Merge branch 'sharp/map-colors' into sharp/small-fixes

Cargo.lock

@@ -4896,11 +4896,13 @@ dependencies = [
  "hashbrown",
  "image",
  "log 0.4.8",
+ "num 0.2.1",
  "num_cpus",
  "specs",
  "uvth",
  "vek 0.10.0",
  "veloren-common",
+ "veloren-world",
 ]
 
 [[package]]

client/Cargo.toml

@@ -6,10 +6,12 @@ edition = "2018"
 
 [dependencies]
 common = { package = "veloren-common", path = "../common", features = ["no-assets"] }
+world = { package = "veloren-world", path = "../world" }
 
 byteorder = "1.3.2"
 uvth = "3.1.1"
 image = "0.22.3"
+num = "0.2.0"
 num_cpus = "1.10.1"
 log = "0.4.8"
 specs = "0.15.1"

client/src/lib.rs

@@ -30,9 +30,13 @@ use common::{
     vol::RectVolSize,
     ChatType,
 };
+// TODO: remove CONFIG dependency by passing CONFIG.sea_level explicitly.
+// In general any WORLD dependencies need to go away ASAP... we should see if we
+// can pull out map drawing into common somehow.
 use hashbrown::HashMap;
 use image::DynamicImage;
 use log::{error, warn};
+use num::traits::FloatConst;
 use std::{
     net::SocketAddr,
     sync::Arc,
@@ -40,6 +44,10 @@ use std::{
 };
 use uvth::{ThreadPool, ThreadPoolBuilder};
 use vek::*;
+use world::{
+    sim::{neighbors, Alt},
+    CONFIG,
+};
 
 // The duration of network inactivity until the player is kicked
 // @TODO: in the future, this should be configurable on the server
@@ -95,7 +103,7 @@ impl Client {
                 entity_package,
                 server_info,
                 time_of_day,
-                world_map: (map_size, world_map),
+                world_map,
             } => {
                 // TODO: Display that versions don't match in Voxygen
                 if server_info.git_hash != common::util::GIT_HASH.to_string() {
@@ -121,10 +129,98 @@ impl Client {
                 let entity = state.ecs_mut().apply_entity_package(entity_package);
                 *state.ecs_mut().write_resource() = time_of_day;
 
-                assert_eq!(world_map.len(), (map_size.x * map_size.y) as usize);
+                let map_size = world_map.dimensions;
+                let max_height = world_map.max_height;
+                let rgba = world_map.rgba;
+                assert_eq!(rgba.len(), (map_size.x * map_size.y) as usize);
+                let [west, east] = world_map.horizons;
+                let scale_angle =
+                    |a: u8| (a as Alt / 255.0 / <Alt as FloatConst>::FRAC_2_PI()).tan();
+                let scale_height =
+                    |h: u8| h as Alt * max_height as Alt / 255.0 + CONFIG.sea_level as Alt;
+
+                log::debug!("Preparing image...");
+                let unzip_horizons = |(angles, heights): (Vec<_>, Vec<_>)| {
+                    (
+                        angles.into_iter().map(scale_angle).collect::<Vec<_>>(),
+                        heights.into_iter().map(scale_height).collect::<Vec<_>>(),
+                    )
+                };
+                let horizons = [unzip_horizons(west), unzip_horizons(east)];
+
+                // Redraw map (with shadows this time).
+                let mut world_map = vec![0u32; rgba.len()];
+                let mut map_config = world::sim::MapConfig::default();
+                map_config.lgain = 1.0;
+                map_config.gain = max_height;
+                map_config.horizons = Some(&horizons);
+                let rescale_height =
+                    |h: Alt| (h as f32 - map_config.focus.z as f32) / map_config.gain as f32;
+                let bounds_check = |pos: Vec2<i32>| {
+                    pos.reduce_partial_min() >= 0
+                        && pos.x < map_size.x as i32
+                        && pos.y < map_size.y as i32
+                };
+                map_config.generate(
+                    |pos| {
+                        let (rgba, downhill_wpos) = if bounds_check(pos) {
+                            let posi = pos.y as usize * map_size.x as usize + pos.x as usize;
+                            let [r, g, b, a] = rgba[posi].to_le_bytes();
+                            // Compute downhill.
+                            let downhill = {
+                                let mut best = -1;
+                                let mut besth = a;
+                                // TODO: Fix to work for dynamic WORLD_SIZE (i.e. map_size).
+                                for nposi in neighbors(posi) {
+                                    let nbh = rgba[nposi].to_le_bytes()[3];
+                                    if nbh < besth {
+                                        besth = nbh;
+                                        best = nposi as isize;
+                                    }
+                                }
+                                best
+                            };
+                            let downhill_wpos = if downhill < 0 {
+                                None
+                            } else {
+                                Some(
+                                    Vec2::new(
+                                        (downhill as usize % map_size.x as usize) as i32,
+                                        (downhill as usize / map_size.x as usize) as i32,
+                                    ) * TerrainChunkSize::RECT_SIZE.map(|e| e as i32),
+                                )
+                            };
+                            (Rgba::new(r, g, b, a), downhill_wpos)
+                        } else {
+                            (Rgba::zero(), None)
+                        };
+                        let wpos = pos * TerrainChunkSize::RECT_SIZE.map(|e| e as i32);
+                        let downhill_wpos = downhill_wpos
+                            .unwrap_or(wpos + TerrainChunkSize::RECT_SIZE.map(|e| e as i32));
+                        let alt = rescale_height(scale_height(rgba.a));
+                        world::sim::MapSample {
+                            rgb: Rgb::from(rgba),
+                            alt: alt as Alt,
+                            downhill_wpos,
+                            connections: None,
+                        }
+                    },
+                    |wpos| {
+                        let pos = wpos.map2(TerrainChunkSize::RECT_SIZE, |e, f| e / f as i32);
+                        rescale_height(if bounds_check(pos) {
+                            let posi = pos.y as usize * map_size.x as usize + pos.x as usize;
+                            scale_height(rgba[posi].to_le_bytes()[3])
+                        } else {
+                            CONFIG.sea_level as Alt
+                        })
+                    },
+                    |pos, (r, g, b, a)| {
+                        world_map[pos.y * map_size.x as usize + pos.x] =
+                            u32::from_le_bytes([r, g, b, a]);
+                    },
+                );
                 let mut world_map_raw = vec![0u8; 4 * world_map.len()/*map_size.x * map_size.y*/];
                 LittleEndian::write_u32_into(&world_map, &mut world_map_raw);
-                log::debug!("Preparing image...");
                 let world_map = Arc::new(
                     image::DynamicImage::ImageRgba8({
                         // Should not fail if the dimensions are correct.

