add Inverted Pendulum example with PD control

examples/CommonInterfaces/CommonGraphicsAppInterface.h

@@ -62,6 +62,9 @@ struct CommonGraphicsApp
 	{
 	}
 
+	virtual void dumpNextFrameToPng(const char* pngFilename){}
+    virtual void dumpFramesToVideo(const char* mp4Filename){}
+   
 	virtual void drawGrid(DrawGridData data=DrawGridData()) = 0;
 	virtual void setUpAxis(int axis) = 0;
 	virtual int getUpAxis() const = 0;

examples/ExampleBrowser/CMakeLists.txt

@@ -102,6 +102,8 @@ SET(App_ExampleBrowser_SRCS
   ../Vehicles/Hinge2Vehicle.h
   ../MultiBody/TestJointTorqueSetup.cpp
   ../MultiBody/TestJointTorqueSetup.h
+  ../MultiBody/InvertedPendulumPDControl.cpp
+  ../MultiBody/InvertedPendulumPDControl.h
  ../MultiBody/MultiBodyConstraintFeedback.cpp
   ../MultiBody/MultiDofDemo.cpp
   ../MultiBody/MultiDofDemo.h

examples/ExampleBrowser/ExampleEntries.cpp

@@ -16,12 +16,14 @@
 #include "../Importers/ImportColladaDemo/ImportColladaSetup.h"
 #include "../Importers/ImportSTLDemo/ImportSTLSetup.h"
 #include "../Importers/ImportURDFDemo/ImportURDFSetup.h"
+
 #include "../GyroscopicDemo/GyroscopicSetup.h"
 #include "../Constraints/Dof6Spring2Setup.h"
 #include "../Constraints/ConstraintPhysicsSetup.h"
 #include "../MultiBody/TestJointTorqueSetup.h"
 #include "../MultiBody/MultiBodyConstraintFeedback.h"
 #include "../MultiBody/MultiDofDemo.h"
+#include "../MultiBody/InvertedPendulumPDControl.h"
 #include "../VoronoiFracture/VoronoiFractureDemo.h"
 #include "../SoftDemo/SoftDemo.h"
 #include "../Constraints/ConstraintDemo.h"
@@ -96,14 +98,14 @@ static ExampleEntry gDefaultExamples[]=
 	ExampleEntry(1,"Gyroscopic", "Show the Dzhanibekov effect using various settings of the gyroscopic term. You can select the gyroscopic term computation using btRigidBody::setFlags, with arguments BT_ENABLE_GYROSCOPIC_FORCE_EXPLICIT (using explicit integration, which adds energy and can lead to explosions), BT_ENABLE_GYROSCOPIC_FORCE_IMPLICIT_WORLD, BT_ENABLE_GYROSCOPIC_FORCE_IMPLICIT_BODY. If you don't set any of these flags, there is no gyroscopic term used.", GyroscopicCreateFunc),
 
 
-
+	
 
 	ExampleEntry(0,"MultiBody"),
 	ExampleEntry(1,"MultiDofCreateFunc","Create a basic btMultiBody with 3-DOF spherical joints (mobilizers). The demo uses a fixed base or a floating base at restart.", MultiDofCreateFunc),
 	ExampleEntry(1,"TestJointTorque","Apply a torque to a btMultiBody with 1-DOF joints (mobilizers). This setup is similar to API/TestHingeTorque.", TestJointTorqueCreateFunc),
  ExampleEntry(1,"Constraint Feedback", "The example shows how to receive joint reaction forces in a btMultiBody. Also the applied impulse is available for a btMultiBodyJointMotor", MultiBodyConstraintFeedbackCreateFunc),
-	
+	ExampleEntry(1,"Inverted Pendulum PD","Keep an inverted pendulum up using open loop PD control", InvertedPendulumPDControlCreateFunc),
-	
+
 #ifdef INCLUDE_CLOTH_DEMOS
 	ExampleEntry(0,"Soft Body"),
 	ExampleEntry(1,"Cloth","Simulate a patch of cloth.", SoftDemoCreateFunc,0),

examples/ExampleBrowser/premake4.lua

@@ -77,6 +77,7 @@
 		"../MultiBody/MultiDofDemo.cpp",
 		"../MultiBody/TestJointTorqueSetup.cpp",
 		"../MultiBody/MultiBodyConstraintFeedback.cpp",
+		"../MultiBody/InvertedPendulumPDControl.cpp",
 		"../ThirdPartyLibs/stb_image/*",
 		"../ThirdPartyLibs/Wavefront/tiny_obj_loader.*",
 		"../ThirdPartyLibs/tinyxml/*",

