Add an example for projection (#250)

CHANGELOG.md

@@ -4,7 +4,8 @@
 
 ### Added
 
-- `TriMesh` now implements `Shape::feature_normal_at_point` to retrieve the normal of a face, when passing a `FeatureId::Face`.
+- Implement `::to_trimesh` in 2d for `Cuboid` and `Aabb`.
+- Implement `Shape::feature_normal_at_point` for `TriMesh` to retrieve the normal of a face, when passing a `FeatureId::Face`.
 
 ## v0.17.1
 

crates/parry2d/examples/common_macroquad2d.rs

@@ -0,0 +1,109 @@
+use std::f32::consts::{FRAC_PI_2, FRAC_PI_4};
+
+use macroquad::prelude::*;
+use macroquad::{
+    color::{Color, WHITE},
+    math::Vec2,
+    shapes::draw_line,
+};
+use nalgebra::Point2;
+use parry2d::math::Real;
+use parry2d::shape::TriMesh;
+
+#[allow(dead_code)]
+fn main() {
+    println!(
+        "This module contains helper functions to use macroquad,
+    isolated from the rest of the examples for the sake of simplicity."
+    );
+}
+
+#[allow(dead_code)]
+pub fn mquad_from_na(a: Point2<Real>) -> Vec2 {
+    Vec2::new(a.x, a.y)
+}
+
+#[allow(dead_code)]
+pub fn na_from_mquad(a: Vec2) -> Point2<Real> {
+    Point2::new(a.x, a.y)
+}
+
+#[allow(dead_code)]
+pub fn draw_polyline(polygon: Vec<(Vec2, Vec2)>, color: Color) {
+    for i in 0..polygon.len() {
+        let a = polygon[i].0;
+        let b = polygon[i].1;
+        draw_line_2d(a, b, color);
+    }
+}
+
+#[allow(dead_code)]
+pub fn easy_draw_text(text: &str) {
+    macroquad::text::draw_text(text, 10.0, 48.0 + 18.0, 30.0, WHITE);
+}
+
+#[allow(dead_code)]
+pub fn lissajous_2d(t: f32) -> Vec2 {
+    // Some hardcoded parameters to have a pleasing lissajous trajectory.
+    let (a, b, delta_x, delta_y) = (3.0, 2.0, FRAC_PI_2, FRAC_PI_4);
+
+    let x = (a * t + delta_x).sin();
+    let y = (b * t + delta_y).sin();
+    Vec2::new(x, y) * 0.75f32
+}
+
+#[allow(dead_code)]
+pub fn draw_line_2d(a: Vec2, b: Vec2, color: Color) {
+    draw_line(a.x, a.y, b.x, b.y, 2f32, color);
+}
+
+#[allow(dead_code)]
+pub fn draw_trimesh2(trimesh: &TriMesh, offset: Vec2) {
+    let vertices = trimesh.vertices();
+    for v in trimesh.indices() {
+        let v0 = mquad_from_na(vertices[v[0] as usize]) + offset;
+        let v1 = mquad_from_na(vertices[v[1] as usize]) + offset;
+        let v2 = mquad_from_na(vertices[v[2] as usize]) + offset;
+
+        draw_line(v0.x, v0.y, v1.x, v1.y, 2f32, WHITE);
+        draw_line(v0.x, v0.y, v2.x, v2.y, 2f32, WHITE);
+        draw_line(v2.x, v2.y, v1.x, v1.y, 2f32, WHITE);
+    }
+}
+
+#[allow(dead_code)]
+pub fn draw_polygon(polygon: &[Point2<f32>], scale: f32, shift: Point2<f32>, color: Color) {
+    for i in 0..polygon.len() {
+        let a = polygon[i];
+        let b = polygon[(i + 1) % polygon.len()];
+        draw_line(
+            a.x * scale + shift.x,
+            a.y * scale + shift.y,
+            b.x * scale + shift.x,
+            b.y * scale + shift.y,
+            2.0,
+            color,
+        );
+    }
+}
+
+#[allow(dead_code)]
+pub fn draw_point(point: Point2<f32>, scale: f32, shift: Point2<f32>, color: Color) {
+    let edge_len = 0.15;
+    draw_line(
+        (point.x - edge_len) * scale + shift.x,
+        point.y * scale + shift.y,
+        (point.x + edge_len) * scale + shift.x,
+        point.y * scale + shift.y,
+        2.0,
+        color,
+    );
+    draw_line(
+        point.x * scale + shift.x,
+        (point.y - edge_len) * scale + shift.y,
+        point.x * scale + shift.x,
+        (point.y + edge_len) * scale + shift.y,
+        2.0,
+        color,
+    );
+}

