Shadow Mapping Outline Quick introduction to computer graphics. - - PowerPoint PPT Presentation

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Shadow Mapping Outline Quick introduction to computer graphics. - - PowerPoint PPT Presentation

Oct 07, 2023 371 likes •541 views

Shadow Mapping Outline Quick introduction to computer graphics. Why Shadows ? The shadow mapping algorithm. Strengths and weaknesses You will ... Get an abstract view of how Computer Graphics works. Be able to outline the

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SLIDE 1

Shadow Mapping

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SLIDE 2

Outline

 Quick introduction to computer graphics.  Why Shadows ?  The shadow mapping algorithm.  Strengths and weaknesses

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SLIDE 3

You will ...

 Get an abstract view of how Computer

Graphics works.

 Be able to outline the the shadow mapping

algorithm.

 Know that this technique is used in current

games.

 Be able to list some weaknesses and strengths

  • f shadow mapping.
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SLIDE 4

Computer graphics

 A set of data: triangles in 3D space.

 Provided by an artist.

 Methods of “rendering” (Drawing) these

triangles on a computer screen.

 Developed by a programmer.

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SLIDE 5

Computer Graphics: the artist

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SLIDE 6

Computer Graphics: the programmer

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Read data Material Specification View Position Light Position Graphics Processing Unit

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SLIDE 7

Computer Graphics: The GPU

Material Specification

View Position Light Position

Graphics Processing Unit Color Buffer Depth buffer

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SLIDE 8

Why Shadows ?

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SLIDE 9

Shadow mapping: Step one.

Material Specification View Position Light Position Graphics Processing Unit

View from Light Position

Depth buffer Color Buffer Shadow Map!

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SLIDE 10

How does it work?

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SLIDE 11

Shadow mapping: Step two.

Graphics Processing Unit

Depth buffer

Color Buffer Shadow Map!

Material Specification View Position Light Position Graphics Processing Unit Depth buffer

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SLIDE 12

Strengths

 Price/Performance

ratio.

 Linear cost in number

  • f drawn “triangles”.

 Extensible.  Simple.

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SLIDE 13

Problems

 Detached shadows.  Incorrectly shadowed

surfaces.

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SLIDE 14

Causes and possible solutions.

Sampling related problems.

Increase shadowmap resolution.

Add small constant to “distances” in order to avoid self-shadowing.

Very unstable!

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SLIDE 15

Even in professional products.

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SLIDE 16

The end!

We have seen...

 Very high level introduction to Computer graphics.  How shadows enhance realism.

 Shadow mapping.

 Currently popular algorithm for generating shadows.  Good performance.  Reasonable results.  But unstable! (small changes to input...)  Research topic: see GPU Gems 3. GPU Pro. (new

articles on the topic still popping up)