onSurfaceChanged

The onSurfaceChanged method is a callback function typically found in graphics frameworks, particularly within Android's OpenGL ES development. It is invoked when the surface underlying the OpenGL ES drawing area changes. This can occur for several reasons, such as the initial creation of the surface, a change in its dimensions (width or height), or a change in its format.

When onSurfaceChanged is called, it provides new width and height parameters for the surface. Developers must use these new dimensions to update their OpenGL ES rendering state. This usually involves reconfiguring the viewport, which defines the area of the screen where rendering occurs, and potentially recalculating projection matrices that determine how 3D objects are projected onto the 2D screen. Failing to update these settings can lead to rendering artifacts, such as stretched or improperly scaled graphics, or even crashes.

The typical signature of this method, as seen in Android, is onSurfaceChanged(GL10 gl, int width, int height). The gl parameter is an instance of the OpenGL ES API. The width and height parameters represent the new dimensions of the surface in pixels. It is a crucial part of the lifecycle management for OpenGL ES contexts, ensuring that rendering adapts correctly to the available screen space.