Add aabb check for much fps!

src/hit3d.rs

@@ -1,3 +1,5 @@
+use bevy::{math::Vec3A, render::primitives::Aabb};
+
 use crate::prelude::*;
 
 /// Hit data for 3d objects in Global (not Local) space and the distance from the Camera
@@ -49,10 +51,52 @@ impl Triangle {
     }
 }
 
+pub(crate) fn intersects_aabb_3d(ray: &Ray3d, aabb: &Aabb, gt: &GlobalTransform) -> Option<Hit3d> {
+    let world_to_model = gt.compute_matrix().inverse();
+    let ray_dir: Vec3A =  world_to_model.transform_vector3(*ray.direction).into();
+    let ray_origin: Vec3A = world_to_model.transform_point3(ray.origin).into();
+
+    let t0 = (aabb.min() - ray_origin) / ray_dir;
+    let t1 = (aabb.max() - ray_origin) / ray_dir;
+    let t_min = t0.min(t1);
+    let t_max = t0.max(t1);
+
+    let mut hit_near = t_min.x;
+    let mut hit_far = t_max.x;
+
+    if hit_near > t_max.y || t_min.y > hit_far {
+        return None;
+    }
+
+    if t_min.y > hit_near {
+        hit_near = t_min.y;
+    }
+    if t_max.y < hit_far {
+        hit_far = t_max.y;
+    }
+
+    if (hit_near > t_max.z) || (t_min.z > hit_far) {
+        return None;
+    }
+
+    if t_min.z > hit_near {
+        hit_near = t_min.z;
+    }
+    if t_max.z < hit_far {
+        hit_far = t_max.z;
+    }
+    Some(Hit3d { distance: (hit_near + hit_far) / 2.0 })
+}
+
 /// 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 intersects3d(ray: &Ray3d, mesh: &Mesh, gt: &GlobalTransform) -> Option<Hit3d> {
+    // First do an Aabb intersection test
+    if let Some(aabb) = mesh.compute_aabb() {
+        // Do the Aabb test
+        if let Some(_) = intersects_aabb_3d(ray, &aabb, gt) {
+            // If it passes that do the real intersection test
             let attr = MeshVertexAttribute::new("Vertex_Position", 0, VertexFormat::Float32x3);
             if let Some(verts) = mesh.attribute(attr) {
                 if let Some(idxs) = mesh.indices() {
@@ -114,4 +158,10 @@ pub(crate) fn intersects3d(ray: &Ray3d, mesh: &Mesh, gt: &GlobalTransform) -> Op
             } else {
                 None
             }
+        } else {
+            None
+        }
+    } else {
+        None
+    }
 }