This is a screen capture of a radar display I wrote using Qt and OpenGL. The display runs in real-time at a rate of about +60 fps as the radar rotates at 10 RPM. Each radar return contains about 4K samples 16-bit, and I draw all of them (no decimation) via OpenGL calls. The display supports multiple views, panning, zooming, etc. as well as multiple input channels. Each input channel writes to an offscreen framebuffer, and an update of the screen is a simple compositing of the textures associated with the offscreen framebuffers and additional graphical data such as range/azimuth markings, extraction and track plots.
I created the simulated phosphor effect using a disc texture with an alpha contour that fades the older pixels as the disc rotates along with the radar. There is also some slight bloom effect for very high-intensity returns.
Here is a short video that highlights some of the features of the PPI display, especially the compositing of various features in OpenGL for fast rendering.