picking + entity names
This commit is contained in:
Jonas H
245
src/picking.rs
245
src/picking.rs
@@ -1,7 +1,10 @@
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use crate::camera::Camera;
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use crate::mesh::Mesh;
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use glam::{Mat4, Vec3, Vec4};
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use crate::components::TreeInstancesComponent;
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use crate::entity::EntityHandle;
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use crate::loaders::mesh::Mesh;
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use crate::world::World;
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pub struct Ray
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{
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pub origin: Vec3,
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@@ -15,7 +18,8 @@ impl Ray
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screen_y: f32,
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screen_width: u32,
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screen_height: u32,
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camera: &Camera,
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view: &Mat4,
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projection: &Mat4,
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) -> Self
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{
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let ndc_x = (2.0 * screen_x) / screen_width as f32 - 1.0;
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@@ -23,10 +27,8 @@ impl Ray
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let clip_coords = Vec4::new(ndc_x, ndc_y, -1.0, 1.0);
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let view_matrix = camera.view_matrix();
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let projection_matrix = camera.projection_matrix();
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let inv_projection = projection_matrix.inverse();
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let inv_view = view_matrix.inverse();
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let inv_projection = projection.inverse();
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let inv_view = view.inverse();
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let eye_coords = inv_projection * clip_coords;
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let eye_coords = Vec4::new(eye_coords.x, eye_coords.y, -1.0, 0.0);
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@@ -34,54 +36,215 @@ impl Ray
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let world_coords = inv_view * eye_coords;
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let direction = Vec3::new(world_coords.x, world_coords.y, world_coords.z).normalize();
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Ray {
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origin: camera.position,
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direction,
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}
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let origin = inv_view.col(3).truncate();
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Ray { origin, direction }
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}
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pub fn intersects_mesh(&self, mesh: &Mesh, transform: &Mat4) -> Option<f32>
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pub fn intersects_aabb(&self, min: Vec3, max: Vec3) -> Option<f32>
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{
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let inv_transform = transform.inverse();
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let local_origin = inv_transform.transform_point3(self.origin);
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let local_direction = inv_transform.transform_vector3(self.direction).normalize();
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let inv_dir = Vec3::new(
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1.0 / self.direction.x,
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1.0 / self.direction.y,
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1.0 / self.direction.z,
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);
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let mut closest_distance = f32::MAX;
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let mut hit = false;
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let t1 = (min - self.origin) * inv_dir;
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let t2 = (max - self.origin) * inv_dir;
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for triangle_idx in (0..mesh.num_indices).step_by(3)
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let tmin = t1.min(t2);
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let tmax = t1.max(t2);
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let tenter = tmin.x.max(tmin.y).max(tmin.z);
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let texit = tmax.x.min(tmax.y).min(tmax.z);
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if tenter <= texit && texit >= 0.0
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{
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let distance =
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self.intersects_triangle_local(local_origin, local_direction, mesh, triangle_idx);
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if let Some(d) = distance
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{
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if d < closest_distance
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{
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closest_distance = d;
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hit = true;
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}
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}
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}
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if hit
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{
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Some(closest_distance)
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Some(tenter.max(0.0))
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}
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else
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{
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None
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}
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}
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}
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fn intersects_triangle_local(
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&self,
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local_origin: Vec3,
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local_direction: Vec3,
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_mesh: &Mesh,
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_triangle_idx: u32,
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) -> Option<f32>
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fn transform_aabb(aabb_min: Vec3, aabb_max: Vec3, model: &Mat4) -> (Vec3, Vec3)
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{
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let corners = [
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Vec3::new(aabb_min.x, aabb_min.y, aabb_min.z),
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Vec3::new(aabb_max.x, aabb_min.y, aabb_min.z),
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Vec3::new(aabb_min.x, aabb_max.y, aabb_min.z),
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Vec3::new(aabb_max.x, aabb_max.y, aabb_min.z),
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Vec3::new(aabb_min.x, aabb_min.y, aabb_max.z),
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Vec3::new(aabb_max.x, aabb_min.y, aabb_max.z),
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Vec3::new(aabb_min.x, aabb_max.y, aabb_max.z),
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Vec3::new(aabb_max.x, aabb_max.y, aabb_max.z),
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];
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let mut world_min = Vec3::splat(f32::MAX);
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let mut world_max = Vec3::splat(f32::MIN);
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for corner in &corners
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{
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let world_corner = model.transform_point3(*corner);
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world_min = world_min.min(world_corner);
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world_max = world_max.max(world_corner);
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}
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(world_min, world_max)
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}
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fn intersect_triangle(origin: Vec3, dir: Vec3, v0: Vec3, v1: Vec3, v2: Vec3) -> Option<f32>
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{
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let edge1 = v1 - v0;
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let edge2 = v2 - v0;
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let h = dir.cross(edge2);
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let a = edge1.dot(h);
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if a.abs() < 1e-7
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{
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return None;
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}
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let f = 1.0 / a;
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let s = origin - v0;
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let u = f * s.dot(h);
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if !(0.0..=1.0).contains(&u)
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{
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return None;
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}
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let q = s.cross(edge1);
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let v = f * dir.dot(q);
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if v < 0.0 || u + v > 1.0
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{
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return None;
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}
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let t = f * edge2.dot(q);
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if t > 1e-7
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{
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Some(t)
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}
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else
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{
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None
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}
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}
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/// Ray–mesh triangle intersection in local space, returning world-space distance.
