More Statistics

One followup to Naty’s article (below): Ke-Sen Huang’s page has submission and acceptance stats for many recent conferences.

If you have five minutes to kill, it’s fun to search on various phrases at the Google Trends site. Buzzwords like “cloud computing” have trackable data, but most graphics terms don’t have enough traffic to be worth recording. Here are some examples of graphics-related terms that have sufficient hit-counts:

  • Ray Tracing – I like how Google Trends points out relevant articles for various spikes.
  • SSAO – some definite spikes there, and what’s with all the traffic from Brazil? Is this the end of some word in Portugese? But there aren’t really hits before 2007, so I guess it’s real…
  • Collision detection, SIGGRAPH, and computer graphics – is interest in these areas waning, or are they simply established and not newsworthy? But then, GPU is going up.
  • Companies and products are fun to try: Larrabee, NVIDIA, Crytek.
  • You can also compare various terms. Here’s “DirectX programming, OpenGL programming, iPhone programming“. Pretty easy to guess which one is going up. Surprisingly un-spikey for DirectX and OpenGL.
  • And of course, Real-Time Rendering – Various random spikes; South Korea loves us.
Happy hunting, and please do comment if you find any interesting results.

Graphics Conference Paper Acceptance Statistics

I recently ran across this link to acceptance rates for papers in graphics conferences.  The SIGGRAPH chart has some missing years (including the first four), presumably because data was not available.  Graphing the trends yields some interesting information:

Excluding years before 1985 (when the conference was still “finding its legs” and acceptance rates were very high), the acceptance rate has hovered between 14.9% (1998) and 23.7% (2007).  The long-term trend appears to be that the acceptance rate is flat, and the number of submitted and accepted papers steadily increase.  In the shorter term, submitted papers appear to be flat or even declining after 2003, with accepted papers following suit (2009 has the lowest number of accepted papers since 2002).  I’m not sure why that is; a 2003 flattening seems too late to be attributable to the dot-com collapse and too early to be related to the big graphics conference restructuring of 2008 (where Eurographics was moved to spring and SIGGRAPH Asia was introduced).  If anyone has a good guess, please leave a comment.

I didn’t bother graphing the other conferences.  The Eurographics table only has information from 1998 (the conference has existed since 1979, only five years less than SIGGRAPH).  From 2002 on the acceptance rate has been similar to SIGGRAPH (before that it was significantly higher).  The I3D table is pretty complete; it shows consistently high acceptance rates, between 25% (1999) and 42% (2008).  Graphics Interface and EGSR (EGWR in earlier years) have similarly high acceptance rates.

ShaderX7

ShaderX7 has been out for a few months now, but due to its size (at 773 pages, it is by far the largest of the series) I haven’t been able to finish going through it until recently.  Here are the chapters I found most interesting (click the link for the rest of this post): Continue reading →

EGSR and HPG 2009 papers

Ke-Sen Huang has what looks like the full lists of papers for both HPG 2009 and EGSR 2009.  Both of these lists are only available on Ke-Sen’s site at the moment; presumably they will appear on the HPG and EGSR websites soon.  I have had high hopes for these conferences, especially given the somewhat disappointing real-time content of the SIGGRAPH 2009 papers program.  EGSR has historically had some good real-time stuff in it, and the new HPG (High-Performance Graphics) conference has a highly relevant area of focus.  So how do the paper lists stack up?

EGSR 2009 has a bunch of potentially interesting papers, including some on GPU-accelerated ray-tracing and photon mapping.  Some have intriguing titles (but no other information, so it’s hard to guess how relevant they are): Fast Global Illumination on Dynamic Height Fields, Efficient and Accurate Rendering of Complex Light Sources.  One paper I found particularly interesting is Hierarchical Image-Space Radiosity for Interactive Global Illumination (available here):  This paper extends an I3D 2009 paper (Multiresolution Splatting for Indirect Illumination) which described an “Instant Radiosity”-type approach (using lots of point light sources to simulate indirect bounces), rendering into a pyramid of frame buffers at different resolutions.  The pyramid was finally collapsed into a single frame buffer to generate the final frame.  I found the multiresolution rendering approach interesting, but the implementation was very slow.  The EGSR 2009 paper speeds this part of the algorithm up significantly, and adds some other extensions and improvements.  I wouldn’t run off and implement this paper into a game engine (it has some significant limitations, and is not nearly fast enough on current hardware), but it does suggest some interesting research directions.

