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GPU Gems
The book is intended for an audience already familiar with programmable GPUs and high-level shading languages and is divided into six parts that concentrate on particular domains of graphics programming. Each part contains between five andd nine chapters, with the entire book containing a total of 42 chapters. Each chapter was written by a different renowned expert(s) from a gaming company, tool developer, film studio, or the academic community. About half of the contributors are from NVIDIA's Developer Technology group. The chapters focus on effects and techniques that help developers to get the most out of current programmable graphics hardware. With approximately twenty pages per chapter, the contributors are able to describe various effects and techniques in-depth, as well as delve into the required mathematics.
All the shaders in the book are written in the high-level shading languages Cg and HLSL. The demo programs on the CD-ROM that accompanies the book use both Direct3D and OpenGL as graphics API, depending on the authors' preferences. Even though the shaders are in Cg and HLSL, it should be fairly straightforward for OpenGL programmers who might prefer to use the recently released OpenGL Shading Language to port the shaders, as the syntax is very similar.
The first part of the book deals with natural effects and contains chapters on rendering realistic water surfaces, water caustics, flames, and grass. Two chapters look behind the scenes of NVIDIA's Dawn demo, which shows a dancing fairy with realistically lit skin. There is also a chapter on Perlin noise (improved version) and its implementation on GPUs that was written by Ken Perlin himself.
The second part of the book concentrates on lighting and shadows. There are chapters from people at Pixar Animation Studios that describe some of the lighting and shadow techniques used in their computer-generated movie productions, as well as a chapter on managing visibility for per-pixel lighting. In the shadow department, the two predominant ways of rendering shadows in real-time, shadow mapping and shadow volumes, are discussed with possible optimizations and improvements. The chapter by Simon Kozlov on methods to improve perspective shadow maps presents some especially interesting new material on the topic.
The third part of the book covers materials and contains chapters on subsurface scattering, ambient occlusion, image-based lighting, spatial BRDFs, and how to use them efficiently in real-time, while part four describes various techniques for image processing (being used more frequently in computer games), mostly in the form of post-processing filters. The chapters presented in this section deal with various depth-of-field techniques, a number of filtering techniques using shaders, and the real-time glow effect seen in many of the newer games (especially in Tron 2.0). Not surprisingly, one of the authors of this chapter is John O'Rorke from Monolith Productions, a developer of the game. Contributors from Industrial Light & Magic introduce the OpenEXR file format used for storing high-dynamic-range image files (see openexr.org).
Part five, titled "Perfomance and Practicalities," is a collection of chapters that deal more with software engineering aspects of developing software that uses shaders. In particular, there are chapters on optimizing performance and detecting bottlenecks, using occlusion queries efficiently, integrating shaders into applications and content creation packages (in particular Cinema4D), and how to develop shaders using NVIDIA's FX Composer tool. There is also an interesting chapter on converting shaders written in the RenderMan shading language, a language for offline rendering, to real-time shaders. The chapter uses a fur shader from the movie "Stuart Little" to demonstrate this conversion. With the large increase of GPU processing power, more shaders from the offline rendering world will enter the realm of real-time graphics and it will be useful to re-use already existing resources, such as RenderMan shaders.
The final part of the book deals with a topic that has recently received a lot of attention by graphics researchers - a topic called General Purpose GPU or GPGPU programming, i.e. using the GPU for other things than rendering triangles. This part comprises chapters on performing computations, in particular fluid dynamics, on the GPU, chapters on volume rendering, and a nice chapter on generating stereograms on the GPU. As a side note, there is a website that deals exclusively with news in the GPGPU community at gpgpu.org.
The book contains a many images that show the presented effects in action, and also plenty of diagrams and illustrations that explain more complicated techniques in detail. Unlike Randima Fernando's previously released book, The Cg Tutorial, which I have also reviewed in the past on Slashdot, the book and all of its illustrations and images are printed entirely in color. The large number and high quality of the illustrations is probably one of the best features of this book that makes even the more advanced effects easily comprehensible.
The book comes with a CD-ROM that contains sample applications for most of the chapters in the book. Some of these applications include the full source code, whereas others, such as NVIDIA's Dawn demo (also described in some of the book's chapters), are included as executables only. It must be noted that all applications run exclusively on Windows, even though some of the samples that are available in source code form and use OpenGL could probably be built to run on other operating systems as well. Furthermore, about half of the samples require what Fernando and Kilgard in The Cg Tutorial call a fourth-generation graphics card to run, in particular, an NVIDIA GeForceFX card. Note that most samples that require a GeforceFX will not run on comparable ATI hardware. This comes as no surprise since GPU Gems is predominantly an NVIDIA book. It should be noted, however, that the techniques, effects, and shaders presented in the book's text are generally applicable to programmable GPUs and are equally useful when working with graphics hardware from vendors other than NVIDIA.
This is a great book that every programmer involved in game development and/or real-time computer graphics should have on his/her shelf. For the game programmer it is critical to stay up-to-date with the latest and greatest effects available with modern GPUs in order to remain competitive when creating the gaming experience. For the graphics developer, it is interesting to see how the immense processing power of current graphics hardware can be exploited in graphics applications. This book offers insight on both of these topics and more, and I highly recommend it.
A few notes from reader Akalgonov: Reader akalgonov contributes a few more thoughts on the book:
"The sample programs and demos require shader support, Cg, OpenGL, or the latest version of DirectX to run. On the plus side, the majority of the companion topics included pre-compiled binaries (but not the runtime dynamic link libraries) or an AVI illustrating the subject in addition to the source code. While the CD contains over 600 MB of examples from the text, it provided only 23 of the 42 topics covered in the book. Since most of the articles provide an overview and references to a topic, additional material on the CD would have been beneficial.
