GLSL types — GLSL has most of the default basic types we know from languages like C: int, float, double, uint and bool. GLSL also features two container types that we'll be using a lot throughout the tutorials, namely vectors and matrices. 

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 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.

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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I think there comes a time in every persons life where they just need to go to the darkest, most dismal place.

This generation... they have a different attitude. Instead of sitting and watching something, they want to be a part of it - they're very hedonistic and sensual.

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Writing about 2,000 words in three hours every morning, 'Casino Royale' dutifully produced itself. I wrote nothing and made no corrections until the book was finished. If I had looked back at what I had written the day before I might have despaired.

There are so many quirky characters, it's easy to fall in love with any number of the characters on 'The Carrie Diaries'.

As the world undergoes a major transformation, it's the time of significant opportunity and also threat.

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One shouldn't know the future.

I knew that discrimination existed, even though there were many individuals who were not prejudiced.

Imagination needs to be fed.

50 Cent's a songwriter. He understood and liked my music, but he didn't understand me.

The only thing that matters is submitting to the will of God.

Pride without competence is as much a sin as competence without confidence.

My prayer became 'May I find peace... May I love this life no matter what.' I was seeking an inner refuge, an experience of presence and wholeness that could carry me through whatever losses might come.

'Ordinary Grace' freed me. I don't have to write only Cork O'Connor novels now. I'm liberated. I can write whatever I want to write.

Paths are many, Truth is ONE!

A toddling little girl is a centre of common feeling which makes the most dissimilar people understand each other.

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Are we a nation that educates the world's best and brightest in our universities, only to send them home to create businesses in countries that compete against us? Or are we a nation that encourages them to stay and create jobs, businesses, and industries right here in America?

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The work that is truly productive is the domain of a steadily smaller and more elite fraction of humanity.

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A woman who thinks she is intelligent demands the same rights as man. An intelligent woman gives up.