wgpu"
+version.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+license.workspace = true
+repository.workspace = true
+description = "Reusable headless wgpu scene renderer and projection camera"
+publish = false
+
+[dependencies]
+wgpu = { version = "30.0.1", default-features = false, features = ["std", "dx12", "metal", "gles", "vulkan", "wgsl"], optional = true }
+
+[features]
+default = []
+wgpu = ["dep:wgpu"]
+
+[lints]
+workspace = true

crates/metacrate-rendering-wgpu/src/lib.rs

@@ -0,0 +1,426 @@
+//! Cross-platform projection camera and headless `wgpu` triangle renderer.
+
+#![allow(clippy::missing_errors_doc)]
+
+type CameraBasis = ([f32; 3], [f32; 3], [f32; 3]);
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct Camera {
+    pub position: [f32; 3],
+    pub forward: [f32; 3],
+    pub up: [f32; 3],
+    pub vertical_fov_degrees: f32,
+}
+
+impl Camera {
+    pub fn look_at(
+        position: [f32; 3],
+        target: [f32; 3],
+        up: [f32; 3],
+        vertical_fov_degrees: f32,
+    ) -> Result<Self, RenderError> {
+        let forward = normalize([
+            target[0] - position[0],
+            target[1] - position[1],
+            target[2] - position[2],
+        ])?;
+        let camera = Self {
+            position,
+            forward,
+            up: normalize(up)?,
+            vertical_fov_degrees,
+        };
+        camera.basis()?;
+        Ok(camera)
+    }
+
+    fn basis(self) -> Result<CameraBasis, RenderError> {
+        if !(10.0..=140.0).contains(&self.vertical_fov_degrees)
+            || self
+                .position
+                .iter()
+                .chain(self.forward.iter())
+                .chain(self.up.iter())
+                .any(|value| !value.is_finite())
+        {
+            return Err(RenderError::InvalidScene);
+        }
+        let forward = normalize(self.forward)?;
+        let right = normalize(cross(forward, self.up))?;
+        Ok((right, cross(right, forward), forward))
+    }
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct Triangle {
+    pub vertices: [[f32; 3]; 3],
+    pub colors_srgb: [[u8; 4]; 3],
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub struct RenderLimits {
+    pub width: u32,
+    pub height: u32,
+    pub max_triangles: usize,
+    pub far_distance: u32,
+}
+
+#[derive(Clone, Copy, Debug, Eq, PartialEq)]
+pub enum RenderError {
+    AdapterUnavailable,
+    InvalidScene,
+    ResourceLimit,
+    TimedOut,
+    Readback,
+}
+
+impl std::fmt::Display for RenderError {
+    fn fmt(&self, formatter: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        formatter.write_str(match self {
+            Self::AdapterUnavailable => "wgpu adapter is unavailable",
+            Self::InvalidScene => "render scene is invalid",
+            Self::ResourceLimit => "render resource limit exceeded",
+            Self::TimedOut => "wgpu render timed out",
+            Self::Readback => "wgpu readback failed",
+        })
+    }
+}
+
+impl std::error::Error for RenderError {}
+
+fn normalize(value: [f32; 3]) -> Result<[f32; 3], RenderError> {
+    let length = dot(value, value).sqrt();
+    if length < 0.0001 {
+        return Err(RenderError::InvalidScene);
+    }
+    Ok([value[0] / length, value[1] / length, value[2] / length])
+}
+
+fn dot(left: [f32; 3], right: [f32; 3]) -> f32 {
+    left[0] * right[0] + left[1] * right[1] + left[2] * right[2]
+}
+
+fn cross(left: [f32; 3], right: [f32; 3]) -> [f32; 3] {
+    [
+        left[1] * right[2] - left[2] * right[1],
+        left[2] * right[0] - left[0] * right[2],
+        left[0] * right[1] - left[1] * right[0],
+    ]
+}
+
+#[cfg(feature = "wgpu")]
+pub struct Renderer {
+    device: wgpu::Device,
+    queue: wgpu::Queue,
+    pipeline: wgpu::RenderPipeline,
+}
+
+#[cfg(feature = "wgpu")]
+const VERTEX_ATTRIBUTES: [wgpu::VertexAttribute; 2] =
+    wgpu::vertex_attr_array![0 => Float32x3, 1 => Float32x4];
+
+#[cfg(feature = "wgpu")]
+impl Renderer {
+    pub async fn new() -> Result<Self, RenderError> {
+        let instance = wgpu::Instance::new(wgpu::InstanceDescriptor::new_without_display_handle());
+        let adapter = instance
+            .request_adapter(&wgpu::RequestAdapterOptions {
+                power_preference: wgpu::PowerPreference::LowPower,
+                ..Default::default()
+            })
+            .await
+            .map_err(|_| RenderError::AdapterUnavailable)?;
+        let (device, queue) = adapter
+            .request_device(&wgpu::DeviceDescriptor {
