Fixed bug where intertia tensors were not reset when unlocking axes

Assets/Scenes/PhysicsSandbox.shade

@@ -11,7 +11,7 @@
     RigidBody Component:
       Type: Dynamic
       Auto Mass: false
-      Mass: 1
+      Mass: 10
       Drag: 1
       Angular Drag: 1
       Use Gravity: false

Assets/Scripts/Tests/PhysicsTestObj.cs

@@ -83,8 +83,8 @@ public class PhysicsTestObj : Script
             if (Input.GetKeyDown(moveInputKeys[i]))
                 move[i] = true;
 
-            //if (Input.GetKeyDown(rotateInputKeys[i]))
-            //    rotate[i] = true;
+            if (Input.GetKeyDown(rotateInputKeys[i]))
+                rotate[i] = true;
         }
     }
 
@@ -97,8 +97,9 @@ public class PhysicsTestObj : Script
 
             if (shouldMove)
             {
-                Vector3 offset = new Vector3(0.25f, 0.0f, 0.0f);
-                rb.AddForceAtLocalPos(moveVec[i] * forceAmount, offset);
+                //Vector3 offset = new Vector3(0.25f, 0.0f, 0.0f);
+                //rb.AddForceAtLocalPos(moveVec[i] * forceAmount, offset);
+                rb.AddForce(moveVec[i] * forceAmount);
                 move[i] = false;
             }
 

SHADE_Engine/src/Physics/Dynamics/SHRigidBody.cpp

@@ -511,11 +511,12 @@ namespace SHADE
       // Reset angular velocity along X-axis
       angularVelocity.x = 0.0f;
       // Set inertia tensor on the x-axis to 0
-      localInvInertia.m[0][0] = worldInvInertia.m[0][0] = 0.0f;
+      localInvInertia.m[0][0] = 0.0f;
     }
     else
     {
       flags &= ~VALUE;
+      computeInertiaTensor();
     }
   }
 
@@ -530,11 +531,12 @@ namespace SHADE
       // Reset angular velocity along Y-axis
       angularVelocity.y = 0.0f;
       // Set inertia tensor on the y-axis to 0
-      localInvInertia.m[1][1] = worldInvInertia.m[1][1] = 0.0f;
+      localInvInertia.m[1][1] = 0.0f;
     }
     else
     {
       flags &= ~VALUE;
+      computeInertiaTensor();
     }
   }
 
@@ -549,11 +551,12 @@ namespace SHADE
       // Reset angular velocity along Z-axis
       angularVelocity.z = 0.0f;
       // Set inertia tensor on the z-axis to 0
-      localInvInertia.m[2][2] = worldInvInertia.m[2][2] = 0.0f;
+      localInvInertia.m[2][2] = 0.0f;
     }
     else
     {
       flags &= ~VALUE;
+      computeInertiaTensor();
     }
   }
 
@@ -606,20 +609,59 @@ namespace SHADE
 
   void SHRigidBody::ComputeMassData() noexcept
   {
-    // TODO: Compute total inertia and centroid from composited colliders using the Parallel Axis Theorem.
+    computeCentroid();
+    computeMassAndInertiaTensor();
+  }
+
+  /*-----------------------------------------------------------------------------------*/
+  /* Private Member Function Definition                                                */
+  /*-----------------------------------------------------------------------------------*/
+
+  void SHRigidBody::computeCentroid() noexcept
+  {
+    // TODO
+  }
+
+  void SHRigidBody::computeMass() noexcept
+  {
     // TODO: If auto mass in enabled, compute total mass based from each collider.
     // TODO: If auto mass disabled, compute inertia tensor for each shape using the ratio of its mass / total mass by comparing the volume / total volume.
+  }
 
-    if (collider && !collider->GetCollisionShapes().empty())
+  void SHRigidBody::computeInertiaTensor() noexcept
+  {
+    // TODO: Compute total inertia from composited colliders using the Parallel Axis Theorem.
+
+    if (!collider || collider->GetCollisionShapes().empty())
+    {
+      localInvInertia.m[0][0] = localInvInertia.m[1][1] = localInvInertia.m[2][2] = invMass;
+    }
+    else
     {
       // HACK: For now, take only the first shape as we are testing with non-composited colliders. We are using the center as the centroid.
       const auto* FIRST_SHAPE = collider->GetCollisionShape(0);
       localInvInertia = SHMatrix::Inverse(FIRST_SHAPE->GetInertiaTensor(1.0f / invMass));
     }
-    else
+  }
+
+  void SHRigidBody::computeMassAndInertiaTensor() noexcept
+  {
+    // TODO: If auto mass in enabled, compute total mass based from each collider.
+    // TODO: If auto mass disabled, compute inertia tensor for each shape using the ratio of its mass / total mass by comparing the volume / total volume.
+
+    // TODO: Compute total inertia from composited colliders using the Parallel Axis Theorem.
+
+    if (!collider || collider->GetCollisionShapes().empty())
     {
       localInvInertia.m[0][0] = localInvInertia.m[1][1] = localInvInertia.m[2][2] = invMass;
     }
+    else
+    {
+      // HACK: For now, take only the first shape as we are testing with non-composited colliders. We are using the center as the centroid.
+      const auto* FIRST_SHAPE = collider->GetCollisionShape(0);
+      localInvInertia = SHMatrix::Inverse(FIRST_SHAPE->GetInertiaTensor(1.0f / invMass));
+    }
+    
   }
 
 } // namespace SHADE

SHADE_Engine/src/Physics/Dynamics/SHRigidBody.h

@@ -252,6 +252,16 @@ namespace SHADE
     uint16_t      flags;
 
     SHMotionState motionState;
+
+    /*-----------------------------------------------------------------------------------*/
+    /* Member Functions                                                                  */
+    /*-----------------------------------------------------------------------------------*/
+
+    void computeCentroid            ()  noexcept;
+    void computeMass                ()  noexcept;
+    void computeInertiaTensor       ()  noexcept;
+    void computeMassAndInertiaTensor()  noexcept;
+    
   };
 
 } // namespace SHADE

SHADE_Engine/src/Physics/Interface/PhysicsObject/SHPhysicsObject.cpp

@@ -92,8 +92,12 @@ namespace SHADE
 
     // Link with collider if it exists
     if (collider)
+    {
       collider->SetRigidBody(rigidBody);
+      rigidBody->SetCollider(collider);
+    }
 
+    rigidBody->ComputeMassData();
     return rigidBody;
   }
 
@@ -119,7 +123,10 @@ namespace SHADE
 
     // Link with rigidBody if it exists
     if (rigidBody)
+    {
       rigidBody->SetCollider(collider);
+      collider->SetRigidBody(rigidBody);
+    }
 
     return collider;
   }
@@ -131,7 +138,10 @@ namespace SHADE
 
     // Unlink with rigid body
     if (rigidBody)
+    {
       rigidBody->SetCollider(nullptr);
+      rigidBody->ComputeMassData();
+    }
   }
 
   /*-----------------------------------------------------------------------------------*/