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

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.

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

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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Silicon Valley does not breed great technology. Instead, the smartest people from around the world tend to move to Silicon Valley.

Every band I knew or played with had flyers and properly-recorded demos and contacts; I couldn't even get a gig.

Across the country military families are facing dire financial circumstances due to longer than expected tours of duties. They are being penalized for their patriotism - no one should have to choose between doing right by their country and doing right by their families.

Using no control and using humor will build a relationship and make a dent to where the client puts the counselor in their quality world and then begins to relate and seek out the counselor. Effective therapy begins with the acceptance of the therapist into the client's quality world.

The most dangerous thing for a branded product is low interest.

Hawaii is not a state of mind but a state of grace.

I pinch myself every day anyway. Everyone knows the road I have had in the game and how I have managed to get myself to where I am today.

My mind may be sober, but my confidence is high!

An artist carries on throughout his life a mysterious, uninterrupted conversation with his public.

Essays entitled critical are epistles addressed to the public through which the mind of the recluse relieves itself of its impressions.

Sports teaches you character, it teaches you to play by the rules, it teaches you to know what it feels like to win and lose-it teaches you about life.

I love performing in front of people, no matter where they come from or what language they speak.

People often say I have so much energy, that I never stop; but that's what it takes to accomplish your goals.

The Xbox 360 is the first console that I've ever worked with that actually has development tools that are better for games than what we've had on PC.

I admire Johann Strauss a lot. I believe he was a genius of his time.

I met in the street a very poor young man who was in love. His hat was old, his coat worn, his cloak was out at the elbows, the water passed through his shoes, - and the stars through his soul.

Perhaps it is partly that we need to love books ourselves as parents, grandparents and teachers in order to pass on that passion for stories to our children. It's not about testing and reading schemes, but about loving stories and passing on that passion to our children.

Feeling gratitude and not expressing it is lil wrapping a present and not giving it.

Human nature fascinates me.

There is always the need to carry on.

Godot is whatever it is in life that you are waiting for: 'I'm waiting to win the lottery. I'm waiting to fall in love'. For me, as a child, it was Christmas. At least that eventually came.

Sensuality without love is a sin; love without sensuality is worse than a sin.

India has to be transformed into a developed nation, a prosperous nation and a healthy nation, with a value system.

You can have information and ease of use and have artistic integrity at the same time. The art of being a good Web designer is getting yourself into that middle ground and treating it as a final destination instead of as a compromise.