The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Non-Photorealistic Rendering Techniques for a Game Engine COMP 238 Final Project

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Remember NPR Quake?

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie How did they do it? “grep”-ed the Quake source code for OpenGL calls Pulled them out into one source file Added dynamic loading support Started coding different visual styles

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie How about a “cartoon” look? Silhouettes Creases Shading Shadows Walls

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Silhouettes Flip the normals and extend the edges of backfacing polygons.

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Creases (1) Add thin quadrilaterals at each edge, forming an angle with the polygon.

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Creases (2) It actually works!

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Shadows The function is there, but it’s never called :(. Just draw a projection of each model on a horizontal plane (not always correct, but works out pretty well).

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Cartoon-style shading 1D texture coordinate at vertex = amount of light received

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Walls No lighting information available, so… Replace with “hand-drawn” texture. Add charcoal style for lines (one thick line and several jittered thin lines).

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Result

The UNIVERSITY of NORTH CAROLINA at CHAPEL HILL Adrian Ilie Bibliography [1] Alex Mohr, Michael Gleicher: "Non-Invasive, Interactive, Stylized Rendering". The 2001 ACM Symposium on Interactive 3D Graphics. [2] Ramesh Raskar: "Hardware Support for Non-photorealistic Rendering", Eurographics [3] Bert Freudenberg, Maic Masuch, Thomas Strothotte: "Walk- Through Illustrations: Frame-Coherent Pen-and-Ink Style in a Game Engine", Siggraph/Eurographics Graphics Hardware, LA, [4] Adam Lake, Carl Marshall, Mark Harris, Marc Blackstein: "Hardware Support for Non-photorealistic Rendering", Siggraph/Eurographics Graphics Hardware, LA, [5] Jeff Lander: "Shades of Disney: Opaquing a 3D World", Game Developer Magazine, March 2000.