add back the 'swapBuffers' in VR demo (slightly lower performance, but easier to use demo.

fix issue related to TinyRenderer shadowbuffer API change

examples/TinyRenderer/TinyRenderer.h

@@ -30,7 +30,7 @@ struct TinyRenderObjectData
     
     TGAImage& m_rgbColorBuffer;
     b3AlignedObjectArray<float>& m_depthBuffer;//required, hence a reference
-    b3AlignedObjectArray<float>* m_shadowBuffer;
+    b3AlignedObjectArray<float>* m_shadowBuffer;//optional, hence a pointer
     b3AlignedObjectArray<int>* m_segmentationMaskBufferPtr;//optional, hence a pointer
     
     TinyRenderObjectData(TGAImage& rgbColorBuffer,b3AlignedObjectArray<float>&depthBuffer);

examples/TinyRenderer/main.cpp

@@ -147,7 +147,6 @@ int main(int argc, char* argv[])
                 
                 renderData.m_rgbColorBuffer.set(x,y,color);
 				renderData.m_depthBuffer[x+y*textureWidth] = -1e30f;
-                renderData.m_shadowBuffer[x+y*textureWidth] = -1e30f;
             }
         }