or, There's a glitch in the matrix...
Had some fun today playing with some shaders - I've been converting to a deferred shading system as this better supports some of the effects I want to employ, such as screen space ambient occlusion (SSAO), some particular lighting effects from some old 'toys' that I'd made such as line-based light emitters which works really well for laser weapon effects.
So here I was tinkering along, and noticed that I was causing the GPU to drop out on some pixel blocks, in particular it seemed this was on elements where some of my HUD/collision avoidance colouring was being applied:
After panning the camera around to see what effect it had, I zoomed in and Whoa! Well thats one new and exciting way to draw wireframes!
Upon further investigation it does seem that I hadn't actually installed a driver for this card. The Radeon 46xx series driver now comes from a legacy driver package, I'd just installed the standard driver package, hadn't realised all I'd achieved was to install the AMD driver installer, and had in fact been using the default Windows 7 in-box driver.
Once rectified, and with the SSAO pass displaying something other than black I was presented with a quite fortunate accident. I had got some shader code in the wrong order, and this was causing the SSAO to be applied after the fog, BUT that and my 'inaccessible terrain' overlay made the hill sides look pretty damn swish! Now I just have to get them to look that good not by accident!