Basic 3d select implemented0

examples/select.rs

@@ -3,7 +3,6 @@
 /// Example to illustrate selecting objects in 3d space
 ///
 use bevy::{
-    math::Vec3A,
     prelude::*,
     render::mesh::MeshVertexAttribute,
     render::render_resource::{Extent3d, TextureDimension, TextureFormat},
@@ -153,10 +152,16 @@ impl Triangle {
     }
 }
 
+#[derive(Debug)]
+struct Hit {
+    distance: f32,
+    point: Vec3,
+}
+
 /// Heavily synthesized by these two things:
 /// * Textbook: https://www.scratchapixel.com/lessons/3d-basic-rendering/ray-tracing-rendering-a-triangle/ray-triangle-intersection-geometric-solution.html
 /// * Example: https://github.com/aevyrie/bevy_mod_raycast/blob/435d8ef100738797161ac3a9b910ea346a4ed6e6/src/raycast.rs#L43
-fn intersects(ray: &Ray, gt: &GlobalTransform, mesh: &Mesh) -> Option<f32> {
+fn intersects(ray: &Ray, gt: &GlobalTransform, mesh: &Mesh) -> Option<Hit> {
     let attr = MeshVertexAttribute::new("Vertex_Position", 0, VertexFormat::Float32x3);
     if let Some(verts) = mesh.attribute(attr) {
         if let Some(idxs) = mesh.indices() {
@@ -201,12 +206,15 @@ fn intersects(ray: &Ray, gt: &GlobalTransform, mesh: &Mesh) -> Option<f32> {
                                         && triangle.normal().dot(c1) > 0.0
                                         && triangle.normal().dot(c2) > 0.0
                                 };
-                                hit.then_some(d)
+                                hit.then_some(Hit {
+                                    distance: d,
+                                    point: p,
+                                })
                             } else {
                                 None
                             }
                         })
-                        .min_by(|a, b| a.total_cmp(b))
+                        .min_by(|a, b| a.distance.total_cmp(&b.distance))
                 }
                 _ => None,
             }

src/display3d.rs

@@ -4,8 +4,9 @@ use crate::{
 };
 use bevy::{
     core_pipeline::Skybox,
-    input::mouse::{MouseMotion, MouseWheel},
+    input::mouse::{MouseButtonInput, MouseMotion, MouseWheel},
     render::render_resource::{TextureViewDescriptor, TextureViewDimension},
+    window::PrimaryWindow,
 };
 
 pub(crate) struct Display3dPlugin;
@@ -25,6 +26,9 @@ impl Plugin for Display3dPlugin {
                     set_board_model.run_if(any_component_added::<Board3d>),
                     set_piece_position.run_if(any_component_changed::<BoardIndex>),
                     set_piece_texture.run_if(any_component_changed::<Side>),
+                    select_3d
+                        .run_if(in_state(GameState::Display3d))
+                        .run_if(on_event::<MouseButtonInput>()),
                 ),
             )
             .add_systems(
@@ -37,6 +41,7 @@ impl Plugin for Display3dPlugin {
                     mouse_zoom
                         .run_if(in_state(GameState::Display3d))
                         .run_if(on_event::<MouseWheel>()),
+                    selected_gizmo,
                 )
                     .run_if(resource_exists::<debug::DebugEnabled>()),
             )
@@ -229,15 +234,18 @@ fn gizmo_system(mut gizmos: Gizmos) {
 
 /// TODO: This has bad feel, needs to be tuned
 fn move_camera(
+    buttons: Res<Input<MouseButton>>,
     mut events: EventReader<MouseMotion>,
     mut camera: Query<&mut Transform, (With<Display3d>, With<Camera>)>,
 ) {
     events.iter().for_each(|MouseMotion { delta }| {
+        if buttons.pressed(MouseButton::Left) {
             camera.iter_mut().for_each(|mut t| {
                 t.rotate_around(Vec3::ZERO, Quat::from_rotation_y(delta.x / 256.0));
                 t.rotate_around(Vec3::ZERO, Quat::from_rotation_x(delta.y / 256.0));
                 t.look_at(Vec3::ZERO, Vec3::Y);
             });
+        }
     });
 }
 
@@ -367,3 +375,66 @@ fn set_piece_texture(
         }
     })
 }
+
+/// Function for selecting entities based on ray intersection
+fn select_3d(
+    mut events: EventReader<MouseButtonInput>,
+    query: Query<(Entity, &Handle<Mesh>, &GlobalTransform)>,
+    meshes: Res<Assets<Mesh>>,
+    cameras: Query<(&Camera, &GlobalTransform)>,
+    windows: Query<&Window, With<PrimaryWindow>>,
+    parents: Query<Entity, (With<Piece3d>, Without<game::Selected>)>,
+    children: Query<&Children>,
+    mut commands: Commands,
+    selected: Query<Entity, (With<game::Selected>, With<Piece3d>)>,
+) {
+    events
+        .iter()
+        .filter(|ev| ev.state == ButtonState::Pressed)
+        .for_each(|_| {
+            windows.iter().for_each(|window| {
+                window.cursor_position().and_then(|pos| {
+                    cameras.iter().for_each(|(camera, gt)| {
+                        camera.viewport_to_world(gt, pos).and_then(|ray| {
+                            query
+                                .iter()
+                                .filter_map(|(entity, handle, gt)| {
+                                    meshes.get(handle).map(|mesh| (entity, mesh, gt))
+                                })
+                                .for_each(|(entity, mesh, gt)| {
+                                    hit3d::intersects(&ray, mesh, &gt).and_then(|_hit| {
+                                        parents
+                                            .iter()
+                                            .find(|&parent| {
+                                                children
+                                                    .iter_descendants(parent)
+                                                    .any(|child| child == entity)
+                                            })
+                                            .iter()
+                                            .for_each(|&parent| {
+                                                // TODO: Only remove/insert component if different
+                                                selected.iter().for_each(|s| {
+                                                    commands.entity(s).remove::<game::Selected>();
+                                                });
+                                                commands.entity(parent).insert(game::Selected);
+                                            });
+                                        Some(())
+                                    });
+                                });
+                            Some(())
+                        });
+                    });
+                    Some(())
+                });
+            });
+        });
+}
+
+fn selected_gizmo(
+    selected: Query<&Transform, (With<game::Selected>, With<Piece3d>)>,
+    mut gizmos: Gizmos,
+) {
+    selected.iter().for_each(|transform| {
+        gizmos.cuboid(transform.clone(), Color::GREEN);
+    })
+}

