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

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.

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.

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 most you get is what you ask for.

Great minds discuss ideas. Average minds discuss events. Small minds discuss people.

I tend to like poems that engage me - that is to say, which do not bore me.

I would designate as science fiction in the best sense: they are visions and anticipations by which we seek to attain a true knowledge, but, in fact, they are only imaginations whereby we seek to draw near to the reality.

It's like with a girl: it's more fun to meet and slowly, gradually learn things about each other. A little mystery is always nice and it's interesting to still learn new things about someone you are involved with.

Our laws governing lobbying and campaign contributions have struck the right balance between the wishes of the people and those of private industry, so why are we so quick to doubt that the same great results can be achieved by putting the government's justice-dealing branch on the same market-based course?

Well, I'm about to do another western, a pilot for HBO this fall.

One does not become fully human painlessly.

Heroes are created by popular demand sometimes out of the scantiest materials.

I just hate people who are lazy. To be on my team, you have to have energy and a sense of wanting to learn. That really excites me.

In my 20s I was such a serious, boring-looking person. I would never do my nails. I never even danced. But I was taught by the women. They had gone through hell, but they would dance and sing. I came to realise I can't argue for a happy world if I am not happy myself.

I used my captors' names every chance I had. It was intentional, a way of reminding them that I saw them, of pegging them, of making them see me in return.

The enemy is within the gates; it is with our own luxury, our own folly, our own criminality that we have to contend.

We need to do whatever it takes to get our children together and pay attention to them, because that's our future. What's in the hearts and minds of our children is what's in our future.

I believe we have a responsibility, even if our job is to lead a nonprofit organization, as private citizens to be good citizens and to make our voices heard.

I get very nervous about not being around the office.

For the meaning of life differs from man to man, from day to day and from hour to hour. What matters, therefore, is not the meaning of life in general but rather the specific meaning of a person's life at a given moment.

I do think of myself very strongly as a New Zealander, but when I moved out to the States, I was aware that I didn't want to just live in a satellite community of only other New Zealanders.

A good newspaper, I suppose, is a nation talking to itself.

My dad was real hard on me. He wasn't really big on congratulating and stuff like that.

The lunch in a normal American restaurant is very problematic for me. I don't like to have hot food for lunch.

Wanting something does not give you the right to have it.

Washington State has a strong tradition of a positive relationship - positive working relationship between labor and management, whether in the private sector or the public sector. It needs to continue to be that way.

Where we're not wrong or where the cost of settling is so much that it is totally disproportionate to the harm or the error that we made, we're not going to settle.