+                label: Some("metacrate-rendering-wgpu"),
+                required_features: wgpu::Features::empty(),
+                required_limits: wgpu::Limits::downlevel_defaults(),
+                memory_hints: wgpu::MemoryHints::MemoryUsage,
+                ..Default::default()
+            })
+            .await
+            .map_err(|_| RenderError::AdapterUnavailable)?;
+        let shader = device.create_shader_module(wgpu::ShaderModuleDescriptor {
+            label: Some("metacrate-rendering-wgpu-shader"),
+            source: wgpu::ShaderSource::Wgsl(
+                r"
+struct VertexInput { @location(0) position: vec3<f32>, @location(1) color: vec4<f32>, };
+struct VertexOutput { @builtin(position) position: vec4<f32>, @location(0) color: vec4<f32>, };
+@vertex fn vs_main(input: VertexInput) -> VertexOutput {
+    var output: VertexOutput;
+    output.position = vec4<f32>(input.position, 1.0);
+    output.color = input.color;
+    return output;
+}
+@fragment fn fs_main(input: VertexOutput) -> @location(0) vec4<f32> { return input.color; }
+"
+                .into(),
+            ),
+        });
+        let layout = device.create_pipeline_layout(&wgpu::PipelineLayoutDescriptor {
+            label: Some("metacrate-rendering-wgpu-layout"),
+            bind_group_layouts: &[],
+            immediate_size: 0,
+        });
+        let pipeline = device.create_render_pipeline(&wgpu::RenderPipelineDescriptor {
+            label: Some("metacrate-rendering-wgpu-pipeline"),
+            layout: Some(&layout),
+            vertex: wgpu::VertexState {
+                module: &shader,
+                entry_point: Some("vs_main"),
+                compilation_options: wgpu::PipelineCompilationOptions::default(),
+                buffers: &[Some(wgpu::VertexBufferLayout {
+                    array_stride: 7 * std::mem::size_of::<f32>() as u64,
+                    step_mode: wgpu::VertexStepMode::Vertex,
+                    attributes: &VERTEX_ATTRIBUTES,
+                })],
+            },
+            primitive: wgpu::PrimitiveState {
+                topology: wgpu::PrimitiveTopology::TriangleList,
+                cull_mode: None,
+                ..Default::default()
+            },
+            depth_stencil: Some(wgpu::DepthStencilState {
+                format: wgpu::TextureFormat::Depth32Float,
+                depth_write_enabled: Some(true),
+                depth_compare: Some(wgpu::CompareFunction::Less),
+                stencil: wgpu::StencilState::default(),
+                bias: wgpu::DepthBiasState::default(),
+            }),
+            multisample: wgpu::MultisampleState::default(),
+            fragment: Some(wgpu::FragmentState {
+                module: &shader,
+                entry_point: Some("fs_main"),
+                compilation_options: wgpu::PipelineCompilationOptions::default(),
+                targets: &[Some(wgpu::ColorTargetState {
+                    format: wgpu::TextureFormat::Rgba8UnormSrgb,
+                    blend: None,
+                    write_mask: wgpu::ColorWrites::ALL,
+                })],
+            }),
+            multiview_mask: None,
+            cache: None,
+        });
+        Ok(Self {
+            device,
+            queue,
+            pipeline,
+        })
+    }
+
+    #[allow(clippy::too_many_lines)]
+    pub fn render(
+        &self,
+        camera: Camera,
+        triangles: &[Triangle],
+        background_srgb: [u8; 4],
+        limits: RenderLimits,
+    ) -> Result<Vec<u8>, RenderError> {
+        let (vertices, vertex_count) = gpu_vertices(camera, triangles, limits)?;
+        let vertex_buffer = self.device.create_buffer(&wgpu::BufferDescriptor {
+            label: Some("metacrate-rendering-wgpu-vertices"),
+            size: vertices.len().max(4) as u64,
+            usage: wgpu::BufferUsages::VERTEX | wgpu::BufferUsages::COPY_DST,
+            mapped_at_creation: false,
+        });
+        if !vertices.is_empty() {
+            self.queue.write_buffer(&vertex_buffer, 0, &vertices);
+        }
+        let extent = wgpu::Extent3d {
+            width: limits.width,
+            height: limits.height,
+            depth_or_array_layers: 1,
+        };
+        let color = self.device.create_texture(&wgpu::TextureDescriptor {
+            label: Some("metacrate-rendering-wgpu-color"),
+            size: extent,
+            mip_level_count: 1,
+            sample_count: 1,
+            dimension: wgpu::TextureDimension::D2,