common/src/msg/server.rs

@@ -25,13 +25,125 @@ pub enum PlayerListUpdate {
     Alias(u64, String),
 }
 
+#[derive(Debug, Clone, Serialize, Deserialize)]
+/// World map information.  Note that currently, we always send the whole thing
+/// in one go, but the structure aims to try to provide information as locally
+/// as possible, so that in the future we can split up large maps into multiple
+/// WorldMapMsg fragments.
+///
+/// TODO: Update message format to make fragmentable, allowing us to send more
+/// information without running into bandwidth issues.
+///
+/// TODO: Add information for rivers (currently, we just prerender them on the
+/// server, but this is not a great solution for LoD.  The map rendering code is
+/// already set up to be able to take advantage of the rivrer rendering being
+/// split out, but the format is a little complicated for space reasons and it
+/// may take some tweaking to get right, so we avoid sending it for now).
+///
+/// TODO: measure explicit compression schemes that might save space, e.g.
+/// repeating the "small angles" optimization that works well on more detailed
+/// shadow maps intended for height maps.
+pub struct WorldMapMsg {
+    /// World map dimensions (width × height)
+    pub dimensions: Vec2<u32>,
+    /// Max height (used to scale altitudes).
+    pub max_height: f32,
+    /// RGB+A; the alpha channel is currently a proxy for altitude.
+    /// Entries are in the usual chunk order.
+    pub rgba: Vec<u32>,
+    /// Horizon mapping.  This is a variant of shadow mapping that is
+    /// specifically designed for height maps; it takes advantage of their
+    /// regular structure (e.g. no holes) to compress all information needed
+    /// to decide when to cast a sharp shadow into a single nagle, the "horizon
+    /// angle."  This is the smallest angle with the ground at which light can
+    /// pass through any occluders to reach the chunk, in some chosen
+    /// horizontal direction.  This would not be sufficient for a more
+    /// complicated 3D structure, but it works for height maps since:
+    ///
+    /// 1. they have no gaps, so as soon as light can shine through it will
+    /// always be able to do    so, and
+    /// 2. we only care about lighting from the top, and only from the east and
+    /// west    (since at a large scale like this we mostly just want to
+    /// handle variable sunlight;    moonlight would present more challenges
+    /// but we currently have no plans to try to cast    accurate shadows in
+    /// moonlight).
+    ///
+    /// Our chosen format is two pairs of vectors,
+    /// with the first pair representing west-facing light (casting shadows on
+    /// the left side)  and the second representing east-facing light
+    /// (casting shadows on the east side).
+    ///
+    /// The pair of vectors consists of (with each vector in the usual chunk
+    /// order):
+    ///
+    /// * Horizon angle pointing east (1 byte, scaled so 1 unit = 255° / 360).
+    ///   We might consider switching to tangent if that represents the
+    ///   information we care about better.
+    /// * Approximate (floor) height of maximal occluder. We currently use this
+    ///   to try to deliver some approximation of soft shadows, which isn't that
+    ///   big a deal on the world map but is probably needed in order to ensure
+    ///   smooth transitions between chunks in LoD view.  Additionally, when we
+    ///   start using the shadow information to do local lighting on the world
+    ///   map, we'll want a quick way to test where we can go out of shadoow at
+    ///   arbitrary heights (since the player and other entities cajn find
+    ///   themselves far from the ground at times).  While this is only an
+    ///   approximation to a proper distance map, hopefully it will give us
+    ///   something  that feels reasonable enough for Veloren's style.
+    ///
+    /// NOTE: On compression.
+    ///
+    /// Horizon mapping has a lot of advantages for height maps (simple, easy to
+    /// understand, doesn't require any fancy math or approximation beyond
+    /// precision loss), though it loses a few of them by having to store
+    /// distance to occluder as well.  However, just storing tons
+    /// and tons of regular shadow maps (153 for a full day cycle, stored at
+    /// irregular intervals) combined with clever explicit compression and
+    /// avoiding recording sharp local shadows (preferring retracing for
+    /// these), yielded a compression rate of under 3 bits per column! Since
+    /// we likely want to avoid per-column shadows for worlds of the sizes we
+    /// want, we'd still need to store *some* extra information to create
+    /// soft shadows, but it would still be nice to try to drive down our
+    /// size as much as possible given how compressible shadows of height
+    /// maps seem to be in practice.  Therefore, we try to take advantage of the
+    /// way existing compression algorithms tend to work to see if we can
+    /// achieve significant gains without doing a lot of custom work.
+    ///
+    /// Specifically, since our rays are cast east/west, we expect that for each
+    /// row, the horizon angles in each direction should be sequences of
+    /// monotonically increasing values (as chunks approach a tall
+    /// occluder), followed by sequences of no shadow, repeated
+    /// until the end of the map.  Monotonic sequences and same-byte sequences
+    /// are usually easy to compress and existing algorithms are more likely
+    /// to be able to deal with them than jumbled data.  If we were to keep
+    /// both directions in the same vector, off-the-shelf compression would
+    /// probably be less effective.
+    ///
+    /// For related reasons, rather than storing distances as in a standard
+    /// distance map (which would lead to monotonically *decreaing* values
+    /// as we approached the occluder from a given direction), we store the
+    /// estimated *occluder height.*  The idea here is that we replace the
+    /// monotonic sequences with constant sequences, which are extremely
+    /// straightforward to compress and mostly handled automatically by anything
+    /// that does run-length encoding (i.e. most off-the-shelf compression
+    /// algorithms).
+    ///
+    /// We still need to benchmark this properly, as there's no guarantee our
+    /// current compression algorithms will actually work well on this data
+    /// in practice.  It's possible that some other permutation (e.g. more
+    /// bits reserved for "distance to occluder" in exchange for an even
+    /// more predictible sequence) would end up compressing better than storing
+    /// angles, or that we don't need as much precision as we currently have
+    /// (256 possible angles).
+    pub horizons: [(Vec<u8>, Vec<u8>); 2],
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 pub enum ServerMsg {
     InitialSync {
         entity_package: sync::EntityPackage<EcsCompPacket>,
         server_info: ServerInfo,
         time_of_day: state::TimeOfDay,
-        world_map: (Vec2<u32>, Vec<u32>),
+        world_map: WorldMapMsg,
     },
     PlayerListUpdate(PlayerListUpdate),
     StateAnswer(Result<ClientState, (RequestStateError, ClientState)>),

server/src/lib.rs

@@ -28,7 +28,7 @@ use crate::{
 use common::{
     comp,
     event::{EventBus, ServerEvent},
-    msg::{ClientMsg, ClientState, ServerInfo, ServerMsg},
+    msg::{server::WorldMapMsg, ClientMsg, ClientState, ServerInfo, ServerMsg},
     net::PostOffice,
     state::{State, TimeOfDay},
     sync::WorldSyncExt,
@@ -66,7 +66,7 @@ pub struct Tick(u64);
 pub struct Server {
     state: State,
     world: Arc<World>,
-    map: Vec<u32>,
+    map: WorldMapMsg,
 
     postoffice: PostOffice<ServerMsg, ClientMsg>,
 
@@ -117,7 +117,12 @@ impl Server {
         #[cfg(not(feature = "worldgen"))]
         let world = World::generate(settings.world_seed);
         #[cfg(not(feature = "worldgen"))]
-        let map = vec![0];
+        let map = WorldMapMsg {
+            dimensions: Vec2::new(1, 1),
+            max_height: 1.0,
+            rgba: vec![0],
+            horizons: [(vec![0], vec![0]), (vec![0], vec![0])],
+        };
 
         #[cfg(feature = "worldgen")]
         let spawn_point = {
@@ -475,7 +480,7 @@ impl Server {
                             .create_entity_package(entity, None, None, None),
                         server_info: self.server_info.clone(),
                         time_of_day: *self.state.ecs().read_resource(),
-                        world_map: (WORLD_SIZE.map(|e| e as u32), self.map.clone()),
+                        world_map: self.map.clone(),
                     });
                 log::debug!("Done initial sync with client.");
 

world/examples/city.rs

@@ -30,6 +30,6 @@ fn main() {
             }
         }
 
-        win.update_with_buffer(&buf).unwrap();
+        win.update_with_buffer_size(&buf, W, H).unwrap();
     }
 }

world/examples/turb.rs

@@ -34,7 +34,7 @@ fn main() {
             }
         }
 
-        win.update_with_buffer(&buf).unwrap();
+        win.update_with_buffer_size(&buf, W, H).unwrap();
 
         _time += 1.0 / 60.0;
     }

world/examples/view.rs

@@ -71,6 +71,6 @@ fn main() {
             scale -= 6;
         }
 
-        win.update_with_buffer(&buf).unwrap();
+        win.update_with_buffer_size(&buf, W, H).unwrap();
     }
 }

world/examples/water.rs

@@ -1,8 +1,13 @@
 use common::{terrain::TerrainChunkSize, vol::RectVolSize};
+use rayon::prelude::*;
 use std::{f64, io::Write, path::PathBuf, time::SystemTime};
 use vek::*;
 use veloren_world::{
-    sim::{self, MapConfig, MapDebug, WorldOpts, WORLD_SIZE},
+    sim::{
+        self, get_horizon_map, uniform_idx_as_vec2, vec2_as_uniform_idx, MapConfig, MapDebug,
+        MapSample, WorldOpts, WORLD_SIZE,
+    },
+    util::Sampler,
     World, CONFIG,
 };
 
