From 1bc1f0621e06c658dea855cfbf4b804f5389ebaf Mon Sep 17 00:00:00 2001
From: Daniel Chappuis <chappuis.daniel@gmail.com>
Date: Thu, 15 Oct 2020 22:23:32 +0200
Subject: [PATCH] Optimizations

---
 src/systems/DynamicsSystem.cpp | 26 +++++++++++++++++---------
 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/src/systems/DynamicsSystem.cpp b/src/systems/DynamicsSystem.cpp
index b30506d6..409c9dac 100644
--- a/src/systems/DynamicsSystem.cpp
+++ b/src/systems/DynamicsSystem.cpp
@@ -47,7 +47,8 @@ void DynamicsSystem::integrateRigidBodiesPositions(decimal timeStep, bool isSpli
 
     const decimal isSplitImpulseFactor = isSplitImpulseActive ? decimal(1.0) : decimal(0.0);
 
-    for (uint32 i=0; i < mRigidBodyComponents.getNbEnabledComponents(); i++) {
+    const uint32 nbRigidBodyComponents = mRigidBodyComponents.getNbEnabledComponents();
+    for (uint32 i=0; i < nbRigidBodyComponents; i++) {
 
         // Get the constrained velocity
         Vector3 newLinVelocity = mRigidBodyComponents.mConstrainedLinearVelocities[i];
@@ -74,7 +75,8 @@ void DynamicsSystem::updateBodiesState() {
 
     RP3D_PROFILE("DynamicsSystem::updateBodiesState()", mProfiler);
 
-    for (uint32 i=0; i < mRigidBodyComponents.getNbEnabledComponents(); i++) {
+    const uint32 nbRigidBodyComponents = mRigidBodyComponents.getNbEnabledComponents();
+    for (uint32 i=0; i < nbRigidBodyComponents; i++) {
 
         // Update the linear and angular velocity of the body
         mRigidBodyComponents.mLinearVelocities[i] = mRigidBodyComponents.mConstrainedLinearVelocities[i];
@@ -89,7 +91,7 @@ void DynamicsSystem::updateBodiesState() {
     }
 
     // Update the position of the body (using the new center of mass and new orientation)
-    for (uint32 i=0; i < mRigidBodyComponents.getNbEnabledComponents(); i++) {
+    for (uint32 i=0; i < nbRigidBodyComponents; i++) {
 
         Transform& transform = mTransformComponents.getTransform(mRigidBodyComponents.mBodiesEntities[i]);
         const Vector3& centerOfMassWorld = mRigidBodyComponents.mCentersOfMassWorld[i];
@@ -98,7 +100,8 @@ void DynamicsSystem::updateBodiesState() {
     }
 
     // Update the local-to-world transform of the colliders
-    for (uint32 i=0; i < mColliderComponents.getNbEnabledComponents(); i++) {
+    const uint32 nbColliderComponents = mColliderComponents.getNbEnabledComponents();
+    for (uint32 i=0; i < nbColliderComponents; i++) {
 
         // Update the local-to-world transform of the collider
         mColliderComponents.mLocalToWorldTransforms[i] = mTransformComponents.getTransform(mColliderComponents.mBodiesEntities[i]) *
@@ -119,7 +122,8 @@ void DynamicsSystem::integrateRigidBodiesVelocities(decimal timeStep) {
     resetSplitVelocities();
 
     // Integration component velocities using force/torque
-    for (uint32 i=0; i < mRigidBodyComponents.getNbEnabledComponents(); i++) {
+    const uint32 nbEnabledRigidBodyComponents = mRigidBodyComponents.getNbEnabledComponents();
+    for (uint32 i=0; i < nbEnabledRigidBodyComponents; i++) {
 
         assert(mRigidBodyComponents.mSplitLinearVelocities[i] == Vector3(0, 0, 0));
         assert(mRigidBodyComponents.mSplitAngularVelocities[i] == Vector3(0, 0, 0));
@@ -137,7 +141,8 @@ void DynamicsSystem::integrateRigidBodiesVelocities(decimal timeStep) {
     // Apply gravity force
     if (mIsGravityEnabled) {
 
-        for (uint32 i=0; i < mRigidBodyComponents.getNbEnabledComponents(); i++) {
+        const uint32 nbRigidBodyComponents = mRigidBodyComponents.getNbEnabledComponents();
+        for (uint32 i=0; i < nbRigidBodyComponents; i++) {
 
             // If the gravity has to be applied to this rigid body
             if (mRigidBodyComponents.mIsGravityEnabled[i]) {
@@ -162,7 +167,8 @@ void DynamicsSystem::integrateRigidBodiesVelocities(decimal timeStep) {
     // Using Taylor Serie for e^(-x) : e^x ~ 1 + x + x^2/2! + ...
     //                              => e^(-x) ~ 1 - x
     //                 => v2 = v1 * (1 - c * dt)
-    for (uint32 i=0; i < mRigidBodyComponents.getNbEnabledComponents(); i++) {
+    const uint32 nbRigidBodyComponents = mRigidBodyComponents.getNbEnabledComponents();
+    for (uint32 i=0; i < nbRigidBodyComponents; i++) {
 
         const decimal linDampingFactor = mRigidBodyComponents.mLinearDampings[i];
         const decimal angDampingFactor = mRigidBodyComponents.mAngularDampings[i];
@@ -177,7 +183,8 @@ void DynamicsSystem::integrateRigidBodiesVelocities(decimal timeStep) {
 void DynamicsSystem::resetBodiesForceAndTorque() {
 
     // For each body of the world
-    for (uint32 i=0; i < mRigidBodyComponents.getNbComponents(); i++) {
+    const uint32 nbRigidBodyComponents = mRigidBodyComponents.getNbComponents();
+    for (uint32 i=0; i < nbRigidBodyComponents; i++) {
         mRigidBodyComponents.mExternalForces[i].setToZero();
         mRigidBodyComponents.mExternalTorques[i].setToZero();
     }
@@ -186,7 +193,8 @@ void DynamicsSystem::resetBodiesForceAndTorque() {
 // Reset the split velocities of the bodies
 void DynamicsSystem::resetSplitVelocities() {
 
-    for(uint32 i=0; i < mRigidBodyComponents.getNbEnabledComponents(); i++) {
+    const uint32 nbRigidBodyComponents = mRigidBodyComponents.getNbEnabledComponents();
+    for(uint32 i=0; i < nbRigidBodyComponents; i++) {
         mRigidBodyComponents.mSplitLinearVelocities[i].setToZero();
         mRigidBodyComponents.mSplitAngularVelocities[i].setToZero();
     }