From 8236837dd035aeaab7e4819bace0c41611801986 Mon Sep 17 00:00:00 2001
From: Andrew Meadows <andrew@highfidelity.io>
Date: Wed, 14 Jan 2015 15:00:31 -0800
Subject: [PATCH] add ShapeInfo::computeVolume()

---
 libraries/shared/src/ShapeInfo.cpp | 35 ++++++++++++++++++++++++++++++
 libraries/shared/src/ShapeInfo.h   |  1 +
 2 files changed, 36 insertions(+)

diff --git a/libraries/shared/src/ShapeInfo.cpp b/libraries/shared/src/ShapeInfo.cpp
index d402a048a0..a1e72cdca0 100644
--- a/libraries/shared/src/ShapeInfo.cpp
+++ b/libraries/shared/src/ShapeInfo.cpp
@@ -24,18 +24,21 @@ void ShapeInfo::clear() {
 void ShapeInfo::setBox(const glm::vec3& halfExtents) {
     _type = BOX_SHAPE;
     _data.clear();
+    // _data[0] = < halfX, halfY, halfZ >
     _data.push_back(halfExtents);
 }
 
 void ShapeInfo::setSphere(float radius) {
     _type = SPHERE_SHAPE;
     _data.clear();
+    // _data[0] = < radius, radius, radius >
     _data.push_back(glm::vec3(radius));
 }
 
 void ShapeInfo::setCylinder(float radius, float halfHeight) {
     _type = CYLINDER_SHAPE;
     _data.clear();
+    // _data[0] = < radius, halfHeight, radius >
     // NOTE: default cylinder has (UpAxis = 1) axis along yAxis and radius stored in X
     _data.push_back(glm::vec3(radius, halfHeight, radius));
 }
@@ -43,6 +46,7 @@ void ShapeInfo::setCylinder(float radius, float halfHeight) {
 void ShapeInfo::setCapsule(float radius, float halfHeight) {
     _type = CAPSULE_SHAPE;
     _data.clear();
+    // _data[0] = < radius, halfHeight, radius >
     _data.push_back(glm::vec3(radius, halfHeight, radius));
 }
 
@@ -58,3 +62,34 @@ glm::vec3 ShapeInfo::getBoundingBoxDiagonal() const {
     }
     return glm::vec3(0.0f);
 }
+
+float ShapeInfo::computeVolume() const {
+    const float DEFAULT_VOLUME = 1.0f;
+    float volume = DEFAULT_VOLUME;
+    switch(_type) {
+        case BOX_SHAPE: {
+            // factor of 8.0 because the components of _data[0] are all halfExtents
+            volume = 8.0f * _data[0].x * _data[0].y * _data[0].z;
+            break;
+        }
+        case SPHERE_SHAPE: {
+            float radius = _data[0].x;
+            volume = 4.0f * PI * radius * radius * radius / 3.0f;
+            break;
+        }
+        case CYLINDER_SHAPE: {
+            float radius = _data[0].x;
+            volume = PI * radius * radius * 2.0f * _data[0].y;
+            break;
+        }
+        case CAPSULE_SHAPE: {
+            float radius = _data[0].x;
+            volume = PI * radius * radius * (2.0f * _data[0].y + 4.0f * radius / 3.0f);
+            break;
+        }
+        default:
+            break;
+    }
+    assert(volume > 0.0f);
+    return volume;
+}
diff --git a/libraries/shared/src/ShapeInfo.h b/libraries/shared/src/ShapeInfo.h
index 7ba290122c..9b4c587c3f 100644
--- a/libraries/shared/src/ShapeInfo.h
+++ b/libraries/shared/src/ShapeInfo.h
@@ -32,6 +32,7 @@ public:
     const QVector<glm::vec3>& getData() const { return _data; }
 
     glm::vec3 getBoundingBoxDiagonal() const;
+    float computeVolume() const;
 
 protected:
     int _type;