Author Topic: GT64/GT65 colour palette in WinAPE  (Read 2635 times)

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Offline SuTeKH/Epyteor

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GT64/GT65 colour palette in WinAPE
« on: 12:08, 20 November 11 »
Hola tout le monde!
 
I'm looking into an 'obsession project' that requires me to use the grey-scale abilities of the GT-64/GT-65 monitors, but because I use WinAPE exclusively I have a little problem; grey-scaling in WinAPE is easy, so long as you know the RGB values of the source image. However, this produces interesting colours when the 'Linear Palette' option is set in the Display Settings, but produces the correct colours when it is not set.
What I need to know is which of these 'colour' scales is correct to real-hardware? 'Linear Palette' on or off.
 
Here are two pictures with the complete grey-scale in both 'palette modes'. Can someone tell me which is closest to reality?
(obviously, I'd prefer the 'NoLinearPalette' to be right!)
 
Muchos thankos!

Offline Morn

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Re: GT64/GT65 colour palette in WinAPE
« Reply #1 on: 16:43, 20 November 11 »
So, how are we supposed to test this on a real machine? Couldn't you provide a BASIC program that draws this INK pattern on the screen?

Offline SuTeKH/Epyteor

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Re: GT64/GT65 colour palette in WinAPE
« Reply #2 on: 19:13, 20 November 11 »
So, how are we supposed to test this on a real machine? Couldn't you provide a BASIC program that draws this INK pattern on the screen?

Well, if you cycle the first 15 colours;
Code: [Select]

5 REM BASIC PROGRAM #1
10 MODE 0
20 FOR n=1 to 15
30 INK n,n
40 PEN n
50 PRINT CHR$(143);
60 NEXT n
70 END
Does it look like a proper gradient? Or is INK #9 actually darker than INK #8?
 
(... and yes, ignore lines 5 and 70!)

Offline Morn

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Re: GT64/GT65 colour palette in WinAPE
« Reply #3 on: 19:34, 20 November 11 »

Does it look like a proper gradient? Or is INK #9 actually darker than INK #8?

They're almost the same brightness, but #9 is slightly brighter. So it does look like a pretty smooth gradient to me.

I've never really noticed this property of the first 16 INKs on the GT65 before. Fascinating!  :)

Offline MaV

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Re: GT64/GT65 colour palette in WinAPE
« Reply #4 on: 19:36, 20 November 11 »
Does it look like a proper gradient? Or is INK #9 actually darker than INK #8?

Looks like a nonlinear palette to me. (GT65 + CPC464/6128)

Take a look at the Climax G demo for some juicy pictures that exploit this fact (green screen only).
http://sylvestre.cpcscene.com/demo_productions.html
« Last Edit: 19:44, 20 November 11 by MaV »
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Offline SuTeKH/Epyteor

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Re: GT64/GT65 colour palette in WinAPE
« Reply #5 on: 20:27, 20 November 11 »
They're almost the same brightness, but #9 is slightly brighter. So it does look like a pretty smooth gradient to me.
I've never really noticed this property of the first 16 INKs on the GT65 before. Fascinating!  :)

Looks like a nonlinear palette to me. (GT65 + CPC464/6128)

So I'll make sure that LINEAR PALETTE is not ticked in the Display Options.
 
Thank you muchly, sirs.
- JTMS...
 
 
EDIT: In the same vein as CLIMAXG, here's Kaley & Jim in WinAPE-esque grey-scale in overscan!
« Last Edit: 21:20, 20 November 11 by tastefulmrship »

Offline TotO

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Re: GT64/GT65 colour palette in WinAPE
« Reply #6 on: 22:12, 20 November 11 »
Here are two pictures with the complete grey-scale in both 'palette modes'. Can someone tell me which is closest to reality?
If fact, both gradians are done by displaying the same inks... So, it's just a "display" problem and don't have any incidence on your code?

On pictures, linear fail... Really strange. :D
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Offline SuTeKH/Epyteor

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Re: GT64/GT65 colour palette in WinAPE
« Reply #7 on: 22:27, 20 November 11 »
If fact, both gradians are done by displaying the same inks... So, it's just a "display" problem and don't have any incidence on your code?
On pictures, linear fail... Really strange. :D
The problem stems from knowing which INK represents the real 'shade' on real hardware... as it were! If the LINEAR palette is how real looks, then I need to change all my palettes to match, otherwise they're fine.
And it will change the code, as I'll have to move the fade-in INKs to a LINEAR set (0, 1, 2, 3, 4, 5, 6, 7, 9, 8, 11, 10, etc) to look like a proper fade in. Presently it's just 0-26 and then 26-0 to fade out.

My grey-scale images look terrible in LINEAR, yet fine without.
It's strange alright!
« Last Edit: 22:31, 20 November 11 by tastefulmrship »

Offline TotO

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Re: GT64/GT65 colour palette in WinAPE
« Reply #8 on: 22:56, 20 November 11 »
The CPC palette is like I quoted some posts before. (code)
It's a proportional dark to light steps. (first Bleu, then Green, finaly Red)
So, you may try to increase by changing the RGB order to see if you get better ???
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