The Graphics
Pipeline:
Line Clipping &
Line Rasterization
Docsity.com
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Guidelines and tips
Prepare for your exams
Study with the several resources on Docsity
Earn points to download
Earn points by helping other students or get them with a premium plan
Line Clipping and Rasterization in Graphics Pipeline, Slides of Computer Science
An in-depth exploration of line clipping and rasterization in the context of the graphics pipeline. It covers the importance of clipping, various clipping strategies, and the process of rasterizing lines and circles. The document also discusses antialiasing techniques to ensure continuous appearance and accuracy.
Typology: Slides
2012/2013
1 / 62
This page cannot be seen from the preview
Don't miss anything!
Related documents
Partial preview of the text
Download Line Clipping and Rasterization in Graphics Pipeline and more Slides Computer Science in PDF only on Docsity!
The Graphics^ Pipeline: Line Clipping & Line Rasterization
Docsity.com
Last Time?
-^ Ray Tracing vs. Scan Conversion•^ Overview of the Graphics Pipeline•^ Projective Transformations ModelingTransformations Illumination(Shading) Viewing Transformation(Perspective / Orthographic)^ Clipping Projection(to Screen Space) Scan Conversion(Rasterization) Visibility / Display
Docsity.com
Today: Line Clipping & Rasterization
-^ Portions of theobject outsidetheview frustumare removed•^ Rasterizeobjectsinto pixels ModelingTransformations Illumination(Shading) Viewing Transformation(Perspective / Orthographic)^ Clipping^ Projection(to Screen Space) Scan Conversion(Rasterization) Visibility / Display
Docsity.com
Today • Why Clip? • Line Clipping • Overview of Rasterization • Line Rasterization • Circle Rasterization • Antialiased Lines
Docsity.com
Why clip? • Avoid degeneracies– Don’t draw stuffbehind the eye– Avoid divisionby 0 and overflow• Efficiency– Don’t waste time on objectsoutside the image boundary• Other graphics applications (often non-convex)– Hidden-surface removal, Shadows, Picking,Binning, CSG (Boolean) operations (2D & 3D)
Docsity.com
Clipping strategies • Don’t clip (and hope for the best) • Clip on-the-fly during rasterization • Analytical clipping: alter input geometry
Docsity.com
Today • Why Clip? • Point & Line Clipping^ – Plane – Line intersection^ – Segment Clipping^ – Acceleration using outcodes • Overview of Rasterization • Line Rasterization • Circle Rasterization • Antialiased Lines
Docsity.com
Implicit 3D Plane Equation • Plane defined by:^ point
p &^ normal
n^ OR
normal^ n &
offset^ d^
OR
3 points • Implicit plane equation A x +B y +C
z +D = 0
P^ P^0 Docsity.com
Point-to-Plane Distance
P^0 P’
P d^ H = (A,B,C,D)
- If (A,B,C) is normalized:^ d = H•p = H
Tp
(the dot product in homogeneous coordinates) • d is a^ signed distance positive = "inside" negative = "outside"
Docsity.com
Clipping a Point with respect to a Plane
P^0 P’
P d^ H = (A,B,C,D)
- If d = H•p
≥^0 Pass through • If d = H•p < 0: Clip (or cull or reject)
Docsity.com
What are the View Frustum Planes?
H=(^0 near^ H= far^ H= bottom^ H= top^ H= left^ H= right^
–1^ – near ) (^0
1 far^ ) (^0 near bottom
(^0 – near
- top^ 0 ) (^ left^ near
^0 0 )
(– right^ – near
^0 0 )
P ( left , bottom , – near
( right*far/near
,^ top*far/near
, – far )
Docsity.com
Clipping & Transformation • Transform M (e.g. from world space to NDC) • The plane equation is transformed with (M
-1T )^ ( 1,1,1 )
y nearfar z
y x
xo^ eye
z
Docsity.com
Segment Clipping • If H^ •^ p > 0 and H
•q < 0
- clip q to plane • If H^ •^ p < 0 and H
•q > 0
- If H^ •^ p > 0 and H
•q > 0
- If H^ •^ p < 0 and H
•q < 0
p^ n q Docsity.com
Segment Clipping • If H^ •^ p > 0 and H
•q < 0
- clip q to plane • If H^ •^ p < 0 and H
•q > 0
- clip p to plane • If H^ •^ p > 0 and H
•q > 0
- If H^ •^ p < 0 and H
•q < 0
n^ p q Docsity.com