Matt Hoffman

(even with flutter_gpu) lacking, would be nice to have access to SDL3 GPU for rendering. (4/4)

documentation and little in the way of people actually doing it. I'm personally a big fan of SDL3 (and their GPU abstraction layer), but I want more for UI than ImGui, and my tinkering with Flutter for entirely 2d stuff has been nice, but I find it's 3D capabilities (3/?)

@SebAaltonen I saw some tweets a while ago about you using Flutter for UI and it looked like you were running Flutter on top of a custom engine? I'm curious what that tech stack actually looks like. Did you go the custom embedder route and run Skia/Impeller on top of your (1/?)

@leehammoud That statement was probably made without using the profiler, but in general I would think that a sweep needs to find all the things in a given space, and then do a more precise testing on those items. And then doing that twice seems more expensive than just doing the overlap once

@LordNed Old tweet I know, been going this thread, haha! Do you remember if you would know why overlap is cheaper than two sweep checks?

Code doodlin'. Sprinting, Crouching, Double Jump, Sliding. Hard to differentiate without sound, but anims are slightly modified for each state. Double Jump allows changing direction on second jump. Slides end in a crouch, or can launch you if jumping while sliding. #UE4

@FreyaHolmer stackoverflow.com/questions/2352… I think the order is MVP, but it has to (can?) get written PVM - a possible reasoning is linked here, but I feel like '*' associativity would be fairly standard between programming languages by this point.

@LordNed as far as I know the multiplication order is always M*V*P, I've never heard anyone use anything else, but I could just not have been exposed to it

I don't understand Matrices, Quaternions, row vs. column major, left handed vs. right handed coordinate systems, and how all of these systems interplay at all. If you give me an engine with a math/camera library already set up, everything is fine. But

@FreyaHolmer So why do we call it "MVP transform" when the actual multiplication order usually seems to be Projection * View * Model?

@LordNed row vs column major shouldn't affect matrix multiplication whatsoever, ie: M*V*P would be the same regardless - again it's just an array access decision

@FreyaHolmer But I have to store that in the Z (despite being "distance backwards") and not Y+ or whatever my forward axis actually is. I suppose I can't complain (since it works), it just makes me feel like there's still something wrong lurking in the code.

@FreyaHolmer meaning the opposite of what I mentally expect? The one part that does still confuse me though is that despite trying to be Z up, to get the correct "distance" at the start, I convert from world location into a rotation, and then update my offset again to take rotation back out

@leviathan_bound So the actual named views make sense to me.

@leviathan_bound Isn't that consistent though, if you think of it as "View from the Front"? If you were to ask someone for a render "from the front side of a car" you'd expect a view facing the headlights right? Their forward axis is weird though I don't understand why it's y-.

I want to mimick Blender's coordinate system and that's maybe not compatible with Qt's math library? (Though I think they're both right handed, it's not clearly outlined in the documentation though!)

I've been trying to create a basic arc-ball camera (for a week and a half now) and everything is just constantly, subtly wrong. And I can't tell if I've just failed to find the right combination of order for things, or if I'm inherently doomed to fail because

@thegiffman Are your fingers pointed down the + or - axis? Or does it not specify that? ie: Is your middle finger -x or +x? If I want to make a box move further to my left, does that hand tell me I need to move it positively or negatively on the x?

@LordNed What about holding your hand like a gun, using the middle finger as a trigger? You can “shoot” the gun so it recoils, pivoting on x. So y or z can be up, but x is always to the left.

If I look in Blender and go "View, From Front", it has me looking down +Y, so presumably "Forward" is actually -Y. And then Z is up. And to move something visually to the right from this point you go in -X. But I can't contort my right hand into a shape that lets me point in