From 6e322882eb21e66a44a1f055beb75f4b52f9408e Mon Sep 17 00:00:00 2001
From: Daniel Chappuis <chappuis.daniel@gmail.com>
Date: Sun, 5 Nov 2017 23:10:55 +0100
Subject: [PATCH] Fix wrong world AABB computation that caused broad-phase
collision misses
---
src/collision/shapes/CollisionShape.cpp | 50 +++++++++++++++++--------
1 file changed, 34 insertions(+), 16 deletions(-)
diff --git a/src/collision/shapes/CollisionShape.cpp b/src/collision/shapes/CollisionShape.cpp
index d03b4a1c..9622e795 100644
--- a/src/collision/shapes/CollisionShape.cpp
+++ b/src/collision/shapes/CollisionShape.cpp
@@ -32,15 +32,19 @@
using namespace reactphysics3d;
// Constructor
-CollisionShape::CollisionShape(CollisionShapeName name, CollisionShapeType type) : mName(name), mType(type), mScaling(1.0, 1.0, 1.0) {
+CollisionShape::CollisionShape(CollisionShapeName name, CollisionShapeType type)
+ : mType(type), mName(name), mScaling(1.0, 1.0, 1.0) {
}
-// Compute the world-space AABB of the collision shape given a transform
+// Compute the world-space AABB of the collision shape given a transform from shape
+// local-space to world-space. The technique is described in the book Real-Time Collision
+// Detection by Christer Ericson.
/**
* @param[out] aabb The axis-aligned bounding box (AABB) of the collision shape
* computed in world-space coordinates
- * @param transform Transform used to compute the AABB of the collision shape
+ * @param transform Transform from shape local-space to world-space used to compute
+ * the AABB of the collision shape
*/
void CollisionShape::computeAABB(AABB& aabb, const Transform& transform) const {
@@ -51,20 +55,34 @@ void CollisionShape::computeAABB(AABB& aabb, const Transform& transform) const {
Vector3 maxBounds;
getLocalBounds(minBounds, maxBounds);
- // Rotate the local bounds according to the orientation of the body
- Matrix3x3 worldAxis = transform.getOrientation().getMatrix().getAbsoluteMatrix();
- Vector3 worldMinBounds(worldAxis.getColumn(0).dot(minBounds),
- worldAxis.getColumn(1).dot(minBounds),
- worldAxis.getColumn(2).dot(minBounds));
- Vector3 worldMaxBounds(worldAxis.getColumn(0).dot(maxBounds),
- worldAxis.getColumn(1).dot(maxBounds),
- worldAxis.getColumn(2).dot(maxBounds));
+ const Vector3 translation = transform.getPosition();
+ Matrix3x3 matrix = transform.getOrientation().getMatrix();
+ Vector3 resultMin;
+ Vector3 resultMax;
- // Compute the minimum and maximum coordinates of the rotated extents
- Vector3 minCoordinates = transform.getPosition() + worldMinBounds;
- Vector3 maxCoordinates = transform.getPosition() + worldMaxBounds;
+ // For each of the three axis
+ for (int i=0; i<3; i++) {
+
+ // Add translation component
+ resultMin[i] = translation[i];
+ resultMax[i] = translation[i];
+
+ for (int j=0; j<3; j++) {
+ decimal e = matrix[i][j] * minBounds[j];
+ decimal f = matrix[i][j] * maxBounds[j];
+
+ if (e < f) {
+ resultMin[i] += e;
+ resultMax[i] += f;
+ }
+ else {
+ resultMin[i] += f;
+ resultMax[i] += e;
+ }
+ }
+ }
// Update the AABB with the new minimum and maximum coordinates
- aabb.setMin(minCoordinates);
- aabb.setMax(maxCoordinates);
+ aabb.setMin(resultMin);
+ aabb.setMax(resultMax);
}