New CRT shader - Any interest?

[beans]

I’ve realized that I previously uploaded the wrong images to demonstrate the dither. Here’s a better demonstration anyway. There is no dither on the left side and dither on the right side. The image has been enlarged 2x and brightened 3x to make the difference more noticeable without having to be an a dark room. Hopefully you can see the banding on the left side and no banding on the right. You may have to view at 100% or zoom in.

[hunterk]

ah, yeah, nice illustration. it’s very obvious on that shot.

[Cyber]

@beans

The reason that I haven’t is that the current settings are basically “correct” from a theoretical point of view.

@beans

The low pass filter in the rgb and svideo presets can also dim small, bright detail. If you turn it up to 6.0MHz or use the monitor preset (which has no low pass filter), you may notice a difference. But this is faithful to the way CRTs worked as well. See @cgwg’s old post here:

@beans

For example, here’s the output from one of my tests. I generate full screen grayscale images at varying brightness levels (corrected for CRT gamma) and run them through the shader.

@beans

The brightness of the shader is always at the maximum level that it can be without affecting the tonality of the image, and the current options guarantee linearity. Adding a simple gamma adjustment to brighten the output will cause details to be lost in the bright areas compared to an actual CRT, as it does in other shaders with such a feature.

This is some serious theory there. Why not put it to the ultimate test and compare some game screenshots vs against a real CRT or some real CRTs?

I really appreciate your approach and ideas. I vote for leaving out the Gamma control if it goes against the main premise of the shader and allow the shader to be unique in that regard.

Getting this Gamma setting correct is one of the most difficult aspects of CRT Shader preset tweaking that I’ve longed for something like this which auto-compensates for brightness without clipping or losing shadow detail for years.

If you look deep into the history of my forum posts you might see a few asking about that somewhere.

The sad thing about this is that it’s another shader to be added to the now large multitude. What would it do better than my current favourite shaders and what would it do worse?

You ask if there is “any interest?”

I say, change that last part to “if I build it, they will come, eventually…hopefully” and sort of decouple yourself, your work and your expectations from a particular outcome.

Once you like what you’re doing and know what you’re doing is important to you and it passes the litmus test later on of going against a real CRT then eventually you can try to showcase it and garner some media coverage.

If it’s truly game changing and makes it easier to get an accurate output then I’m sure your efforts will be greatly appreciated but not necessarily rewarded.

By the way, the shader operates within certain constraints. Any plans to go the extra mile and incorporate some of the concepts of the Sony Megatron Color Video Monitor Shader when it comes to accuracy and maximizing brightness compensation by using the brightness of the display and HDR where possible?

The development of Sony Megatron Color Video Monitor seems to have stagnated, so if you could combine what’s best of your work with what’s best about the concepts contained within Sony Megatron Color Video Monitor, then going forward your shader might evolve to become one of the top choices for anyone who’s interested in accurate and eye-catching CRT Shader emulation.

You don’t necessarily have to take the exact Megatron approach but you could also test and verify if there is any benefit to using RetroArch’s built-in Global HDR controls with your shader.

[hunterk]

I believe the HDR stuff in the megatron shaders is mostly separate from the mask/scanline stuff, so it’s probably doable to integrate the other 2 shaders as pre-passes for this one. IIRC, the main issue is just that the last pass output needs to be a specific format to trigger the HDR signal.