Properly scaling 2-bit colour to 8-bit colour

[SagarDevAchar]

The Problem

• Scaling 2-bit colour into 8-bits just using << 6 is speedy, but, makes the video output look dull
• Theoretically speaking, it leads to a maximum brightness loss of ~25%

The Solution

• Instead of the << 6, it is wiser to use * 85 for proper usage of all 8-bits available
• The 85 is obtained by dividing the 8-bit value into four equidistant levels [0, 85, 170, 255]

The Implementation

• The solution has been deployed on GitHub Pages and tested (https://sagardevachar.github.io/vga-playground/)
• The output video is vibrant and is closer to what a typical R-2R hardware would produce on a real display
• On observing the FPS of the simulator, we can notice ~6 FPS drop for a few presets (Stripes, Conway) indicating that there is a small impact on performance