Synthpopalooza Posted December 21, 2012 Share Posted December 21, 2012 The other mode of curious interest is ANTIC 6/7 ... better known as Graphics 1 and 2 The character grid is laid out in bitpairs like in ANTIC 4/5 (4x8 char, 4 colors per cell) screen codes 0-31 are undisplayable. For Graphics 9 and 11, here are the layouts screen codes: 00 01 10 11 32-63 0 1 4 5 64-95 0 2 6 8 96-127 0 3 10 13 For Graphics 10: screen codes 00 01 10 11 32-63 PM0 PM1 BAK PF1 64-95 PM0 PM2 BAK BAK 96-127 PM0 PM3 BAK PF3 There is no PF0 or PF2 in this mode, and the second range only allows 3 colors. This is a mode that I have used in demos using a Super IRG style mode for Graphics 1. Quote Link to comment Share on other sites More sharing options...
kenjennings Posted December 22, 2012 Share Posted December 22, 2012 I C. What about a (structured) list about difference between A8 and C64? I am pretty sure the C64 people on AA will help. It could be a post in this thread to which AA users can point the next "convert" Of course along with a link to the "Altirra HW-Manual" to explore the details. The Wikipedia pages have these lists of features for ANTIC, and CTIA/GTIA. Offhand, I don't see anything missing in terms of inherent capability of the hardware. ANTIC: 14 different Playfield graphics modes: 6 character modes4 types of font/glyph rendering [*]8 map modes Output a variable number of blank scan lines Playfield Text and Map modes can be mixed onscreen Variable screen height up to vertical overscan Variable screen width up to horizontal overscan Vertical coarse scrolling Vertical fine scrolling Horizontal coarse scrolling Horizontal fine scrolling Soft, re-definable character set. Performs the DMA for CTIA/GTIA to produce Player/Missile graphics Trigger a CPU-serviced interrupt routine at specific scan lines Non-fixed RAM. This allows RAM for graphics features to be located almost anywhere in the 16-bit memory address range. This applies to: Display lists. Playfield Graphics data Character set fonts Player/Missile Graphics data CTIA and GTIA: It is responsible for interpreting the Playfield graphics data stream from ANTIC to apply color to the display. The GTIA version includes three alternate color interpretation modes for the Playfield graphics. 16 shades of a single hue from the 16 possible hues in the Atari palette. This is accessible in Atari BASIC as Graphics 9. 16 hues in a single shade/luminance value. This is accessible in Atari BASIC as Graphics 11. 9 colors per horizontal line in any hue and luminance from the entire Atari palette of 128 colors accomplished using all five playfield color registers, and the four player/missile color registers. This is accessible in Atari BASIC as Graphics 10. [*]It merges four Player and four Missile overlay objects (aka sprites) per scanline with the Playfield graphics. [*]It checks for collisions between the Players, Missiles, and the Playfield graphics. [*]It is responsible for reading the state of the joysticks' triggers (bottom buttons only in case of Atari 5200 controllers). [*]It contains four input/output pins that are used in different ways depending on the system: In Atari 8-bit computers, three of the pins are used to read state of the console keys (Start/Select/Option). The fourth pin controls the speaker built into the Atari 400/800, used to generate keyboard clicks. On later models there is no internal speaker, but the keyclick is still generated by GTIA and mixed with the regular audio output. In the Atari 5200, the pins are used as part of the process that reads the state of the joysticks' keyboards. Quote Link to comment Share on other sites More sharing options...
Sdw Posted March 17, 2013 Author Share Posted March 17, 2013 BTW, I would love to see your dither-plasma! Here it is, finally released! And on as well. 4 Quote Link to comment Share on other sites More sharing options...
Rybags Posted March 17, 2013 Share Posted March 17, 2013 Nicely done. So this is Mode 4 using just 3 foreground colours? Quote Link to comment Share on other sites More sharing options...
Sdw Posted March 17, 2013 Author Share Posted March 17, 2013 Nicely done. So this is Mode 4 using just 3 foreground colours? Indeed it is, so very straightforward. But you got to start somewhere! Quote Link to comment Share on other sites More sharing options...
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