What is graphics , and how is it made ?

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3 comments, last by Servant of the Lord 10 years, 4 months ago

ok yes am new at this , and just wondering what is graphics and how is it programmed i know that i will take a course in graphics in uni ( am CS major) so just need to know more about it ??

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Basically, graphics are all of the things that you see on your computer screen. There are two popular APIs (Application Programming Interfaces) that are used to render (display) graphics:

1. OpenGL (for 3d graphics)

2. Direct X

These are basically libraries (collections of functions and variables and classes) that build your graphics for you. You could always start from scratch and program your own graphics renderer, but most people prefer to use these because it is a lot of work to make it yourself.

OpenGL is written in both the C and C++ programming languages and I am sure it took either a long time or a lot of people to program it. Or perhaps it took a long time and a lot of people. Chances are you will only learn to use it rather than make your own from scratch. But if you want to make your own, have at it.

Hope that helps.

They call me the Tutorial Doctor.

Think of a lightbulb that can be turned on and off.
Think of a lightbulb that has a switch that can be adjusted in brightness between "fully bright" and "completely off" with various levels of brightness.

Think of three of those lightbulbs side by side. The three bulbs give off different color of light: One is red, one is green, and one is blue.

When you stand far enough from these lightbulbs, if you have them all (Red, Green, and Blue) turned on at full brightness, the colors of the light merges together to make white.
Likewise, you can adjust the lightbulbs with each color at different intensities to make other colors as well.

2msp.jpg
See RGB color model.

So now, take your three lightbulbs, and shrink them down. Make them really tiny. Smaller than the tip of a pen. That's a pixel as displayed on your computer monitor.
Your monitor has millions and millions of tiny "lightbulbs" (so to speak) in combinations of Red, Green, and Blue.
iswk.png

The intensity of those are adjusted to give different light for each different spot on the computer screen.

To adjust the 'brightness' of each 'lightbulb' of Red, Green, and Blue, the computer needs to send the correct intensity to the monitor, and the monitor can decide how to display it. So, in most computer applications nowadays, we send the intensities in a range from 0 to 255, with 255 being fully bright. Other software does other things (like ranges from 0.0 to 1.0 or different methods), but the 0-255 range is fairly common.

We send a triplet of {Red, Green, and Blue} (called an RGB value) for each pixel we want to display.
Sometimes this is displayed as a hexadecimal value, like #FF00AA or similar.

We often store the range in a single 32 bit integer with 8 bits for red, 8 for green, 8 for blue, and 8 extra bits ("alpha") that we use to store extra information not actually given to the monitor but manipulated by software - usually it's used for transparency/opacity.

A single 24 or 32-bit integer can represent a single 'pixel'. An 'image' is a 2D array of integers that represent a rectangular collection of pixels.

thanks guys , i hope its not that hard to study though

Oh definitely not. It just depends how deep you want to go. If you want to know how computers are made from the ground up, you have to start at the bottom and learning about electrical circuits and transistors and such. But if you want to make computer games, you don't need to learn any of that.

You asked "What is graphics, and how is it made?" which is a kinda vague. smile.png We had to guess what it was you were asking about.

TutorialDoctor answered how graphics are used on the videocard (which you don't need to know), and I answered how monitors display graphics (which you also don't need to know).

That's like asking, "What is the sky made of?" - TutorialDoctor answered, "The sky is made out of air and has clouds in it.", I answered, "The appearance of the sky is an illusion caused by sunlight scattering off of the gas particles suspended in our atmosphere." - both are true, and explain a different level of abstraction.

You don't need to know either of those answers if you actually want to fly an airplane. laugh.png

If you ask a more specific question, we could give some better answers more tailored to what you want to know.

You could look up the basic course structure of your "graphics" class, and then ask about some specific things the class covers.

I'm not really sure what a "graphics" class would teach - the word "graphics" is so vague it could mean alot of different things.

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