Faster view frustum culling (#4181)
# Objective - Reduce time spent in the `check_visibility` system ## Solution - Use `Vec3A` for all bounding volume types to leverage SIMD optimisations and to avoid repeated runtime conversions from `Vec3` to `Vec3A` - Inline all bounding volume intersection methods - Add on-the-fly calculated `Aabb` -> `Sphere` and do `Sphere`-`Frustum` intersection tests before `Aabb`-`Frustum` tests. This is faster for `many_cubes` but could be slower in other cases where the sphere test gives a false-positive that the `Aabb` test discards. Also, I tested precalculating the `Sphere`s and inserting them alongside the `Aabb` but this was slower. - Do not test meshes against the far plane. Apparently games don't do this anymore with infinite projections, and it's one fewer plane to test against. I made it optional and still do the test for culling lights but that is up for discussion. - These collectively reduce `check_visibility` execution time in `many_cubes -- sphere` from 2.76ms to 1.48ms and increase frame rate from ~42fps to ~44fps
This commit is contained in:
Robert Swain
parent
e7a9420443
commit
ac8bbafc5c
@ -2,7 +2,7 @@ use std::collections::HashSet;
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use bevy_asset::Assets;
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use bevy_ecs::prelude::*;
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use bevy_math::{Mat4, UVec2, UVec3, Vec2, Vec3, Vec3Swizzles, Vec4, Vec4Swizzles};
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use bevy_math::{Mat4, UVec2, UVec3, Vec2, Vec3, Vec3A, Vec3Swizzles, Vec4, Vec4Swizzles};
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use bevy_reflect::Reflect;
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use bevy_render::{
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camera::{Camera, CameraProjection, OrthographicProjection},
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@ -640,8 +640,8 @@ fn cluster_space_light_aabb(
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light_sphere: &Sphere,
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) -> (Vec3, Vec3) {
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let light_aabb_view = Aabb {
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center: (inverse_view_transform * light_sphere.center.extend(1.0)).xyz(),
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half_extents: Vec3::splat(light_sphere.radius),
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center: Vec3A::from(inverse_view_transform * light_sphere.center.extend(1.0)),
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half_extents: Vec3A::splat(light_sphere.radius),
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};
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let (mut light_aabb_view_min, mut light_aabb_view_max) =
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(light_aabb_view.min(), light_aabb_view.max());
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@ -798,13 +798,13 @@ pub(crate) fn assign_lights_to_clusters(
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false
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} else {
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let light_sphere = Sphere {
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center: light.translation,
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center: Vec3A::from(light.translation),
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radius: light.range,
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};
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let light_in_view = frusta
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.iter()
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.any(|frustum| frustum.intersects_sphere(&light_sphere));
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.any(|frustum| frustum.intersects_sphere(&light_sphere, true));
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if light_in_view {
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lights_in_view_count += 1;
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@ -875,12 +875,12 @@ pub(crate) fn assign_lights_to_clusters(
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let mut cluster_index_estimate = 0.0;
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for light in lights.iter() {
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let light_sphere = Sphere {
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center: light.translation,
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center: Vec3A::from(light.translation),
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radius: light.range,
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};
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// Check if the light is within the view frustum
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if !frustum.intersects_sphere(&light_sphere) {
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if !frustum.intersects_sphere(&light_sphere, true) {
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continue;
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}
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@ -965,12 +965,12 @@ pub(crate) fn assign_lights_to_clusters(
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for light in lights.iter() {
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let light_sphere = Sphere {
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center: light.translation,
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center: Vec3A::from(light.translation),
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radius: light.range,
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};
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// Check if the light is within the view frustum
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if !frustum.intersects_sphere(&light_sphere) {
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if !frustum.intersects_sphere(&light_sphere, true) {
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continue;
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}
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@ -1174,7 +1174,7 @@ pub fn check_light_mesh_visibility(
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// If we have an aabb and transform, do frustum culling
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if let (Some(aabb), Some(transform)) = (maybe_aabb, maybe_transform) {
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if !frustum.intersects_obb(aabb, &transform.compute_matrix()) {
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if !frustum.intersects_obb(aabb, &transform.compute_matrix(), true) {
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continue;
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}
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}
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@ -1209,7 +1209,7 @@ pub fn check_light_mesh_visibility(
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let view_mask = maybe_view_mask.copied().unwrap_or_default();
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let light_sphere = Sphere {
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center: transform.translation,
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center: Vec3A::from(transform.translation),
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radius: point_light.range,
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};
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@ -1242,7 +1242,7 @@ pub fn check_light_mesh_visibility(
