Added software shadows

src/game.rs

@@ -2,8 +2,6 @@ use crate::{debug, game_setup};
 use bevy::prelude::*;
 use bevy_ecs_ldtk::{LdtkWorldBundle, LevelSelection};
 
-use self::darkness::SpotLight2D;
-
 pub mod camera;
 pub mod darkness;
 pub mod ldtk;
@@ -26,15 +24,4 @@ fn setup(mut commands: Commands, assets: Res<AssetServer>) {
         ldtk_handle: assets.load("levels/world.ldtk"),
         ..default()
     });
-
-    commands.spawn((
-        Name::new("Spot light"),
-        SpatialBundle::from_transform(Transform::from_xyz(32.0, 31.0, 0.0).with_rotation(
-            Quat::from_euler(EulerRot::YXZ, 0.0, 0.0, f32::to_radians(-90.0)),
-        )),
-        SpotLight2D {
-            radius: 100.0,
-            angle: 1.0,
-        },
-    ));
 }

src/game/camera.rs

@@ -5,7 +5,7 @@ use bevy::render::camera::ScalingMode;
 use bevy::{input::mouse::MouseMotion, transform::TransformSystem};
 use bevy_ecs_ldtk::prelude::*;
 
-use super::darkness::{PointLight2D, SpotLight2D};
+use super::darkness::{PointLight2D, ShadowMesh, SpotLight2D};
 
 pub struct GameCameraPlugin;
 
@@ -95,6 +95,7 @@ fn camera_setup(mut commands: Commands) {
         ComputedVisibility::default(),
         CameraRoomRestraint,
         PointLight2D { radius: 30.0 },
+        ShadowMesh::default(),
     ));
 }
 
@@ -118,13 +119,32 @@ fn free_system(
     mut free_query: Query<(&mut Transform, &GameCamera, &OrthographicProjection)>,
     mut mouse_events: EventReader<MouseMotion>,
     mouse_input: Res<Input<MouseButton>>,
+    key_input: Res<Input<KeyCode>>,
+    time: Res<Time>,
 ) {
     let raw_mouse_motion: Vec2 = mouse_events.iter().map(|e| e.delta).sum();
     for (mut transform, camera, projection) in free_query.iter_mut() {
         if camera.mode == CameraMode::Free {
-            let mouse_motion = raw_mouse_motion * projection.scale * Vec2::new(-1.0, 1.0);
+            let mut motion = Vec2::ZERO;
             if mouse_input.pressed(MouseButton::Middle) {
-                input_movement(&mut transform, mouse_motion)
+                motion += raw_mouse_motion * projection.scale * Vec2::new(-1.0, 1.0);
+            }
+            motion.x += match (key_input.pressed(KeyCode::A), key_input.pressed(KeyCode::D)) {
+                (true, false) => -1.0,
+                (false, true) => 1.0,
+                (_, _) => 0.0,
+            } * projection.scale
+                * time.delta_seconds()
+                * 100.0;
+            motion.y += match (key_input.pressed(KeyCode::S), key_input.pressed(KeyCode::W)) {
+                (true, false) => -1.0,
+                (false, true) => 1.0,
+                (_, _) => 0.0,
+            } * projection.scale
+                * time.delta_seconds()
+                * 100.0;
+            if motion != Vec2::ZERO {
+                input_movement(&mut transform, motion)
             }
         }
     }

src/game/darkness.rs

@@ -8,6 +8,10 @@ use bevy::{
     sprite::{Material2dPlugin, Mesh2dHandle},
 };
 use bevy_ecs_ldtk::{LdtkLevel, LevelEvent};
+use bevy_prototype_debug_lines::DebugLines;
+use bevy_rapier2d::prelude::{Collider, QueryFilter, RapierContext};
+
+use crate::{debug::DebugMode, util::vec2_intersection};
 
 mod material;
 
