add initial examples, replacing the 'Demos/Demos3'. Will make it work cross-platform, OpenGL3/OpenGL2 and add more examples to it.

examples/OpenGLWindow/opengl_fontstashcallbacks.h

@@ -0,0 +1,55 @@
+#ifndef _OPENGL_FONTSTASH_CALLBACKS_H
+#define _OPENGL_FONTSTASH_CALLBACKS_H
+
+#include "fontstash.h"
+struct PrimInternalData;
+class GLPrimitiveRenderer;
+
+struct	InternalOpenGL2RenderCallbacks : public RenderCallbacks
+{
+
+	virtual PrimInternalData* getData()=0;
+
+	virtual ~InternalOpenGL2RenderCallbacks();
+
+	virtual void updateTexture(sth_texture* texture, sth_glyph* glyph, int textureWidth, int textureHeight);
+	virtual void render(sth_texture* texture);
+	
+	void display2();
+	
+};
+
+void dumpTextureToPng( int screenWidth, int screenHeight, const char* fileName);
+
+struct SimpleOpenGL2RenderCallbacks : public InternalOpenGL2RenderCallbacks
+{
+	PrimInternalData* m_data;
+	virtual PrimInternalData* getData()
+	{
+		return m_data;
+	}
+	SimpleOpenGL2RenderCallbacks(PrimInternalData* data)
+		:m_data(data)
+	{
+	}
+	virtual ~SimpleOpenGL2RenderCallbacks()
+	{
+	}
+};
+
+
+struct	OpenGL2RenderCallbacks : public InternalOpenGL2RenderCallbacks
+{
+	GLPrimitiveRenderer* m_primRender2;
+	virtual PrimInternalData* getData();
+	
+	OpenGL2RenderCallbacks(GLPrimitiveRenderer* primRender);
+	virtual ~OpenGL2RenderCallbacks();
+
+	
+};
+
+
+
+#endif//_OPENGL_FONTSTASH_CALLBACKS_H
+