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last post from Meshuggah333 at the

CRT Emulation?

    Hey there,

    as I see the Mega65 has HDMI and modern resolutions.

    What about CRT Emulation? Ist something like this planned?

    I only like my C64 on a real tube. I think it looks horrible without rasterization, pixel blending, scanlines, some kind of blurr and so on. Even a real C64 on a TFT is looking horrible and the picture has nothing to do with the look the designers had in mind back in the days.

    Same thing for the Mega65 I think and also for the included C64 Mode.

    This question is currently also being discussed on German Forum64.

    There are some good software NTSC and TV Effects out there, even good open source ones but not any FPGA ones I've heard of yet.

    So do you think I and other's who love the retro look will be satisfied with the Mega65 Output?

    I think most of users don't want exchange modern SD card data access to old, but retro looking, real 1541 floppy drives without any acceleration...
    When you look at many places where is info about M65 you can see: 8-bit computer for 21st century...
    Ok, it can be realized by converter to composite video, but how you want to use higher resolution than 720x(480 NTSC)/(576 PAL), maybe 768H?
    Or want you lack new VIC-IV modes?
    Ok, if you want - use it!
    In my eyes C128 VIC-IIe can produce 11 new colors which are without TV blur not possible to display.
    One missing thing for me is lightpen, current displays can use pens or touch, but rather want to add support for current pen/touch possibilities than old lightpens.
    If is main reason retro-feel, are you using seriously your retrocomputer? This is my Q to you...
    Miro

    Funny you should mention composite output today. We were only talking about this in our weekly meeting. We have a couple of plans for how we can implement real and authentically blurry composite video output. We are not sure if they will be implemented initially, but we are making provision for them.

    As for light pen, we haven't looked at supporting a light-pen yet. There would be problems with doing this on an LCD display, as you don't have a bright beam to sync to, so it would be CRT only, even if we can implement it.

    Paul.

    Wow, I didn't expect this.
    Thank you Mr. Gardners. I will definetly buy and or kickstarter this project.
    Have a look at MAME. There are a lot of open gl filters an even a guy from nvidia wrote some open source CRT code.
    Im not sure if you can use this code to implement it in FPGA Software since I'm not a programmer.
    OpenEMU (on mac) has also a very very(!) Nice NTSC Effect with chromatic abberation and so on. Sourcecode available. It's one of the best I've seen so far.

    @Mikrosoft: Even with higher resolution output (and C65 1024x400 is not high resolution) this CRT masks look very nice and real when applied before sending it to 1080P Output.

    I could provide pictures but check it our yourself. MAME ist hard to configure though.

    First up, as mentioned elsewhere, we intend to have real composite out, for the genuine experience.

    Second, as groepaz mentioned, it is possible to implement these sorts of filters in an FPGA. The trade-off involves memory bandwidth, and as I understand it, having enough of a buffer while outputting a frame of video, that the necessary nearby pixels can be retained to input into the filter.

    A cheaper approximation can be done by just blurring horizontally, and varying the brightness of each physical raster line based on where in the composite raster line it falls.

    simply said, you need one line "backbuffer" (simulating the PAL "delay line") and then one matrix multiplications plus some linear interpolation and moving average per pixel. its a lot of memory lookups, which kinda sucks =) (for a "perfect" simulation you need to actually encode and decode composite video, which involves even more lookups and multiplications - most software implementations i have seen dont do this either)

    CRT emulation in Vice64 is great, I have no idea how they do it but it looks very good.
    They don't seem to emulate composite but a slightly blurry desaturated svideo signal. You can set scanline shade level, blurring (horizontal I guess), Odd lines phase and offset.
    Something close to that would be good enough for me.

    So what's the plan for recreating somehow the CRT look & feel?
    Wouldn't be possible to dedicate an FPGA core or an entire FPGA to the task?
    Being a longtime user of emulators and old consoles I know that a CRT, real or emulated, is essential to the authentic experience; modern displays used directly are simply ugly to see.
    I hope that a solution is possible.

    I, too, think convoluted filtering like CRT geometry with phosphor emulation is way out of reach for this project. A simple yet convincing filtering shouldn't be too taxing on resources.
    This filter, if it's implemented, should be an option you can switch on or off at will ( in a config pannel of some sort I guess ). A per screen-mode configuration of said filter would be awesome!

    Firstly:
    When I read about the Mega 65, it was a dream come true for me.
    I have always wanted a C65 like computer.

    When I read the comments on many of the subjects in here, it feels like people are more interested in the C64 emulation, than the C65 (As it really is).

    Why not let them make the Mega 65, and let the C64 stuff come in as a bonus?
    -Commodore made the C65 "Commodore 64" compatible, but not in a sense that it would be working 100%

    I see the Mega 65 as a new 8 bit computer with lots of potential and I am *really* looking forward to see it complete.
    Keep up the good work!

    @Truss: I don't know, but Commodore 65 is intended to be C64 compatible at some degree at least ... So about the Mega65, if it wants to carry the original concept of C65 further, should not forget about the roots. However that's true: even the original C65 was not meant to be a 100% compatible C64 in C64 mode (well, just the CPU is not the very same - think about illegal opcodes -, and so on), that's the other point. And I think, C65GS/Mega65 has already a great work to even lighten this limitations of the original design (for example: think about the incompatibility caused by the different behaviour of read-modify-write opcodes of 65CE02 core, which is already solved - if I know well - for Mega65).

    But I agree, that only "an FPGA C64" it wouldn't be as interesting as Mega65 is, there are projects already like that. C65 is an interesting (however it was way so late to be developed by Commodore, IMHO) machine, and with the original concept, and a proper case/keyboard/etc it really feels as a brand new (and quite modern) 8 bit machine, which is a great feeling! It's just another - though very important! - point, that Mega65 has even more developments over the C65 features, for me, this makes it even more interesting and a "must have" item :) Personally, I felt something similar with C64DTV, that I have something which "looks like" a 8 bit stuff (and not only a software emulation), which carries the original concepts further, and "just can be bought" and ready to be discovered, etc. Mega65 is even better with a proper case, and the general feeling about being a "real computer", which is not so much the case of C64DTV (well, it's just a "joystick", you have to hack it, etc).

    But for sure this was *ONLY* my personal view, nothing more.