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Freddi Fish 5 - can't run - color errors
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zolimax



Joined: 26 Jan 2015
Posts: 6
Freddi Fish 5 - can't run - color errors 

When I try to run Freddi Fish 5 on iOS (8.1) in ScummVM 1.7.0, it only show me the errors:
"Could not initialize color format" and "Error running game: Unsupported color mode"

I tried all versions I found: official eng win, official eng mac, pirated rus win (akella), pirated rus win (7wolf). And all shows me the same. Also, I tried various render modes - but no result.
In Windows version of ScummVM all working good.
Help me to run it, please!

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Post Fri Apr 03, 2015 11:24 pm 
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eriktorbjorn
ScummVM Developer


Joined: 31 Oct 2005
Posts: 3284
Re: Freddi Fish 5 - can't run - color errors 

quote:
Originally posted by zolimax
When I try to run Freddi Fish 5 on iOS (8.1) in ScummVM 1.7.0, it only show me the errors:
"Could not initialize color format" and "Error running game: Unsupported color mode"



The short answer is that this probably means that the game simply isn't supported in the iPhone version of ScummVM. Here's how I understand it:

Unlike the earlier Freddi Fish games, Freddi Fish 5 uses 16-bit graphics instead of 8-bit graphics. With 8-bit graphics, you have a palette of 256 colours and each pixel is one byte specifying which of these colours to use. With 16-bit graphics, you don't need a palette since each pixel is two bytes containing the R, G and B values.

But that's where things get a bit tricky. Usually you'd think of R, G and B each being between 0 and 255, but obviously then you would need 24 bits, not 16. It gets even worse if you also include A for transparency. There are several different ways of encoding this as a 16-bit value, both in how many bits and which particular bits each colour gets.

A game may ask for any format, and as long as the graphics backend supports it, it should work. From what I understand, the Windows/Mac/Linux version of ScummVM knows of ten different 16-bit formats, while the iPhone version only seems to know about one.

Freddi Fish 5 uses RGB555. "555" means that each colour gets five bits (so one bit is unused), and "RGB" tells which five bits each colour gets. Unfortunately, the iPhone version only seems to support RGB565.

(I have no idea how much work it would be to support RGB555. I don't even own an iPhone, let alone know how to write programs for one.)
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Post Sat Apr 04, 2015 7:11 am 
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zolimax



Joined: 26 Jan 2015
Posts: 6
 

Hm.. Strange, if iPhone port know RGB565, it must not be problem to make RGB555 support.
I have read about this formats:

code:
RGB565
R 1111100000000000
G 0000011111100000
B 0000000000011111

RGB555
R 0111110000000000
G 0000001111100000
B 0000000000011111



So, for convert from RGB555 to RGB565 need just make simple shift and disjunction (lowest green bit in RGB565 will be just 0). And after use all like RGB565.
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Post Thu Apr 09, 2015 10:25 pm 
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