examples/MultiBody/InvertedPendulumPDControl.cpp

@@ -0,0 +1,473 @@
+
+#include "InvertedPendulumPDControl.h"
+
+#include "BulletDynamics/Featherstone/btMultiBodyLinkCollider.h"
+#include "BulletDynamics/Featherstone/btMultiBodyJointFeedback.h"
+							
+#include "../CommonInterfaces/CommonMultiBodyBase.h"
+#include "../Utils/b3ResourcePath.h"
+#include "../CommonInterfaces/CommonParameterInterface.h"
+static btScalar radius(0.2);
+static btScalar kp = 100;
+static btScalar kd = 20;
+static btScalar maxForce = 100;
+
+struct InvertedPendulumPDControl : public CommonMultiBodyBase
+{
+    btMultiBody* m_multiBody;
+	btAlignedObjectArray<btMultiBodyJointFeedback*> m_jointFeedbacks;
+    bool m_once;
+	int m_frameCount;
+public:
+
+    InvertedPendulumPDControl(struct GUIHelperInterface* helper);
+    virtual ~InvertedPendulumPDControl();
+
+    virtual void initPhysics();
+
+    virtual void stepSimulation(float deltaTime);
+
+	virtual void resetCamera()
+	{
+		float dist = 5;
+		float pitch = 270;
+		float yaw = 21;
+		float targetPos[3]={-1.34,3.4,-0.44};
+		m_guiHelper->resetCamera(dist,pitch,yaw,targetPos[0],targetPos[1],targetPos[2]);
+	}
+
+
+};
+
+InvertedPendulumPDControl::InvertedPendulumPDControl(struct GUIHelperInterface* helper)
+:CommonMultiBodyBase(helper),
+m_once(true),
+m_frameCount(0)
+{
+}
+
+InvertedPendulumPDControl::~InvertedPendulumPDControl()
+{
+
+}
+
+///this is a temporary global, until we determine if we need the option or not
+extern  bool gJointFeedbackInWorldSpace;
+extern bool gJointFeedbackInJointFrame;
+
+
+
+void InvertedPendulumPDControl::initPhysics()
+{
+	{
+		SliderParams slider("Kp",&kp);
+		slider.m_minVal=-200;
+		slider.m_maxVal=200;
+		m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider);
+    }
+	{
+		SliderParams slider("Kd",&kd);
+		slider.m_minVal=-50;
+		slider.m_maxVal=50;
+		m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider);
+    }
+	{
+		SliderParams slider("max force",&maxForce);
+		slider.m_minVal=0;
+		slider.m_maxVal=100;
+		m_guiHelper->getParameterInterface()->registerSliderFloatParameter(slider);
+    }
+
+	
+
+
+    int upAxis = 1;
+	gJointFeedbackInWorldSpace = true;
+	gJointFeedbackInJointFrame = true;
+
+	m_guiHelper->setUpAxis(upAxis);
+
+    btVector4 colors[4] =
+    {
+        btVector4(1,0,0,1),
+        btVector4(0,1,0,1),
+        btVector4(0,1,1,1),
+        btVector4(1,1,0,1),
+    };
+    int curColor = 0;
+
+
+
+    
+
+	this->createEmptyDynamicsWorld();
+    m_guiHelper->createPhysicsDebugDrawer(m_dynamicsWorld);
+    m_dynamicsWorld->getDebugDrawer()->setDebugMode(
+        //btIDebugDraw::DBG_DrawConstraints
+        +btIDebugDraw::DBG_DrawWireframe
+        +btIDebugDraw::DBG_DrawContactPoints
+        +btIDebugDraw::DBG_DrawAabb
+        );//+btIDebugDraw::DBG_DrawConstraintLimits);
+
+	m_dynamicsWorld->setGravity(btVector3(0,-10,0));
+
+    {
+        bool floating = false;
+        bool damping = false;
+        bool gyro = false;
+        int numLinks = 2;
+        bool spherical = false;					//set it ot false -to use 1DoF hinges instead of 3DoF sphericals
+        bool canSleep = false;
+        bool selfCollide = false;
+          btVector3 linkHalfExtents(0.05, 0.37, 0.1);
+        btVector3 baseHalfExtents(0.04, 0.35, 0.08);
+
+        btVector3 basePosition = btVector3(-0.4f, 3.f, 0.f);
+        //mbC->forceMultiDof();							//if !spherical, you can comment this line to check the 1DoF algorithm
+        //init the base
+        btVector3 baseInertiaDiag(0.f, 0.f, 0.f);
+        float baseMass = 1.f;
+
+        if(baseMass)
+        {
+            //btCollisionShape *shape = new btSphereShape(baseHalfExtents[0]);// btBoxShape(btVector3(baseHalfExtents[0], baseHalfExtents[1], baseHalfExtents[2]));
+			btCollisionShape *shape = new btBoxShape(btVector3(baseHalfExtents[0], baseHalfExtents[1], baseHalfExtents[2]));
