As realtime raytracing is slowly, but steadily, gaining traction, a range of opportunities to mix rasteration-based rendering systems with raytracing are starting to become available: hybrid raytracing where rasterisation is used to provide the hit points for the primary rays, hybrid shadows where shadowmaps are combined with raytracing to achieve smooth or higher detail shadows, hybrid antialiasing where raytracing is used to antialias the edges only, hybrid reflections, where raytracing is used to fill-in the areas that screenspace reflections can’t resolve due to lack of information.
Of these, I found the last one particularly interesting: how well can a limited information lighting technique like SSR be combined with a full-scene aware one like raytracing, so I set about exploring this further.
Continue reading “Hybrid screen-space reflections”
It seems that, due to popular demand, I will be collecting GDC links this year. I will update the page as they are coming in. If I have missed any please add them to the comments and I will update the list.
Note: GDC Vault has now been updated with GDC 2019 and VRDC 2019 presentations. Continue reading “Game Developers Conference 2019 links”
Last week at work a junior colleague asked me where do I get the presentations I’ve been reading from. This made me realise that, understandably, it might not be so obvious and common knowledge for people just starting graphics programming so I compiled a list of online resources I am frequently using to study the state of the art in Rendering. Continue reading “Readings on the State of the Art in Rendering”
A few weeks ago I documented the experiments I made with hybrid raytraced shadows and reflections, describing how raytracing can be set up and used in the context of a deferred rendering architecture. It was great fun and I managed to produce some nice images.
I soon came to realise though that this simplistic approach was mostly suitable for simple models (such as spheres and cubes) as the bounding volume hierarchy (BVH) I created to accelerate scene traversal stored full meshes in the leaves. This reduced the opportunity to accelerate traversal further when a leaf was reached, which is especially bad for large meshes, and complicated the shader a lot by creating many paths through it, potentially increasing thread divergence and reducing occupancy (by increased register allocation). Also the raytracing pass was heavily memory bound, making it scale less well with more complex, and higher polygon, content. The current approach would easily break down when used with more representative game environments/meshes. Continue reading “Hybrid raytraced shadows part 2: performance improvements”
Over the past few years I have interviewed a lot of people for graphics programming posts, both experienced and junior and I’d like to share some thoughts on how can one prepare themselves better for the process. This post is a sort of continuation of the previous one about how can one start learning graphics programming.
This advice applies mainly to junior graphics programmers, I imagine that if you are an experienced one you know what you are doing. Also I should point out that this is from my experience in the various companies that I have worked at. Other companies might view the process differently or have different criteria for selecting applicants. Continue reading “Applying for a graphics programming job”
About a month ago I opened my Twitter account DMs and invited people to ask me questions about rendering and graphics programming. It had a good response and quite a large number of people sent me their questions.
It caught me by surprise though that the majority of questions was not about particular graphics techniques but about how can one start learning graphics programming. This was not about choosing a graphics course, it was people that knew how to program and wanted to switch to or make a start at graphics.
It appears that with all those graphics APIs, the many freely available game engines, the multitude of graphics frameworks and games that continuously raise the bar in graphics, people feel intimidated and overwhelmed. They don’t know where to start. Continue reading “How to start learning graphics programming?”
Unless you’ve been hidden in a cave the past few months, doing your rendering with finger painting, you might have noticed that raytracing is in fashion again with both Microsoft and Apple providing official DirectX (DXR) and Metal support for it.
Of course, I was curious to try it but not having access to a DXR capable machine, I decided to extend my toy engine to add support for it using plain computer shaders instead.
I opted for a hybrid approach that combines rasterisation, for first-hit determination, with raytracing for secondary rays, for shadows/reflection/ambient occlusion etc. This approach is quite flexible as it allows us to mix and match techniques as needed, for example we can perform classic deferred shading adding raytraced ambient occlusion on top or combine raytraced reflections will screen space ambient occlusion, based on our rendering budget. Imagination has already done a lot of work on hybrid rendering, presenting a GPU which supports it in 2014. Continue reading “Hybrid raytraced shadows and reflections”