fix issue with interpolation in testbed application

testbed/common/Box.cpp

@@ -216,6 +216,7 @@ void Box::updateTransform(float interpolationFactor) {
     rp3d::Transform interpolatedTransform = rp3d::Transform::interpolateTransforms(mPreviousTransform,
                                                                                   transform,
                                                                                   interpolationFactor);
+    mPreviousTransform = transform;
 
     // Compute the transform used for rendering the box
     rp3d::decimal matrix[16];

testbed/common/Capsule.cpp

@@ -172,6 +172,7 @@ void Capsule::updateTransform(float interpolationFactor) {
     rp3d::Transform interpolatedTransform = rp3d::Transform::interpolateTransforms(mPreviousTransform,
                                                                                   transform,
                                                                                   interpolationFactor);
+    mPreviousTransform = transform;
 
     // Compute the transform used for rendering the sphere
     rp3d::decimal matrix[16];

testbed/common/Cone.cpp

@@ -173,6 +173,8 @@ void Cone::updateTransform(float interpolationFactor) {
                                                                                   transform,
                                                                                   interpolationFactor);
 
+    mPreviousTransform = transform;
+
     // Compute the transform used for rendering the cone
     rp3d::decimal matrix[16];
     interpolatedTransform.getOpenGLMatrix(matrix);

testbed/common/ConvexMesh.cpp

@@ -211,6 +211,7 @@ void ConvexMesh::updateTransform(float interpolationFactor) {
     rp3d::Transform interpolatedTransform = rp3d::Transform::interpolateTransforms(mPreviousTransform,
                                                                                   transform,
                                                                                   interpolationFactor);
+    mPreviousTransform = transform;
 
     // Compute the transform used for rendering the sphere
     rp3d::decimal matrix[16];

testbed/common/Cylinder.cpp

@@ -172,6 +172,7 @@ void Cylinder::updateTransform(float interpolationFactor) {
     rp3d::Transform interpolatedTransform = rp3d::Transform::interpolateTransforms(mPreviousTransform,
                                                                                   transform,
                                                                                   interpolationFactor);
+    mPreviousTransform = transform;
 
     // Compute the transform used for rendering the cylinder
     rp3d::decimal matrix[16];

testbed/common/Dumbbell.cpp

@@ -208,6 +208,7 @@ void Dumbbell::updateTransform(float interpolationFactor) {
     rp3d::Transform interpolatedTransform = rp3d::Transform::interpolateTransforms(mPreviousTransform,
                                                                                   transform,
                                                                                   interpolationFactor);
+    mPreviousTransform = transform;
 
     // Compute the transform used for rendering the sphere
     rp3d::decimal matrix[16];

testbed/common/Sphere.cpp

@@ -172,6 +172,7 @@ void Sphere::updateTransform(float interpolationFactor) {
     rp3d::Transform interpolatedTransform = rp3d::Transform::interpolateTransforms(mPreviousTransform,
                                                                                   transform,
                                                                                   interpolationFactor);
+    mPreviousTransform = transform;
 
     // Compute the transform used for rendering the sphere
     rp3d::decimal matrix[16];

testbed/src/Scene.h

@@ -37,6 +37,11 @@ struct EngineSettings {
 
        float elapsedTime;       // Elapsed time (in seconds)
        float timeStep;          // Current time step (in seconds)
+
+       /// Constructor
+       EngineSettings() : elapsedTime(0.0f), timeStep(0.0f) {
+
+       }
 };
 
 // Class Scene

testbed/src/TestbedApplication.cpp

@@ -50,8 +50,10 @@ TestbedApplication& TestbedApplication::getInstance() {
 }
 
 // Constructor
-TestbedApplication::TestbedApplication() : mFPS(0), mNbFrames(0), mPreviousTime(0) {
+TestbedApplication::TestbedApplication() : mFPS(0), mNbFrames(0), mPreviousTime(0){
 
+    mCurrentScene = NULL;
+    mEngineSettings.timeStep = DEFAULT_TIMESTEP;
     mIsMultisamplingActive = true;
     mWidth = 1000;
     mHeight = 800;
@@ -174,22 +176,26 @@ void TestbedApplication::updatePhysics() {
         mTimer.update();
 
         // While the time accumulator is not empty
-        while(mTimer.isPossibleToTakeStep()) {
+        while(mTimer.isPossibleToTakeStep(mEngineSettings.timeStep)) {
 
             // Take a physics simulation step
             mCurrentScene->updatePhysics();
 
             // Update the timer
-            mTimer.nextStep();
+            mTimer.nextStep(mEngineSettings.timeStep);
         }
     }
 }
 
 void TestbedApplication::update() {
 
+    // Update the physics
+    updatePhysics();
+
     // Compute the interpolation factor
     float factor = mTimer.computeInterpolationFactor(mEngineSettings.timeStep);
     assert(factor >= 0.0f && factor <= 1.0f);
+    std::cout << "Factor : " << factor << std::endl;
 
     // Notify the scene about the interpolation factor
     mCurrentScene->setInterpolationFactor(factor);

testbed/src/TestbedApplication.h

@@ -33,6 +33,9 @@
 #include "Timer.h"
 #include <GLFW/glfw3.h>
 
+// Constants
+const float DEFAULT_TIMESTEP = 1.0f / 60.0f;
+
 /// Class TestbedApplication
 /// Singleton class representing the application.
 class TestbedApplication {

testbed/src/Timer.h

@@ -52,9 +52,6 @@ class Timer {
 
         // -------------------- Attributes -------------------- //
 
-        /// Timestep dt of the physics engine (timestep > 0.0)
-        double mTimeStep;
-
         /// Last time the timer has been updated
         long double mLastUpdateTime;
 
@@ -98,13 +95,13 @@ class Timer {
         bool isRunning() const;
 
         /// True if it's possible to take a new step
-        bool isPossibleToTakeStep() const;
+        bool isPossibleToTakeStep(float timeStep) const;
 
         /// Compute the time since the last update() call and add it to the accumulator
         void update();
 
         /// Take a new step => update the timer by adding the timeStep value to the current time
-        void nextStep();
+        void nextStep(float timeStep);
 
         /// Compute the interpolation factor
         float computeInterpolationFactor(float timeStep);
@@ -141,16 +138,16 @@ inline void Timer::stop() {
 }
 
 // True if it's possible to take a new step
-inline bool Timer::isPossibleToTakeStep() const {
+inline bool Timer::isPossibleToTakeStep(float timeStep) const {
-    return (mAccumulator >= mTimeStep);
+    return (mAccumulator >= timeStep);
 }
 
 // Take a new step => update the timer by adding the timeStep value to the current time
-inline void Timer::nextStep() {
+inline void Timer::nextStep(float timeStep) {
     assert(mIsRunning);
 
     // Update the accumulator value
-    mAccumulator -= mTimeStep;
+    mAccumulator -= timeStep;
 }
 
 // Compute the interpolation factor