+            shape->calculateLocalInertia(baseMass, baseInertiaDiag);
+            delete shape;
+        }
+
+        bool isMultiDof = true;
+        btMultiBody *pMultiBody = new btMultiBody(numLinks, baseMass, baseInertiaDiag, !floating, canSleep, isMultiDof);
+		
+        m_multiBody = pMultiBody;
+        btQuaternion baseOriQuat(0.f, 0.f, 0.f, 1.f);
+	//	baseOriQuat.setEulerZYX(-.25*SIMD_PI,0,-1.75*SIMD_PI);
+        pMultiBody->setBasePos(basePosition);
+        pMultiBody->setWorldToBaseRot(baseOriQuat);
+        btVector3 vel(0, 0, 0);
+    //	pMultiBody->setBaseVel(vel);
+
+        //init the links
+        btVector3 hingeJointAxis(1, 0, 0);
+        
+        //y-axis assumed up
+        btVector3 parentComToCurrentCom(0, -linkHalfExtents[1] * 2.f, 0);						//par body's COM to cur body's COM offset
+        btVector3 currentPivotToCurrentCom(0, -linkHalfExtents[1], 0);							//cur body's COM to cur body's PIV offset
+        btVector3 parentComToCurrentPivot = parentComToCurrentCom - currentPivotToCurrentCom;	//par body's COM to cur body's PIV offset
+
+        //////
+        btScalar q0 = 1.f * SIMD_PI/ 180.f;
+        btQuaternion quat0(btVector3(1, 0, 0).normalized(), q0);
+        quat0.normalize();
+        /////
+
+        for(int i = 0; i < numLinks; ++i)
+        {
+			float linkMass = 1.f;
+			//if (i==3 || i==2)
+			//	linkMass= 1000;
+			btVector3 linkInertiaDiag(0.f, 0.f, 0.f);
+
+			btCollisionShape* shape = 0;
+			if (i==0)
+			{
+				shape = new btBoxShape(btVector3(linkHalfExtents[0], linkHalfExtents[1], linkHalfExtents[2]));//
+			} else
+			{
+				shape = new btSphereShape(radius);
+			}
+			shape->calculateLocalInertia(linkMass, linkInertiaDiag);
+			delete shape;
+
+
+            if(!spherical)
+			{
+                //pMultiBody->setupRevolute(i, linkMass, linkInertiaDiag, i - 1, btQuaternion(0.f, 0.f, 0.f, 1.f), hingeJointAxis, parentComToCurrentPivot, currentPivotToCurrentCom, false);
+		
+				if (i==0)
+				{
+				pMultiBody->setupRevolute(i, linkMass, linkInertiaDiag, i - 1, 
+					btQuaternion(0.f, 0.f, 0.f, 1.f), 
+					hingeJointAxis, 
+					parentComToCurrentPivot, 
+					currentPivotToCurrentCom, false);
+				} else
+				{
+					btVector3 parentComToCurrentCom(0, -radius * 2.f, 0);						//par body's COM to cur body's COM offset
+					btVector3 currentPivotToCurrentCom(0, -radius, 0);							//cur body's COM to cur body's PIV offset
+					btVector3 parentComToCurrentPivot = parentComToCurrentCom - currentPivotToCurrentCom;	//par body's COM to cur body's PIV offset
+
+
+					pMultiBody->setupFixed(i, linkMass, linkInertiaDiag, i - 1, 
+					btQuaternion(0.f, 0.f, 0.f, 1.f), 
+					parentComToCurrentPivot, 
+					currentPivotToCurrentCom, false);
+				}
+					
+				//pMultiBody->setupFixed(i,linkMass,linkInertiaDiag,i-1,btQuaternion(0,0,0,1),parentComToCurrentPivot,currentPivotToCurrentCom,false);
+		
+			}
+            else
+			{
+                //pMultiBody->setupPlanar(i, linkMass, linkInertiaDiag, i - 1, btQuaternion(0.f, 0.f, 0.f, 1.f)/*quat0*/, btVector3(1, 0, 0), parentComToCurrentPivot*2, false);
+                pMultiBody->setupSpherical(i, linkMass, linkInertiaDiag, i - 1, btQuaternion(0.f, 0.f, 0.f, 1.f), parentComToCurrentPivot, currentPivotToCurrentCom, false);
+			}
+        }
+
+        pMultiBody->finalizeMultiDof();
+
+		//for (int i=pMultiBody->getNumLinks()-1;i>=0;i--)//
+			for (int i=0;i<pMultiBody->getNumLinks();i++)
+		{
+			btMultiBodyJointFeedback* fb = new btMultiBodyJointFeedback();
+			pMultiBody->getLink(i).m_jointFeedback = fb;
+			m_jointFeedbacks.push_back(fb);
+			//break;
+		}
+        btMultiBodyDynamicsWorld* world = m_dynamicsWorld;
+
+        ///
+        world->addMultiBody(pMultiBody);
+        btMultiBody* mbC = pMultiBody;
+        mbC->setCanSleep(canSleep);
+        mbC->setHasSelfCollision(selfCollide);
+        mbC->setUseGyroTerm(gyro);