+            format: wgpu::TextureFormat::Rgba8UnormSrgb,
+            usage: wgpu::TextureUsages::RENDER_ATTACHMENT | wgpu::TextureUsages::COPY_SRC,
+            view_formats: &[],
+        });
+        let depth = self.device.create_texture(&wgpu::TextureDescriptor {
+            label: Some("metacrate-rendering-wgpu-depth"),
+            size: extent,
+            mip_level_count: 1,
+            sample_count: 1,
+            dimension: wgpu::TextureDimension::D2,
+            format: wgpu::TextureFormat::Depth32Float,
+            usage: wgpu::TextureUsages::RENDER_ATTACHMENT,
+            view_formats: &[],
+        });
+        let row_bytes = limits
+            .width
+            .checked_mul(4)
+            .ok_or(RenderError::ResourceLimit)?;
+        let padded_row_bytes = row_bytes.div_ceil(wgpu::COPY_BYTES_PER_ROW_ALIGNMENT)
+            * wgpu::COPY_BYTES_PER_ROW_ALIGNMENT;
+        let readback = self.device.create_buffer(&wgpu::BufferDescriptor {
+            label: Some("metacrate-rendering-wgpu-readback"),
+            size: u64::from(padded_row_bytes)
+                .checked_mul(u64::from(limits.height))
+                .ok_or(RenderError::ResourceLimit)?,
+            usage: wgpu::BufferUsages::COPY_DST | wgpu::BufferUsages::MAP_READ,
+            mapped_at_creation: false,
+        });
+        let color_view = color.create_view(&wgpu::TextureViewDescriptor::default());
+        let depth_view = depth.create_view(&wgpu::TextureViewDescriptor::default());
+        let mut encoder = self
+            .device
+            .create_command_encoder(&wgpu::CommandEncoderDescriptor {
+                label: Some("metacrate-rendering-wgpu-commands"),
+            });
+        {
+            let mut pass = encoder.begin_render_pass(&wgpu::RenderPassDescriptor {
+                label: Some("metacrate-rendering-wgpu-pass"),
+                color_attachments: &[Some(wgpu::RenderPassColorAttachment {
+                    view: &color_view,
+                    depth_slice: None,
+                    resolve_target: None,
+                    ops: wgpu::Operations {
+                        load: wgpu::LoadOp::Clear(wgpu::Color {
+                            r: f64::from(background_srgb[0]) / 255.0,
+                            g: f64::from(background_srgb[1]) / 255.0,
+                            b: f64::from(background_srgb[2]) / 255.0,
+                            a: f64::from(background_srgb[3]) / 255.0,
+                        }),
+                        store: wgpu::StoreOp::Store,
+                    },
+                })],
+                depth_stencil_attachment: Some(wgpu::RenderPassDepthStencilAttachment {
+                    view: &depth_view,
+                    depth_ops: Some(wgpu::Operations {
+                        load: wgpu::LoadOp::Clear(1.0),
+                        store: wgpu::StoreOp::Discard,
+                    }),
+                    stencil_ops: None,
+                }),
+                ..Default::default()
+            });
+            if vertex_count != 0 {
+                pass.set_pipeline(&self.pipeline);
+                pass.set_vertex_buffer(0, vertex_buffer.slice(..));
+                pass.draw(0..vertex_count, 0..1);
+            }
+        }
+        encoder.copy_texture_to_buffer(
+            wgpu::TexelCopyTextureInfo {
+                texture: &color,
+                mip_level: 0,
+                origin: wgpu::Origin3d::ZERO,
+                aspect: wgpu::TextureAspect::All,
+            },
+            wgpu::TexelCopyBufferInfo {
+                buffer: &readback,
+                layout: wgpu::TexelCopyBufferLayout {
+                    offset: 0,
+                    bytes_per_row: Some(padded_row_bytes),
+                    rows_per_image: Some(limits.height),
+                },
+            },
+            extent,
+        );
+        let submission = self.queue.submit([encoder.finish()]);
+        let slice = readback.slice(..);
+        let (sender, receiver) = std::sync::mpsc::sync_channel(1);
+        slice.map_async(wgpu::MapMode::Read, move |result| {
+            let _ = sender.send(result);
+        });
+        self.device
+            .poll(wgpu::PollType::Wait {
+                submission_index: Some(submission),
+                timeout: Some(std::time::Duration::from_secs(5)),
+            })
+            .map_err(|_| RenderError::TimedOut)?;
+        receiver
+            .recv_timeout(std::time::Duration::from_secs(1))
+            .map_err(|_| RenderError::TimedOut)?
