fix some out-of-bounds error in the OpenCL rigid body pipeline

re-enable an OpenCL/gpu rigid body example (box-box stack)

examples/OpenCL/rigidbody/GpuCompoundScene.h

@@ -0,0 +1,50 @@
+#ifndef GPU_COMPOUND_SCENE_H
+#define GPU_COMPOUND_SCENE_H
+
+#include "GpuRigidBodyDemo.h"
+
+class GpuCompoundScene : public GpuRigidBodyDemo
+{
+public:
+
+	GpuCompoundScene(){}
+	virtual ~GpuCompoundScene(){}
+	virtual const char* getName()
+	{
+		return "CompoundOnSphere";
+	}
+
+	static GpuDemo* MyCreateFunc()
+	{
+		GpuDemo* demo = new GpuCompoundScene;
+		return demo;
+	}
+
+	virtual void setupScene(const ConstructionInfo& ci);
+
+	virtual void createStaticEnvironment(const ConstructionInfo& ci);
+
+};
+
+
+class GpuCompoundPlaneScene : public GpuCompoundScene
+{
+public:
+
+	GpuCompoundPlaneScene(){}
+	virtual ~GpuCompoundPlaneScene(){}
+	virtual const char* getName()
+	{
+		return "CompoundOnPlane";
+	}
+
+	static GpuDemo* MyCreateFunc()
+	{
+		GpuDemo* demo = new GpuCompoundPlaneScene;
+		return demo;
+	}
+
+	virtual void createStaticEnvironment(const ConstructionInfo& ci);
+
+};
+#endif //GPU_COMPOUND_SCENE_H