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MESH COLORS
Author: Cem Yuksel, John Keyser & Donald House
Texas A&M University
SIGGRAPH 2010
Speaker: Chung-Yuan Lee
Yuan-Ze University
OUTLINE
Introduction Previous method
Proposed method Mesh color
Filtering Two-dimensional filtering Mip-map filtering Anisotropic filtering
Analysis Summary Reference
INTRODUCTION
Previous method – texture mapping
Intrinsic problems Mapping discontinuities Limitations to model editing after coloring Incorrect filtering …etc
PROPOSED METHOD – MESH COLOR
There are no mapping discontinuities No mapping function is necessary MIP-mapping for level-of-detail filtering is
supported Models can be edited, after coloring, without
resampling The procedure is compatible with the current
real-time graphics pipeline
MESH COLOR STRUCTURE
Mesh color on triangle faces R means different resolution
MESH COLOR STRUCTURE[1,0,0]
[0,1,0] [0,0,1]
MESH COLOR STRUCTURE
Non-uniform Face Resolutions It is straightforward to up-sample or down-
sample along an edge, if two faces sharing a common edge have different resolutions
MESH COLOR STRUCTURE
Editing Mesh Colored Geometry
MESH COLOR STRUCTURE
Non-triangular Meshes Quadrilaterals
Triangle pair Quadrilateral positioning
NURBS Subdivision surfaces
Dividing faces only
FILTERING
For evaluating the color value at any point on the surface or an area, we need a reconstruction filter
Two-dimensional filtering Nearest Linear
MIP-map filtering Anisotropic filtering
TWO-DIMENSIONAL FILTERING
To compute the color value at target point,we need to find out the weights of nearest 3 point to target point
TWO-DIMENSIONAL FILTERING[1,0,0]
[0,1,0] [0,0,1]
If w = 0, we are at the sample point B
weight
TWO-DIMENSIONAL FILTERING
The weights for those color values are w
TWO-DIMENSIONAL FILTERING
The weights are w’ = [1, 1, 1] − w
TWO-DIMENSIONAL FILTERING
Nearest Use the color of the sample with the highest
weight Linear
By blending the colors using the weights
MIP-MAP FILTERING
This face will have n+1 MIP-map levels
MIP-MAP FILTERING
MIP-MAP FILTERING
Face & Edge Vertex
Where Cei is the nearest edge color at the higher level for adjacent edge i
ANISOTROPIC FILTERING
Original
MIP-map filtering
Trilinear filtering
Circularity Distortion
Mapping Chasm
Too fuzzy
ANISOTROPIC FILTERING
original
2x Anisotropic filtering
16xMIP-map filtering
FILTERING
ANALYSIS
Unified content creation
‧Modeling & Painting together
ANALYSIS
Memory efficient
Reduce 20% memory requirement !
Fast
ANALYSIS
hardware
Hardware
Texture mapping on hardware is ~20x faster
ANALYSIS
Correct filtering
SUMMARY
No mapping No Discontinuities Guaranteed 1-1 Correspondence Correct MIP-map Filtering Local Resolution Adjustment Modeling with Painting Compatible with Current Pipeline
SUMMARY Easy to use (for end user) Easy to implement High quality High performance
Mesh Colors will do better than texture mapping , if it has support from Hardware !
REFERENCE
Pictures for Mesh color Cem Yuksel, John Keyser & Donald H. House Texas A&M University “Mesh Colors,“ ACM Transactions on Graphics
(TOG), 29(2) 2010 Pictures for Anisotropic filtering
http://www.csie.ntu.edu.tw/~r89004/hive/mipmap/page_4.html
Copyright© 2000, 2001, 2002 Ping-Che Chen