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NPR Wrapup + Shadows Intro CS 446: Real-Time Rendering & Game Technology. David Luebke University of Virginia. Demo. Today: Chris Palmer (F.E.A.R.) Thursday: Jiajun Zhu. NPR Recap: Painterly Rendering. Impressionistic or “painterly” rendering: Sprinkle particles on object surface
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NPR Wrapup+ Shadows IntroCS 446: Real-Time Rendering & Game Technology David Luebke University of Virginia
Demo • Today: Chris Palmer (F.E.A.R.) • Thursday: Jiajun Zhu Real-Time Rendering
NPR Recap: Painterly Rendering • Impressionistic or “painterly” rendering: • Sprinkle particles on object surface • Draw particles as brushstrokes • Can render images to encode normals, surface curvature, depth, color/tone info Real-Time Rendering
Painterly Rendering Real-Time Rendering
Other Styles • Hatching: • Store different cross-hatch patterns representing different tones as textures • Clever ways to use texture hardware to blend between tones at run-time • More info if time permits… Real-Time Rendering
Other Styles • “Graftals” are a general term used for strokes, decals, little bits of geometry • Dynamic placement of graftals to achieve certain effects/styles: Real-Time Rendering
Other Styles • Technical Illustration Real-Time Rendering
Generalizing NPR • Recent work by researchers in NPR attempts to generalize many of these concepts: Coherent Stylized SilhouettesKalnins, Davidson, Markosian, Finkelstein Real-Time Rendering
Generalizing NPR • Recent work by researchers in NPR attempts to generalize many of these concepts: Suggestive ContoursDeCarlo, Finkelstein, Reinkiewicz, Santella Real-Time Rendering
Gallery of NPR images • Technical Illustration • Coherent Stylized Silhouettes • Suggestive Contours • SIGGRAPH papers… • NPAR Real-Time Rendering
Shadows • An important visual cue, traditionally hard to do in real-time rendering • Outline: • Notation • Planar shadows • Soft shadows • Projective shadows • Shadow volumes • Shadow maps • Shadow optimizations Real-Time Rendering
Notation • Light source • Point vs area • Occluders & receivers • Identify ahead of time? • Self-shadowing? • Shadow • Umbra • Penumbra • Soft vs hard shadows Real-Time Rendering
Planar Shadows • Old trick: project the occluder geometry to a plane and render over ground plane • Can do with a matrix • Z-bias issues • Semiopaque shadows harder • Stencil and Z-buffer tricks • Another option: generate textured rectangle • Problems • Light source inside object (Antishadows) • Only planar receivers no self-shadowing Real-Time Rendering