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.iter()
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.zip(cubemap_visible_entities.iter_mut())
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{
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if frustum.intersects_obb(aabb, &model_to_world) {
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if frustum.intersects_obb(aabb, &model_to_world, true) {
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computed_visibility.is_visible = true;
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visible_entities.entities.push(entity);
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}
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@ -6,12 +6,15 @@ use bevy_reflect::Reflect;
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#[derive(Component, Clone, Debug, Default, Reflect)]
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#[reflect(Component)]
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pub struct Aabb {
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pub center: Vec3,
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pub half_extents: Vec3,
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pub center: Vec3A,
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pub half_extents: Vec3A,
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}
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impl Aabb {
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#[inline]
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pub fn from_min_max(minimum: Vec3, maximum: Vec3) -> Self {
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let minimum = Vec3A::from(minimum);
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let maximum = Vec3A::from(maximum);
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let center = 0.5 * (maximum + minimum);
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let half_extents = 0.5 * (maximum - minimum);
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Self {
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@ -21,9 +24,10 @@ impl Aabb {
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}
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/// Calculate the relative radius of the AABB with respect to a plane
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#[inline]
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pub fn relative_radius(&self, p_normal: &Vec3A, axes: &[Vec3A]) -> f32 {
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// NOTE: dot products on Vec3A use SIMD and even with the overhead of conversion are net faster than Vec3
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let half_extents = Vec3A::from(self.half_extents);
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let half_extents = self.half_extents;
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Vec3A::new(
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p_normal.dot(axes[0]),
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p_normal.dot(axes[1]),
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@ -33,31 +37,35 @@ impl Aabb {
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.dot(half_extents)
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}
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pub fn min(&self) -> Vec3 {
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#[inline]
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pub fn min(&self) -> Vec3A {
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self.center - self.half_extents
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}
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pub fn max(&self) -> Vec3 {
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#[inline]
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pub fn max(&self) -> Vec3A {
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self.center + self.half_extents
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}
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}
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impl From<Sphere> for Aabb {
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#[inline]
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fn from(sphere: Sphere) -> Self {
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Self {
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center: sphere.center,
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half_extents: Vec3::splat(sphere.radius),
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half_extents: Vec3A::splat(sphere.radius),
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}
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}
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}
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#[derive(Debug, Default)]
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pub struct Sphere {
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pub center: Vec3,
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pub center: Vec3A,
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pub radius: f32,
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}
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impl Sphere {
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#[inline]
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pub fn intersects_obb(&self, aabb: &Aabb, local_to_world: &Mat4) -> bool {
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let aabb_center_world = *local_to_world * aabb.center.extend(1.0);
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let axes = [
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@ -65,7 +73,7 @@ impl Sphere {
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Vec3A::from(local_to_world.y_axis),
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Vec3A::from(local_to_world.z_axis),
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];
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let v = Vec3A::from(aabb_center_world) - Vec3A::from(self.center);
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let v = Vec3A::from(aabb_center_world) - self.center;
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let d = v.length();
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let relative_radius = aabb.relative_radius(&(v / d), &axes);
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d < self.radius + relative_radius
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@ -96,8 +104,8 @@ impl Plane {
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/// `Plane` unit normal
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#[inline]
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pub fn normal(&self) -> Vec3 {
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self.normal_d.xyz()
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pub fn normal(&self) -> Vec3A {
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Vec3A::from(self.normal_d)
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}
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/// Signed distance from the origin along the unit normal such that n.p + d = 0 for point p in
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@ -127,6 +135,7 @@ impl Frustum {
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// projection matrix is from Foundations of Game Engine Development 2
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// Rendering by Lengyel. Slight modification has been made for when
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// the far plane is infinite but we still want to cull to a far plane.