src/hit3d.rs

@@ -0,0 +1,117 @@
+use bevy::render::{
+    mesh::{MeshVertexAttribute, VertexAttributeValues},
+    render_resource::VertexFormat,
+};
+
+use crate::prelude::*;
+
+/// Struct containing hit data
+/// The point in Global (not Local) space and the distance from the Camera
+#[derive(Debug)]
+pub(crate) struct Hit {
+    distance: f32,
+    point: Vec3,
+}
+
+/// A 3D Triangle used for ray-intersection tests
+#[derive(Debug)]
+struct Triangle {
+    v0: Vec3,
+    v1: Vec3,
+    v2: Vec3,
+}
+
+/// Helper functions for ray-intersect testing
+impl Triangle {
+    fn normal(&self) -> Vec3 {
+        (self.edge_a()).cross(self.edge_b())
+    }
+
+    fn edge_a(&self) -> Vec3 {
+        self.v1 - self.v0
+    }
+
+    fn edge_b(&self) -> Vec3 {
+        self.v2 - self.v0
+    }
+
+    fn edge0(&self) -> Vec3 {
+        self.v1 - self.v0
+    }
+
+    fn edge1(&self) -> Vec3 {
+        self.v2 - self.v1
+    }
+
+    fn edge2(&self) -> Vec3 {
+        self.v0 - self.v2
+    }
+}
+
+/// Heavily synthesized from these two resources:
+/// * Textbook: https://www.scratchapixel.com/lessons/3d-basic-rendering/ray-tracing-rendering-a-triangle/ray-triangle-intersection-geometric-solution.html
+/// * Example: https://github.com/aevyrie/bevy_mod_raycast/blob/435d8ef100738797161ac3a9b910ea346a4ed6e6/src/raycast.rs#L43
+pub(crate) fn intersects(ray: &Ray, mesh: &Mesh, gt: &GlobalTransform) -> Option<Hit> {
+    let attr = MeshVertexAttribute::new("Vertex_Position", 0, VertexFormat::Float32x3);
+    if let Some(verts) = mesh.attribute(attr) {
+        if let Some(idxs) = mesh.indices() {
+            match verts {
+                VertexAttributeValues::Float32x3(vals) => {
+                    idxs.iter()
+                        .array_chunks::<3>()
+                        // Convert arrays to vec3
+                        .map(|[x, y, z]| {
+                            [
+                                Vec3::from_array(vals[x]),
+                                Vec3::from_array(vals[y]),
+                                Vec3::from_array(vals[z]),
+                            ]
+                        })
+                        // Transform each point by the global transform
+                        .map(|[a, b, c]| {
+                            [
+                                gt.transform_point(a),
+                                gt.transform_point(b),
+                                gt.transform_point(c),
+                            ]
+                        })
+                        // Collect everything into a triangle for easy operations
+                        .map(|[v0, v1, v2]| Triangle { v0, v1, v2 })
+                        .filter_map(|triangle| {
+                            // Calculate the distance this ray hits the plane normal to the tri
+                            if let Some(d) = ray.intersect_plane(triangle.v0, triangle.normal()) {
+                                // Calculate the point on that plane which intersects
+                                let p = ray.get_point(d);
+                                // Inside out test
+                                let hit = {
+                                    // Determine if p is w/in edge0
+                                    let c0 = triangle.edge0().cross(p - triangle.v0);
+                                    // Determine if p is w/in edge1
+                                    let c1 = triangle.edge1().cross(p - triangle.v1);
+                                    // Determine if p is w/in edge2
+                                    let c2 = triangle.edge2().cross(p - triangle.v2);
+
+                                    // Check all three at once
+                                    triangle.normal().dot(c0) > 0.0
+                                        && triangle.normal().dot(c1) > 0.0
+                                        && triangle.normal().dot(c2) > 0.0
+                                };
+                                hit.then_some(Hit {
+                                    distance: d,
+                                    point: p,
+                                })
+                            } else {
+                                None
+                            }
+                        })
+                        .min_by(|a, b| a.distance.total_cmp(&b.distance))
+                }
+                _ => None,
+            }
+        } else {
+            None
+        }
+    } else {
+        None
+    }
+}

src/main.rs

@@ -1,9 +1,12 @@
+#![feature(iter_array_chunks)] // used in ray.rs
+
 mod audio;
 mod credits;
 mod debug;
 mod display2d;
 mod display3d;
 mod game;
+mod hit3d;
 mod loading;
 mod menu;
 mod prelude;