@@ -18,26 +23,92 @@ fn main() {
     let map_file =
         // "map_1575990726223.bin";
         // "map_1575987666972.bin";
-        "map_1576046079066.bin";
+        // "map_1576046079066.bin";
+        "map_1579539133272.bin";
     let mut _map_file = PathBuf::from("./maps");
     _map_file.push(map_file);
 
     let world = World::generate(5284, WorldOpts {
         seed_elements: false,
+        world_file: sim::FileOpts::LoadAsset(veloren_world::sim::DEFAULT_WORLD_MAP.into()),
         // world_file: sim::FileOpts::Load(_map_file),
-        world_file: sim::FileOpts::Save,
+        // world_file: sim::FileOpts::Save,
         ..WorldOpts::default()
     });
+    log::info!("Sampling data...");
+    let sampler = world.sim();
+
+    let samples_data = {
+        let column_sample = world.sample_columns();
+        (0..WORLD_SIZE.product())
+            .into_par_iter()
+            .map(|posi| {
+                column_sample
+                    .get(uniform_idx_as_vec2(posi) * TerrainChunkSize::RECT_SIZE.map(|e| e as i32))
+            })
+            .collect::<Vec<_>>()
+            .into_boxed_slice()
+    };
+    let refresh_map_samples = |config: &MapConfig| {
+        (0..WORLD_SIZE.product())
+            .into_par_iter()
+            .map(|posi| config.sample_pos(sampler, uniform_idx_as_vec2(posi)))
+            .collect::<Vec<_>>()
+            .into_boxed_slice()
+    };
+    let get_map_sample = |map_samples: &[MapSample], pos: Vec2<i32>| {
+        if pos.reduce_partial_min() >= 0
+            && pos.x < WORLD_SIZE.x as i32
+            && pos.y < WORLD_SIZE.y as i32
+        {
+            map_samples[vec2_as_uniform_idx(pos)].clone()
+        } else {
+            MapSample {
+                alt: 0.0,
+                rgb: Rgb::new(0, 0, 0),
+                connections: None,
+                downhill_wpos: (pos + 1) * TerrainChunkSize::RECT_SIZE.map(|e| e as i32),
+            }
+        }
+    };
+
+    let refresh_horizons = |lgain, is_basement, is_water| {
+        get_horizon_map(
+            lgain,
+            Aabr {
+                min: Vec2::zero(),
+                max: WORLD_SIZE.map(|e| e as i32),
+            },
+            CONFIG.sea_level as f64,
+            (CONFIG.sea_level + sampler.max_height) as f64,
+            |posi| {
+                let sample = sampler.get(uniform_idx_as_vec2(posi)).unwrap();
+                if is_basement {
+                    sample.alt as f64
+                } else {
+                    sample.basement as f64
+                }
+                .max(if is_water {
+                    sample.water_alt as f64
+                } else {
+                    -f64::INFINITY
+                })
+            },
+            |a| a,
+            |h| h,
+            /* |[al, ar]| [al, ar],
+             * |[hl, hr]| [hl, hr], */
+        )
+        .ok()
+    };
 
     let mut win =
         minifb::Window::new("World Viewer", W, H, minifb::WindowOptions::default()).unwrap();
 
-    let sampler = world.sim();
-
     let mut focus = Vec3::new(0.0, 0.0, CONFIG.sea_level as f64);
     // Altitude is divided by gain and clamped to [0, 1]; thus, decreasing gain
     // makes smaller differences in altitude appear larger.
-    let mut gain = CONFIG.mountain_scale;
+    let mut gain = /*CONFIG.mountain_scale*/sampler.max_height;
     // The Z component during normal calculations is multiplied by gain; thus,
     let mut lgain = 1.0;
     let mut scale = WORLD_SIZE.x as f64 / W as f64;
@@ -50,7 +121,7 @@ fn main() {
     //
     // "In world space the x-axis will be pointing east, the y-axis up and the
     // z-axis will be pointing south"
-    let mut light_direction = Vec3::new(-0.8, -1.0, 0.3);
+    let mut light_direction = Vec3::new(-/*0.8*/1.3, -1.0, 0.3);
 
     let mut is_basement = false;
     let mut is_water = true;
@@ -58,6 +129,11 @@ fn main() {
     let mut is_temperature = true;
     let mut is_humidity = true;
 
+    let mut horizons = refresh_horizons(lgain, is_basement, is_water);
+    let mut samples = None;
+
+    let mut samples_changed = true;
+    let mut map_samples: Box<[_]> = Box::new([]);
     while win.is_open() {
         let config = MapConfig {
             dimensions: Vec2::new(W, H),
@@ -66,6 +142,8 @@ fn main() {
             lgain,
             scale,
             light_direction,
+            horizons: horizons.as_ref(), /* .map(|(a, b)| (&**a, &**b)) */
+            samples,
 
             is_basement,
             is_water,
@@ -75,19 +153,30 @@ fn main() {
             is_debug: true,
         };
 
+        if samples_changed {
+            map_samples = refresh_map_samples(&config);
+        };
+
         let mut buf = vec![0; W * H];
         let MapDebug {
             rivers,
             lakes,
             oceans,
             quads,
-        } = config.generate(sampler, |pos, (r, g, b, a)| {
+        } = config.generate(
+            |pos| get_map_sample(&map_samples, pos),
+            |pos| config.sample_wpos(sampler, pos),
+            |pos, (r, g, b, a)| {
                 let i = pos.x;
                 let j = pos.y;
                 buf[j * W + i] = u32::from_le_bytes([b, g, r, a]);
-        });
+            },
+        );
 
         if win.is_key_down(minifb::Key::F4) {
+            // Feedback is important since on large maps it can be hard to tell if the
+            // keypress registered or not.
+            println!("Taking screenshot...");
             if let Some(len) = (W * H)
                 .checked_mul(scale as usize)
                 .and_then(|acc| acc.checked_mul(scale as usize))
@@ -100,11 +189,15 @@ fn main() {
                     ..config
                 };
                 let mut buf = vec![0u8; 4 * len];
-                config.generate(sampler, |pos, (r, g, b, a)| {
+                config.generate(
+                    |pos| get_map_sample(&map_samples, pos),
+                    |pos| config.sample_wpos(sampler, pos),
+                    |pos, (r, g, b, a)| {
                         let i = pos.x;
                         let j = pos.y;
                         (&mut buf[(j * x + i) * 4..]).write(&[r, g, b, a]).unwrap();
-                });
+                    },
+                );
                 // TODO: Justify fits in u32.
                 let world_map = image::RgbaImage::from_raw(x as u32, y as u32, buf)
                     .expect("Image dimensions must be valid");
@@ -161,18 +254,39 @@ fn main() {
         let is_camera = win.is_key_down(minifb::Key::C);
         if win.is_key_down(minifb::Key::B) {
             is_basement ^= true;
+            samples_changed = true;
+            horizons = horizons.and_then(|_| refresh_horizons(lgain, is_basement, is_water));
         }
         if win.is_key_down(minifb::Key::H) {
             is_humidity ^= true;
+            samples_changed = true;
         }
         if win.is_key_down(minifb::Key::T) {
             is_temperature ^= true;
+            samples_changed = true;
         }
         if win.is_key_down(minifb::Key::O) {
             is_water ^= true;
+            samples_changed = true;
+            horizons = horizons.and_then(|_| refresh_horizons(lgain, is_basement, is_water));
         }
         if win.is_key_down(minifb::Key::L) {
+            if is_camera {
+                // TODO: implement removing horizon mapping.
+                horizons = if horizons.is_some() {
+                    None
+                } else {
+                    refresh_horizons(lgain, is_basement, is_water)
+                };
+                samples_changed = true;
+            } else {
                 is_shaded ^= true;
+                samples_changed = true;
+            }
+        }
+        if win.is_key_down(minifb::Key::M) {
+            samples = samples.xor(Some(&*samples_data));
+            samples_changed = true;
         }
         if win.is_key_down(minifb::Key::W) {
             if is_camera {
@@ -206,6 +320,8 @@ fn main() {
             if is_camera {
                 if (lgain * 2.0).is_normal() {
                     lgain *= 2.0;
+                    horizons =
+                        horizons.and_then(|_| refresh_horizons(lgain, is_basement, is_water));
                 }
             } else {
                 gain += 64.0;
@@ -215,6 +331,8 @@ fn main() {
             if is_camera {
                 if (lgain / 2.0).is_normal() {
                     lgain /= 2.0;
+                    horizons =
+                        horizons.and_then(|_| refresh_horizons(lgain, is_basement, is_water));
                 }
             } else {
                 gain = (gain - 64.0).max(64.0);
@@ -223,6 +341,7 @@ fn main() {
         if win.is_key_down(minifb::Key::R) {
             if is_camera {
                 focus.z += spd * scale;
+                samples_changed = true;
             } else {
                 if (scale * 2.0).is_normal() {
                     scale *= 2.0;
@@ -232,6 +351,7 @@ fn main() {
         if win.is_key_down(minifb::Key::F) {
             if is_camera {
                 focus.z -= spd * scale;
+                samples_changed = true;
             } else {
                 if (scale / 2.0).is_normal() {
                     scale /= 2.0;
@@ -239,6 +359,6 @@ fn main() {
             }
         }
 
