lecture8 - CSE472 Computer Graphics Illumination and...

Info iconThis preview shows pages 1–12. Sign up to view the full content.

View Full Document Right Arrow Icon
1 CSE472 Computer Graphics Illumination and Shading Light/surface physics The Hall illumination model Chapter 8 + material in notes
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2 CSE472 Computer Graphics Discrete Illumination Models What occurs when light strikes a surface  is quite  complex.   Continuous process Light from infinite angle reflected in infinite directions We are determining intensity of a pixel with… Finite number of lights Finite reflections into space Finite illumination directions Hence, we must have a  discrete model  for lighting  and illumination.
Background image of page 2
3 CSE472 Computer Graphics Illumination Models What should a lighting model entail? Discrete Lights Types of reflection Commercial systems can be quite complex Most start with a basic model and embellish to  pick up details that are missing
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
4 CSE472 Computer Graphics Elements of Lighting at a point N V L R N – The surface normal L – Vector to the light V – Vector to the eye R – Reflection direction
Background image of page 4
5 CSE472 Computer Graphics Reflection What we need is the amount of light reflected to the eye This consists of several components…
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
6 CSE472 Computer Graphics Diffuse Reflection Diffuse reflection  - light reflected in all  directions equally (or close to equally).   Most objects have a component of diffuse  reflection other than pure specular reflection objects like  mirrors.   What determines the intensity of diffuse  reflection?  
Background image of page 6
7 CSE472 Computer Graphics Diffuse Reflection Characteristics Since the intensity is the same in every  direction, the only other characteristic is the  angle between the light and the surface  normal.  The smaller this angle, the greater  the diffuse reflection:
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
8 CSE472 Computer Graphics Lambert’s Law w L N L N w ' / cos w w = θ cos ' w w = Diffuse reflection decreases intensity by the cosine of the angle between the light and surface normal. θ
Background image of page 8
9 CSE472 Computer Graphics Specular Reflection Specular reflection  - If the light hits the  surface and is reflected off mostly  in a  reflection direction, we have specular  reflection. There is usually some diffusion. A perfect specular object (no diffusion at all) is a  mirror.   Most objects have some specular characteristics
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
10 CSE472 Computer Graphics Diffuse and Specular colors Typically the colors reflected for diffuse and specular reflection are different Diffuse – Generally the surface appearance Specular – The color of bright highlights, often more white then the surface color
Background image of page 10
11 CSE472 Computer Graphics Where do these come from?
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 12
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 39

lecture8 - CSE472 Computer Graphics Illumination and...

This preview shows document pages 1 - 12. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online