@@ -16,7 +20,7 @@ pub use material::*;
 // Needs to be the same as in darkness.wgsl
 pub const MAX_POINT_LIGHTS: usize = 64;
 pub const MAX_SPOT_LIGHTS: usize = 64;
-pub const SHADOWMAP_RESOLUTION: usize = 256;
+pub const SHADOWMAP_RESOLUTION: usize = 1024;
 
 pub struct DarknessPlugin;
 
@@ -24,11 +28,12 @@ impl Plugin for DarknessPlugin {
     fn build(&self, app: &mut App) {
         app.register_type::<PointLight2D>()
             .register_type::<SpotLight2D>()
+            .register_type::<ShadowMesh>()
             .register_type::<VisibilityBlocker>()
             .register_asset_reflect::<DarknessMaterial>()
             .add_plugins(Material2dPlugin::<DarknessMaterial>::default())
             .add_systems(Update, add_to_level)
-            .add_systems(Last, prepare_lights);
+            .add_systems(Last, (prepare_lights, prepare_shadows).chain());
     }
 }
 
@@ -82,6 +87,19 @@ pub(crate) struct GpuSpotLight2D {
 #[reflect(Component)]
 pub struct VisibilityBlocker;
 
+#[derive(Reflect, Default, Debug, Clone, Copy)]
+pub struct ShadowVertex {
+    pub point: Vec2,
+    pub angle: f32,
+}
+
+#[derive(Component, Reflect, Default, Debug, Clone)]
+#[reflect(Component)]
+pub struct ShadowMesh {
+    pub light_index: usize,
+    pub vertices: Vec<ShadowVertex>,
+}
+
 fn add_to_level(
     mut commands: Commands,
     mut level_events: EventReader<LevelEvent>,
@@ -146,9 +164,9 @@ fn add_to_level(
                             DarknessMeshBundle {
                                 transform: Transform::from_xyz(0.0, 0.0, 100.0),
                                 mesh: Mesh2dHandle(meshes.add(plane)),
-                                material: materials.add(DarknessMaterial::new(
-                                    Color::rgba(0.0, 0.0, 0.0, 0.75),
-                                    Some(images.add(Image::new(
+                                material: materials.add(DarknessMaterial {
+                                    color: Color::rgba(0.0, 0.0, 0.0, 0.75),
+                                    shadowmap_texture: Some(images.add(Image::new(
                                         Extent3d {
                                             width: width as u32,
                                             height: height as u32,
@@ -158,7 +176,8 @@ fn add_to_level(
                                         vec![0; width * height * 4],
                                         bevy::render::render_resource::TextureFormat::R32Float,
                                     ))),
-                                )),
+                                    ..default()
+                                }),
                                 ..default()
                             },
                         ));
@@ -171,14 +190,21 @@ fn add_to_level(
 }
 
