Complete triangle mesh code (and more refactoring)

README.md

@@ -24,7 +24,7 @@ This list may be changed or extended in the future.
   - [x] Triangle normal generation
   - [x] Color mapping on triangles
   - [x] Triangle mesh struct
-  - [ ] Triangle mesh intersection test
+  - [x] Triangle mesh intersection test
 - [ ] Bounding boxes
 - [ ] Direct lighting
   - [ ] Point light sources

src/main.rs

@@ -52,13 +52,10 @@ fn render(camera: &Camera, scene: &Scene, filename: &str) -> std::io::Result<()>
 
 fn main() -> std::io::Result<()> {
 
-    let camera = Camera::new(Point3::new(0.0,1.0,0.0), Vector3::new(0.0,0.0,1.0), 1.0, 16.0 / 9.0, 2.0, 720);
+    let camera = Camera::new(Point3::new(0.0,0.0,0.0), Vector3::new(0.0,0.0,1.0), 1.0, 16.0 / 9.0, 2.0, 480);
 
     let scene = vec![
-        Object::new(Plane::new(Point3::new(0.0, 0.0, -1.0), Vector3::x(), Vector3::z(),
+        Object::new(TriangleMesh::singleton(Point3::new(-1.0, -1.0, 3.0), Point3::new(0.0, 1.0, 3.0), Point3::new(1.0, -1.0, 3.0), |t, u, v| Color::new(t, u, v)))
-            |x, y| Color::gray(y / 30.0)
-        )),
-        Object::new(Sphere::new(0.0, 1.0, 4.0, 1.0, |x, y| Color::new(0.0, x, y)))
     ];
 
     render(&camera, &scene, "out.ppm")

src/object/plane.rs

@@ -17,6 +17,7 @@ pub struct Plane {
                                             // Input coordinates are defined in terms of the axes above.
 }
 
+#[allow(dead_code)]
 impl Plane {
     // Creates a new plane.
     pub fn new<F: 'static>(center: Point3<f32>, x_axis: Vector3<f32>, y_axis: Vector3<f32>, texture: F) -> Self

src/object/sphere.rs

@@ -16,6 +16,7 @@ pub struct Sphere {
                                             // Uses spherical coordinates (normalized from 0-1) as input.
 }
 
+#[allow(dead_code)]
 impl Sphere {
     // Creates a new sphere.
     pub fn new<F: 'static>(x: f32, y: f32, z: f32, radius: f32, texture: F) -> Self

src/object/triangle.rs

@@ -1,5 +1,7 @@
 extern crate nalgebra as na;
 
+use std::cmp::Ordering;
+
 use na::*;
 use na::geometry::Point3;
 
@@ -11,6 +13,7 @@ pub struct Triangle {
     pub v2: usize,
     pub v3: usize,
 
+    normal: Unit<Vector3<f32>>, // Precalculated normal vector.
     area: f32, // Precalculated area for barycentric calculations.
 
     texture: Box<dyn Fn(f32, f32, f32) -> Color> // Texture map.
@@ -18,7 +21,7 @@ pub struct Triangle {
 }
 
 pub struct TriangleMesh {
-    pub points: Vec<Point3<f32>>,
+    pub vertices: Vec<Point3<f32>>,
     pub tris: Vec<Triangle>
 }
 
@@ -47,7 +50,7 @@ impl Triangle {
         (t, u, v)
     }
 
-    fn intersect(&self, vertices: &Vec<Point3<f32>>, ray: Ray) -> Option<f32> {
+    fn intersect_(&self, vertices: &Vec<Point3<f32>>, ray: Ray) -> Option<(f32, f32, f32)> {
         let vect2_1 = self.vertex2(vertices) - self.vertex1(vertices);
         let vect3_1 = self.vertex3(vertices) - self.vertex1(vertices);
 
@@ -66,53 +69,51 @@ impl Triangle {
 
         if v < 0.0 || (u + v) > 1.0 { return None; }
 
-        let t = vect3_1.dot(&q_vect) / det;
+        let t = 1.0 - u - v;
 
-        // Convert from barycentric coordinates
+        Some((t, u, v))
-        Some(distance(&ray.origin, &self.from_bary(vertices, t, u, v)))
     }
 
-    fn normal(&self, vertices: &Vec<Point3<f32>>, _point: Point3<f32>) -> Unit<Vector3<f32>> {
+    fn intersect(&self, vertices: &Vec<Point3<f32>>, ray: Ray) -> Option<f32> {
-        Unit::new_normalize((self.vertex2(vertices) - self.vertex1(vertices)).cross(&(self.vertex3(vertices) - self.vertex1(vertices))))
+        self.intersect_(vertices, ray).map(|(t, u, v)| distance(&ray.origin, &self.from_bary(vertices, t, u, v)))
     }
 
     fn getcolor(&self, vertices: &Vec<Point3<f32>>, point: Point3<f32>) -> Color {
-        // Converting back and forth between barycentric coordinates
-        // like this is terrible, but it's necessary for this object to
-        // match the interface the other objects use.
         let (t, u, v) = self.to_bary(vertices, point);
-
         (*self.texture)(t, u, v)
     }
 }
 