What about HPG 2009, the new kid on the block?  Given the partial descent of this conference from the Interactive Ray-Tracing symposium, one would expect a fair bit of ray-tracing-related papers, but there aren’t that many: out of 21 papers, 4 papers explicitly mention ray-tracing, and 3 more deal with dynamic construction of bounding volume hierarchies (a particular concern of ray-tracing algorithms).  Many of the remaining papers deal with other (and to my mind, more interesting) rendering algorithms.  Data-Parallel Rasterization of Micropolygons With Defocus and Motion Blur appears to describe an algorithm similar to REYES (which powers Pixar’s Renderman).  There are two papers on image space techniques (Hardware-Accelerated Global Illumination by Image Space Photon Mapping and Image Space Gathering), which is a “hot” area right now following the popularity of SSAO and related techniques.  There are two papers relating to the important topic of antialiasing (A Directionally Adaptive Edge Anti-Aliasing Filter and Morphological Antialiasing).  One paper (Stream Compaction for Deferred Shading) relates to deferred shading, which is also a “hot” topic in game rendering at the moment.

I look forward to the preprints becoming available, so we can see if these papers live up to the promise of their titles (anmd perhaps discover some surprises among the more ambiguously-titled papers).

Bits of News

Just some quick bits to chew on for breakfast:

  • Microsoft announced Project Natal at E3; the (simulated) video is entertaining. Lionhead Studios’ demo is also worth a look. Somehow a little creepy, and I suspect in practice there’s a high likelihood that a user will quickly run off the rails and not do what’s expected, but still. Considering how limited the Eye Toy is compared to its hype, I’m not holding my breath, but it’s interesting to know & think about. (thanks to Adam Felt for the link)
  • New book out, Graphics Shaders: Theory and Practice. It’s about GLSL, you can find the Table of Contents and other front matter at the book’s site (look to the right side). I hope to get a copy and give a review at some point.
  • I mentioned Mark Haigh-Hutchinson’s Real-Time Cameras book in an earlier post. The, honestly, touching story of its history is republished on Mark DeLoura’s blog at Gamasutra.
  • Nice history of graphics cards, with many pictures.
  • Humus describes a clever particle rendering optimization technique (update), and provides a utility. Basically, make the polygon fit the visible part of the particle to save on fill rate. One of those ideas that I suspect many of us have wondered if it’s worth doing. It is, and it’s great to have someone actually test it out and publish the results.
  • This is an interesting concept: with an NVIDIA card and their new driver you can now turn on ambient occlusion for 22 games that don’t actually use this technique in their shipped shaders. In itself, this feature is a minor plus, but brings up all sorts of questions, such as buying into a particular brand to improve quality, who controls and who can modify the artistic look of a game, etc. (thanks to Mauricio Vives for the link)
  • Old, but if you haven’t seen it before, it’s a must: transparent screens.

Deferred lighting approaches

In Section 7.9.2 of Real-Time Rendering, we discussed deferred rendering approaches, including “partially-deferred” methods where some subset of shader properties are written to buffers.  Since publication, a particular type of partially-deferred method has gained some popularity.  There are a few different variants of this approach that are worth discussing; more details “under the fold”.

Continue reading →

Game Engine Gems CFP

As I mentioned in a previous post, Eric Lengyel is heading up a new project, a book series called “Game Engine Gems”. It turns out that we ran across the website before it was announced (moral: there’s no hiding on the internet). He’s sent out an official call for papers today – see the book’s website for basic information.

I’m posting today to mention a few dates not currently shown on the website (though I expect this will change soon):

  • August 1 – Final day to submit article proposals
  • August 15 – Authors notified of acceptance
  • October 15 – Final day to submit completed articles

Contact Eric for more information.

SIGGRAPH 2009 courses

No sooner had I written about the full SIGGRAPH 2009 course list not being up yet, and bam! there it is.  As I hinted at, there is a lot of stuff there for real-time rendering folks.  Some highlights:

Advances in Real-Time Rendering in 3D Graphics and Games (two-parter; second part here):  This (somewhat awkwardly-named course) has been my favorite thing at SIGGRAPH for the past three years.  Each year it presents all-new material.  Previous courses have seen the debut of important rendering techniques algorithms like SSAO, signed distance-field vector texturing, and wrinkle mapping, as well as details on the rendering secrets behind games like Halo 3, Crysis, Starcraft 2, Half-Life 2, Team Fortress 2, and LittleBigPlanet.  Not much is known about this year’s content, except that it will include details on Crytek’s new global illumination algorithm; but this is one course I know I’m going to!

Beyond Programmable Shading (another two-parter):  GPGPU was promoted by GPU manufacturers in an attempt to find non-graphics uses for their products, and then turned full circle as people realized that drawing pretty pictures is really the best way to use massive general-purpose computing power.  Between CUDA, OpenCL, and Larrabee, this has been a pretty hot topic.  This is the second year that this course has been presented; last year had information on all the major APIs, and some case studies including a presentation on id’s Voxel Octree research.  A subsequent SIGGRAPH Asia presentation added some new material, such as a presentation on real-time implementations of Renderman‘s REYES algorithm.  This year, presenters include people from NVIDIA, AMD, Intel and Stanford; I expect this course to add significant new material, given the rapid development of the field.