crates/parry2d/examples/point_in_poly2d.rs

@@ -1,3 +1,6 @@
+mod common_macroquad2d;
+
+use common_macroquad2d::{draw_point, draw_polygon};
 use macroquad::prelude::*;
 use nalgebra::{Point2, UnitComplex, Vector2};
 use parry2d::utils::point_in_poly2d;
@@ -15,14 +18,14 @@ async fn main() {
     loop {
         clear_background(BLACK);
 
-        /*
-         * Compute polygon intersections.
-         */
         spikes
             .iter_mut()
             .for_each(|pt| *pt = animation_rotation * *pt);
         draw_polygon(&spikes, RENDER_SCALE, spikes_render_pos, BLUE);
 
+        /*
+         * Compute polygon intersections.
+         */
         for point in &test_points {
             if point_in_poly2d(point, &spikes) {
                 draw_point(*point, RENDER_SCALE, spikes_render_pos, RED);
@@ -71,38 +74,3 @@ fn grid_points() -> Vec<Point2<f32>> {
     }
     pts
 }
-
-fn draw_polygon(polygon: &[Point2<f32>], scale: f32, shift: Point2<f32>, color: Color) {
-    for i in 0..polygon.len() {
-        let a = polygon[i];
-        let b = polygon[(i + 1) % polygon.len()];
-        draw_line(
-            a.x * scale + shift.x,
-            a.y * scale + shift.y,
-            b.x * scale + shift.x,
-            b.y * scale + shift.y,
-            2.0,
-            color,
-        );
-    }
-}
-
-fn draw_point(point: Point2<f32>, scale: f32, shift: Point2<f32>, color: Color) {
-    let edge_len = 0.15;
-    draw_line(
-        (point.x - edge_len) * scale + shift.x,
-        point.y * scale + shift.y,
-        (point.x + edge_len) * scale + shift.x,
-        point.y * scale + shift.y,
-        2.0,
-        color,
-    );
-    draw_line(
-        point.x * scale + shift.x,
-        (point.y - edge_len) * scale + shift.y,
-        point.x * scale + shift.x,
-        (point.y + edge_len) * scale + shift.y,
-        2.0,
-        color,
-    );
-}

crates/parry2d/examples/polygons_intersection2d.rs

@@ -1,3 +1,6 @@
+mod common_macroquad2d;
+
+use common_macroquad2d::draw_polygon;
 use macroquad::prelude::*;
 use nalgebra::{Point2, UnitComplex, Vector2};
 use parry2d::shape::Ball;
@@ -111,18 +114,3 @@ fn spikes_polygon() -> Vec<Point2<f32>> {
 
     polygon
 }
-
-fn draw_polygon(polygon: &[Point2<f32>], scale: f32, shift: Point2<f32>, color: Color) {
-    for i in 0..polygon.len() {
-        let a = polygon[i];
-        let b = polygon[(i + 1) % polygon.len()];
-        draw_line(
-            a.x * scale + shift.x,
-            a.y * scale + shift.y,
-            b.x * scale + shift.x,
-            b.y * scale + shift.y,
-            2.0,
-            color,
-        );
-    }
-}

