From 4e65b76b8ce2c7e99113f15359c191654877babc Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Thu, 11 Apr 2024 15:58:34 +0200
Subject: [PATCH] Optimize `BoundingSphere.Intersects` to be inlined by the
 compiler

---
 Source/Engine/Core/Math/BoundingSphere.cpp                  | 6 +++++-
 Source/Engine/Graphics/Materials/MaterialShaderFeatures.cpp | 6 +++---
 2 files changed, 8 insertions(+), 4 deletions(-)

diff --git a/Source/Engine/Core/Math/BoundingSphere.cpp b/Source/Engine/Core/Math/BoundingSphere.cpp
index 5b95ca0cc..dbd312dd2 100644
--- a/Source/Engine/Core/Math/BoundingSphere.cpp
+++ b/Source/Engine/Core/Math/BoundingSphere.cpp
@@ -51,7 +51,11 @@ bool BoundingSphere::Intersects(const BoundingBox& box) const
 
 bool BoundingSphere::Intersects(const BoundingSphere& sphere) const
 {
-    return CollisionsHelper::SphereIntersectsSphere(*this, sphere);
+    const Real radiisum = Radius + sphere.Radius;
+    const Real x = Center.X - sphere.Center.X;
+    const Real y = Center.Y - sphere.Center.Y;
+    const Real z = Center.Z - sphere.Center.Z;
+    return x * x + y * y + z * z <= radiisum * radiisum;
 }
 
 ContainmentType BoundingSphere::Contains(const Vector3& point) const
diff --git a/Source/Engine/Graphics/Materials/MaterialShaderFeatures.cpp b/Source/Engine/Graphics/Materials/MaterialShaderFeatures.cpp
index b6d7ef23a..c36fd9758 100644
--- a/Source/Engine/Graphics/Materials/MaterialShaderFeatures.cpp
+++ b/Source/Engine/Graphics/Materials/MaterialShaderFeatures.cpp
@@ -76,7 +76,7 @@ void ForwardShadingFeature::Bind(MaterialShader::BindParameters& params, Span<by
     for (int32 i = 0; i < cache->EnvironmentProbes.Count(); i++)
     {
         const RenderEnvironmentProbeData& probe = cache->EnvironmentProbes.Get()[i];
-        if (CollisionsHelper::SphereIntersectsSphere(objectBounds, BoundingSphere(probe.Position, probe.Radius)))
+        if (objectBounds.Intersects(BoundingSphere(probe.Position, probe.Radius)))
         {
             noEnvProbe = false;
             probe.SetShaderData(data.EnvironmentProbe);
@@ -96,7 +96,7 @@ void ForwardShadingFeature::Bind(MaterialShader::BindParameters& params, Span<by
     for (int32 i = 0; i < cache->PointLights.Count() && data.LocalLightsCount < MaxLocalLights; i++)
     {
         const auto& light = cache->PointLights[i];
-        if (CollisionsHelper::SphereIntersectsSphere(objectBounds, BoundingSphere(light.Position, light.Radius)))
+        if (objectBounds.Intersects(BoundingSphere(light.Position, light.Radius)))
         {
             light.SetShaderData(data.LocalLights[data.LocalLightsCount], false);
             data.LocalLightsCount++;
@@ -105,7 +105,7 @@ void ForwardShadingFeature::Bind(MaterialShader::BindParameters& params, Span<by
     for (int32 i = 0; i < cache->SpotLights.Count() && data.LocalLightsCount < MaxLocalLights; i++)
     {
         const auto& light = cache->SpotLights[i];
-        if (CollisionsHelper::SphereIntersectsSphere(objectBounds, BoundingSphere(light.Position, light.Radius)))
+        if (objectBounds.Intersects(BoundingSphere(light.Position, light.Radius)))
         {
             light.SetShaderData(data.LocalLights[data.LocalLightsCount], false);
             data.LocalLightsCount++;