From 2299bb7718c51dabb764b9874f4d229c80036b44 Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Wed, 5 Jul 2017 09:17:06 -0700
Subject: [PATCH] supply minimum shape rather than null

---
 libraries/physics/src/ShapeManager.cpp |  7 -------
 libraries/shared/src/ShapeInfo.cpp     | 24 ++++++++++++++++++++----
 libraries/shared/src/ShapeInfo.h       |  2 ++
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/libraries/physics/src/ShapeManager.cpp b/libraries/physics/src/ShapeManager.cpp
index fd3e35d28a..77716f671b 100644
--- a/libraries/physics/src/ShapeManager.cpp
+++ b/libraries/physics/src/ShapeManager.cpp
@@ -32,13 +32,6 @@ const btCollisionShape* ShapeManager::getShape(const ShapeInfo& info) {
     if (info.getType() == SHAPE_TYPE_NONE) {
         return nullptr;
     }
-    const float MIN_SHAPE_DIAGONAL_SQUARED = 3.0e-4f; // 1 cm cube
-    if (4.0f * glm::length2(info.getHalfExtents()) < MIN_SHAPE_DIAGONAL_SQUARED) {
-        // tiny shapes are not supported
-        // qCDebug(physics) << "ShapeManager::getShape -- not making shape due to size" << diagonal;
-        return nullptr;
-    }
-
     DoubleHashKey key = info.getHash();
     ShapeReference* shapeRef = _shapeMap.find(key);
     if (shapeRef) {
diff --git a/libraries/shared/src/ShapeInfo.cpp b/libraries/shared/src/ShapeInfo.cpp
index 583bceeaf2..496e94f8bd 100644
--- a/libraries/shared/src/ShapeInfo.cpp
+++ b/libraries/shared/src/ShapeInfo.cpp
@@ -15,6 +15,9 @@
 
 #include "NumericalConstants.h" // for MILLIMETERS_PER_METER
 
+// Bullet doesn't support arbitrarily small shapes
+const float MIN_HALF_EXTENT = 0.005f; // 0.5 cm
+
 void ShapeInfo::clear() {
     _url.clear();
     _pointCollection.clear();
@@ -26,14 +29,20 @@ void ShapeInfo::clear() {
 }
 
 void ShapeInfo::setParams(ShapeType type, const glm::vec3& halfExtents, QString url) {
+    _url = "";
     _type = type;
-    _halfExtents = halfExtents;
+    setHalfExtents(halfExtents);
     switch(type) {
         case SHAPE_TYPE_NONE:
             _halfExtents = glm::vec3(0.0f);
             break;
         case SHAPE_TYPE_BOX:
-        case SHAPE_TYPE_SPHERE:
+            break;
+        case SHAPE_TYPE_SPHERE: {
+                float radius = glm::length(halfExtents) / SQUARE_ROOT_OF_3;
+                radius = glm::max(radius, MIN_HALF_EXTENT);
+                _halfExtents = glm::vec3(radius);
+            }
             break;
         case SHAPE_TYPE_COMPOUND:
         case SHAPE_TYPE_STATIC_MESH:
@@ -48,14 +57,15 @@ void ShapeInfo::setParams(ShapeType type, const glm::vec3& halfExtents, QString
 void ShapeInfo::setBox(const glm::vec3& halfExtents) {
     _url = "";
     _type = SHAPE_TYPE_BOX;
-    _halfExtents = halfExtents;
+    setHalfExtents(halfExtents);
     _doubleHashKey.clear();
 }
 
 void ShapeInfo::setSphere(float radius) {
     _url = "";
     _type = SHAPE_TYPE_SPHERE;
-    _halfExtents = glm::vec3(radius, radius, radius);
+    radius = glm::max(radius, MIN_HALF_EXTENT);
+    _halfExtents = glm::vec3(radius);
     _doubleHashKey.clear();
 }
 
@@ -68,6 +78,8 @@ void ShapeInfo::setPointCollection(const ShapeInfo::PointCollection& pointCollec
 void ShapeInfo::setCapsuleY(float radius, float halfHeight) {
     _url = "";
     _type = SHAPE_TYPE_CAPSULE_Y;
+    radius = glm::max(radius, MIN_HALF_EXTENT);
+    halfHeight = glm::max(halfHeight, 0.0f);
     _halfExtents = glm::vec3(radius, halfHeight, radius);
     _doubleHashKey.clear();
 }
@@ -239,3 +251,7 @@ const DoubleHashKey& ShapeInfo::getHash() const {
     }
     return _doubleHashKey;
 }
+
+void ShapeInfo::setHalfExtents(const glm::vec3& halfExtents) {
+    _halfExtents = glm::max(halfExtents, glm::vec3(MIN_HALF_EXTENT));
+}
diff --git a/libraries/shared/src/ShapeInfo.h b/libraries/shared/src/ShapeInfo.h
index 17e4703fc2..0ffdf1310d 100644
--- a/libraries/shared/src/ShapeInfo.h
+++ b/libraries/shared/src/ShapeInfo.h
@@ -89,6 +89,8 @@ public:
     const DoubleHashKey& getHash() const;
 
 protected:
+    void setHalfExtents(const glm::vec3& halfExtents);
+
     QUrl _url; // url for model of convex collision hulls
     PointCollection _pointCollection;
     TriangleIndices _triangleIndices;