@ -8,7 +8,7 @@ In this chapter we are going to apply what we've learned so far and repeat it al
*"The grid provides a framework within which human intuition and invention can operate and that it can subvert. Within the chaos of nature patterns provide a constrast and promise of order. From early patterns on pottery to geometric mosaics in Roman baths, people have long used grids to enhance their lives with decoration."* [*10 PRINT*, Mit Press, (2013)](http://10print.org/)
First let's remember the [```fract()```](http://www.shaderific.com/glsl-functions/#fractionalpart) function, which is in essence the modulo of one (```mod(x,1.0)```) because it returns the fractional part of a number. In other words, ```fract()``` returns the number after the floating point. Our normalized coordinate system variable (```st```) already goes from 0.0 to 1.0 so it doesn't make sense to do something like:
First let's remember the [```fract()```](../glossary/index.html#fract.md) function, which is in essence the modulo of one ([```mod(x,1.0)```](../glossary/index.html#mod.md)) because it returns the fractional part of a number. In other words, [```fract()```](../glossary/index.html#fract.md) returns the number after the floating point. Our normalized coordinate system variable (```st```) already goes from 0.0 to 1.0 so it doesn't make sense to do something like:
```glsl
void main(){
@ -22,11 +22,9 @@ void main(){
But if we scale the normalized coordinate system up - let's say by three - we will get three sequences of linear interpolations between 0-1: the first one between 0-1, the second one for the floating points between 1-2 and the third one for the floating points between 2-3.
____comment the code below with some comments about where the interpolation by three is happening____
Now it's time to draw something on each subspace in the same way we did in previous chapters, by uncommenting line 25. Because we are multiplying equally in x and y the aspect ratio of the space doesn't change and shapes will be as expected.
Now it's time to draw something on each subspace in the same way we did in previous chapters, by uncommenting line 27. Because we are multiplying equally in x and y the aspect ratio of the space doesn't change and shapes will be as expected.
Try some of the following exercises to get a deeper understanding:
@ -40,11 +38,17 @@ Try some of the following exercises to get a deeper understanding:
Since each subdivision or cell is a smaller version of the normalized coordinate system we have already been using we can apply a matrix transformation to it in order to translate, rotate or scale the space inside.
____comment the code below with some comments about where the matrix transformations are happening____
* Combine different layers of patterns like this one to compose your own [Scottish Tartan Patterns](https://www.google.com/search?q=scottish+patterns+fabric&tbm=isch&tbo=u&source=univ&sa=X&ei=Y1aFVfmfD9P-yQTLuYCIDA&ved=0CB4QsAQ&biw=1399&bih=799#tbm=isch&q=Scottish+Tartans+Patterns).
[  ](http://graphicriver.net/item/vector-pattern-scottish-tartan/6590076)
### Offset patterns
@ -64,11 +68,7 @@ By multiplying *x* by a half the space coordinate duplicate it size (which is th
____fix the previous two paragraphs with Jen____
Now we can apply some offset to odd rows to give a *brick* effect to our tiles. Check line number 10 and 11 of the following code:
____check if lines 10 and 11 are still the right lines____
____comment the code below with notes about where the brick offset is happening____
Now we can apply some offset to odd rows to give a *brick* effect to our tiles. Check line number 14 and 15 of the following code:
Patricio Gonzalez Vivo
9 years ago