+        //
+        if(!damping)
+        {
+            mbC->setLinearDamping(0.f);
+            mbC->setAngularDamping(0.f);
+        }else
+        {	mbC->setLinearDamping(0.1f);
+            mbC->setAngularDamping(0.9f);
+        }
+        //
+    	
+
+        //////////////////////////////////////////////
+        if(numLinks > 0)
+        {
+            btScalar q0 = 180.f * SIMD_PI/ 180.f;
+            if(!spherical)
+                if(mbC->isMultiDof())
+                    mbC->setJointPosMultiDof(0, &q0);
+                else
+                    mbC->setJointPos(0, q0);
+            else
+            {
+                btQuaternion quat0(btVector3(1, 1, 0).normalized(), q0);
+                quat0.normalize();
+                mbC->setJointPosMultiDof(0, quat0);
+            }
+        }
+        ///
+
+        btAlignedObjectArray<btQuaternion> world_to_local;
+        world_to_local.resize(pMultiBody->getNumLinks() + 1);
+
+        btAlignedObjectArray<btVector3> local_origin;
+        local_origin.resize(pMultiBody->getNumLinks() + 1);
+        world_to_local[0] = pMultiBody->getWorldToBaseRot();
+        local_origin[0] = pMultiBody->getBasePos();
+        double friction = 1;
+        {
+
+        //	float pos[4]={local_origin[0].x(),local_origin[0].y(),local_origin[0].z(),1};
+            float quat[4]={-world_to_local[0].x(),-world_to_local[0].y(),-world_to_local[0].z(),world_to_local[0].w()};
+
+
+            if (1)
+            {
+                btCollisionShape* shape = new btBoxShape(btVector3(baseHalfExtents[0],baseHalfExtents[1],baseHalfExtents[2]));//new btSphereShape(baseHalfExtents[0]);
+                m_guiHelper->createCollisionShapeGraphicsObject(shape);
+
+                btMultiBodyLinkCollider* col= new btMultiBodyLinkCollider(pMultiBody, -1);
+                col->setCollisionShape(shape);
+
+                btTransform tr;
+                tr.setIdentity();
+//if we don't set the initial pose of the btCollisionObject, the simulator will do this 
+				//when syncing the btMultiBody link transforms to the btMultiBodyLinkCollider
+               
+                tr.setOrigin(local_origin[0]);
+				btQuaternion orn(btVector3(0,0,1),0.25*3.1415926538);
+				
+                tr.setRotation(orn);
+                col->setWorldTransform(tr);
+
+				bool isDynamic = (baseMass > 0 && floating);
+				short collisionFilterGroup = isDynamic? short(btBroadphaseProxy::DefaultFilter) : short(btBroadphaseProxy::StaticFilter);
+				short collisionFilterMask = isDynamic? 	short(btBroadphaseProxy::AllFilter) : 	short(btBroadphaseProxy::AllFilter ^ btBroadphaseProxy::StaticFilter);
+
+
+                world->addCollisionObject(col,collisionFilterGroup,collisionFilterMask);//, 2,1+2);
+
+                btVector3 color(0.0,0.0,0.5);
+                m_guiHelper->createCollisionObjectGraphicsObject(col,color);
+
+//                col->setFriction(friction);
+                pMultiBody->setBaseCollider(col);
+
+            }
+        }
+
+
+        for (int i=0; i < pMultiBody->getNumLinks(); ++i)
+        {
+            const int parent = pMultiBody->getParent(i);
+            world_to_local[i+1] = pMultiBody->getParentToLocalRot(i) * world_to_local[parent+1];
+            local_origin[i+1] = local_origin[parent+1] + (quatRotate(world_to_local[i+1].inverse() , pMultiBody->getRVector(i)));
+        }
+
+
+        for (int i=0; i < pMultiBody->getNumLinks(); ++i)
+        {
+
+            btVector3 posr = local_origin[i+1];
+        //	float pos[4]={posr.x(),posr.y(),posr.z(),1};
+
+            float quat[4]={-world_to_local[i+1].x(),-world_to_local[i+1].y(),-world_to_local[i+1].z(),world_to_local[i+1].w()};
+			btCollisionShape* shape =0;
+
+			if (i==0)
+			{
+				shape = new btBoxShape(btVector3(linkHalfExtents[0],linkHalfExtents[1],linkHalfExtents[2]));//btSphereShape(linkHalfExtents[0]);