-        win.update_with_buffer(&buf).unwrap();
+        win.update_with_buffer_size(&buf, W, H).unwrap();
     }
 }

world/src/column/mod.rs

@@ -122,7 +122,7 @@ impl<'a> ColumnGen<'a> {
     }
 }
 
-fn river_spline_coeffs(
+pub fn river_spline_coeffs(
     // _sim: &WorldSim,
     chunk_pos: Vec2<f64>,
     spline_derivative: Vec2<f32>,
@@ -145,7 +145,7 @@ fn river_spline_coeffs(
 /// curve"... hopefully this works out okay and gives us what we want (a
 /// river that extends outwards tangent to a quadratic curve, with width
 /// configured by distance along the line).
-fn quadratic_nearest_point(
+pub fn quadratic_nearest_point(
     spline: &Vec3<Vec2<f64>>,
     point: Vec2<f64>,
 ) -> Option<(f64, Vec2<f64>, f64)> {

world/src/config.rs

@@ -64,5 +64,5 @@ pub const CONFIG: Config = Config {
     river_roughness: 0.06125,
     river_max_width: 2.0,
     river_min_height: 0.25,
-    river_width_to_depth: 1.0,
+    river_width_to_depth: 8.0,
 };

world/src/sim/map.rs

@@ -1,12 +1,16 @@
 use crate::{
-    sim::{RiverKind, WorldSim, WORLD_SIZE},
+    column::{quadratic_nearest_point, river_spline_coeffs, ColumnSample},
+    sim::{
+        neighbors, uniform_idx_as_vec2, vec2_as_uniform_idx, Alt, RiverKind, WorldSim,
+        NEIGHBOR_DELTA, WORLD_SIZE,
+    },
     CONFIG,
 };
 use common::{terrain::TerrainChunkSize, vol::RectVolSize};
-use std::{f32, f64};
+use std::{f32, f64, iter};
 use vek::*;
 
-pub struct MapConfig {
+pub struct MapConfig<'a> {
     /// Dimensions of the window being written to.  Defaults to WORLD_SIZE.
     pub dimensions: Vec2<usize>,
     /// x, y, and z of top left of map (defaults to (0.0, 0.0,
@@ -43,6 +47,14 @@ pub struct MapConfig {
     ///
     /// Defaults to (-0.8, -1.0, 0.3).
     pub light_direction: Vec3<f64>,
+    /// If Some, uses the provided horizon map.
+    ///
+    /// Defaults to None.
+    pub horizons: Option<&'a [(Vec<Alt>, Vec<Alt>); 2]>,
+    /// If Some, uses the provided column samples to determine surface color.
+    ///
+    /// Defaults to None.
+    pub samples: Option<&'a [Option<ColumnSample<'a>>]>,
     /// If true, only the basement (bedrock) is used for altitude; otherwise,
     /// the surface is used.
     ///
@@ -81,7 +93,7 @@ pub struct MapDebug {
     pub oceans: u32,
 }
 
-impl Default for MapConfig {
+impl<'a> Default for MapConfig<'a> {
     fn default() -> Self {
         let dimensions = WORLD_SIZE;
         Self {
@@ -90,7 +102,9 @@ impl Default for MapConfig {
             gain: CONFIG.mountain_scale,
             lgain: TerrainChunkSize::RECT_SIZE.x as f64,
             scale: WORLD_SIZE.x as f64 / dimensions.x as f64,
-            light_direction: Vec3::new(-0.8, -1.0, 0.3),
+            light_direction: Vec3::new(-1.2, -1.0, 0.8),
+            horizons: None,
+            samples: None,
 
             is_basement: false,
             is_water: true,
@@ -102,15 +116,291 @@ impl Default for MapConfig {
     }
 }
 