Efficient Substitutes for Subdivision Surfaces: Tessellation is another hot topic; Direct3D 11 is mostly designed around this and Compute Shaders (the topic of the previous course).  There has been a lot of work on mapping subdivision surfaces and other types of high-order surface representations to D3D11 hardware.  Including presenters from ILM, Valve, and NVIDIA, this course promises to be a great overview of the state of the art.

Color Imaging: Color is one of the most fundamental topics in rendering.  This course is presented by some of the leading researchers on color and HDR imaging, and should be well worth attending.

Advanced Material Appearance Modeling: Previous versions of this course were the basis for an excellent book on material appearance modeling.  This is a great overview of an important rendering topic, and well worth attending if you haven’t seen it in previous years.

Visual Algorithms in Post-Production: It is well-known that you can find the latest academic rendering research at SIGGRAPH, but there is always a lot of material from the trenches of film effects and animation production as well.  A surprisingly large percentage of this is relevant for real-time and game graphics.  This course has presenters from film production as well as graphics academia describing ways in which academic research is used for film post-production.  I think our community can learn a lot from the film production folks; this course is high on my list.

The Digital Emily Project: Photoreal Facial Modeling and Animation: Last year, Digital Emily was one of the most impressive technology demonstrations; it was the result of a collaboration between Paul Debevec‘s group at USC and Image Metrics, a leading facial capture company.  In this course, presenters from both ICT and Image Metrics describe how this was done, as well as more recent research.

Real-Time Global Illumination for Dynamic Scenes: Real-time global illumination is another active topic of research.  This course is presented by the researchers who have done some of the best (and most practical-looking) work in this area.  It will be interesting to compare the techniques from this course with Crytek’s technique (presented in the “Advances in Real-Time Rendering” course).

SIGGRAPH 2009 papers

Ke-Sen Huang has had a SIGGRAPH 2009 papers page up for a while, and this weekend he’s added a bunch of new papers.

I found two of these to be of direct relevance to real-time rendering:

Gaussian KD-Trees for High-Dimensional Filtering: This paper generalizes the approach used in the SIGGRAPH 2007 bilateral grid paper.  Large-scale image filters are typically performed on downscaled buffers for better performance, but this cannot normally be done for bilateral filters (which are used in real-time rendering for things like filtering SSAO).  The bilateral grid is a three-dimensional low-resolution grid, where the third dimension is the image intensity (it could also be depth or some other scalar quantity).  However, bilateral grids cannot be used to accelerate bilateral filters based on higher-dimensional quantities like RGB color or depth + surface normal; this paper addresses that limitation.

Modeling Human Color Perception under Extended Luminance Levels: An understanding of human color perception is fundamental to computer graphics; many rendering processes are perceptual rather than physical (such as tone mapping and color correction), but even physical computations are affected by the properties of human vision (such as the range of visible wavelengths and the fact that human color perception is trichromatic, or three-dimensional).  Most computer graphics people are familiar with color spaces such as CIE XYZ, but color appearance models such as CIECAM02 are less familiar.  These are used to model the effects of adaptation, background, etc. on color perception.  Current color appearance models are based on perceptual experiments performed under relatively low luminance values; this paper extends the experiments to high values, up to about 17,000 candelas per square meter (white paper in noon sunlight), and propose a new color appearance model based on their findings.  I also found the background and related work sections illuminating for their succinct overview of the current state of color science.

Two more papers, although not directly relevant to real-time rendering, are interesting and thought-provoking:

Single Scattering in Refractive Media with Triangle Mesh Boundaries: This paper finds a rapid (although not quite real-time) solution to refraction in objects composed of faceted or smooth triangle meshes.  The methods described here are interesting and look like they could inspire some real-time techniques, perhaps on the next generation of graphics hardware.

Fabricating Microgeometry for Custom Surface Reflectance: This one is not useful for rendering, but is just plain cool.  Instead of using the microfacet model to predict the appearance of surfaces based on their structure, they turn the idea around and construct surfaces so that they have a desired appearance.  One of the examples they show (inspired by Figure 1 in this paper), is a material with a teapot-shaped highlight! Well, with their current fabrication methods it is really a teapot-shaped reflection cast on a wall, but once manufacturers get their hands on this, all kinds of weird and wonderful materials will start showing up.

So far the yield of papers relevant to real-time rendering practitioners is disappointingly low; perhaps more relevant papers will show up when the official list is published.  In any case, the early list of courses has a lot of relevant material, and I have reason to believe the final list will have even more good stuff on it.  In addition, the Talks (formerly Sketches) program always has useful stuff, Will Wright is giving a keynote speech, and the Electronic Theater (which is back, renamed as the Evening Theater) now has real-time content, so there are more than enough reasons to attend SIGGRAPH this year (and it’s in New Orleans!).  Registration has already started!