+			} else
+			{
+				
+				shape = new btSphereShape(radius);
+			}
+
+            m_guiHelper->createCollisionShapeGraphicsObject(shape);
+            btMultiBodyLinkCollider* col = new btMultiBodyLinkCollider(pMultiBody, i);
+
+            col->setCollisionShape(shape);
+            btTransform tr;
+            tr.setIdentity();
+            tr.setOrigin(posr);
+            tr.setRotation(btQuaternion(quat[0],quat[1],quat[2],quat[3]));
+            col->setWorldTransform(tr);
+     //       col->setFriction(friction);
+			bool isDynamic = 1;//(linkMass > 0);
+			short collisionFilterGroup = isDynamic? short(btBroadphaseProxy::DefaultFilter) : short(btBroadphaseProxy::StaticFilter);
+			short collisionFilterMask = isDynamic? 	short(btBroadphaseProxy::AllFilter) : 	short(btBroadphaseProxy::AllFilter ^ btBroadphaseProxy::StaticFilter);
+
+			//if (i==0||i>numLinks-2)
+			{
+				world->addCollisionObject(col,collisionFilterGroup,collisionFilterMask);//,2,1+2);
+				   btVector4 color = colors[curColor];
+			curColor++;
+			curColor&=3;
+            m_guiHelper->createCollisionObjectGraphicsObject(col,color);
+
+
+            pMultiBody->getLink(i).m_collider=col;
+			}
+         
+        }
+    }
+
+	
+}
+char fileName[1024];
+
+static btAlignedObjectArray<btScalar> qDesiredArray;
+void InvertedPendulumPDControl::stepSimulation(float deltaTime)
+{
+	
+	static btScalar offset = -0.1*SIMD_PI;
+
+	m_frameCount++;
+	if ((m_frameCount&0xff)==0 )
+	{
+		offset = -offset;
+	}
+	btScalar target= SIMD_PI+offset;
+	qDesiredArray.resize(0);
+	qDesiredArray.resize(m_multiBody->getNumLinks(),target);
+
+	for (int joint = 0; joint<m_multiBody->getNumLinks();joint++)
+	{
+		int dof1 = 0;
+		btScalar qActual = m_multiBody->getJointPosMultiDof(joint)[dof1];
+		btScalar qdActual = m_multiBody->getJointVelMultiDof(joint)[dof1];
+	//	b3Printf("Joint Pos[%d]=%f, Vel = %f\n", joint, qActual, qdActual);
+	
+		btScalar positionError = (qDesiredArray[joint]-qActual);
+	
+		btScalar force = kp * positionError - kd*qdActual;
+		btClamp(force,-maxForce,maxForce);
+		
+	//	b3Printf("force = %f positionError = %f, qDesired = %f\n", force,positionError, target);
+		m_multiBody->addJointTorque(joint, force);
+	
+		//btScalar torque = m_multiBody->getJointTorque(0);
+		//    b3Printf("t = %f,%f,%f\n",torque,torque,torque);//[0],torque[1],torque[2]);
+	
+	}
+
+	
+	
+
+	if (m_frameCount==100)
+	{
+		const char* gPngFileName = "pendulum";
+	
+
+		if (gPngFileName)
+        {
+
+			
+            //printf("gPngFileName=%s\n",gPngFileName);
+
+            sprintf(fileName,"%s%d.png",gPngFileName,m_frameCount);
+			b3Printf("Made screenshot %s",fileName);
+			this->m_guiHelper->getAppInterface()->dumpNextFrameToPng(fileName);
+        }
+	}
+    m_dynamicsWorld->stepSimulation(1./240,0);
+
+	static int count = 0;
+	if ((count& 0x0f)==0)
+	{
+#if 0
+	for (int i=0;i<m_jointFeedbacks.size();i++)
+	{
+
+			b3Printf("F_reaction[%i] linear:%f,%f,%f, angular:%f,%f,%f",
+			i,
+			m_jointFeedbacks[i]->m_reactionForces.m_topVec[0],
+			m_jointFeedbacks[i]->m_reactionForces.m_topVec[1],
+			m_jointFeedbacks[i]->m_reactionForces.m_topVec[2],
+
+		m_jointFeedbacks[i]->m_reactionForces.m_bottomVec[0],
+			m_jointFeedbacks[i]->m_reactionForces.m_bottomVec[1],
+			m_jointFeedbacks[i]->m_reactionForces.m_bottomVec[2]
+
+		);
+
+	}
+#endif
+	}
+	count++;
+
+
+	/*
+    b3Printf("base angvel = %f,%f,%f",m_multiBody->getBaseOmega()[0],
+             m_multiBody->getBaseOmega()[1],
+             m_multiBody->getBaseOmega()[2]
+             );
+    */
+    btScalar jointVel =m_multiBody->getJointVel(0);
+    
+//    b3Printf("child angvel = %f",jointVel);
+    
+    
+    
+}
+
+
+class CommonExampleInterface*    InvertedPendulumPDControlCreateFunc(struct CommonExampleOptions& options)
+{
+	return new InvertedPendulumPDControl(options.m_guiHelper);
+}