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///
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/// Transforms the ray into local mesh space, tests every triangle with
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/// Möller–Trumbore, then maps the closest local hit back to a world-space
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/// distance so results can be compared across entities.
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fn intersect_mesh_triangles(ray: &Ray, mesh: &Mesh, model: &Mat4) -> Option<f32>
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{
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if mesh.cpu_indices.is_empty()
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{
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return None;
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}
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let inv_model = model.inverse();
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let local_origin = inv_model.transform_point3(ray.origin);
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let local_dir = inv_model.transform_vector3(ray.direction);
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let mut closest_t = f32::MAX;
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let mut hit = false;
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for tri in mesh.cpu_indices.chunks_exact(3)
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{
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let v0 = Vec3::from(mesh.cpu_positions[tri[0] as usize]);
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let v1 = Vec3::from(mesh.cpu_positions[tri[1] as usize]);
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let v2 = Vec3::from(mesh.cpu_positions[tri[2] as usize]);
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if let Some(t) = intersect_triangle(local_origin, local_dir, v0, v1, v2)
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{
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if t < closest_t
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{
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closest_t = t;
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hit = true;
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}
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}
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}
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if hit
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{
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let local_hit = local_origin + local_dir * closest_t;
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let world_hit = model.transform_point3(local_hit);
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Some((world_hit - ray.origin).length())
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}
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else
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{
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None
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}
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}
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fn intersect_instances(
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ray: &Ray,
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mesh: &Mesh,
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tree_instances: &TreeInstancesComponent,
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) -> Option<f32>
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{
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let mut closest: Option<f32> = None;
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for instance in &tree_instances.instances
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{
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let instance_model = Mat4::from_scale_rotation_translation(
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instance.scale,
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instance.rotation,
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instance.position,
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);
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let (world_min, world_max) = transform_aabb(mesh.aabb_min, mesh.aabb_max, &instance_model);
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if let Some(d) = ray.intersects_aabb(world_min, world_max)
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{
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if closest.map_or(true, |c| d < c)
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{
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closest = Some(d);
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}
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}
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}
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closest
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}
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pub fn pick_entity(ray: &Ray, world: &World) -> Option<EntityHandle>
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{
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let mut closest_entity = None;
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let mut closest_distance = f32::MAX;
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for (&entity, mesh_component) in &world.meshes.components
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{
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let transform = match world.transforms.get(entity)
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{
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Some(t) => t,
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None => continue,
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};
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let model = transform.to_matrix();
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let distance = if let Some(tree_instances) = world.tree_instances.get(entity)
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{
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intersect_instances(ray, &mesh_component.mesh, tree_instances)
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}
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else
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{
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let (world_min, world_max) = transform_aabb(
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mesh_component.mesh.aabb_min,
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mesh_component.mesh.aabb_max,
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&model,
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);
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if ray.intersects_aabb(world_min, world_max).is_none()
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{
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continue;
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}
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intersect_mesh_triangles(ray, &mesh_component.mesh, &model)
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};
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if let Some(d) = distance
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{
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if d < closest_distance
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{
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closest_distance = d;
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closest_entity = Some(entity);
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}
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}
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}
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closest_entity
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}
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