What is Anti Aliasing and What Does It Do? -last part

Multisampling

Multisampling is a more efficient but slightly less kind of Anti-Aliasing. Multisampling takes multiple samples for each pixel. In a standard example the quincunx method takes samples in the corners & sample in the middle. Each of these samples is given a weight the corners are given a weight of 1/8 each & the centre sample is given a weight of 1/2. The color of the pixel is then determined by similar calculations to Supersampling.

 

With multisampling each cell on has samples in it. Taking a glance at the diagram below you can see that the other samples are taken from neighboring cells. So multisampling takes in to account the colors around the pixel in query. This is the way you receive a blend of color to accomplish the desired result. It is important to note that Multisampling only happens when a cell is covered my over color, otherwise a single color is selected & does not need to be calculated.

Levels of Anti-Aliasing

This refers to the amount of samples taken to pick the color of the pixel. The higher the sample rate the better the quality of picture but the slower the picture will be rendered. FSAA will be often called FSAA 2x or FSAA 4x, 6x & 8x are also available but have a bigger performance hit & need more powerful graphics cards.

2x FSAA

The picture above shows samples taken from a graphics card using FSAA 2x, samples are taken in corners & used to produce the pixels color. With FSAA 4x below you simply double the amount of samples taken for each pixel from FSAA 2x.

4x FSAA

When this is completed on every pixel along an edge, the blending is much smoother & even less noticeable. As always though, the trick is to balance quality & performance for your individual machine.

Pros & Cons - The Summary

There are pros & cons for using anti-aliasing in both games & applications. They have been through them but here is a rapid summery to help you make up your mind if using AA or FSAA is best for you & your PC

Pros

• Smoothes out screen fonts
• Rounded edges look to have smooth curves
• Type can be simpler to read due to better quality fonts
• Games look a lot prettier & more realistic

Cons

• Tiny text can be blurred to read
• Already sharp edges can be made fuzzier
• You can’t print out Anti-Aliased text as it blurs
• Static picture sizes are larger
• Games are affected by lower frame rates