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#[inline]
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pub fn from_view_projection(
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view_projection: &Mat4,
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view_translation: &Vec3,
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@ -148,24 +157,29 @@ impl Frustum {
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Self { planes }
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}
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pub fn intersects_sphere(&self, sphere: &Sphere) -> bool {
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for plane in &self.planes {
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if plane.normal_d().dot(sphere.center.extend(1.0)) + sphere.radius <= 0.0 {
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#[inline]
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pub fn intersects_sphere(&self, sphere: &Sphere, intersect_far: bool) -> bool {
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let sphere_center = sphere.center.extend(1.0);
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let max = if intersect_far { 6 } else { 5 };
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for plane in &self.planes[..max] {
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if plane.normal_d().dot(sphere_center) + sphere.radius <= 0.0 {
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return false;
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}
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}
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true
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}
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pub fn intersects_obb(&self, aabb: &Aabb, model_to_world: &Mat4) -> bool {
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let aabb_center_world = *model_to_world * aabb.center.extend(1.0);
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#[inline]
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pub fn intersects_obb(&self, aabb: &Aabb, model_to_world: &Mat4, intersect_far: bool) -> bool {
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let aabb_center_world = model_to_world.transform_point3a(aabb.center).extend(1.0);
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let axes = [
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Vec3A::from(model_to_world.x_axis),
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Vec3A::from(model_to_world.y_axis),
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Vec3A::from(model_to_world.z_axis),
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];
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for plane in &self.planes {
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let max = if intersect_far { 6 } else { 5 };
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for plane in &self.planes[..max] {
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let p_normal = Vec3A::from(plane.normal_d());
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let relative_radius = aabb.relative_radius(&p_normal, &axes);
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if plane.normal_d().dot(aabb_center_world) + relative_radius <= 0.0 {
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@ -215,10 +229,10 @@ mod tests {
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// Sphere outside frustum
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let frustum = big_frustum();
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let sphere = Sphere {
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center: Vec3::new(0.9167, 0.0000, 0.0000),
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center: Vec3A::new(0.9167, 0.0000, 0.0000),
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radius: 0.7500,
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};
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assert!(!frustum.intersects_sphere(&sphere));
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assert!(!frustum.intersects_sphere(&sphere, true));
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}
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#[test]
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@ -226,10 +240,10 @@ mod tests {
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// Sphere intersects frustum boundary
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let frustum = big_frustum();
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let sphere = Sphere {
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center: Vec3::new(7.9288, 0.0000, 2.9728),
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center: Vec3A::new(7.9288, 0.0000, 2.9728),
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radius: 2.0000,
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};
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assert!(frustum.intersects_sphere(&sphere));
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assert!(frustum.intersects_sphere(&sphere, true));
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}
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// A frustum
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@ -251,10 +265,10 @@ mod tests {
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// Sphere surrounds frustum
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let frustum = frustum();
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let sphere = Sphere {
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center: Vec3::new(0.0000, 0.0000, 0.0000),
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center: Vec3A::new(0.0000, 0.0000, 0.0000),
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radius: 3.0000,
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};
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assert!(frustum.intersects_sphere(&sphere));
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assert!(frustum.intersects_sphere(&sphere, true));
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}
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#[test]
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@ -262,10 +276,10 @@ mod tests {
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// Sphere is contained in frustum
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let frustum = frustum();
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let sphere = Sphere {
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center: Vec3::new(0.0000, 0.0000, 0.0000),
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center: Vec3A::new(0.0000, 0.0000, 0.0000),
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radius: 0.7000,
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};
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assert!(frustum.intersects_sphere(&sphere));
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assert!(frustum.intersects_sphere(&sphere, true));
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}
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#[test]
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@ -273,10 +287,10 @@ mod tests {
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// Sphere intersects a plane
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let frustum = frustum();
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let sphere = Sphere {
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center: Vec3::new(0.0000, 0.0000, 0.9695),
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center: Vec3A::new(0.0000, 0.0000, 0.9695),
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radius: 0.7000,
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};
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assert!(frustum.intersects_sphere(&sphere));
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assert!(frustum.intersects_sphere(&sphere, true));
