Class9

Class9 - Class 9 Procedural Textures and Environment Maps...

Info iconThis preview shows pages 1–9. Sign up to view the full content.

View Full Document Right Arrow Icon
Class 9. Procedural Textures and Environment Maps HW5 Ulrich Neumann CS580 (Computer Graphics Rendering)
Background image of page 1

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

View Full DocumentRight Arrow Icon
Texture can set any parameters Textures can be used to modify or set any parameters of the rendering process Geometry, surface characteristics, lighting and shading model, Displacement, normal perturbation, shadow maps, reflection, etc. .. (survey of textures - Heckbert, and any books)
Background image of page 2
Texture I/O Texture output parameters can be 1D, 2D, 3D, . .. any-D Texture input parameters can be 2D (u,v), or 3D (u,v,w) for surface or volume mappings Input/Output parameters can also include surface orientation vectors Tangent (t) , normal (n) , binormal (s) (usually specified in model space) (u,v, t,n,s) can be used to orient a bumpmap texture on a surface Normal perturbation is f(u,v) = (dn/dt, dn/ds) A 2D parameter (uv) maps to a 2D modification of a 3D vector at each pixel – bump mapping
Background image of page 3

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

View Full DocumentRight Arrow Icon
Bump Mapping Use texture to perturb normals - create a bump-like effect + = original surface bump map modified surface NOTE : Does not alter the actual geometry Bump map only affects the shading process … so there is inconsistency at silhouette edges
Background image of page 4
Bump Map Examples
Background image of page 5

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

View Full DocumentRight Arrow Icon
Textures are general mapping functions Lookup table images are only one evaluation method Mathematical or procedural functions are another.
Background image of page 6
Fractal texture(1) A fractal texture function is evaluated as an iterative function in the plane This is perfect for a texture since we have 2D texture coords A Mandlebrot set X = X 2 + C where X and C are complex numbers X = (Xr + Xi) i=sqrt(-1) C = texture coords u+vi, X = 0+0i initially Complex multiply XY = (Xr Yr - XiYi) r + (Xr Yi + XiYr) i
Background image of page 7

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

View Full DocumentRight Arrow Icon
Fractal texture(2) The Julia set is also X = X 2 + C – X = u+vi C = constant C = (-0.12375+0.56805i) or (-0.012+0.74i) : possible start values For either function, do N-iterations and evaluate the result X – N = 100 – 500 (for example – higher N means more detail) – Length (X) = sqrt(Xr 2 + |Xi| 2 ) measured after iterations
Background image of page 8
Image of page 9
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 04/22/2010 for the course CS 580 at USC.

Page1 / 25

Class9 - Class 9 Procedural Textures and Environment Maps...

This preview shows document pages 1 - 9. Sign up to view the full document.

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