Is there a way to retrieve a single pixel from a rendertarget? I can retrieve the whole rendertarget, but it’s prohibitively slow on a (slower) machine that can otherwise render the scene just fine. open gl’s readpixels allows to specify an area that’s not the whole screen, and I expect it to be faster if the area is smaller (i.e. only one pixel), but urho’s getdata always fetches the whole screen.
My ray casting fragment shader creates a lookup from screen space to world space that I want to use to get the world coordinates at the mouse pointer.