9.Surface Detail (Rendering 3) Flashcards
What are two methods of adding surface detail to rendered images?
Texture Mapping
Bump Mapping
Is procedural mapping a type of bump mapping?
No, it is texture mapping
So how is procedural mapping implemented, what does it modify?
- Texture pattern computed during rendering
- based on algorithms/rules
- modifies pixel coloue
What is the most commonly use type if texture mapping?
Image based
- defines by an image
- modify pixel colours
What are the pixels of a texture image called?
texel
How is a a texture mapped to a polygon?
RASTERIZATIOn
- Each texture coordinate is mapped to a polygon vertex (x,y,z)
- then these coordinates are interpolated (averaged) across the polygon face
- texel and pixel colour are BLENDEDD
What may happen if texture is applied to polygon but then camera changes?
Texture/pixel resolution mismatch
Way to solve pixel resolution > texel resolution. Ho does it work?
Bilinear interpolation filter
Compute texel colour from adjacent texels
-average HORIZONTALLY & VERTICALLY
What may be a side effect of bi interpolation filter?
Blurry
Method of solving texel resolution > pixel resolution. What is the idea of this?
MipMap filtering
“The further we are from the viewpoint the less detail we need “
How to create a mipmap?
original texture t0 is down sampled to t1,t2,..
Each of these is stored in memory
How to render the mimap?
Select one of the texture depending on the distance of the pixel from the viewpoint
How can textures be used to add accurate illumination to a real time scene?
Lightmaps
Why do some surfaces look ruff?
Surface normals
How to alter surface normal to create bump?
- Scale by Nu, Nv bu,bv (bump verctors)
- N’ = N+buNu+bvNv