examples/MultiBody/InvertedPendulumPDControl.h

@@ -0,0 +1,7 @@
+#ifndef INVERTED_PENDULUM_PD_CONTROL_H
+#define INVERTED_PENDULUM_PD_CONTROL_H
+
+class CommonExampleInterface*    InvertedPendulumPDControlCreateFunc(struct CommonExampleOptions& options);
+
+#endif //INVERTED_PENDULUM_PD_CONTROL_H
+

examples/OpenGLWindow/SimpleOpenGL3App.cpp

@@ -695,7 +695,7 @@ void SimpleOpenGL3App::swapBuffer()
         //m_data->m_renderTexture->disable();
         //if (m_data->m_ffmpegFile==0)
         //{
-        //    m_data->m_frameDumpPngFileName = 0;
+        m_data->m_frameDumpPngFileName = 0;
         //}
     }
 	m_window->startRendering();
@@ -727,9 +727,12 @@ void SimpleOpenGL3App::dumpFramesToVideo(const char* mp4FileName)
     {
         pclose(m_data->m_ffmpegFile);
     }
-    m_data->m_ffmpegFile = popen(cmd, "w");
+	if (mp4FileName)
+	{
+		m_data->m_ffmpegFile = popen(cmd, "w");
 
-    m_data->m_frameDumpPngFileName = mp4FileName;
+		m_data->m_frameDumpPngFileName = mp4FileName;
+	}
 }
 void SimpleOpenGL3App::dumpNextFrameToPng(const char* filename)
 {
@@ -739,7 +742,7 @@ void SimpleOpenGL3App::dumpNextFrameToPng(const char* filename)
     m_data->m_frameDumpPngFileName = filename;
 
 //you could use m_renderTexture to allow to render at higher resolutions, such as 4k or so
-    /*if (!m_data->m_renderTexture)
+    if (!m_data->m_renderTexture)
     {
             m_data->m_renderTexture = new GLRenderToTexture();
             GLuint renderTextureId;
@@ -764,7 +767,7 @@ void SimpleOpenGL3App::dumpNextFrameToPng(const char* filename)
     }
 
     bool result = m_data->m_renderTexture->enable();
-*/
+
 }
 
 void SimpleOpenGL3App::setUpAxis(int axis)