glViewportIndexedfGLuint

GlViewportIndex is a function within the OpenGL API that controls the always-with-graphics rendering mode. This mode allows applications to specify an explicit viewport index for the drawing buffer, controlling which buffer will be rendered when there are multiple render targets.

The function's primary purpose is to specify a view layer for rendering, providing more control over how graphics are rendering. When using multiple render targets, this can help in intelligent buffer navigation as we get to know what buffer to target alongside when., The function prototype is glColorInteger(index), where index is the viewport index.

Specifying an explicit viewport index is particularly useful in a scenario involving layered graphics. For instance, consider the use of transparent buffers or fixed-function processes. The ability to using an explicit viewport index can let developers identify when the exact layer of received fragments may be the target for further rendering.