crates/parry2d/examples/project_point2d.rs

@@ -0,0 +1,89 @@
+mod common_macroquad2d;
+
+use common_macroquad2d::{draw_line_2d, draw_trimesh2, lissajous_2d, mquad_from_na, na_from_mquad};
+use macroquad::prelude::*;
+use nalgebra::{Point3, UnitComplex, Vector2};
+use parry2d::math::{Isometry, Translation};
+use parry2d::query::PointQuery;
+use parry2d::shape::{Cuboid, TriMesh, TriMeshFlags};
+
+#[macroquad::main("parry3d::query::PlaneIntersection")]
+async fn main() {
+    //
+    // This is useful to test for https://github.com/dimforge/parry/pull/248
+    let _points = vec![
+        Point3::from([0.0, 0.0, 0.0]),
+        Point3::from([0.0, 0.0, 1.0]),
+        Point3::from([1.0, 0.0, 0.0]),
+        Point3::from([1.0, 0.0, 1.0]),
+    ];
+    let _indices: Vec<[u32; 3]> = vec![[0, 1, 2], [1, 3, 2]];
+
+    let scale = 200f32;
+    let (points, indices) = Cuboid::new(Vector2::new(0.2 * scale, 0.5 * scale)).to_trimesh();
+
+    let trimesh = TriMesh::with_flags(points, indices, TriMeshFlags::ORIENTED);
+    for _i in 1.. {
+        clear_background(BLACK);
+
+        let elapsed_time = get_time() as f32;
+        let slow_elapsed_time = elapsed_time / 3.0;
+
+        let offset = Vec2::new(screen_width() / 2f32, screen_height() / 2f32);
+
+        let point_to_project = lissajous_2d(slow_elapsed_time) * scale + offset;
+        let translation = Translation::new(offset.x, offset.y);
+        let rot = UnitComplex::identity();
+        let projected_point = trimesh.project_point(
+            &Isometry::from_parts(translation, rot),
+            &na_from_mquad(point_to_project),
+            true,
+        );
+
+        /*
+         *
+         * Render the projection
+         *
+         */
+        let color = if projected_point.is_inside {
+            RED
+        } else {
+            YELLOW
+        };
+
+        draw_line_2d(
+            point_to_project,
+            mquad_from_na(projected_point.point),
+            color,
+        );
+        draw_circle(point_to_project.x, point_to_project.y, 10f32, color);
+
+        draw_line_2d(
+            point_to_project,
+            mquad_from_na(projected_point.point),
+            color,
+        );
+
+        // fixed local point inside the shape
+        let point_to_project = Vec2::ZERO;
+        let projected_point = trimesh.project_local_point(&na_from_mquad(point_to_project), true);
+        let color = if projected_point.is_inside {
+            RED
+        } else {
+            YELLOW
+        };
+        // convert to "world" space
+        let point_to_project = point_to_project * scale + offset;
+        draw_circle(point_to_project.x, point_to_project.y, 10f32, color);
+
+        draw_line_2d(
+            point_to_project,
+            mquad_from_na(projected_point.point) * scale + offset,
+            color,
+        );
+        // Mesh is rendered in the back, so we can see the other graphics elements
+        draw_trimesh2(&trimesh, offset);
+
+        next_frame().await
+    }
+}

crates/parry2d/examples/raycasts_animated.rs

@@ -1,3 +1,6 @@
+mod common_macroquad2d;
+
+use common_macroquad2d::draw_point;
 use macroquad::prelude::*;
 use nalgebra::{Isometry2, Point2, UnitComplex, Vector2};
 use parry2d::math::Isometry;
@@ -99,26 +102,6 @@ fn draw_polygon(
     }
 }
 
-fn draw_point(point: Point2<f32>, scale: f32, shift: Point2<f32>, color: Color) {
-    let edge_len = 0.15;
-    draw_line(
-        (point.x - edge_len) * scale + shift.x,
-        point.y * scale + shift.y,
-        (point.x + edge_len) * scale + shift.x,
-        point.y * scale + shift.y,
-        2.0,
-        color,
-    );
-    draw_line(
-        point.x * scale + shift.x,
-        (point.y - edge_len) * scale + shift.y,
-        point.x * scale + shift.x,
-        (point.y + edge_len) * scale + shift.y,
-        2.0,
-        color,
-    );
-}
-
 fn drawline_from_to(
     from: Point2<f32>,
     to: Point2<f32>,

crates/parry3d/Cargo.toml

@@ -173,6 +173,11 @@ name = "plane3d"
 path = "examples/plane3d.rs"
 doc-scrape-examples = true
 
+[[example]]
+name = "plane_intersection"
+path = "examples/plane_intersection.rs"
+doc-scrape-examples = true
+
 [[example]]
 name = "polyline3d"
 path = "examples/polyline3d.rs"