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Atari demoscene BBS
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Posted by: Cyg / BLaBla
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Sep,28.2012-11:56
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Hi Anders !
I just read this article, you could then be interested in the last Photochrome 5 release if you are not already aware of it : http://www.leonik.net/dml/sec_pcs.py
Here are some technical details about Hicolor :
- as Zerkman, I created my own converter, not Spectrum nor Photochrome. It is easily manageable to be compliant with any rendering methods (regular like Spectrum & blitter or not like using movem) and at any resolution & number of colors. It runs on PC for now and was simply developped in VB.Net, I don't think I will port it to Atari or if it's possible due to the high number of calculation it needs.
- my optimizerter had a serious bug in the methodology, it didn't allow to reach the best possible quality as it tooked the worst results in some cases ! Now it is far better and should compete with Zerkman :-)
- it's not only a static picture converter, it can also prepare the bitmap & the palettes to be used in dynamic hicolor effects like crossfades, bump/phong, blur, colors effects, and lots of other stuff.
It is based on layers, very easy to manage for graphist :
- a bitmap layer, to display a picture,
- another bitmap layer for the 2nd picture displayed in a crossfade effect,
- a normal map layer for bump effect and phong if combined with a picture,
- a textel layer used for effects based on textures projections like tunnels, infinite plans, etc.
- a z-depth layer for lightning variations on the colors or depth of field like effects.
- a screen partitioning layer to cut the screen into 256 distinct areas, useful for apparition effects, per zone effects.
- it is possible to mix all of this layers with transparency or supperposition.
The limits are the time to mix all of it on the Atari side and the final rendering quality.
Crossfade between 2 pictures is many more difficult to optimize than a solo picture, complexity is the square (from 3 RVB to 6 dimensions).
For any high color mode the displaying method cost a lot on Atari, the time left on Atari is poor, about 30% per VBL.
To optimize the time to calculate the effects, I share the palettes between several line, so the calculation time is divided by the sharing amount with a remaining precision at pixel, useful for Phong/Bump/Textured FX, 3 lines are sharing a common set of palettes/colors.
In STreet Art I doubled a same line of pixels with a sharing palette, since Japan the pixels are optimized by line and share a common palette for several lines, a per pixel precision is obtained, but the quality will decrease and has to be tuned.
Pixels are not moving at all during the effects but only colors, color are moving individually or by group of common change: identical lightning degree, or Z value, or zone.
By default Hicolor modes are (determined by the displaying rountine) :
192 pixels wide with 48 colors per line + 2 fixed color
320 pixels wide with 54 colors per line + 2 fixed color
400 pixels wide with 48 colors per line : STE only, using blitter + hardsync per line and fullscreen overscan
I just made a comparison with Photochrome 5 in mode "m3" which should be the best, but there's a lot of options for dithering methods that I didn't test.
I posted a sample here : http://forum.8bitchip.info/software-17/high-color-video-playback-on-ste/ with non-interlace and interlaced mode
Happy to share with you
Best regards,
Cyg / BLaBla
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Date
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Multicolour pics
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evil
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Aug,24.2012-20:44
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Re: Multicolour pics
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D-mog
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Aug,24.2012-21:44
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Re: Multicolour pics
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RA/pdx
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Aug,24.2012-22:55
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Re: Multicolour pics
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Bod/STAX
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Aug,31.2012-16:41
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Re: Multicolour pics
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Cyg / BLaBla
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Sep,28.2012-11:56
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Re: Multicolour pics
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Cyprian
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Sep,29.2012-10:51
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Re: Multicolour pics
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Cyprian
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Sep,29.2012-10:54
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Re: Multicolour pics
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Cyg / BLaBla
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Sep,30.2012-12:36
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Re: Multicolour pics
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Cyprian
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Sep,30.2012-16:24
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Re: Multicolour pics
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Cyg / BLaBla
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Sep,30.2012-18:48
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Re: Multicolour pics
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nativ
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Sep,30.2012-23:40
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Re: Multicolour pics
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evil
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Sep,29.2012-14:38
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Re: Multicolour pics
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zerkman
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Oct,01.2012-05:39
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What's the anti-troll code?
That's your personal code to be able to add comments and messages on the dhs.nu site.
Don't have a code or forgot it? Fix it here.
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