One embodiment provides a system that facilitates the execution of a web application. During operation, the system loads a native code module that includes a scenegraph renderer into a secure runtime environment. Next, the system uses the scenegraph renderer to create a scenegraph from a graphics model associated with the web application and generate a set of rendering commands from the scenegraph. The system then writes the rendering commands to a command buffer and reads the rendering commands from the command buffer. Finally, the system uses the rendering commands to render, for the web application, an image corresponding to the graphics model by executing the rendering commands using a graphics-processing unit (GPU).