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I've been working on an existing Apple II emulator, OpenEmulator, which takes an interesting (and as far as I know, unique in the Apple II emulator world) appro
by zellyn 10y ago
I've been working on an existing Apple II emulator, OpenEmulator, which takes an interesting (and as far as I know, unique in the Apple II emulator world) approach: it renders a fairly raw NTSC-like signal, and then uses GPU shaders to convert to colors, while adding fairly realistic CRT effects, like persistence, curvature, dot masks, etc.
The result is an emulation that is incredibly close to what I see when I walk downstairs and run my test code on the real Apple IIe in my basement. I guess that's what happens when a DSP person writes an emulator :-) (The original author has disappeared themselves from the internet, unfortunately.)
- zellyn 10y agoOh, one more note: I do not believe it would work with a light gun.
- eropple 10y agoDepending on the latencies and frame drawing speeds, a Zapper-type ("show a light on the screen, poll whether the gun sees it") might work, but probably not. A Super Scope-type (going off hblanks) definitely would not.
- braveo 10y agoIt's pretty common in the world of emulators, it's just that a lot of people don't care and choose not to use the plugins for it (I'm one of those people).
- XaspR8d 10y agoRelatedly, if anyone hasn't read it, Kyle Pittman has a lovely rundown of his attempts at emulating various CRT-effects digitally during development of the indie game Super Win the Game: http://www.gamasutra.com/blogs/KylePittman/20150420/241442/CRT_Simulation_in_Super_Win_the_Game.php http://www.gamasutra.com/blogs/KylePittman/20150420/241442/C... Of course, most people (Pittman included) felt that configuring the visually emulation too accurately was annoying and/or unbelievable. :P
- tlb 10y agoI made an attempt at this around 2001, as part of the XScreensaver collection. See video at https://youtu.be/p3QZqhp67l8?t=30s https://youtu.be/p3QZqhp67l8?t=30s. It generates an NTSC signal, adds noise, and recovers the H and V sync and color in a DSP implementation following the schematic of an old TV. It reproduces the color fringing of text and many other cherished artifacts of Apple ][ computing.
- zellyn 10y agoAwesome! I've actually seen people reference that as the most accurate emulation they'd ever seen. Perhaps we should add noise to the OpenEmulator one too! :-) [Edit] the bending, and shadowing to the right of the characters is amazing :-)
- Zardoz84 10y agoIt remember me a lot when I plugged my Spectrum +3 via composite video to my small TV when I was a child.
- to3m 10y agoThere's an Electron/VIC20/2600/Oric emulator that does this too: https://github.com/TomHarte/CLK https://github.com/TomHarte/CLK - looks authentically horrid and it's got that somewhat elusive 50Hz feel. (Not many 50Hz Electron games, though! Firetrack is one.)