+            .map_err(|_| RenderError::Readback)?;
+        let mapped = slice
+            .get_mapped_range()
+            .map_err(|_| RenderError::Readback)?;
+        let mut rgba = Vec::with_capacity(row_bytes as usize * limits.height as usize);
+        for row in mapped
+            .chunks_exact(padded_row_bytes as usize)
+            .take(limits.height as usize)
+        {
+            rgba.extend_from_slice(&row[..row_bytes as usize]);
+        }
+        drop(mapped);
+        readback.unmap();
+        Ok(rgba)
+    }
+}
+
+#[cfg(feature = "wgpu")]
+#[allow(clippy::cast_precision_loss)] // Render dimensions and distance are bounded well below f32's exact integer range.
+fn gpu_vertices(
+    camera: Camera,
+    triangles: &[Triangle],
+    limits: RenderLimits,
+) -> Result<(Vec<u8>, u32), RenderError> {
+    if limits.width == 0
+        || limits.height == 0
+        || limits.far_distance == 0
+        || triangles.len() > limits.max_triangles
+        || triangles
+            .iter()
+            .flat_map(|triangle| triangle.vertices.iter().flatten())
+            .any(|value| !value.is_finite())
+    {
+        return Err(RenderError::InvalidScene);
+    }
+    let basis = camera.basis()?;
+    let aspect = limits.width as f32 / limits.height as f32;
+    let focal = 1.0 / (camera.vertical_fov_degrees.to_radians() / 2.0).tan();
+    let mut bytes = Vec::with_capacity(triangles.len() * 3 * 7 * std::mem::size_of::<f32>());
+    let mut count = 0u32;
+    for triangle in triangles {
+        let projected = triangle.vertices.map(|world| {
+            let delta = [
+                world[0] - camera.position[0],
+                world[1] - camera.position[1],
+                world[2] - camera.position[2],
+            ];
+            let z = dot(delta, basis.2);
+            [
+                dot(delta, basis.0) * focal / aspect / z,
+                dot(delta, basis.1) * focal / z,
+                (z / limits.far_distance as f32).clamp(0.0, 1.0),
+                z,
+            ]
+        });
+        if projected.iter().any(|vertex| vertex[3] <= 0.05) {
+            continue;
+        }
+        for (vertex, color) in projected.into_iter().zip(triangle.colors_srgb) {
+            let color = color.map(|channel| f32::from(channel) / 255.0);
+            for value in vertex[..3].iter().chain(color.iter()) {
+                bytes.extend_from_slice(&value.to_ne_bytes());
+            }
+            count = count.checked_add(1).ok_or(RenderError::ResourceLimit)?;
+        }
+    }
+    Ok((bytes, count))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn look_at_builds_a_valid_projection_camera() {
+        let camera =
+            Camera::look_at([1.0, 2.0, 3.0], [5.0, 2.0, 3.0], [0.0, 0.0, 1.0], 60.0).unwrap();
+        assert!(
+            camera
+                .forward
+                .into_iter()
+                .zip([1.0, 0.0, 0.0])
+                .all(|(actual, expected)| (actual - expected).abs() < f32::EPSILON)
+        );
+        assert!(Camera::look_at([0.0; 3], [0.0; 3], [0.0, 0.0, 1.0], 60.0).is_err());
+    }
+}

programs/src/test_client.rs

@@ -39,7 +39,7 @@ const MAX_INPUT_LINES: usize = 4096;
 const MAX_CLIENTS: usize = 64;
 const MAX_COMMAND_BYTES: usize = 4096;
 const MAX_MESSAGE_BYTES: usize = 1023;
-const EVENT_QUEUE_CAPACITY: usize = 512;
+const EVENT_QUEUE_CAPACITY: usize = 16_384;
 const MAX_PACKET_LOG_COUNT: usize = 10_000;
 const MAX_PACKET_LOG_BYTES: u64 = 16 * 1024 * 1024;
 const MAX_LOADED_COMMANDS: usize = 128;