I have never been able to find an explanation of transformation

bump, i want a nice 3D programming thread too

>>58918327
Canonical 3D graphics code seems to use projective geometry, which is no longer taught as a working subject. I believe this is done so as to enable translations to be performed as matrix rotations, but it feels like a bit of a hack.

I'm sure someone in the 1970s thought this was a good idea, but the rest of us are stuck with no real theory as to why we must do things this way.

Read up on linear algebra, affine geometry and projective geometry, in this order.

You should be able to understand most stuff afterwards

>>58918327
What's wrong with glm?

>>58920362
So that's why no one seems to know how it's supposed to work?

>>58920522
It's a bad habit to apply something without learning it.
If things like GLM didn't exist then the knowledge for how to do all this without libraries would be abundant, and GLM wouldn't be necessary.
Really, whoever made GLM should have just made a tutorial instead, it's not like so much code goes into matrix transformations that a library is necessary. It's just that it's very hard to learn what to do.

So what's what you don't understand, OP?

>>58921461
Largely, what the vertex shader should look like if there is only one matrix passed into it (most people pass in three, which makes no sense performance-wise)

>>58921989
If the question is about performance, then passing more uniform parameters is not too bad

If the question is about why three matrices, then it's because that's the way the model works. You have your projection, your view and your model. Passing in three matrices allows you to operate at the appropriate coordinate system (if you need to)

I could definitely help but I don't want to do your homework. I took courses in uni that touched on this issue 100% hence how I know it's homework.

>>58922050
The question isn't about either, it's about how to do it with only one matrix passed into the vertex shader.
Like, I'm pretty sure my way of setting gl_Position is wrong.

>>58922084
That looks like an old shader variable...

Anyway, gl_Position = position.xyz/position.w should do it if your matrix is ok

>>58922139
Do you mean (position.xyz/position.w, 1.0)?
And am I mistaken if I think that simply doing (position) is identical? Because I thought that gl_Position.xyz was divided by gl_Position.w, though that may be wrong.

>>58922209
oh I can't remember if gl_Position is a vec3 or a vec4

If it's a vec4, then simply doing
gl_Position = YourMatrix * vec4(position, 1.0f);
should do it

>>58922248
It's a vec4.
And position is a vec4 too, a 1.0 is tacked onto the vertex position so it can be multiplied by the matrix since you can't multiply a mat4 with a vec3.

STOP HELPING OP WITH HIS HOMEWORK! OMG GUYS, HOW THE FUCK ARE WE SUPPOSED TO GET SMARTER IF YOU KEEP HELPING US?

>>58920561
It's only really rotations and length that can be tricky. And it's not that tricky if you passed high school math.

>>58922082
If I was taking this in university, I would have study notes available that would solve all my problems.

>>58918327
Just understand conceptually how a vector in 3d space can be rotated by multiplying the individual Cartesian components,

Then realise that an object in 3d space can be represented by multiple points as vectors,

The same individual rotation of a vector applies to all vectors in total rotating the object

>>58925147
>let me explain to you the most basic details of the thing you have almost fully implemented
Please consider deleting your 4chan account

>>58922336
I really don't know what this is supposed to mean, even as sarcasm.