+#[allow(dead_code)]
 impl TriangleMesh {
-    pub fn new(points: Vec<Point3<f32>>, tris: Vec<(usize, usize, usize, Box<dyn Fn(f32, f32, f32) -> Color>)>) -> Self {
+    pub fn new(vertices: Vec<Point3<f32>>, tris: Vec<(usize, usize, usize, Box<dyn Fn(f32, f32, f32) -> Color>)>) -> Self {
         let triangles = tris.into_iter()
                             .map(|(v1, v2, v3, f)| Triangle {
                                 v1: v1,
                                 v2: v2,
                                 v3: v3,
-                                area: tri_area(&points[v1], &points[v2], &points[v3]),
+                                normal: Unit::new_normalize((&vertices[v2] - &vertices[v1]).cross(&(&vertices[v3] - &vertices[v1]))),
+                                area: tri_area(&vertices[v1], &vertices[v2], &vertices[v3]),
                                 texture: f
                             }).collect();
         TriangleMesh {
-            points: points,
+            vertices: vertices,
             tris: triangles
         }
     }
 
-    pub fn new_solid(points: Vec<Point3<f32>>, tris: Vec<(usize, usize, usize)>, color: Color) -> Self {
+    pub fn new_solid(vertices: Vec<Point3<f32>>, tris: Vec<(usize, usize, usize)>, color: Color) -> Self {
         let triangles = tris.into_iter()
                             .map(|(v1, v2, v3)| Triangle {
                                 v1: v1,
                                 v2: v2,
                                 v3: v3,
-                                area: tri_area(&points[v1], &points[v2], &points[v3]),
+                                normal: Unit::new_normalize((&vertices[v2] - &vertices[v1]).cross(&(&vertices[v3] - &vertices[v1]))),
+                                area: tri_area(&vertices[v1], &vertices[v2], &vertices[v3]),
                                 texture: Box::new(move |_, _, _| color)
                             }).collect();
         TriangleMesh {
-            points: points,
+            vertices: vertices,
             tris: triangles
         }
     }
@@ -120,3 +121,82 @@ impl TriangleMesh {
     pub fn singleton<F: 'static>(vertex1: Point3<f32>, vertex2: Point3<f32>, vertex3: Point3<f32>, texture: F) -> Self
         where F: Fn(f32, f32, f32) -> Color
         { TriangleMesh::new(vec![vertex1, vertex2, vertex3], vec![(0, 1, 2, Box::new(texture))]) }
+
+    pub fn singleton_solid(vertex1: Point3<f32>, vertex2: Point3<f32>, vertex3: Point3<f32>, color: Color) -> Self
+        { TriangleMesh::singleton(vertex1, vertex2, vertex3, move |_, _, _| color) }
+
+
+    fn closest_tri(&self, point: Point3<f32>) -> &Triangle {
+        self.tris.iter()
+            .map(move |tri| {
+
+                let rel_pos = point - tri.vertex1(&self.vertices);
+                let proj_point3 = rel_pos - (*tri.normal * tri.normal.dot(&rel_pos));
+
+                let (t, u, v) = tri.to_bary(&self.vertices, Point3::from(proj_point3));
+
+                let t = clamp(t, 0.0, 1.0);
+                let u = clamp(u, 0.0, 1.0);
+                let v = clamp(v, 0.0, 1.0);
+
+                let point_new = tri.from_bary(&self.vertices, t, u, v);
+
+                (tri, distance(&point, &point_new))
+            })
+            .min_by(|a, b| a.1.partial_cmp(&b.1).unwrap_or(Ordering::Equal))
+            .unwrap().0
+    }
+}
+
+impl Surface for TriangleMesh {
+    fn intersect(&self, ray: Ray) -> Option<f32> {
+        self.tris.iter()
+             .filter_map(|tri| tri.intersect(&self.vertices, ray))
+             .min_by(|a, b| a.partial_cmp(&b).unwrap_or(Ordering::Equal))
+    }
+
+    fn normal(&self, point: Point3<f32>) -> Unit<Vector3<f32>> {
+        self.closest_tri(point).normal
+    }
+
+    fn getcolor(&self, point: Point3<f32>) -> Color {
+        self.closest_tri(point).getcolor(&self.vertices, point)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    fn roundcolor(color: Color) -> Color {
+        Color::new((color.red * 100.0).round() / 100.0, (color.green * 100.0).round() / 100.0, (color.blue * 100.0).round() / 100.0)
+    }
+
+    #[test]
+    fn triangle_intersect() {
+        let triangle = TriangleMesh::singleton_solid(Point3::new(0.0, 0.0, 0.0), Point3::new(1.0, 1.0, 0.0), Point3::new(0.0, 0.0, 1.0), Color::black());
+
+        let ray = Ray::new(Point3::new(0.5, 5.0, 0.3), Vector3::new(0.0, -1.0, 0.0));
+
+        let (t, u, v) = triangle.tris[0].intersect_(&triangle.vertices, ray).unwrap();
+
+        println!("{},{},{}", t, u, v);
+
+        assert!(t >= 0.0 && t <= 1.0);
+        assert!(u >= 0.0 && u <= 1.0);
+        assert!(v >= 0.0 && v <= 1.0);
+    }
+
+    #[test]
+    fn triangle_getcolor() {
+        let triangle = TriangleMesh::singleton(Point3::new(0.0, 0.0, 0.0), Point3::new(1.0, 1.0, 0.0), Point3::new(0.0, 0.0, 1.0), |t, u, v| Color::new(t, u, v));
+
+        let t = 0.4;
+        let u = 0.1;
+        let v = 1.0 - t - u;
+
+        let point = triangle.tris[0].from_bary(&triangle.vertices, t, u, v);
+
+        assert_eq!(roundcolor(triangle.getcolor(point)), roundcolor(Color::new(t, u, v)));
+    }
+}