Thomas Harte
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84d1c2e47d
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Fixed end of sync time calculation and ensured the pretend capacitor is emptied by the decision to retrace and doesn't refill during retrace.
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2015-08-05 20:29:20 -04:00 |
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Thomas Harte
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04c2640b15
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Made a quick attempt to allow vsync triggers only on the raising edge of a sync signal. Will need to investigate more thoroughly.
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2015-08-03 08:42:05 -04:00 |
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Thomas Harte
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5313b48ebd
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I'm ashamed to admit, I: played with numbers until enough things looked stable such that I can investigate other things. Discovery: my PAL autodetection was way off. Fixed, hopefully.
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2015-08-02 20:32:18 -04:00 |
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Thomas Harte
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55017b78a5
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Made an attempt to unify my variable storage (and, technically, to get beam size correct across the frame).
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2015-08-02 19:30:45 -04:00 |
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Thomas Harte
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6e52e5df1c
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Full separate 'lateral' usage is go. Also probably at some point I need to throw in a phase property, which this new flexibility will help with.
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2015-08-02 14:32:29 -04:00 |
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Thomas Harte
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3ab6585789
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Started making the format of data included in a CRTFrame less a matter of variously hard-coded magic constants. Which will allow me to separate the idea of an internal lateral position from the direct texture coordinate, avoiding precision sampling errors at the top and bottom.
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2015-08-02 14:25:21 -04:00 |
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Thomas Harte
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be421587ad
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Eliminated the vertical retrace counter; vertical retrace ends when the beam gets back to the top.
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2015-08-02 13:48:35 -04:00 |
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Thomas Harte
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de4f2bf5dd
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Maybe the 10 lines resource I saw meant 10 lines including charge time?
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2015-07-31 19:00:40 -04:00 |
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Thomas Harte
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5f1d76e855
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Can't seem to find any documentation: assumed horizontal sync is generated during vertical.
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2015-07-31 18:49:02 -04:00 |
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Thomas Harte
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c1a12ad4df
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Fix to make sure end of vertical sync is always correctly spotted as an event, rather than just happening off the books. So I can now watch Joust roll to its heart's content.
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2015-07-31 18:15:59 -04:00 |
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Thomas Harte
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9c91f1a2eb
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Added an attempt at NTSC/PAL autodetection, based on number of missed vertical syncs.
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2015-07-31 18:04:33 -04:00 |
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Thomas Harte
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a5d66e9dd6
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Factored out a few more constants, started trying to ensure there's enough slack and the mechanisms in place for the CathodeRayView to hold onto two frames if it desires, for potential phosphor simulation, switched once again to additive blending — much more like a real CRT — and added a sine function across the width of spans per my understanding of how an electron gun actually fires.
Why do all this when overall timing is still so far off? It helps me more easily see how overall timing is so far off.
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2015-07-31 17:47:10 -04:00 |
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Thomas Harte
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6ad3fbbaf2
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Slowed flywheel adjustments a little, the better to highlight phase errors for the time being.
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2015-07-30 23:00:54 -04:00 |
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Thomas Harte
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cfe758daa0
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A tweak here, a tweak there, to help with debugging.
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2015-07-30 21:29:40 -04:00 |
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Thomas Harte
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20c2d98b9a
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Converted remaining spaces to real tabs.
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2015-07-30 20:51:32 -04:00 |
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Thomas Harte
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1fa7a77793
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Continuing in my attempts to figure out the complete absence of graphics from some games: there are 262 lines on an NTSC screen, not 256. Also ensured that the CRT has a little spare range at the edges so that its generated triangles don't wrap around just because of integer overflow.
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2015-07-30 20:07:20 -04:00 |
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Thomas Harte
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98efae2536
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Reintroduced emergency vertical sync — so that output occurs even when the emulation isn't catching syncs properly — and switched some spaces to tabs.
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2015-07-30 17:16:49 -04:00 |
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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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