I found the wide range of subjects quite interesting - and was refreshed that the topics actually seemed "ahead of the curve" in terms of hardware requirements. However in order to provide more subject depth, it seemed that the text could have been split into two volumes in order to expand the existing chapters with sufficient depth. As the material is just enough to get one started, the subject treatment may disappoint some readers seeking to apply the clever and unique techniques presented in the book directly or those hoping to use the book as an opportunity to learn some of the advanced features provided in a programming graphical processing unit."
Martin Ecker has been involved in real-time graphics programming for more than 9 years and works as a games developer for arcade games, and works on the open source project XEngine. You can purchase GPU Gems -- Programming Techniques, Tips, and Tricks for Real-Time Graphics from bn.com. Slashdot welcomes readers' book reviews -- to see your own review here, read the book review guidelines, then visit the submission page.
If you're interested in thsi stuff, also check out Real Time Rendering by Tomas Moller and Eric Haines. It's one of my favorites and contains an amazing amount of information..
google for rtChess.
The ray tracing engine has since seen a 40% performance boost and has added photon mapping and scales nicely with more CPUs - I just haven't written a game with it since. I don't think a GPU implementation will be much faster. nVidia seems to think they make general purpose processors now - HAH what a laugh.
Two points:
First, Why? Most people don't even make movies that are raytraced.
Second, they already are doing raytracing on the GPU. Purcell had one working in 2002. There was a presentation on it, in a course at SIGGRAPH 2003. The GPU is maybe a little faster than the CPU, right now, for raytracing.
"Tweaking OpenGL" is kind of like saying "tweaking the CPU", any more. It's fairly close to a generalized stream processor. And their specs already are open enough to have figured this out. Look at GPGPU and read some more about how people are doing amazing stuff on the GPU today. No need to wait for ATI and NVidia to open up any specs - they already did. Cg and GLSlang are fully up to the task.
And, photon mapping and similar techniques are much more sophisticated than raw raytracing.
Education is the silver bullet.
http://graphics.stanford.edu/papers/rtongfxi s/
http://graphics.stanford.edu/papers/tpurcell_thes
http://graphics.stanford.edu/papers/photongfx
(And not a karma whore in sight.)
Open up their specs so you can write a real-time raytracer? Why can't you use Cg or HLSL like others have done? Why do you need to write to the video card directly? You have full access to the programmability of the GPU through these languages. If not, program the damned thing in their version of assembler through the DirectX or OpenGL APIs. Unless by "tweaking OpenGL or DirectX" you mean "programming the GPU", your statement seems flat-out wrong.
Don't believe you can do it? Here's a link some projects that do real-time raytacing, radiosity, photon mapping, and subsurface scattering, all on GPUs. These GPUs are programmable without them opening up their specs.
(The desire for them to open up their specs is for other reasons, not because they are hiding some functionality from you.)
if computer video hardware was designed in such a way that when graphics were not being processed, the GPU could be used for general number crunching. In other words, if it is possible to do load balancing between the GPU and the CPU.
While it would probably be possible to use a GPU for general purpose number crunching, I believe it would make the GPU unable to send a signal to your monitor at the same time.
I asked the same question back in the days of RC5-64 and I was told that it was not feasible for just that video signal reason. I was told I would not be able to use my video card while it was crunching.
Correct me if I am wrong, though!
I fail to see how one million rays per second is "real time" for most images people associate with ray-tracing. Even at one ray per pixel, you're limited to a single 500x500 image per second. But the value of ray tracing is the recursion: one ray hits an object, and anywhere between 2 and 200 rays result (counting for any subsequent recursions, lights and diffusions).
Your budget: 1000000 rays per second. Take a guess at an average of 10 rays per resulting pixel including all recursion, and you're down to a paltry 100x100 pixels at 10fps. You fail on all metrics of expected quality: poor fidelity, poor resolution, and poor framerate. Even on faster CPUs, you haven't made up the difference for what users want to see.
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There are serious investigations into making cache optimized algorithms. For example, the matrix transposition and array index bit reversal algorithms have been investigated in two papers. Also, Bailey's 4-step and 6-step FFT algorithms are also cache efficient. The latter example shows that a complex algorithm such as a FFT can be made cache efficient with the sacrafice of only a few extra computations. Perhaps it would be prudent to use a hybrid ray-tracer/polynomial renderer to section each portion of the screen into regions that will only access a particular portion of memory. In fact, texture mapping is a lot like that. But I propose that we section the geometry into sections that are localized in memory. This will require more computation in the form of checking which ray goes where but it might be possible to create a viable ray tracer/polygon renderer that produces images of ray tracing caliber. By polygon renderer I mean the renderers that we currently use in gaming.
Some references about cache efficiency.
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p.p.s.
Here's the listing from Froogle (just in case you haven't used it yet)
I'm not sure that's gonna happen. The fact of the matter is that current graphics hardware is fast approaching the point where raytracing will be irrelevant.
Actually, AFAIK the opposite is true.
Raytracers scale very nicely with geometric complexity: O(log n). So as the virtual environments continue to grow, raytracing should gain popularity over scan conversion. Have a look at this - that's 50 million triangles raytraced at 4-5 fps!
Most of the current interactive raytracing is still done on parallel computers or PC clusters, but there are a lot of optimizations that can be combined to achieve interactivity even on a single CPU. And hardware architectures are underway as well...