 fn prepare_lights(
+    mut shadow_mesh_query: Query<&mut ShadowMesh>,
     mut materials: ResMut<Assets<DarknessMaterial>>,
     mut images: ResMut<Assets<Image>>,
+    mut debug_draw: ResMut<DebugLines>,
+    debug_mode: Res<DebugMode>,
+    rapier_context: Res<RapierContext>,
+    visibility_blocker_query: Query<&VisibilityBlocker>,
+    transform_query: Query<&GlobalTransform>,
+    collider_query: Query<&Collider>,
     material_query: Query<&Handle<DarknessMaterial>>,
-    point_light_query: Query<(&GlobalTransform, &PointLight2D)>,
-    spot_light_query: Query<(&GlobalTransform, &SpotLight2D)>,
+    point_light_query: Query<(&GlobalTransform, &PointLight2D, Entity)>,
+    spot_light_query: Query<(&GlobalTransform, &SpotLight2D, Entity)>,
 ) {
-    let point_lights: Vec<(_, _)> = point_light_query.iter().collect();
-    let spot_lights: Vec<(_, _)> = spot_light_query.iter().collect();
+    let point_lights: Vec<(_, _, _)> = point_light_query.iter().collect();
+    let spot_lights: Vec<(_, _, _)> = spot_light_query.iter().collect();
     for handle in &material_query {
         let material = match materials.get_mut(handle) {
             Some(material) => material,
@@ -197,27 +223,62 @@ fn prepare_lights(
         point_lights
             .iter()
             .enumerate()
-            .for_each(|(i, (transform, light))| {
+            .for_each(|(i, (transform, light, entity))| {
+                let rect = light.aabb();
+                let polygon = get_light_geometry(
+                    &rapier_context,
+                    &visibility_blocker_query,
+                    &transform_query,
+                    &collider_query,
+                    Rect::from_corners(
+                        rect.min + transform.translation().truncate(),
+                        rect.max + transform.translation().truncate(),
+                    ),
+                );
+
+                if let Ok(mut shadow_mesh) = shadow_mesh_query.get_mut(*entity) {
+                    shadow_mesh.light_index = i;
+                    shadow_mesh.vertices = polygon
+                        .iter()
+                        .map(|point| ShadowVertex {
+                            point: *point,
+                            angle: f32::atan2(
+                                point.y - transform.translation().y,
+                                point.x - transform.translation().x,
+                            ),
+                        })
+                        .collect()
+                }
+
+                if debug_mode.enabled {
+                    for i in 0..polygon.len() {
+                        let p1 = polygon[i];
+                        let p2 = polygon[(i + 1) % polygon.len()];
+                        let t1 = i as f32 / polygon.len() as f32;
+                        let t2 = (i + 1) as f32 / polygon.len() as f32;
+                        let color1 = Color::rgba(1.0 - t1, t1, 0.0, 1.0);
+                        let color2 = Color::rgba(1.0 - t2, t2, 0.0, 1.0);
+                        debug_draw.line_gradient(
+                            p1.extend(0.0),
+                            p2.extend(0.0),
+                            0.0,
+                            color1,
+                            color2,
+                        );
+                    }
+                }
+
                 material.point_lights[i] = GpuPointLight2D {
                     position: transform.translation().truncate(),
                     radius: light.radius,
                 };
-                for x in 0..SHADOWMAP_RESOLUTION {
-                    let offset = (i * SHADOWMAP_RESOLUTION + x) * 4;
-                    let distance = x as f32 / SHADOWMAP_RESOLUTION as f32 * light.radius;
-                    let distance_bytes = bytes_of(&distance);
-                    shadowmap.data[offset + 0] = distance_bytes[0];
-                    shadowmap.data[offset + 1] = distance_bytes[1];
-                    shadowmap.data[offset + 2] = distance_bytes[2];
-                    shadowmap.data[offset + 3] = distance_bytes[3];
-                }
             });
 
