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Lighting
Adjusting Real-Time Lighting for Shadow Volumes and Optimized Meshes
Abstract: Lighting an entire mesh is well understood and presents no real, unexpected artifacts. However, when more complex rendering systems optimize the number of polygons being rendered, like backface-culling from the light's point of view, lighting artifacts are introduced. When culling is done based on face normals and lighting is done based on vertex normals, some adjustments are required. The same applies to self-shadowing meshes that use stencil shadow volumes, since the shadow volumes are extruded based on face normals. Additionally, bump mapping needs even further adjustment, because the normal has nothing to do with the geometric shape of the mesh. This article explores these problems and presents a solution that is accomplished entirely in the pixel shader.
Dynamic Gamma Using Sampled Scene Luminance |  |
Abstract: The human eye constantly samples the brightness of available light and dialates the pupil in response. This variable sensitivity allows it to operate under a much wider range of lighting conditions from dark to bright. By sampling the frame buffer and adjusting the output gamma based on analysis of the data, the technique outlined in this article is able to simulate this type of variable sensitivity and make much better use of video's limited dynamic range. The same technique also allows the simulation of a number of visual phenomena that occur as the eye responds to changing, high dynamic range lighting.
High Dynamic Range Lighting
Abstract: This session shows how to create more realistic environments and lighting through high dynamic imagery and image-based lighting. The course presents how high dynamic range imagery (HDRI) covering the full range of light in the real world can as texture maps in real-time virtual environments and as realistic sources of illumination for CG objects and characters. The course explains the relationship between HDRI, Image-Based Lighting, and Global Illumination, and how the three can be used together to create renderings and composites with extremely high realism. Examples are given using renderings from LightWave 3D, Maya, RADIANCE, and the Arnold rendering system. HDRI file formats, manipulation software, special blur and glare effects, and issues surrounding gamma correction are presented.
Light Scattering: Oh, that Looks Cool! Can we Have it in the Game, Real Quick?
Abstract: Lately a lot of exciting new and old techniques to enhance lighting used in games have become technically feasible on current generation graphics hardware. Surprisingly, or perhaps not so surprisingly – a large number of these techniques have so far not made it into real game applications in any larger way shape or form, sometimes not at all. This talk illustrates the problems encountered and solutions found when trying to go from technology demonstration to real game application using Factor 5’s latest game ‘Star Wars: Rebel Strike’ and the light scattering technique used in it as an example. Related technology used in the game are covered.
Adding Spherical Harmonic Lighting to the Sushi Engine
Abstract: Spherical Harmonic (SH) based lighting solution have entered the mainstream of real-time graphics. This relatively new lighting technique offers many advantages to engine programmers in both performance and advanced lighting realism. The internal engine and shader library that ATI’s demo team uses for their cutting edge technology demos are the case study on how to add support for SH lighting to a real-time graphics environment. This session discusses artist usability, the preprocess tool chain, and runtime issues and solutions they have encountered while adding SH lighting support to their tools, shader library, and engine.
Advanced Real-Time Reflectance
Abstract: Recent advances in graphics hardware and APIs are enabling game developers to use increasingly general reflectance models in their games. However, physics and computer graphics research has generated a large body of knowledge about material reflectance which has not yet been leveraged by game developers. This talk starts with the basic physics of reflectance, and continues to explain the deficiencies of the most commonly-used model (Blinn-Phong). The presentation covers various reflectance models used in the computer graphics literature (such as Cook- Torrance, Ashikhmin-Shirley, Ward, LaFortune and others). Practical implementation methods for these reflectance models on modern programmable hardware are used to realistically render several real-world materials. The presentation concludes by discussing the integratation of these models into the game development pipeline.
Deferred Shading on DX9 Class Hardware and the Xbox
Abstract: Deferred Shading is a rendering technique where all lighting/shading computations are delayed until after the scene is rendered. This technique is used in the non-realtime and raytracing world but only recently has become practical for realtime gaming on the PC and console. For the game developer this means a complete decoupling of geometry rendering from lighting, and removing the problem of determining which geometry interacts with which lights. This also eliminates traditional hardware limitations on the number and types of lights used. A deferred shading engine is capable of taking advantage of the latest hardware and delivering all the cutting edge shading effects you want: 100% per-pixel lighting, extensive material property functions (NDFs, BRDFs), true High Dynamic Range lighting, Volumetric and true 3D shaped lights. The presenters, who have developed and shipped titles using deferred shading, will take the attendees from the high level concepts to the nuts and bolts of developing a deferred shading renderer.
Real-Time Global Illumination
Abstract: The session explores how real-time global illumination game engines can be create on current hardware. A brief history on various global illumination techniques is given and then the presenter explores how they can be adopted in to real-time 3D engines. He also discusses brand new approaches targeted directly at the real-time field.