-impl MapConfig {
+/// Connection kind (per edge).  Currently just supports rivers, but may be
+/// extended to support paths or at least one other kind of connection.
+#[derive(Clone, Copy, Debug)]
+pub enum ConnectionKind {
+    /// Connection forms a visible river.
+    River,
+}
+
+/// Map connection (per edge).
+#[derive(Clone, Copy, Debug)]
+pub struct Connection {
+    /// The kind of connection this is (e.g. river or path).
+    pub kind: ConnectionKind,
+    /// Assumed to be the "b" part of a 2d quadratic function.
+    pub spline_derivative: Vec2<f32>,
+    /// Width of the connection.
+    pub width: f32,
+}
+
+/// Per-chunk data the map needs to be able to sample in order to correctly
+/// render.
+#[derive(Clone, Debug)]
+pub struct MapSample {
+    /// the base RGB color for a particular map pixel using the current settings
+    /// (i.e. the color *without* lighting).
+    pub rgb: Rgb<u8>,
+    /// Surface altitude information
+    /// (correctly reflecting settings like is_basement and is_water)
+    pub alt: f64,
+    /// Downhill chunk (may not be meaningful on ocean tiles, or at least edge
+    /// tiles)
+    pub downhill_wpos: Vec2<i32>,
+    /// Connection information about any connections to/from this chunk (e.g.
+    /// rivers).
+    ///
+    /// Connections at each index correspond to the same index in
+    /// NEIGHBOR_DELTA.
+    pub connections: Option<[Option<Connection>; 8]>,
+}
+
+impl<'a> MapConfig<'a> {
+    /// A sample function that grabs the connections at a chunk.
+    ///
+    /// Currently this just supports rivers, but ideally it can be extended past
+    /// that.
+    ///
+    /// A sample function that grabs surface altitude at a column.
+    /// (correctly reflecting settings like is_basement and is_water).
+    ///
+    /// The altitude produced by this function at a column corresponding to a
+    /// particular chunk should be identical to the altitude produced by
+    /// sample_pos at that chunk.
+    ///
+    /// You should generally pass a closure over this function into generate
+    /// when constructing a map for the first time.
+    /// However, if repeated construction is needed, or alternate base colors
+    /// are to be used for some reason, one should pass a custom function to
+    /// generate instead (e.g. one that just looks up the height in a cached
+    /// array).
+    pub fn sample_wpos(&self, sampler: &WorldSim, wpos: Vec2<i32>) -> f32 {
+        let MapConfig {
+            focus,
+            gain,
+
+            is_basement,
+            is_water,
+            ..
+        } = *self;
+
+        (sampler
+            .get_wpos(wpos)
+            .map(|s| {
+                if is_basement { s.basement } else { s.alt }.max(if is_water {
+                    s.water_alt
+                } else {
+                    -f32::INFINITY
+                })
+            })
+            .unwrap_or(CONFIG.sea_level)
+            - focus.z as f32)
+            / gain as f32
+    }
+
+    /// Samples a MapSample at a chunk.
+    ///
+    /// You should generally pass a closure over this function into generate
+    /// when constructing a map for the first time.
+    /// However, if repeated construction is needed, or alternate base colors
+    /// are to be used for some reason, one should pass a custom function to
+    /// generate instead (e.g. one that just looks up the color in a cached
+    /// array).
+    pub fn sample_pos(&self, sampler: &WorldSim, pos: Vec2<i32>) -> MapSample {
+        let MapConfig {
+            focus,
+            gain,
+            samples,
+
+            is_basement,
+            is_water,
+            is_shaded,
+            is_temperature,
+            is_humidity,
+            // is_debug,
+            ..
+        } = *self;
+
+        let true_sea_level = (CONFIG.sea_level as f64 - focus.z) / gain as f64;
+
+        let (
+            chunk_idx,
+            alt,
+            basement,
+            water_alt,
+            humidity,
+            temperature,
+            downhill,
+            river_kind,
+            spline_derivative,
+        ) = sampler
+            .get(pos)
+            .map(|sample| {
+                (
+                    Some(vec2_as_uniform_idx(pos)),
+                    sample.alt,
+                    sample.basement,
+                    sample.water_alt,
+                    sample.humidity,
+                    sample.temp,
+                    sample.downhill,
+                    sample.river.river_kind,
+                    sample.river.spline_derivative,
+                )
+            })
+            .unwrap_or((
+                None,
+                CONFIG.sea_level,
+                CONFIG.sea_level,
+                CONFIG.sea_level,
+                0.0,
+                0.0,
+                None,
+                None,
+                Vec2::zero(),
+            ));
+
+        let humidity = humidity.min(1.0).max(0.0);
+        let temperature = temperature.min(1.0).max(-1.0) * 0.5 + 0.5;
+        let wpos = pos * TerrainChunkSize::RECT_SIZE.map(|e| e as i32);
+        let column_rgb = samples
+            .and_then(|samples| {
+                chunk_idx
+                    .and_then(|chunk_idx| samples.get(chunk_idx))
+                    .map(Option::as_ref)
+                    .flatten()
+            })
+            .map(|sample| {
+                // TODO: Eliminate the redundancy between this and the block renderer.
+                let grass_depth = (1.5 + 2.0 * sample.chaos).min(alt - basement);
+                let wposz = if is_basement { basement } else { alt };
+                if is_basement && wposz < alt - grass_depth {
+                    Lerp::lerp(
+                        sample.sub_surface_color,
+                        sample.stone_col.map(|e| e as f32 / 255.0),
+                        (alt - grass_depth - wposz as f32) * 0.15,
+                    )
+                    .map(|e| e as f64)
+                } else {
+                    Lerp::lerp(
+                        sample.sub_surface_color,
+                        sample.surface_color,
+                        ((wposz as f32 - (alt - grass_depth)) / grass_depth).powf(0.5),
+                    )
+                    .map(|e| e as f64)
+                }
+            });
+
+        let downhill_wpos = downhill
+            .map(|downhill_pos| downhill_pos)
+            .unwrap_or(wpos + TerrainChunkSize::RECT_SIZE.map(|e| e as i32));
+        let alt = if is_basement { basement } else { alt };
+
+        let true_water_alt = (alt.max(water_alt) as f64 - focus.z) / gain as f64;
+        let true_alt = (alt as f64 - focus.z) / gain as f64;
+        let water_depth = (true_water_alt - true_alt).min(1.0).max(0.0);
+        let alt = true_alt.min(1.0).max(0.0);
+
+        let water_color_factor = 2.0;
+        let g_water = 32.0 * water_color_factor;
+        let b_water = 64.0 * water_color_factor;
+        let column_rgb = column_rgb.unwrap_or(Rgb::new(
+            if is_shaded || is_temperature {
+                1.0
+            } else {
+                0.0
+            },
+            if is_shaded { 1.0 } else { alt },
+            if is_shaded || is_humidity { 1.0 } else { 0.0 },
+        ));
+        let mut connections = [None; 8];
+        let mut has_connections = false;
+        // TODO: Support non-river connections.
+        // TODO: Support multiple connections.
+        let river_width = river_kind.map(|river| match river {
+            RiverKind::River { cross_section } => cross_section.x,
+            RiverKind::Lake { .. } | RiverKind::Ocean => TerrainChunkSize::RECT_SIZE.x as f32,
+        });
+        if let (Some(river_width), true) = (river_width, is_water) {
+            let downhill_pos = downhill_wpos.map2(TerrainChunkSize::RECT_SIZE, |e, f| e / f as i32);
+            NEIGHBOR_DELTA
+                .iter()
+                .zip((&mut connections).iter_mut())
+                .filter(|&(&offset, _)| downhill_pos - pos == Vec2::from(offset))
+                .for_each(|(_, connection)| {
+                    has_connections = true;
+                    *connection = Some(Connection {
+                        kind: ConnectionKind::River,
+                        spline_derivative,
+                        width: river_width,
+                    });
+                });
+        };
+        let rgb = match (river_kind, (is_water, true_alt >= true_sea_level)) {
+            (_, (false, _)) | (None, (_, true)) | (Some(RiverKind::River { .. }), _) => {
+                let (r, g, b) = (
+                    (column_rgb.r
+                        * if is_temperature {
+                            temperature as f64
+                        } else {
+                            column_rgb.r
+                        })
+                    .sqrt(),
+                    column_rgb.g,
+                    (column_rgb.b
+                        * if is_humidity {
+                            humidity as f64
+                        } else {
+                            column_rgb.b
+                        })
+                    .sqrt(),
+                );
+                Rgb::new((r * 255.0) as u8, (g * 255.0) as u8, (b * 255.0) as u8)
+            },
+            (None, _) | (Some(RiverKind::Lake { .. }), _) | (Some(RiverKind::Ocean), _) => {
+                Rgb::new(
+                    0,
+                    ((g_water - water_depth * g_water) * 1.0) as u8,
+                    ((b_water - water_depth * b_water) * 1.0) as u8,
+                )
+            },
+        };
+
+        MapSample {
+            rgb,
+            alt: if is_water {
+                true_alt.max(true_water_alt)
+            } else {
+                true_alt
+            },
+            downhill_wpos,
+            connections: if has_connections {
+                Some(connections)
+            } else {
+                None
+            },
+        }
+    }
+
     /// Generates a map image using the specified settings.  Note that it will
     /// write from left to write from (0, 0) to dimensions - 1, inclusive,
     /// with 4 1-byte color components provided as (r, g, b, a).  It is up
     /// to the caller to provide a function that translates this information
     /// into the correct format for a buffer and writes to it.
+    ///
+    /// sample_pos is a function that, given a chunk position, returns enough
+    /// information about the chunk to attempt to render it on the map.
+    /// When in doubt, try using `MapConfig::sample_pos` for this.
+    ///
+    /// sample_wpos is a simple function that, given a *column* position,
+    /// returns the approximate altitude at that column.  When in doubt, try
+    /// using `MapConfig::sample_wpos` for this.
     pub fn generate(
         &self,
-        sampler: &WorldSim,
+        sample_pos: impl Fn(Vec2<i32>) -> MapSample,
+        sample_wpos: impl Fn(Vec2<i32>) -> f32,
+        // sampler: &WorldSim,
         mut write_pixel: impl FnMut(Vec2<usize>, (u8, u8, u8, u8)),
     ) -> MapDebug {
         let MapConfig {
@@ -120,23 +410,29 @@ impl MapConfig {
             lgain,
             scale,
             light_direction,
+            horizons,
 
-            is_basement,
-            is_water,
             is_shaded,
-            is_temperature,
+            // is_debug,
-            is_humidity,
+            ..
-            is_debug,
         } = *self;
 
+        let light_direction = Vec3::new(
+            light_direction.x,
+            light_direction.y,
+            0.0, // we currently ignore light_direction.z.
+        );
+        let light_shadow_dir = if light_direction.x >= 0.0 { 0 } else { 1 };
+        let horizon_map = horizons.map(|horizons| &horizons[light_shadow_dir]);
         let light = light_direction.normalized();
-        let mut quads = [[0u32; QUADRANTS]; QUADRANTS];
+        let /*mut */quads = [[0u32; QUADRANTS]; QUADRANTS];
-        let mut rivers = 0u32;
+        let /*mut */rivers = 0u32;
-        let mut lakes = 0u32;
+        let /*mut */lakes = 0u32;
-        let mut oceans = 0u32;
+        let /*mut */oceans = 0u32;
 
         let focus_rect = Vec2::from(focus);
-        let true_sea_level = (CONFIG.sea_level as f64 - focus.z) / gain as f64;
+
+        let chunk_size = TerrainChunkSize::RECT_SIZE.map(|e| e as f64);
 
         (0..dimensions.y * dimensions.x)
             .into_iter()
@@ -144,81 +440,148 @@ impl MapConfig {
                 let i = chunk_idx % dimensions.x as usize;
                 let j = chunk_idx / dimensions.x as usize;
 
-                let pos =
+                let wposf = focus_rect + Vec2::new(i as f64, j as f64) * scale;
-                    (focus_rect + Vec2::new(i as f64, j as f64) * scale).map(|e: f64| e as i32);
+                let pos = wposf.map(|e: f64| e as i32);
+                let wposf = wposf * chunk_size;
 