         material.spot_light_count = spot_lights.len() as i32;
         spot_lights
             .iter()
             .enumerate()
-            .for_each(|(i, (transform, light))| {
+            .for_each(|(i, (transform, light, entity))| {
                 material.spot_lights[i] = GpuSpotLight2D {
                     position: transform.translation().truncate(),
                     radius: light.radius,
@@ -227,6 +288,7 @@ fn prepare_lights(
                     padding2: 0,
                     padding3: 0,
                 };
+                // TODO: Remove when shadowmapping is done
                 for x in 0..SHADOWMAP_RESOLUTION {
                     let offset = ((i + MAX_POINT_LIGHTS) * SHADOWMAP_RESOLUTION + x) * 4;
                     let distance = x as f32 / SHADOWMAP_RESOLUTION as f32 * light.radius;
@@ -239,3 +301,172 @@ fn prepare_lights(
             });
     }
 }
+
+fn prepare_shadows(
+    mut materials: ResMut<Assets<DarknessMaterial>>,
+    mut images: ResMut<Assets<Image>>,
+    shadow_mesh_query: Query<(&ShadowMesh, &GlobalTransform), Changed<ShadowMesh>>,
+    material_query: Query<&Handle<DarknessMaterial>>,
+) {
+    // TODO: Check that the shadow mesh overlaps the darkness material
+    for handle in &material_query {
+        let material = match materials.get_mut(handle) {
+            Some(material) => material,
+            None => continue,
+        };
+
+        let shadowmap = match &material.shadowmap_texture {
+            Some(handle) => match images.get_mut(&handle) {
+                Some(image) => image,
+                None => continue,
+            },
+            None => continue,
+        };
+
+        for (shadow_mesh, global_transform) in &shadow_mesh_query {
+            let shadow_map = calculate_shadow_map(
+                global_transform.translation().truncate(),
+                &shadow_mesh.vertices,
+            );
+            for x in 0..SHADOWMAP_RESOLUTION {
+                let offset = (shadow_mesh.light_index * SHADOWMAP_RESOLUTION + x) * 4;
+                let distance_bytes = bytes_of(&shadow_map[x]);
+                shadowmap.data[offset + 0] = distance_bytes[0];
+                shadowmap.data[offset + 1] = distance_bytes[1];
+                shadowmap.data[offset + 2] = distance_bytes[2];
+                shadowmap.data[offset + 3] = distance_bytes[3];
+            }
+        }
+    }
+}
+
+fn calculate_shadow_map(
+    global_position: Vec2,
+    vertices: &Vec<ShadowVertex>,
+) -> [f32; SHADOWMAP_RESOLUTION] {
+    let mut shadow_map = [0.0; SHADOWMAP_RESOLUTION];
+    let mut next_index = 0;
+    for x in 0..SHADOWMAP_RESOLUTION {
+        let angle = (x as f32 / SHADOWMAP_RESOLUTION as f32) * 2.0 * std::f32::consts::PI
+            - std::f32::consts::PI;
+        while angle >= vertices[next_index % vertices.len()].angle && next_index < vertices.len() {
+            next_index += 1;
+        }
+
+        let prev_vertex = if next_index == 0 {
+            vertices[vertices.len() - 1]
+        } else {
+            vertices[(next_index - 1) % vertices.len()]
+        };
+        let next_vertex = vertices[next_index % vertices.len()];
+
+        let distance = match vec2_intersection(
+            global_position,
+            global_position
+                + Vec2 {
+                    x: angle.cos(),
+                    y: angle.sin(),
+                },
+            prev_vertex.point,
+            next_vertex.point,
+        ) {
+            Some(point) => global_position.distance(point),
+            None => global_position.distance(prev_vertex.point),
+        };
+        shadow_map[x] = distance;
+    }
+    shadow_map
+}
+
+fn get_light_geometry(
+    rapier_context: &Res<RapierContext>,
+    visibility_blocker_query: &Query<&VisibilityBlocker>,
+    transform_query: &Query<&GlobalTransform>,
+    collider_query: &Query<&Collider>,
+    aabb: Rect,
+) -> Vec<Vec2> {
+    let mut points = vec![
+        Vec2::new(aabb.min.x, aabb.min.y),
