added a basic test for SimpleOpenGL3

Demos3/SimpleOpenGL3/main.cpp

@@ -0,0 +1,38 @@
+#include "../../btgui/OpenGLWindow/SimpleOpenGL3App.h"
+#include "Bullet3Common/b3Vector3.h"
+#include "assert.h"
+
+int main(int argc, char* argv[])
+{
+	
+	float dt = 1./120.f;
+	
+	SimpleOpenGL3App* app = new SimpleOpenGL3App("SimpleOpenGL3App",1024,768);
+	app->m_instancingRenderer->setCameraDistance(13);
+	app->m_instancingRenderer->setCameraPitch(0);
+	app->m_instancingRenderer->setCameraTargetPosition(b3MakeVector3(0,0,0));
+
+	GLint err = glGetError();
+    assert(err==GL_NO_ERROR);
+	
+	do
+	{
+		GLint err = glGetError();
+		assert(err==GL_NO_ERROR);
+		app->m_instancingRenderer->init();
+		app->m_instancingRenderer->updateCamera();
+		
+		app->drawGrid();
+		char bla[1024];
+		static int frameCount = 0;
+		frameCount++;
+		sprintf(bla,"Simple test frame %d\n", frameCount);
+		
+		app->drawText(bla,10,10);
+		app->swapBuffer();
+	} while (!app->m_window->requestedExit());
+
+	
+	delete app;
+	return 0;
+}