[Scummvm-devel] Testing needed for GSoC OpenGL Branch

[Max Horn]

Am 12.08.2010 um 07:46 schrieb vgvgf:

> Hi,
> 
> On Sat, Aug 7, 2010 at 6:45 AM, Max Horn <max at quendi.de> wrote:
>> but did you read what Yotam wrote (the part you quoted right before your text) ? He asked what the point is in having the 5/4, 5/3, 16/9 etc. modes. And quite frankly, I am wondering about that, too. It seems those modes are not necessary at all.
>> 
>> Please explain why you / your mentors think that those specific fixed rates are necessary, now that you can scale to arbitrary resolutions.
> 
> I think those extra options are only for the user personal taste.
> While it is easy to switch to a fullscreen mode with the desired
> aspect ratio, in some lcds those modes may be simulated by the monitor
> and the screen will not be seen properly.

Actually, I thought the idea was to never switch the screen resolution at all when going to full screen mode. But rather either
I) scale to fit the full screen (ignore aspect ratio), 
II) scale up as much as possible while retaining AR
III) or scale as much as possible with a game specific AR (i.e. scaling 320x200 to 320x240). 

I don't see why any other option would be necessary, desirable, or make any sense... The only reason we have those fixed aspect ratios in the "old" SDL backend is as a hack, a workaround, for the inability o scale to arbitrary resolutions. I can't recall any user explicitly requesting those, except as a workaround for this inability... :)


> Also, it is hard to resizing
> the window and maintain the screen aspect ratio, so this aspect ratios
> corrections can help in that.

Are you now talking about windowed mode? In windowed mode, we would not care about the screen's aspect ratio at all. We would only offer these modes:
1) run with fixed AR (320x200 games thus run AR 16:10)
2) run with AR correction for games that need it (e.g. upscale certain 320x200 games to 320x240, AR 4:3)
3) unlock ratio, and let the user resize arbitrarily.

(in addition, we would allow the user to quickly switch to 1x, 2x and 3x, ... scaling, with either the original AR, or corrected AR).

At least I can't think of any reason why a user might want to use windowed mode and force a game to use 5:4 mode or 16:9... That would just distort the graphics. 


> However, as you and yotam said, they may
> not be really needed and is a feature that will not be really used.
> 
> What I have not implemented is an option for maintaining the original
> size, that seems a good feature to implement. I will implement it, but
> should I delete the aspect ratio correction option defined in
> "desired_screen_aspect_ratio", along with the options for forcing
> 16/9, 16/10, 4/3, 5/4 and 5/3 aspect ratios?

Yes, this has always been a crude hack, a fig leaf to cover up the fact that we cannot deal better with arbitrary screen resolutions.

> An alternative can be
> only to add the option selected in "desired_screen_aspect_ratio" only
> if it was defined in the configuration file by the user, by default
> "desired_screen_aspect_ratio" has as value "auto" and that would be
> ignored.
> 
> Regarding the maintaining the original size option, for example, in
> case that a scaling factor of x3 is used  (So, a 320x240 game would be
> 960x720) and a fullscreen mode like 640x480 is used, should I downsize
> the game screen to 640x480 or just leave it at its current size (And
> some parts will be left out of screen)?

In full screen mode, there is no need for 3x scaling, only options I, II, and III from above.
In windowed mode, you should not allow 3x scaling if the screen is not big enough.


Bye,
Max