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.

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)

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

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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The only dead bodies from marijuana are in the prisons and at the hands of the police. This is ridiculous.

Rock n' roll can get quite overwhelming. You can get caught up in the cycle.

A romantic comedy has to be funny and make you think about life; but the obstacle that has to be overcome is key.

E-Verify is a very commonsense reform that we can implement here in the state of Florida. I think I share a lot of Floridians' frustration that it didn't pass and a lot of the politics that were taking place behind the scenes.

Socialism is a fraud, a comedy, a phantom, a blackmail.

A rose, isn't quite as beautiful as it once was, when after its thorn pricks you.

I think stories can grow out of the visual. It can be an engine for literacy.

Whatever course you decide upon, there is always someone to tell you that you are wrong. There are always difficulties arising which tempt you to believe that your critics are right. To map out a course of action and follow it to an end requires courage.

There is something very unsettling about being with someone when they die. People say it's peaceful. It's not peaceful. It's the most personal thing you can do, is die, and you feel almost like you're invading someone's most personal moment by being there.

Youth is a disease from which we all recover.

There is nothing very remarkable about being immortal; with the exception of mankind, all creatures are immortal, for they know nothing of death. What is divine, terrible, and incomprehensible is to know oneself immortal.

At the age of four with paper hats and wooden swords we're all Generals. Only some of us never grow out of it.

Some people say it might be good for your career to die and then come back again. I have died many ways, car crashes, motorcycle crashes, etc. But, I am still alive.

In the very few interviews I've made, it doesn't matter how long we've talked to each other, the headline is still just about my paycheck.

You have to understand your own personal DNA. Don't do things because I do them or Steve Jobs or Mark Cuban tried it. You need to know your personal brand and stay true to it.

I think comedy is so specific, so hard. I'd audition for comedies and think, 'I can't pull this off.'

What I wasn't prepared for were the feelings of anxiety that it stirred in me. I wasn't prepared for the initial feeling of I don't want to have to do that again. I was scared.

White people scare the crap out of me.

When I embraced the rock hat, when I put it on two or three years ago, when I realized I'm gonna go and make really focused rock albums, it felt like wearing an old shoe. It was a perfect fit.

Sometimes I wonder if I'm a character being written, or if I'm writing myself.

If you want to stay perfect, you cannot go undefeated with a blemish on your record.

Iranian filmmakers are not passive. They fight whenever they can, as creative expression means a lot to them. The restrictions and censorship in Iran are a bit like the British weather: one day it's sunny, the next day it's raining. You just have to hope you walk out into the sunshine.

I don't want to kill ads. I think advertising is great, and I'm very aware that there's multiple revenue streams in television, subscription and advertising. But I also don't want to put my head in the sand, and I think the world is changing.

I was thrown into a community production of 'Bye Bye Birdie' or something when I was a kid. I wanted to just build the sets, but I wasn't allowed to just build the sets unless I auditioned for the play. So I auditioned for the play and was thrown into the chorus. During the course of that I fell in love with it, and I never really turned back.