Indexed graphics for retro engine?

[Shadowblitz16]

On Thursday, 19 September 2019 at 23:32:13 UTC, norm wrote:
> On Thursday, 19 September 2019 at 20:47:45 UTC, Shadowblitz16 
> wrote:
>> [...]
>
> I'd create a fragment shader to convert each pixel to 8 bit. 
> There are many examples on the web about creating fragment 
> shaders and 2d opengl scenes, i.e. a 2d scene where OpenGL 
> coordinates are integer pixel coordinates. Once you get that 
> you then just implement the conversion routine.
>
> Using the shader you can render the image as a textured quad 
> and send the colour look up table down as an additional 1d 
> texture. This way you can have several D arrays for each colour 
> table and simply swap the texture buffer pointer to instantly 
> switch colours.
>
> You can also get cool effects this way when you move to 3d 
> using 8 bit colour tables.

the issue with using openGL is its complex and hard to get 
working with a widget library