Thomas Harte
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596d34190c
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Fixed: write pointer is calculated only after write x and y are known. This is probably the memory handling problem?
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2015-07-28 08:15:54 -04:00 |
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Thomas Harte
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1f229ee6f7
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More tweaks to provide a stable image, at least for the time being.
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2015-07-27 20:18:25 -04:00 |
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Thomas Harte
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01109d441b
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Made an attempt at NTSC colours. Hard coded in RGB, not composite. Short cuts, tsk.
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2015-07-27 19:04:03 -04:00 |
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Thomas Harte
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31e9a53a44
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Removed some debugging code.
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2015-07-27 16:43:51 -04:00 |
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Thomas Harte
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caffe56a2d
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Slightly expanded width of cathode ray gun, decided to figure out exactly how to deal with off-by-one lengths and precision at a later date, ensured that failure to catch vertical sync doesn't cause out-of-bounds buffer access on the hard-coded, assumed large enough, 512x512 data textures.
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2015-07-27 00:28:47 -04:00 |
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Thomas Harte
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65bb31d55b
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With around about a thousand issues, not the least of which being sometimes unsafe memory accesses, I've at last got pixels on screen.
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2015-07-26 23:50:43 -04:00 |
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Thomas Harte
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e53fbcf9ea
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Reshuffled to make the OpenGL view explicitly a conduit for CRT-style output, and to give it responsibility for frame drawing. Which is still an awkward thread hop for the time being, but I've yet to read up on the advocated approach to multithreading with an NSOpenGLView; it looked like special provisions were available.
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2015-07-26 15:13:46 -04:00 |
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Thomas Harte
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dd428c5d4d
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Slightly relaxed time it takes to recognise vertical sync; considered what to do about reviving proper vertical sync but then gave up.
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2015-07-24 23:56:25 -04:00 |
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Thomas Harte
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cea2580000
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Upped internal precision a little.
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2015-07-24 23:36:44 -04:00 |
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Thomas Harte
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ecb2898bd5
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The overall architecture of who has responsibility for what is now very askew but: the CRT now outputs a tightly packed short buffer, with the probable OpenGL destination in mind. So it's now all fixed arithmetic internally. CRTFrame is reduced to a plain C struct with the intention that the OpenGL view will take responsibility for it and stop doing the back-and-forth sprint on getting buffer data. The Atari 2600 now outputs explicit blanks rather than level blacks for its border, so that it's easier visually to debug the CRT in its form as far as it has currently progressed: to drawing lines where the cathode ray gun would run while outputting pixel. I note that I'm still not quite getting vertical sync right yet — I'm just accepting it anywhere in teh frame — but that should be an easy fix.
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2015-07-24 23:29:45 -04:00 |
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Thomas Harte
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d72287a776
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Looked up normal retrace time (it's a lot less than 16µs and 26 scanlines — more like 7 and 10) and that the visible portion of a line is defined to start about 12 µs after the start of hsync, put the first two numbers into my CRT to make that more accurate, then derived a newer guess about what the Atari 2600 does for each of its 228 cycles. The text version of a frame is now looking pretty good. So it's probably time to hit OpenGL and the OS X side of things. Though I'll have a quick look to find out whether I can learn the exact real Atari 2600 timings before moving on.
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2015-07-23 19:24:25 -04:00 |
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Thomas Harte
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33c06baffa
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Explicitly separated vertical and horizontal sync event tracking, so as explicitly to be able to handle a coincidental simultaneous occurrence of both. Also for clarity.
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2015-07-23 18:53:18 -04:00 |
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Thomas Harte
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5203f31bf4
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Reintroduced a console examination of the output runs being received after fixing a failure to complete or restart frames over in the CRT; weirdly it seems that sync is being obeyed but raster position is off. So work to do.
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2015-07-22 20:45:10 -04:00 |
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Thomas Harte
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065050115f
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Made an attempt to switch to a triple-buffering scheme for CRT outputs, with an eye towards asynchronicity.
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2015-07-22 20:33:20 -04:00 |
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Thomas Harte
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b503e13380
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Fix one: vertical scan speed was failing to allow for the number of cycles in a line.
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2015-07-22 18:56:35 -04:00 |
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Thomas Harte
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963cb2f6fb
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Attempted to switch to slightly more meaningful names within the CRT and implemented a delegate to investigate output. Working on it.
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2015-07-22 18:15:18 -04:00 |
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Thomas Harte
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908c171d2d
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Commented the heck out of this thing, to put my thoughts in order if nothing else.
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2015-07-21 16:37:39 -04:00 |
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Thomas Harte
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a1a1b15d18
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Made a quick attempt to accumulate a list of detected output runs. Which means finally having to specify normal frame height. I'm already at too many magic formulae though, so this will need proper revision when I'm next awake. Definitely my horizontal position advancement is way off.
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2015-07-20 23:18:56 -04:00 |
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Thomas Harte
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4fa315ab4d
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This looks a lot closer to correct. The loss of horizontal sync during vertical sync is odd but the two should be fully decoupled in here. I'll have to check. Probably I've got something wrong. There are approximate sinusoidals when re-establishing sync, so that's promising as to the flywheel.
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2015-07-20 21:58:32 -04:00 |
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Thomas Harte
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4695295dd1
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Made complete attempt at sync discrimination. But I seem somehow to be locking such that horizontal sync is in the middle of the line. Obviously my flywheel is at fault somehow.
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2015-07-20 21:43:00 -04:00 |
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Thomas Harte
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4e4c082a05
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Made some minor attempt at proper sync response. I think I've gone way off piste and overcomplicated it.
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2015-07-19 23:43:22 -04:00 |
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Thomas Harte
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4a1e9fe2a8
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Rephrased the CRT as owning an arbitrary number of buffers and vending storage space for pixel output. That much better maps to potential implementations of this thing in GLSL, with ES 2.0's limitations kept in mind.
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2015-07-19 21:21:34 -04:00 |
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Thomas Harte
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7df5025eef
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Started sketching out the delegate interface that will allow a branch from the CRT into whatever native display system is used by a particular platform.
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2015-07-19 18:32:42 -04:00 |
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Thomas Harte
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6f78ecdc9c
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Made first genuine attempt at outputting a meaningful CRT stream. Which shows some significant errors. So work to do.
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2015-07-19 16:48:14 -04:00 |
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Thomas Harte
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2d0f861474
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Incoming: a 'CRT' class, to receive information intended for a cathode ray tube. To decode sync, etc.
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2015-07-19 13:36:27 -04:00 |
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