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}
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#[test]
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@ -284,10 +298,10 @@ mod tests {
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// Sphere intersects 2 planes
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let frustum = frustum();
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let sphere = Sphere {
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center: Vec3::new(1.2037, 0.0000, 0.9695),
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center: Vec3A::new(1.2037, 0.0000, 0.9695),
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radius: 0.7000,
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};
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assert!(frustum.intersects_sphere(&sphere));
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assert!(frustum.intersects_sphere(&sphere, true));
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}
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#[test]
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@ -295,10 +309,10 @@ mod tests {
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// Sphere intersects 3 planes
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let frustum = frustum();
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let sphere = Sphere {
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center: Vec3::new(1.2037, -1.0988, 0.9695),
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center: Vec3A::new(1.2037, -1.0988, 0.9695),
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radius: 0.7000,
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};
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assert!(frustum.intersects_sphere(&sphere));
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assert!(frustum.intersects_sphere(&sphere, true));
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}
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#[test]
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@ -306,10 +320,10 @@ mod tests {
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// Sphere avoids intersecting the frustum by 1 plane
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let frustum = frustum();
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let sphere = Sphere {
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center: Vec3::new(-1.7020, 0.0000, 0.0000),
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center: Vec3A::new(-1.7020, 0.0000, 0.0000),
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radius: 0.7000,
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};
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assert!(!frustum.intersects_sphere(&sphere));
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assert!(!frustum.intersects_sphere(&sphere, true));
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}
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// A long frustum.
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@ -331,10 +345,10 @@ mod tests {
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// Sphere outside frustum
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let frustum = long_frustum();
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let sphere = Sphere {
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center: Vec3::new(-4.4889, 46.9021, 0.0000),
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center: Vec3A::new(-4.4889, 46.9021, 0.0000),
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radius: 0.7500,
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};
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assert!(!frustum.intersects_sphere(&sphere));
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assert!(!frustum.intersects_sphere(&sphere, true));
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}
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#[test]
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@ -342,9 +356,9 @@ mod tests {
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// Sphere intersects frustum boundary
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let frustum = long_frustum();
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let sphere = Sphere {
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center: Vec3::new(-4.9957, 0.0000, -0.7396),
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center: Vec3A::new(-4.9957, 0.0000, -0.7396),
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radius: 4.4094,
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};
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assert!(frustum.intersects_sphere(&sphere));
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assert!(frustum.intersects_sphere(&sphere, true));
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}
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}
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@ -1,5 +1,6 @@
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mod render_layers;
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use bevy_math::Vec3A;
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pub use render_layers::*;
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use bevy_app::{CoreStage, Plugin};
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@ -12,7 +13,7 @@ use bevy_transform::TransformSystem;
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use crate::{
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camera::{Camera, CameraProjection, OrthographicProjection, PerspectiveProjection},
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mesh::Mesh,
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primitives::{Aabb, Frustum},
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primitives::{Aabb, Frustum, Sphere},
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};
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/// User indication of whether an entity is visible
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@ -181,10 +182,20 @@ pub fn check_visibility(
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}
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// If we have an aabb and transform, do frustum culling
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if let (Some(aabb), None, Some(transform)) =
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if let (Some(model_aabb), None, Some(transform)) =
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(maybe_aabb, maybe_no_frustum_culling, maybe_transform)
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{
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if !frustum.intersects_obb(aabb, &transform.compute_matrix()) {
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let model = transform.compute_matrix();
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let model_sphere = Sphere {
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center: model.transform_point3a(model_aabb.center),
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radius: (Vec3A::from(transform.scale) * model_aabb.half_extents).length(),
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};
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// Do quick sphere-based frustum culling
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if !frustum.intersects_sphere(&model_sphere, false) {
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continue;
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}
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// If we have an aabb, do aabb-based frustum culling
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if !frustum.intersects_obb(model_aabb, &model, false) {
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continue;
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}
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}
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