We haven't much of a chance to talk about GLSL vector types. Before going further it's important to learn more about these variables and the subject of colors is a great way to find out more about them.
If you are familiar with object oriented programming paradigms you've probably noticed that we have been accessing the data inside the vectors like any regular C-like ```struct```.
@ -126,6 +126,10 @@ Try the following exercises:
* Read [Josep's Alvers book Interaction of Color](http://www.goodreads.com/book/show/111113.Interaction_of_Color) and use the following shaders examples as practice.
Before jumping to the next chapter let’s stop and rewind. Go back and take look at the functions in previous examples. You will notice ```in``` before the type of the arguments. This is a [*qualifier*](http://www.shaderific.com/glsl-qualifiers/#inputqualifier) and in this case it specifies that the variable is read only. In future examples we will see that it is also possible to define arguments as ```out``` or ```inout```. This last one, ```inout```, is conceptually similar to passing an argument by reference which will give us the possibility to modify a passed variable.
@ -134,9 +138,8 @@ Before jumping to the next chapter let’s stop and rewind. Go back and take loo
int newFunction(in vec4 aVec4, // read-only
out vec3 aVec3, // write-only
inout int aInt); // read-write
```
```
You may not believe it but now we have all the elements to make cool drawings. In the next chapter we will learn how to combine all our tricks to make geometric forms by *blending* the space. Yep... *blending* the space.
## Shapes
Finally! We have been building skills for this moment! You have learned most of the GLSL foundations, types and functions. You have practiced your shaping equations over and over. Now is the time to put it all together. You are up for this challenge! In this chapter you'll learn how to draw simple shapes in a parallel procedural way.
In 1996, sixteen years after Perlin's Noise and five years before his Simplex Noise, [Steven Worley wrote a paper call “A Cellular Texture Basis Function”](http://www.rhythmiccanvas.com/research/papers/worley.pdf). In it he describes a procedural texturing technique now extensively use by the graphics community.
Patricio Gonzalez Vivo
8 years ago