SSAO again

Because I suck, I haven't done any real work on the game again. As usual, I did waste some time messing with useless stuff though!

Behold the power of the resurrected SSAO fakery. I really like the way it looks from a top-down perspective... probably a best-case use of this kind of hack, as the view-dependence is not readily apparent.


The starry-bloom is turned off again... somehow I've introduced a NaN-producing step to it, which propogates through the post process pipeline to make gigantic hexagonal black areas on the final render. 'Cos I suck.

Even more deferred tentacles

Just a quicky today.

These are lighting-only shots showing the same scene with and without screen-space ambient occlusion, the latest hacktastic post process to take the rendering world by storm. Unfortunately I have to concede that even my less than stellar implementation does add a lot to the rendering, for a moderate cost, so I guess I'll be jumping on the bandwagon. It's an especially useful technique when combined with deferred lighting, as attempting any real shadowing with a bucketload of small point lights is very bonkers, so the illusion that the faked ambient occlusion provides is doubly useful.

As an aside, I do like my dungeon fairy lights. They add such a nice ambience...

Before (no SSAO):



After (mit SSAO):

Deferred Tentacles

Further work on the deferred rendering side. I finally found an example online using FBOs with a stencil buffer, and thereby discovered that despite using a combined depth-stencil renderbuffer it needs to be attached to the frame buffer object twice, once as a depth attachment and once as a stencil attachment. Sigh.

That done, efficient rendering of small lights via z-and-stencil-tested spheres works nicely!

Behold the scene, containing no less than fifty ickle lights, plus the large shadow-casting light from the player's avatar.


The majority of the screen is taken up by the final composite image. On the right, small sections show a sample of the buffers involved (yes, I don't even turn off my debugging chuffle before posting, I'm that lazy). Top is the SSAO term (very low intensity in the final image, as it looks pants). Below that are the lighting accumulation buffer, world-space normal, and finally unlit diffuse buffers.

Lastly, the image displays some filthy aliasing as the source render targets are only 512x512, violently scaled up to match the screen resolution. I should fix that.

Edit: here's a version using 1024x768 buffers throughout. Ouch, bye-bye framerate. Need to fix my absurd pixel shader usage methinks.

Visual fluffs

As my other post is waffly and dull, I thought I'd post some equally dull screenshots.

First, we have soft shadows and a general framerate improvement. I found I wasn't using buffer objects for my mesh streams (bad!), switched to position-only streams for shadow rendering when possible and changed the shadow buffer format to rgba16f. All this has reduced the frame time hugely, even after I started adding more crazy stuff. For comparison, a similar scene with blurred shadows was previously in the single-figure frame rate. Ouch. Still vastly too slow at the moment of course, but moving in the correct direction.

The soft shadows are done with a simple 3x3 guassian blur over the cube. It has errors on the cube edges for some reason, as can be seen in the nice black line across the lower right quarter of the image, but even with fairly low res maps and a small kernel the reduction in aliasing makes things look nicer. Hooray!


The second screenshot shows a half-finished unsmoothed SSAO post process. It's using a deferred rendering setup, with a few render targets for diffuse, normal, depth and lighting information at the moment, although for this screenshot only the depth info is used of course. Lots to do here, and I'd like to get a scene with more interesting visual fluff to show off the AO effect better...

Anyway, hopefully that helped balance up the wordiness of the previous post.