Re: Problem Converting Apple IIgs' RGB to VGA?

["Bryan Parkoff" <nospam@nospam.com>]

"mdj" <mdj.mdj@gmail.com> wrote in message 
1157354773.335306.248880@p79g2000cwp.googlegroups.com">news:1157354773.335306.248880@p79g2000cwp.googlegroups.com...
>
> Bryan Parkoff wrote:
>
>>     I think that 16 bit RGB screen is better for speed with small size of
>> video buffers than 24 bit RGB so emulators can run smoothly using 16 bit 
>> RGB
>> screen in 640x480x16 (614400 bytes).  Too huge data size in video buffer
>> such as 1024x768x32 (3MB) may slow to update 60 frames per second.  It is
>> sad that 8 bit RGB is no longer supported in Microsoft DirectX 9.0  What 
>> do
>> you think?
>
> On current hardware, you might find that 16 bit visuals are actually
> slower to update than 24/32

Matt,

    Hi, how do you know that 16 bit RGB data is slower than 24/32 bit RGB 
data?  I use D3DFMT_R5G6B5 (16 bit RGB) that it is faster than 
D3DFMT_X8R8G8B8 (24 bit RGB).  I did test to compare both versions.  If you 
change from 640x480x16 resolution to 320x200x16 resolution, it will be 
running much faster than 640x480x16 resolution because it has short size of 
video data.  I would predict to run 60-70 frames per second, but 640x480x24 
resolution might run between 30-40 frames per second.
    Who is complaining to say why 16 bit data type is bad practice to use, 
but 8 bit or 32 bit data type is only the answer.  8 bit is faster than 16 
bit and 32 bit, but 16 bit is slower than 8 bit and 32 bit.  Who cares if 
they place 16 bit into 32 bit register and use mask to clear higher 31th bit 
to 16th bit?  It does not make any difference what is important to use 16 
bit or 32 bit.

Bryan Parkoff