-                let (alt, basement, water_alt, humidity, temperature, downhill, river_kind) =
+                let chunk_idx = if pos.reduce_partial_min() >= 0
-                    sampler
+                    && pos.x < WORLD_SIZE.x as i32
-                        .get(pos)
+                    && pos.y < WORLD_SIZE.y as i32
-                        .map(|sample| {
+                {
-                            (
+                    Some(vec2_as_uniform_idx(pos))
-                                sample.alt,
+                } else {
-                                sample.basement,
+                    None
-                                sample.water_alt,
+                };
-                                sample.humidity,
+
-                                sample.temp,
+                let MapSample {
-                                sample.downhill,
+                    rgb,
-                                sample.river.river_kind,
+                    alt,
+                    downhill_wpos,
+                    ..
+                } = sample_pos(pos);
+
+                let alt = alt as f32;
+                let wposi = pos * TerrainChunkSize::RECT_SIZE.map(|e| e as i32);
+                let mut rgb = rgb.map(|e| e as f64 / 255.0);
+
+                // Material properties:
+                //
+                // For each material in the scene,
+                //  k_s = (RGB) specular reflection constant
+                let mut k_s = Rgb::new(1.0, 1.0, 1.0);
+                //  k_d = (RGB) diffuse reflection constant
+                let mut k_d = rgb;
+                //  k_a = (RGB) ambient reflection constant
+                let mut k_a = rgb;
+                //  α = (per-material) shininess constant
+                let mut alpha = 4.0; // 4.0;
+
+                // Compute connections
+                let mut has_river = false;
+                // NOTE: consider replacing neighbors with local_cells, since it is more
+                // accurate (though I'm not sure if it can matter for these
+                // purposes).
+                chunk_idx
+                    .map(|chunk_idx| neighbors(chunk_idx).chain(iter::once(chunk_idx)))
+                    .into_iter()
+                    .flatten()
+                    .for_each(|neighbor_posi| {
+                        let neighbor_pos = uniform_idx_as_vec2(neighbor_posi);
+                        let neighbor_wpos = neighbor_pos.map(|e| e as f64) * chunk_size;
+                        let MapSample { connections, .. } = sample_pos(neighbor_pos);
+                        NEIGHBOR_DELTA
+                            .iter()
+                            .zip(
+                                connections
+                                    .as_ref()
+                                    .map(|e| e.iter())
+                                    .into_iter()
+                                    .flatten()
+                                    .into_iter(),
                             )
-                        })
+                            .for_each(|(&delta, connection)| {
-                        .unwrap_or((
+                                let connection = if let Some(connection) = connection {
-                            CONFIG.sea_level,
+                                    connection
-                            CONFIG.sea_level,
+                                } else {
-                            CONFIG.sea_level,
+                                    return;
-                            0.0,
+                                };
-                            0.0,
+                                let downhill_wpos = neighbor_wpos
-                            None,
+                                    + Vec2::from(delta).map(|e: i32| e as f64) * chunk_size;
-                            None,
+                                let coeffs = river_spline_coeffs(
-                        ));
+                                    neighbor_wpos,
-                let humidity = humidity.min(1.0).max(0.0);
+                                    connection.spline_derivative,
-                let temperature = temperature.min(1.0).max(-1.0) * 0.5 + 0.5;
+                                    downhill_wpos,
-                let pos = pos * TerrainChunkSize::RECT_SIZE.map(|e| e as i32);
+                                );
-                let downhill_pos = (downhill
+                                let (_t, _pt, dist) = if let Some((t, pt, dist)) =
-                    .map(|downhill_pos| downhill_pos)
+                                    quadratic_nearest_point(&coeffs, wposf)
-                    .unwrap_or(pos + TerrainChunkSize::RECT_SIZE.map(|e| e as i32))
+                                {
-                    - pos)
+                                    (t, pt, dist)
-                    + pos;
+                                } else {
-                let downhill_alt = sampler
+                                    let ndist = wposf.distance_squared(neighbor_wpos);
-                    .get_wpos(downhill_pos)
+                                    let ddist = wposf.distance_squared(downhill_wpos);
-                    .map(|s| if is_basement { s.basement } else { s.alt })
+                                    if ndist <= ddist {
-                    .unwrap_or(CONFIG.sea_level);
+                                        (0.0, neighbor_wpos, ndist)
-                let alt = if is_basement { basement } else { alt };
+                                    } else {
-                let cross_pos = pos
+                                        (1.0, downhill_wpos, ddist)
-                    + ((downhill_pos - pos)
+                                    }
+                                };
+                                let connection_dist = (dist.sqrt()
+                                    - (connection.width as f64 * 0.5).max(1.0))
+                                .max(0.0);
+                                if connection_dist == 0.0 {
+                                    match connection.kind {
+                                        ConnectionKind::River => {
+                                            has_river = true;
+                                        },
+                                    }
+                                }
+                            });
+                    });
+
+                // Color in connectins.
+                let water_color_factor = 2.0;
+                let g_water = 32.0 * water_color_factor;
+                let b_water = 64.0 * water_color_factor;
+                if has_river {
+                    let water_rgb = Rgb::new(0, ((g_water) * 1.0) as u8, ((b_water) * 1.0) as u8)
+                        .map(|e| e as f64 / 255.0);
+                    rgb = water_rgb;
+                    k_s = Rgb::new(1.0, 1.0, 1.0);
+                    k_d = water_rgb;
+                    k_a = water_rgb;
+                    alpha = 0.255;
+                }
+
+                let downhill_alt = sample_wpos(downhill_wpos);
+                let cross_pos = wposi
+                    + ((downhill_wpos - wposi)
                         .map(|e| e as f32)
                         .rotated_z(f32::consts::FRAC_PI_2)
                         .map(|e| e as i32));
-                let cross_alt = sampler
+                let cross_alt = sample_wpos(cross_pos);
-                    .get_wpos(cross_pos)
-                    .map(|s| if is_basement { s.basement } else { s.alt })
-                    .unwrap_or(CONFIG.sea_level);
                 // Pointing downhill, forward
                 // (index--note that (0,0,1) is backward right-handed)
                 let forward_vec = Vec3::new(
-                    (downhill_pos.x - pos.x) as f64,
+                    (downhill_wpos.x - wposi.x) as f64,
-                    (downhill_alt - alt) as f64 * lgain,
+                    ((downhill_alt - alt) * gain) as f64 * lgain,
-                    (downhill_pos.y - pos.y) as f64,
+                    (downhill_wpos.y - wposi.y) as f64,
                 );
                 // Pointing 90 degrees left (in horizontal xy) of downhill, up
                 // (middle--note that (1,0,0), 90 degrees CCW backward, is right right-handed)
                 let up_vec = Vec3::new(
-                    (cross_pos.x - pos.x) as f64,
+                    (cross_pos.x - wposi.x) as f64,
-                    (cross_alt - alt) as f64 * lgain,
+                    ((cross_alt - alt) * gain) as f64 * lgain,
-                    (cross_pos.y - pos.y) as f64,
+                    (cross_pos.y - wposi.y) as f64,
                 );
+                // let surface_normal = Vec3::new(lgain * (f.y * u.z - f.z * u.y), -(f.x * u.z -
+                // f.z * u.x), lgain * (f.x * u.y - f.y * u.x)).normalized();
                 // Then cross points "to the right" (upwards) on a right-handed coordinate
                 // system. (right-handed coordinate system means (0, 0, 1.0) is
                 // "forward" into the screen).
                 let surface_normal = forward_vec.cross(up_vec).normalized();
-                let light = (surface_normal.dot(light) + 1.0) / 2.0;
-                let light = (light * 0.9) + 0.1;
 
