The vector datatype allows for some interesting and flexible component selection called swizzling. Swizzling allows for the following syntax:

Shaders are also very isolated programs in that they're not allowed to communicate with each other; the only communication they have is via their inputs and outputs.

Shaders always begin with a version declaration, followed by a list of input and output variables, uniforms and its main function. Each shader's entry point is at its main function where we process any input variables and output the results in its output variables

GLSL types

GLSL Vector Container A vector in GLSL is a 1,2,3 or 4 component container for any of the basic types just mentioned. They can take the following form (n represents the number of components)

Components of a vector can be accessed via vec.xwhere x is the first component of the vector. You can use .x, .y, .z and .w to access their first, second, third and fourth component respectively. GLSL also allows you to use rgba for colors or stpq for texture coordinates, accessing the same components.

We can also pass vectors as arguments to different vector constructor calls, reducing the number of arguments required:

ins and outs Shaders are nice little programs on their own, but they are part of a whole and for that reason we want to have inputs and outputs on the individual shaders so that we can move stuff around. GLSL defined the in and out keywords specifically for that purpose.

ins and outs 2 Each shader can specify inputs and outputs using those keywords and wherever an output variable matches with an input variable of the next shader stage they're passed along. The vertex and fragment shader differ a bit though

If we want to send data from one shader to the other we'd have to declare an output in the sending shader and a similar input in the receiving shader. When the types and the names are equal on both sides OpenGL will link those variables together and then it is possible to send data between shaders

Uniforms Uniforms are another way to pass data from our application on the CPU to the shaders on the GPU

To declare a uniform in GLSL we simply add the uniform keyword to a shader with a type and a name. From that point on we can use the newly declared uniform in the shader. Let's see if this time we can set the color of the triangle via a uniform

If you declare a uniform that isn't used anywhere in your GLSL code the compiler will silently remove the variable from the compiled version which is the cause for several frustrating errors; keep this in mind!

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Anger repressed can poison a relationship as surely as the cruelest words.

Emphasize your strengths on your resume, in your cover letters and in your interviews. It may sound obvious, but you'd be surprised how many people simply list everything they've ever done. Convey your passion and link your strengths to measurable results. Employers and interviewers love concrete data.

As soon as I gave birth, it was as if you understand them. They become people, not kids. You start to identify with them. You see yourself in them.

My background is sociology. Combined with my graphic approach, if I could do some film projects, I think I'd be very good at making documentaries eventually, but people don't think of me for that, of course. But dialogue is something I know I can be good at.

Family was real important in putting me on my path. I'm so blessed to come from a home with a mother and a father.

The character I play is a wonderful compilation of things I hate about myself and things I love about myself and things that I've invented to make her even more interesting than me.

Since I was 9 years old, I have been working, hustling to find my own projects - from telenovelas to record deals, etc. etc. Way before I met my husband.

I did a lot of musicals when I first started my career, so I can carry a tune well.

I missed New York. Every break I had from the series, I'd fly back to the East Coast just to get back onstage.

If you become a creative writer with the idea that you are going to make a whole lot of money, then maybe this isn't the best choice for you.

The adults don't know what's happening on the kids' universe and the kids don't know what's happening on the adults' universe.

He who fears to weep, should learn to be kind to those who weep.

The American taxpayers are a powerful force. They don't want their taxes raised. Obama and the Democrats have a fight with the American people, not with me.

Experience is easy to provide and quickly put to good use by people with all the other qualities.

I imagine the life of an atheistic praying mantis to be rather torturous.

I'm doing a Dylan Thomas film, Map of Love, with Mick Jagger producing again. It's a wonderful script.

I have no hesitation in applying a law regardless of what I might think about it.

My idea of an amusement park story is getting adventurers to go tour environmental disaster areas. After all, if the entire Great Barrier Reef gets killed, which seems like an extremely lively possibility, what are you going to do with all that rotting limestone?

I have lost friends some by deathothers by sheer inability to cross the street.

The achievement of one goal should be the starting point of another.

'I Told You' is for all the people who've been doubted, the underdogs.

I think the pageant system is about empowering women. I think that aspect of it is great, but when you take parents who are forcing their children to do anything, I don't think it's healthy.

In many ways, that affection is the real reward for 56 years in the business. Although the money ain't exactly bad either.

Organizating is what you do before you do something, so that when you do it, it's not all mixed up.