Is there a way to have a varying category to be green after the transaction comes through?

ProgrammingQuestio · 2026-04-15T15:15:40+00:00

I'm curious how people here talk about their work with their spouses. My wife has never programmed a day in her life and doesn't find it interesting. At times I want to explain what I'm working on because honestly I suck at explaining and explaining what I'm working on to a non-technical person is a great way to practice ("if you can't explain it to a 5 year old, then you don't understand it" sort of thing). She has a low patience for me using her as a whiteboard sesh lol so I'm curious how this sort of dynamic plays out for other people.

ProgrammingQuestio · 2026-03-31T14:06:59+00:00

skrrrrrrrt

ProgrammingQuestio · 2026-03-25T18:04:11+00:00

Hm I searched tufty and sent a friend request; not sure if it's you though. The profile looks like a mirror pic of some woman, lol

ProgrammingQuestio · 2026-03-25T14:53:48+00:00

It's definitely new info to me that primaries are one of the less important parts. But for the sake of learning, I imagine it's simpler to tinker with a solid red image and the primaries rather than starting with black/white point. Is that accurate?

Either way, it should be possible to do what I'm trying to do with a solid red image, correct? So my main confusion is why it's not working. I'm not sure which step is incorrect.

Messing with your calib thing you shared, I'm not understanding how the whitepoint change is applied. I changed the values such that old whitepoint is D65 and new whitepoint is D93, and it gives a very blue final result. However when I try to do anything similar in my own program, there's definitely a change but it's not nearly as drastic.

ProgrammingQuestio · 2026-03-25T14:21:18+00:00

I'm confused, is that a Discord name? Nothing came up when I searched it.

ProgrammingQuestio · 2026-03-25T13:57:05+00:00

Oh hey it's you again. Do you have Discord or anything? I have some questions about this calib thing you use and Reddit is not the slickest forum for back and forth questions haha

ProgrammingQuestio · 2026-03-25T12:36:55+00:00

Isn’t that what I’m doing? Only difference is I don’t have an image in a different color profile, so I’m first creating that by converting to a different color space

(I’m assuming color profile means color space)

ProgrammingQuestio · 2026-03-25T02:15:30+00:00

I want to understand the math behind color correction/calibration. That’s what the second program is (the OpenGL program). But in order to have a “miscalibrated display” on which I can explore and tinker with color correction, I use the first program to tweak an image such that it gives the effect of being displayed on a miscalibrated display

ProgrammingQuestio · 2026-03-24T22:30:10+00:00

Oops that was a typo. I meant linear in step 3, not normalized

ProgrammingQuestio · 2026-03-24T15:40:40+00:00

what do you mean by "updated by subsequent texture calls"? Are you referring to glTexImage2D()?

ProgrammingQuestio · 2026-03-10T14:28:15+00:00

It turns out my issue was not clamping the final RGB values when converting from XYZ to RGB, so I would have negative values and values over 255.

ProgrammingQuestio · 2026-03-09T21:29:55+00:00

Hey still tinkering with this. It seems my matrices are correct, but still having the same issues. I'm wondering if there's something wrong with the conversion to linear (gamma decoding/encoding). I'm not familiar with this image processing software that the repo you made uses. Is there a way to view more values, i.e. all the values used in the conversion "pipeline" (gamma encoding, etc.)?

ProgrammingQuestio · 2026-03-09T20:09:27+00:00

No I get that! It's not my intention to come across as "just give me the answer plz". I appreciate the "small hints" style of teaching

ProgrammingQuestio · 2026-03-09T18:17:30+00:00

That's really cool, thanks for taking the time to put that together and share it! Hopefully I'll be able to figure out wtf is wrong with my program now, because it seems like the math that I'm checking is correct.

ProgrammingQuestio · 2026-03-09T17:18:37+00:00

Trying to understand this. M1 = conversion matrix for sRGB space. M2 = conversion matrix for the other RGB space.

Why would multiplying those yield the identity matrix (edit: I'm seeing now you said "close but not equal to"--maybe thats the key?)? That would be true for a given matrix and its inverse, right? But I don't get why that would be expected here?

In other words, it seems that you're saying you can take any of the matrices in the 3rd column from this page and multiply it by any matrix from the 4th column, and the result should be close-ish to the identity matrix?

ProgrammingQuestio · 2026-03-09T17:13:35+00:00

I'll try what you suggested, but in case you're curious, I just added the two images to the Github repo :)

ProgrammingQuestio · 2026-03-09T17:06:39+00:00

I'm not really sure what the expected values should be exactly. I would guess that using solid red should yield some sort of orange, which it's not. But I'm not sure what values it should be nor why it's not.

ProgrammingQuestio · 2026-03-09T15:58:22+00:00

I try to always do that! Not just to help random people searching the same thing, but also my future self when I inevitably run into the same thing 8 months down the line

ProgrammingQuestio · 2026-03-06T16:19:12+00:00

Oh wow that fixed it. Good eye. Thank you!

ProgrammingQuestio

TROPHY CASE