-                let true_water_alt = (alt.max(water_alt) as f64 - focus.z) / gain as f64;
+                // TODO: Figure out if we can reimplement debugging.
-                let true_alt = (alt as f64 - focus.z) / gain as f64;
+                /* if is_debug {
-                let water_depth = (true_water_alt - true_alt).min(1.0).max(0.0);
-                let water_alt = true_water_alt.min(1.0).max(0.0);
-                let alt = true_alt.min(1.0).max(0.0);
-                if is_debug {
                     let quad = |x: f32| {
                         ((x as f64 * QUADRANTS as f64).floor() as usize).min(QUADRANTS - 1)
                     };
@@ -237,62 +600,84 @@ impl MapConfig {
                         },
                         None => {},
                     }
+                } */
+
+                let shade_frac = horizon_map
+                    .and_then(|(angles, heights)| {
+                        chunk_idx
+                            .and_then(|chunk_idx| angles.get(chunk_idx))
+                            .map(|&e| (e as f64, heights))
+                    })
+                    .and_then(|(e, heights)| {
+                        chunk_idx
+                            .and_then(|chunk_idx| heights.get(chunk_idx))
+                            .map(|&f| (e, f as f64))
+                    })
+                    .map(|(angle, height)| {
+                        let w = 0.1;
+                        if angle != 0.0 && light_direction.x != 0.0 {
+                            let deltax = height / angle;
+                            let lighty = (light_direction.y / light_direction.x * deltax).abs();
+                            let deltay = lighty - height;
+                            let s = (deltay / deltax / w).min(1.0).max(0.0);
+                            // Smoothstep
+                            s * s * (3.0 - 2.0 * s)
+                        } else {
+                            1.0
                         }
-
-                let water_color_factor = 2.0;
-                let g_water = 32.0 * water_color_factor;
-                let b_water = 64.0 * water_color_factor;
-                let rgb = match (river_kind, (is_water, true_alt >= true_sea_level)) {
-                    (_, (false, _)) | (None, (_, true)) => {
-                        let (r, g, b) = (
-                            (if is_shaded { alt } else { alt }
-                                * if is_temperature {
-                                    temperature as f64
-                                } else if is_shaded {
-                                    alt
-                                } else {
-                                    0.0
                     })
-                            .sqrt(),
+                    .unwrap_or(1.0);
-                            if is_shaded { 0.4 + (alt * 0.6) } else { alt },
+
-                            (if is_shaded { alt } else { alt }
+                let rgb = if is_shaded {
-                                * if is_humidity {
+                    // Phong reflection model with shadows:
-                                    humidity as f64
+                    //
-                                } else if is_shaded {
+                    // I_p = k_a i_a + shadow * Σ {m ∈ lights} (k_d (L_m ⋅ N) i_m,d + k_s (R_m ⋅
-                                    alt
+                    // V)^α i_m,s)
+                    //
+                    // where for the whole scene,
+                    //  i_a = (RGB) intensity of ambient lighting component
+                    let i_a = Rgb::new(0.1, 0.1, 0.1);
+                    //  V = direction pointing towards the viewer (e.g. virtual camera).
+                    let v = Vec3::new(0.0, 0.0, -1.0).normalized();
+                    // let v = Vec3::new(0.0, -1.0, 0.0).normalized();
+                    //
+                    // for each light m,
+                    //  i_m,d = (RGB) intensity of diffuse component of light source m
+                    let i_m_d = Rgb::new(1.0, 1.0, 1.0);
+                    //  i_m,s = (RGB) intensity of specular component of light source m
+                    let i_m_s = Rgb::new(0.45, 0.45, 0.45);
+                    // let i_m_s = Rgb::new(0.45, 0.45, 0.45);
+
+                    // for each light m and point p,
+                    //  L_m = (normalized) direction vector from point on surface to light source m
+                    let l_m = light;
+                    //  N = (normalized) normal at this point on the surface,
+                    let n = surface_normal;
+                    //  R_m = (normalized) direction a perfectly reflected ray of light from m would
+                    // take from point p      = 2(L_m ⋅ N)N - L_m
+                    let r_m = (-l_m).reflected(n); // 2 * (l_m.dot(n)) * n - l_m;
+                    //
+                    // and for each point p in the scene,
+                    //  shadow = computed shadow factor at point p
+                    // FIXME: Should really just be shade_frac, but with only ambient light we lose
+                    // all local lighting detail... some sort of global illumination (e.g.
+                    // radiosity) is of course the "right" solution, but maybe we can find
+                    // something cheaper?
+                    let shadow = 0.2 + 0.8 * shade_frac;
+
+                    let lambertian = l_m.dot(n).max(0.0);
+                    let spec_angle = r_m.dot(v).max(0.0);
+
+                    let ambient = k_a * i_a;
+                    let diffuse = k_d * lambertian * i_m_d;
+                    let specular = k_s * spec_angle.powf(alpha) * i_m_s;
+                    (ambient + shadow * (diffuse + specular)).map(|e| e.min(1.0))
                 } else {
-                                    0.0
+                    rgb
-                                })
+                }
-                            .sqrt(),
+                .map(|e| (e * 255.0) as u8);
-                        );
-                        let light = if is_shaded { light } else { 1.0 };
-                        (
-                            (r * light * 255.0) as u8,
-                            (g * light * 255.0) as u8,
-                            (b * light * 255.0) as u8,
-                        )
-                    },
-                    (Some(RiverKind::Ocean), _) => (
-                        0,
-                        ((g_water - water_depth * g_water) * 1.0) as u8,
-                        ((b_water - water_depth * b_water) * 1.0) as u8,
-                    ),
-                    (Some(RiverKind::River { .. }), _) => (
-                        0,
-                        g_water as u8 + (alt * (127.0 - g_water)) as u8,
-                        b_water as u8 + (alt * (255.0 - b_water)) as u8,
-                    ),
-                    (None, _) | (Some(RiverKind::Lake { .. }), _) => (
-                        0,
-                        (((g_water + water_alt * (127.0 - 32.0)) + (-water_depth * g_water)) * 1.0)
-                            as u8,
-                        (((b_water + water_alt * (255.0 - b_water)) + (-water_depth * b_water))
-                            * 1.0) as u8,
-                    ),
-                };
-
-                let rgba = (rgb.0, rgb.1, rgb.2, (255.0 * alt.max(water_alt)) as u8);
 
+                let rgba = (rgb.r, rgb.g, rgb.b, 255);
                 write_pixel(Vec2::new(i, j), rgba);
             });
 

world/src/sim/mod.rs

@@ -14,12 +14,12 @@ pub use self::{
         get_rivers, mrec_downhill, Alt, RiverData, RiverKind,
     },
     location::Location,
-    map::{MapConfig, MapDebug},
+    map::{MapConfig, MapDebug, MapSample},
     settlement::Settlement,
     util::{
-        cdf_irwin_hall, downhill, get_oceans, local_cells, map_edge_factor, neighbors,
+        cdf_irwin_hall, downhill, get_horizon_map, get_oceans, local_cells, map_edge_factor,
-        uniform_idx_as_vec2, uniform_noise, uphill, vec2_as_uniform_idx, InverseCdf, ScaleBias,
+        neighbors, uniform_idx_as_vec2, uniform_noise, uphill, vec2_as_uniform_idx, InverseCdf,
-        NEIGHBOR_DELTA,
+        ScaleBias, NEIGHBOR_DELTA,
     },
 };
 
@@ -33,6 +33,7 @@ use crate::{
 };
 use common::{
     assets,
+    msg::server::WorldMapMsg,
     terrain::{BiomeKind, TerrainChunkSize},
     vol::RectVolSize,
 };
@@ -41,7 +42,7 @@ use noise::{
     BasicMulti, Billow, Fbm, HybridMulti, MultiFractal, NoiseFn, RangeFunction, RidgedMulti,
     Seedable, SuperSimplex, Worley,
 };
-use num::{Float, Signed};
+use num::{traits::FloatConst, Float, Signed};
 use rand::{Rng, SeedableRng};
 use rand_chacha::ChaChaRng;
 use rayon::prelude::*;
@@ -1101,9 +1102,9 @@ impl WorldSim {
             )
         };
         let flux_old = get_multi_drainage(&mstack, &mrec, &*mwrec, boundary_len);
-        let flux_rivers = get_drainage(&water_alt_pos, &dh, boundary_len);
+        // let flux_rivers = get_drainage(&water_alt_pos, &dh, boundary_len);
         // TODO: Make rivers work with multi-direction flux as well.
-        // let flux_rivers = flux_old.clone();
+        let flux_rivers = flux_old.clone();
 
         let water_height_initial = |chunk_idx| {
             let indirection_idx = indirection[chunk_idx];
@@ -1307,17 +1308,75 @@ impl WorldSim {
 
