An Apple I Emulator in shader language
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An Apple I Emulator in shader language
1–10 of 19 posts
Re: An Apple I Emulator in shader language
#2Careful: froze my browser (Chromium) for 30secs or so
Shader language programming is one of most fascinating environments I know. Everything tells me that reading and writing data via texture coordinate lookups should be orders of magnitude slower than "normal" programming, yet it often is orders of magnitude faster.
Re: An Apple I Emulator in shader language
#3Nice! I'd pondered using this technique for a while; since each shader compute element is a fairly powerful processor on its own, this can effectively run one copy of the emulator for every pixel.
Unfortunately since emulation is an "embarrasingly serial" problem, it doesn't go particularly quickly.
Re: An Apple I Emulator in shader language
#4Careful: froze my browser (Chromium) for 30secs or so Shader language programming is one of most fascinating environments I know. Everything tells me that reading and writing data via texture coordinate lookups should be orders of magnitude slower than "normal" programming, yet it often is orders of magnitude faster.
To be clear, this particular emulator is a lot slower than an Apple I emulator on a normal CPU.
Re: An Apple I Emulator in shader language
#5Nice! I'd pondered using this technique for a while; since each shader compute element is a fairly powerful processor on its own, this can effectively run one copy of the emulator for every pixel. Unfortunately since emulation is an "embarrasingly serial" problem, it doesn't go particularly quickly.
Actually, not inherently serial. If you think about, an Apple consists of a lot of chips, which could be nicely modeled in say, Verilog, which is good for modelling parallel stuff. But it does not lend itself well to shader language.
Re: An Apple I Emulator in shader language
#6Can't run it on Linux in Chrome or Firefox, even though the console says WebGL support is available.
Re: An Apple I Emulator in shader language
#7Can't run it on Linux in Chrome or Firefox, even though the console says WebGL support is available.
Shader compilers are pretty bad an result depends on browser and driver. There is plenty of platform differences when accessing uninitialized memory, using more complicated constructs like structures, performing math operation with undefined result, incorrectly defining if function argument is in,out or inout.
Re: An Apple I Emulator in shader language
#8Can't run it on Linux in Chrome or Firefox, even though the console says WebGL support is available.
That sounds like a Linux problem.
Re: An Apple I Emulator in shader language
#9Nice! I'd pondered using this technique for a while; since each shader compute element is a fairly powerful processor on its own, this can effectively run one copy of the emulator for every pixel. Unfortunately since emulation is an "embarrasingly serial" problem, it doesn't go particularly quickly.
Actually, not inherently serial. If you think about, an Apple consists of a lot of chips, which could be nicely modeled in say, Verilog, which is good for modelling parallel stuff. But it does not lend itself well to shader language.
To clarify: it does not lend itself well to ShaderToy, because the computational model is hamstrung by the fact that the threads can't communicate with each other within a draw call. On a more modern GPU platform with compute shaders, you get a lot more of that, and I think interesting things will happen. I'm personally really looking forward to WebGPU, as I think it will make a lot of this stuff much more accessible.
Re: An Apple I Emulator in shader language
#10Wow, I was expecting graphics in the style of Return of the Obra Dinn, but this is much more impressive.
Lucas Pope's work on bringing the 1-bit aesthetic into the modern age is fascinating in itself. One of my favorite excerpts is how Pope 'stabilized dither' in order to reduce the harsh effects that dithering moving images can create: https://forums.tigsource.com/index.php?topic=40832.msg136374...