We introduce image-space radiosity and a hierarchical variant as a method for interactively approximating diffuse indirect illumination in fully dynamic scenes. As oft observed, diffuse indirect illumination contains mainly low-frequency details that do not require independent computations at every pixel. Prior work leverages this to reduce computation costs by clustering and caching samples in world or object space. This often involves scene preprocessing, complex data structures for caching, or wasted computations outside the view frustum. We instead propose clustering computations in image space, allowing the use of cheap hardware mipmapping and implicit quadtrees to allow coarser illumination computations. We build on a recently introduced multiresolution splatting technique combined with an image-space lightcut algorithm to intelligently choose virtual point lights for an interactive, one-bounce instant radiosity solution. Intelligently selecting point lights from our reflective shadow map enables temporally coherent illumination similar to results using more than 4096 regularly-sampled VPLs.
We present the Haptic Shading Framework (HSF), a framework for procedurally defining haptic texture. HSF haptic texture shaders are short procedures allowing an application-programmer to easily define interesting haptic surface interaction and the parameters that control the surface properties. These shaders provide the illusion of surface characteristics by altering previously calculated forces from object collision in the haptic pipeline.HSF can be used in an existing haptic application with few modifications. The framework consists of user-programmable modules that are dynamically loaded. This framework and all user-defined procedures are written in C++, with a provided library of useful math and geometry functions. These functions are meant to mimic RenderMan functionality, creating a familiar shading environment. As we demonstrate, many procedural shading methods and algorithms can be directly adopted for haptic shading.
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