+        Vec2::new(aabb.max.x, aabb.min.y),
+        Vec2::new(aabb.max.x, aabb.max.y),
+        Vec2::new(aabb.min.x, aabb.max.y),
+    ];
+
+    let collider = Collider::cuboid(aabb.half_size().x, aabb.half_size().y);
+    let mut filter = QueryFilter::new().exclude_sensors();
+    let predicate = |coll_entity| visibility_blocker_query.get(coll_entity).is_ok();
+    filter.predicate = Some(&predicate);
+
+    rapier_context.intersections_with_shape(aabb.center(), 0.0, &collider, filter, |coll| {
+        let transform = transform_query
+            .get(coll)
+            .expect("Collider should have GlobalTransform");
+        if let Ok(collider) = collider_query.get(coll) {
+            if let Some(cuboid) = collider.as_cuboid() {
+                let rect = Rect::from_center_half_size(
+                    transform.translation().truncate(),
+                    cuboid.half_extents(),
+                );
+                points.push(rect.min);
+                points.push(rect.max);
+                points.push(Vec2::new(rect.min.x, rect.max.y));
+                points.push(Vec2::new(rect.max.x, rect.min.y));
+            }
+        }
+        true
+    });
+
+    // FIXME: light source may not always be at bounding box center
+    // for example: optimal spot light bounding box
+    let center = aabb.center();
+    points.sort_unstable_by(|a, b| {
+        f32::atan2(a.y - center.y, a.x - center.x)
+            .partial_cmp(&f32::atan2(b.y - center.y, b.x - center.x))
+            .unwrap()
+    });
+
+    // Build visibility polygon
+    let mut polygon: Vec<_> = vec![];
+    for point in points.drain(..) {
+        /// We shoot 2 rays offset by this angle from the edge to catch what is beyond it.
+        const ANGLE_OFFSET: f32 = 0.0001;
+        /// Multiplier for hypotenuse when the other two sides are the same length. Or sqrt(2).
+        const HYPOTENUSE_MULT: f32 = 1.4142135623730951;
+        offset_cast(
+            aabb.center(),
+            (point - aabb.center()).normalize_or_zero(),
+            aabb.half_size().max_element() * HYPOTENUSE_MULT,
+            true,
+            filter,
+            ANGLE_OFFSET,
+            &rapier_context,
+        )
+        .iter()
+        .for_each(|ray| polygon.push(aabb.center() + *ray));
+    }
+
+    polygon
+}
+
+fn offset_cast(
+    ray_origin: Vec2,
+    ray_dir: Vec2,
+    max_toi: f32,
+    solid: bool,
+    filter: QueryFilter,
+    angle_offset: f32,
+    rapier_context: &Res<RapierContext>,
+) -> Vec<Vec2> {
+    let dir1 = Vec2::new((-angle_offset).cos(), (-angle_offset).sin()).rotate(ray_dir);
+    let dir2 = Vec2::new(angle_offset.cos(), angle_offset.sin()).rotate(ray_dir);
+    let ray1 = rapier_context.cast_ray(ray_origin, dir1, max_toi, solid, filter);
+    let ray2 = rapier_context.cast_ray(ray_origin, dir2, max_toi, solid, filter);
+    let toi1 = ray1.map_or(max_toi, |(_, toi)| toi);
+    let toi2 = ray2.map_or(max_toi, |(_, toi)| toi);
+
+    if (toi1 - toi2).abs() > toi1 * 0.1 {
+        vec![dir1 * toi1, dir2 * toi2]
+    } else {
+        vec![(dir1 * toi1 + dir2 * toi2) / 2.0]
+    }
+}

src/util.rs

@@ -124,6 +124,23 @@ pub fn move_towards_vec3(from: Vec3, to: Vec3, amount: f32) -> Vec3 {
     from + diff.normalize() * length.min(amount)
 }
 
+/// Get the intersection point (if any) of 2d lines a and b.
+/// Lines are defined by 2 points on the line
+pub fn vec2_intersection(a1: Vec2, a2: Vec2, b1: Vec2, b2: Vec2) -> Option<Vec2> {
+    let a_dir = a2 - a1;
+    let b_dir = b2 - b1;
+    let determinant = a_dir.perp_dot(b_dir);
+    if determinant.abs() <= f32::EPSILON {
+        return None;
+    }
+    Some(
+        Vec2 {
+            x: a_dir.x * (b1.x * b2.y - b1.y * b2.x) - (a1.x * a2.y - a1.y * a2.x) * b_dir.x,
+            y: (a1.x * a2.y - a1.y * a2.x) * -b_dir.y + a_dir.y * (b1.x * b2.y - b1.y * b2.x),
+        } / determinant,
+    )
+}
+
 pub fn loop_value(from: f32, to: f32, value: f32) -> f32 {
     let range = to - from;
     if !range.is_normal() {