Reusing Shading for Interactive Global Illumination
Abstract: This session presents recent techniques that reuse shading information to bridge the gap between slow shading and fast interactive image update. The common approach in all these systems is that shading is sparsely sampled and reconstructed for interactive rendering. This session covers several recent techniques including image-based techniques, mesh-based approaches, and four-dimensional approaches. This session also reviews key concepts in global illumination, and describe the state of the art in fast ray tracing. The techniques that are discussed include frameless rendering, image warping, the render cache and edge- and-point rendering, shading cache and corrective texturing, and four dimensional approaches such as 4D radiance interpolants and holodeck. Fast ray tracers such as GPU-based and CPU-accelerated approaches are also discussed.
Inexpensive Underwater Caustics Using Cg
Abstract: This article explains an aesthetics-driven method for rendering the underwater lighting effects known as "caustics" in real-time. We believe the technique is fully original, and has very low computational cost. The results look remarkably realistic, and the method can easily be implemented in most graphics hardware. This simplified approach has proven very successful in many fractal-related disciplines, such as mountain and cloud rendering or tree modeling. This article should satisfy both those interested in water rendering algorithms, as well as those wanting an introduction to pixel shader programming in Cg.
Methods for Dynamic, Photorealistic Terrain Lighting | |
Abstract: This article will present several methods for producing high-quality, physically based lighting solutions for terrain under dynamic lighting conditions. Topics include: Sunlight (Horizon Angles, Shadow Ellipses, and PTMs), Skylight (Radiosity Approximations and Patches), Animated Cloud Shadows, Video-Based Solutions, and Nonterrain Objects.
Cube Map Lighting Techniques | |
Abstract: This article will describe some ways to encode different lighting conditions as well as other properties within cube maps. It will give a brief overview of the properties of cube maps and how to index into them. Topics include: Physical Properties of Cube Maps, Getting data to/from a Cube Map, Rendering with the Cube Map, Encoding Cloud Cover, Encoding Lights in a Cube Map, Encoding Diffuse Lighting in a Cube Map, and Encoding a Day/Night Cycle into a Cube Map.
Textures as Lookup Tables for Per-Pixel Lighting Computations
Abstract: In this article, we show ways to use texture maps as a means to solve functions through a lookup table, focusing on lighting computations. This technique saves precious pixel shader instructions, and in many cases, it is the only way to make certain per-pixel effects possible on the current generation of hardware.
Rendering with Handcrafted Shading Models
Abstract: This article proposes a simple technique called normal distribution function (NDF) shading. It allows an artist to handcraft shading models, with the shape and color of highlights simply stored in bitmaps. The technique uses per-pixel shading, and can also be used in conjunction with bump mapping. Anisotropic shading models can also be created.
A Modified Phong-Blinn Light Model for Shadowed Areas  |  |
Tony Barrera (Barrera Kristiansen AB), Anders Hast (Creative Media Lab, University of Gävle), and Ewert Bengtsson (Center for Image Analysis, Uppsala University)
Graphics Programming Methods, 2003. |
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Real-Time Light-Atmosphere Interactions for Outdoor Scenes | |
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Stochastic Iteration for Nondiffuse Global Illumination | |
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Metropolis Sampling in Random Walk Global Illumination Algorithms | |
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Metropolis Density Estimation | |
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Real-Time Relighting of Compressed Panoramas | |
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Hemisphere Lighting With Radiosity Maps
Abstract: Hemisphere lighting is a simple way of emulating the indirect light contributions found in a typical outdoor scene. Any kind of complex radiosity lighting could be modeled by encoding the surrounding light sources into an HDR (high dynamic range) cubemap, but it is impractical to update such a cubemap in realtime as large numbers of objects move around the world. So we need to approximate, cutting down the complexities of the real world into a more efficient realtime model. The lighting model in this article was designed for fast moving objects in outdoor environments. Its goals were to tie the moving objects in with their surroundings, to convey a sensation of speed, and to be capable of rendering large numbers of meshes at a good framerate on first generation shader hardware.
Implementing Lighting Models With HLSL
Abstract: This article examines using the High Level Shader Language (HLSL) which comes with DirectX 9. This is an overview article that serves as a good introduction to the topic.
Dynamic Per-Pixel Lighting Techniques
Abstract: This article presents several techniques that can be used to perform dynamic lighting effects on a per-pixel basis. These methods have the advantage that they don't require highly tessellated geometry, and can often be performed at little performance cost on multitexturing graphics hardware.
Motif-Based Static Lighting | |
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Simulated Real-Time Lighting Using Vertex Color Interpolation | |
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