From 58df6cdaff4b90fd7c97c0df023a05c380393683 Mon Sep 17 00:00:00 2001
From: Daniel Chappuis <chappuis.daniel@gmail.com>
Date: Fri, 22 Nov 2019 21:31:51 +0100
Subject: [PATCH] Optimizations

---
 src/collision/shapes/ConcaveMeshShape.cpp | 20 +++++++++-----------
 src/containers/List.h                     | 11 +++++++++++
 src/engine/OverlappingPairs.cpp           |  9 ++++++++-
 src/systems/CollisionDetectionSystem.cpp  |  1 -
 src/systems/ContactSolverSystem.h         |  1 -
 5 files changed, 28 insertions(+), 14 deletions(-)

diff --git a/src/collision/shapes/ConcaveMeshShape.cpp b/src/collision/shapes/ConcaveMeshShape.cpp
index 90e26078..240defd8 100644
--- a/src/collision/shapes/ConcaveMeshShape.cpp
+++ b/src/collision/shapes/ConcaveMeshShape.cpp
@@ -127,8 +127,14 @@ void ConcaveMeshShape::computeOverlappingTriangles(const AABB& localAABB, List<V
     List<int> overlappingNodes(allocator);
     mDynamicAABBTree.reportAllShapesOverlappingWithAABB(localAABB, overlappingNodes);
 
+    const uint nbOverlappingNodes = overlappingNodes.size();
+
+    // Add space in the list of triangles vertices/normals for the new triangles
+    triangleVertices.addWithoutInit(nbOverlappingNodes * 3);
+    triangleVerticesNormals.addWithoutInit(nbOverlappingNodes * 3);
+
     // For each overlapping node
-    for (uint i=0; i < overlappingNodes.size(); i++) {
+    for (uint i=0; i < nbOverlappingNodes; i++) {
 
         int nodeId = overlappingNodes[i];
 
@@ -136,18 +142,10 @@ void ConcaveMeshShape::computeOverlappingTriangles(const AABB& localAABB, List<V
         int32* data = mDynamicAABBTree.getNodeDataInt(nodeId);
 
         // Get the triangle vertices for this node from the concave mesh shape
-        Vector3 trianglePoints[3];
-        getTriangleVertices(data[0], data[1], trianglePoints);
-        triangleVertices.add(trianglePoints[0]);
-        triangleVertices.add(trianglePoints[1]);
-        triangleVertices.add(trianglePoints[2]);
+        getTriangleVertices(data[0], data[1], &(triangleVertices[i * 3]));
 
         // Get the vertices normals of the triangle
-        Vector3 verticesNormals[3];
-        getTriangleVerticesNormals(data[0], data[1], verticesNormals);
-        triangleVerticesNormals.add(verticesNormals[0]);
-        triangleVerticesNormals.add(verticesNormals[1]);
-        triangleVerticesNormals.add(verticesNormals[2]);
+        getTriangleVerticesNormals(data[0], data[1], &(triangleVerticesNormals[i * 3]));
 
         // Compute the triangle shape ID
         shapeIds.add(computeTriangleShapeId(data[0], data[1]));
diff --git a/src/containers/List.h b/src/containers/List.h
index 8139069c..31f0dad6 100755
--- a/src/containers/List.h
+++ b/src/containers/List.h
@@ -294,6 +294,17 @@ class List {
             mSize++;
         }
 
+        /// Add a given numbers of elements at the end of the list but do not init them
+        void addWithoutInit(uint nbElements) {
+
+            // If we need to allocate more memory
+            if (mSize == mCapacity) {
+                reserve(mCapacity == 0 ? nbElements : (mCapacity + nbElements) * 2);
+            }
+
+            mSize += nbElements;
+        }
+
         /// Try to find a given item of the list and return an iterator
         /// pointing to that element if it exists in the list. Otherwise,
         /// this method returns the end() iterator
diff --git a/src/engine/OverlappingPairs.cpp b/src/engine/OverlappingPairs.cpp
index 0b1aad3f..d5886298 100644
--- a/src/engine/OverlappingPairs.cpp
+++ b/src/engine/OverlappingPairs.cpp
@@ -433,8 +433,15 @@ LastFrameCollisionInfo* OverlappingPairs::addLastFrameInfoIfNecessary(uint64 pai
 
     assert(pairIndex < mNbPairs);
 
+    uint32 maxShapeId = shapeId1;
+    uint32 minShapeId = shapeId2;
+    if (shapeId1 < shapeId2) {
+       maxShapeId = shapeId2;
+       minShapeId = shapeId1;
+    }
+
     // Try to get the corresponding last frame collision info
-    const uint64 shapesId = pairNumbers(std::max(shapeId1, shapeId2), std::min(shapeId1, shapeId2));
+    const uint64 shapesId = pairNumbers(maxShapeId, minShapeId);
 
     // If there is no collision info for those two shapes already
     auto it = mLastFrameCollisionInfos[pairIndex].find(shapesId);
diff --git a/src/systems/CollisionDetectionSystem.cpp b/src/systems/CollisionDetectionSystem.cpp
index d0ea855e..befdfa94 100644
--- a/src/systems/CollisionDetectionSystem.cpp
+++ b/src/systems/CollisionDetectionSystem.cpp
@@ -222,7 +222,6 @@ void CollisionDetectionSystem::computeMiddlePhase(NarrowPhaseInput& narrowPhaseI
         assert(mProxyShapesComponents.getBroadPhaseId(mOverlappingPairs.mProxyShapes1[i]) != mProxyShapesComponents.getBroadPhaseId(mOverlappingPairs.mProxyShapes2[i]));
 
         // Check that at least one body is enabled (active and awake) and not static
-        // TODO : Do not test this every frame
         if (mOverlappingPairs.mIsActive[i]) {
 
             const Entity proxyShape1Entity = mOverlappingPairs.mProxyShapes1[i];
diff --git a/src/systems/ContactSolverSystem.h b/src/systems/ContactSolverSystem.h
index 83b7faba..cee3b43d 100644
--- a/src/systems/ContactSolverSystem.h
+++ b/src/systems/ContactSolverSystem.h
@@ -320,7 +320,6 @@ class ContactSolverSystem {
         RigidBodyComponents& mRigidBodyComponents;
 
         /// Reference to the proxy-shapes components
-        // TODO : Do we really need to use this ?
         ProxyShapeComponents& mProxyShapeComponents;
 
         /// True if the split impulse position correction is active