     /// Draw a map of the world based on chunk information.  Returns a buffer of
     /// u32s.
-    pub fn get_map(&self) -> Vec<u32> {
+    pub fn get_map(&self) -> WorldMapMsg {
+        let mut map_config = MapConfig::default();
+        map_config.lgain = 1.0;
+        // Build a horizon map.
+        let scale_angle =
+            |angle: Alt| (angle.atan() * <Alt as FloatConst>::FRAC_2_PI() * 255.0).floor() as u8;
+        let scale_height = |height: Alt| {
+            ((height - CONFIG.sea_level as Alt) * 255.0 / self.max_height as Alt).floor() as u8
+        };
+        let horizons = get_horizon_map(
+            map_config.lgain,
+            Aabr {
+                min: Vec2::zero(),
+                max: WORLD_SIZE.map(|e| e as i32),
+            },
+            CONFIG.sea_level as Alt,
+            (CONFIG.sea_level + self.max_height) as Alt,
+            |posi| {
+                let chunk = &self.chunks[posi];
+                chunk.alt.max(chunk.water_alt) as Alt
+            },
+            |a| scale_angle(a),
+            |h| scale_height(h),
+        )
+        .unwrap();
+
+        let samples_data = {
+            let column_sample = ColumnGen::new(self);
+            (0..WORLD_SIZE.product())
+                .into_par_iter()
+                .map(|posi| {
+                    column_sample.get(
+                        uniform_idx_as_vec2(posi) * TerrainChunkSize::RECT_SIZE.map(|e| e as i32),
+                    )
+                })
+                .collect::<Vec<_>>()
+                .into_boxed_slice()
+        };
+
         let mut v = vec![0u32; WORLD_SIZE.x * WORLD_SIZE.y];
         // TODO: Parallelize again.
-        MapConfig {
+        let config = MapConfig {
             gain: self.max_height,
-            ..MapConfig::default()
+            samples: Some(&samples_data),
-        }
+            is_shaded: false,
-        .generate(&self, |pos, (r, g, b, a)| {
+            ..map_config
+        };
+
+        config.generate(
+            |pos| config.sample_pos(self, pos),
+            |pos| config.sample_wpos(self, pos),
+            |pos, (r, g, b, _a)| {
+                // We currently ignore alpha and replace it with the height at pos, scaled to
+                // u8.
+                let alt = config.sample_wpos(
+                    self,
+                    pos.map(|e| e as i32) * TerrainChunkSize::RECT_SIZE.map(|e| e as i32),
+                );
+                let a = (alt.min(1.0).max(0.0) * 255.0) as u8;
+
                 v[pos.y * WORLD_SIZE.x + pos.x] = u32::from_le_bytes([r, g, b, a]);
-        });
+            },
-        v
+        );
+        WorldMapMsg {
+            dimensions: WORLD_SIZE.map(|e| e as u32),
+            max_height: self.max_height,
+            rgba: v,
+            horizons,
+        }
     }
 
     /// Prepare the world for simulation

world/src/sim/util.rs

@@ -294,6 +294,52 @@ pub fn downhill<F: Float>(
         .into_boxed_slice()
 }
 
+/* /// Bilinear interpolation.
+///
+/// Linear interpolation in both directions (i.e. quadratic interpolation).
+fn get_interpolated_bilinear<T, F>(&self, pos: Vec2<i32>, mut f: F) -> Option<T>
+    where
+        T: Copy + Default + Signed + Float + Add<Output = T> + Mul<f32, Output = T>,
+        F: FnMut(Vec2<i32>) -> Option<T>,
+{
+    // (i) Find downhill for all four points.
+    // (ii) Compute distance from each downhill point and do linear interpolation on
+    // their heights. (iii) Compute distance between each neighboring point
+    // and do linear interpolation on       their distance-interpolated
+    // heights.
+
+    // See http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1990A%26A...239..443S&defaultprint=YES&page_ind=0&filetype=.pdf
+    //
+    // Note that these are only guaranteed monotone in one dimension; fortunately,
+    // that is sufficient for our purposes.
+    let pos = pos.map2(TerrainChunkSize::RECT_SIZE, |e, sz: u32| {
+        e as f64 / sz as f64
+    });
+
+    // Orient the chunk in the direction of the most downhill point of the four.  If
+    // there is no "most downhill" point, then we don't care.
+    let x0 = pos.map2(Vec2::new(0, 0), |e, q| e.max(0.0) as i32 + q);
+    let y0 = f(x0)?;
+
+    let x1 = pos.map2(Vec2::new(1, 0), |e, q| e.max(0.0) as i32 + q);
+    let y1 = f(x1)?;
+
+    let x2 = pos.map2(Vec2::new(0, 1), |e, q| e.max(0.0) as i32 + q);
+    let y2 = f(x2)?;
+
+    let x3 = pos.map2(Vec2::new(1, 1), |e, q| e.max(0.0) as i32 + q);
+    let y3 = f(x3)?;
+
+    let z0 = y0
+        .mul(1.0 - pos.x.fract() as f32)
+        .mul(1.0 - pos.y.fract() as f32);
+    let z1 = y1.mul(pos.x.fract() as f32).mul(1.0 - pos.y.fract() as f32);
+    let z2 = y2.mul(1.0 - pos.x.fract() as f32).mul(pos.y.fract() as f32);
+    let z3 = y3.mul(pos.x.fract() as f32).mul(pos.y.fract() as f32);
+
+    Some(z0 + z1 + z2 + z3)
+} */
+
 /// Find all ocean tiles from a height map, using an inductive definition of
 /// ocean as one of:
 /// - posi is at the side of the world (map_edge_factor(posi) == 0.0)
@@ -335,6 +381,78 @@ pub fn get_oceans<F: Float>(oldh: impl Fn(usize) -> F + Sync) -> BitBox {
     is_ocean
 }
 
+/// Finds the horizon map for sunlight for the given chunks.
+pub fn get_horizon_map<F: Float + Sync, A: Send, H: Send>(
+    lgain: F,
+    bounds: Aabr<i32>,
+    minh: F,
+    maxh: F,
+    h: impl Fn(usize) -> F + Sync,
+    to_angle: impl Fn(F) -> A + Sync,
+    to_height: impl Fn(F) -> H + Sync,
+) -> Result<[(Vec<A>, Vec<H>); 2], ()> {
+    let map_size = Vec2::<i32>::from(bounds.size()).map(|e| e as usize);
+    let map_len = map_size.product();
+
+    // Now, do the raymarching.
+    let chunk_x = if let Vec2 { x: Some(x), .. } = TerrainChunkSize::RECT_SIZE.map(F::from) {
+        x
+    } else {
+        return Err(());
+    };
+    // let epsilon = F::epsilon() * if let x = F::from(map_size.x) { x } else {
+    // return Err(()) };
+    let march = |dx: isize, maxdx: fn(isize) -> isize| {
+        let mut angles = Vec::with_capacity(map_len);
+        let mut heights = Vec::with_capacity(map_len);
+        (0..map_len)
+            .into_par_iter()
+            .map(|posi| {
+                let wposi =
+                    bounds.min + Vec2::new((posi % map_size.x) as i32, (posi / map_size.x) as i32);
+                if wposi.reduce_partial_min() < 0
+                    || wposi.y as usize >= WORLD_SIZE.x
+                    || wposi.y as usize >= WORLD_SIZE.y
+                {
+                    return (to_angle(F::zero()), to_height(F::zero()));
+                }
+                let posi = vec2_as_uniform_idx(wposi);
+                // March in the given direction.
+                let maxdx = maxdx(wposi.x as isize);
+                let mut slope = F::zero();
+                let mut max_height = F::zero();
+                let h0 = h(posi);
+                if h0 >= minh {
+                    let maxdz = maxh - h0;
+                    let posi = posi as isize;
+                    for deltax in 1..maxdx {
+                        let posj = (posi + deltax * dx) as usize;
+                        let deltax = chunk_x * F::from(deltax).unwrap();
+                        let h_j_est = slope * deltax;
+                        if h_j_est > maxdz {
+                            break;
+                        }
+                        let h_j_act = h(posj) - h0;
+                        if
+                        /* h_j_est - h_j_act <= epsilon */
+                        h_j_est <= h_j_act {
+                            slope = h_j_act / deltax;
+                            max_height = h_j_act;
+                        }
+                    }
+                }
+                let a = slope * lgain;
+                let h = h0 + max_height;
+                (to_angle(a), to_height(h))
+            })
+            .unzip_into_vecs(&mut angles, &mut heights);
+        (angles, heights)
+    };
+    let west = march(-1, |x| x);
+    let east = march(1, |x| (WORLD_SIZE.x - x as usize) as isize);
+    Ok([west, east])
+}
+
 /// A 2-dimensional vector, for internal use.
 type Vector2<T> = [T; 2];
 /// A 3-dimensional vector, for internal use.