Perspective projection | Graphics Programming | Page 1

shut geode Dec 7, 2022, 9:19 AM

#

Hey folks,

i am doing khan academy linear algebra course and sal defines the projection formula as:

quiet robinBOT Dec 7, 2022, 9:21 AM

#

$latex.png$

shut geode Dec 7, 2022, 9:21 AM

#

s the subspace projection formula a perspective projection? if not how can it be adapted to be one

#

Also is the formula bad?

snow nymph Dec 7, 2022, 9:21 AM

#

I am afraid those are two different concepts in this case

#

This formula projects a vector onto a subspace as mentioned, which is something entirely different than the "projection matrix" often reffered in graphics programming

shut geode Dec 7, 2022, 9:23 AM

#

How so

snow nymph Dec 7, 2022, 9:23 AM

#

Which sort of squishes the area of some defined frustum into a unit cube

shut geode Dec 7, 2022, 9:24 AM

#

Ok so it is possible to make games with that formula

#

Or will it look bad

#

Thx btw

snow nymph Dec 7, 2022, 9:25 AM

#

Hmmm I don't want to say it's not possible, but I am fairly certain that Noone uses that formula

#

For perspective projection that is

shut geode Dec 7, 2022, 9:26 AM

#

Is it just an orthographic formula

#

Or not even that

#

Lol

snow nymph Dec 7, 2022, 9:26 AM

#

Actually yeah, I think you could use this as ortographic

#

You can look at ortographic projection as projecting a 3D space into 2D subspace (the screen)

#

In which case this formula would work

shut geode Dec 7, 2022, 9:28 AM

#

How do i learn about perspective projection

#

Is it complicated

stiff night Dec 7, 2022, 9:33 AM

#

http://www.songho.ca/opengl/gl_projectionmatrix.html

snow nymph Dec 7, 2022, 9:34 AM

#

Ah you were faster 😆

shut geode Dec 7, 2022, 9:36 AM

#

stiff night http://www.songho.ca/opengl/gl_projectionmatrix.html

😮 thanks

shut geode Dec 7, 2022, 9:53 AM

#

1 last question iff thats ok

#

Do i have to code the perspective thing by hand

#

Or does opengl do it

stiff night Dec 7, 2022, 9:55 AM

#

opengl does not do it unless you use the legacy API

#

normally you would use a math library like glm to make a perspective projection matrix for you

snow nymph Dec 7, 2022, 9:57 AM

#

Altho there is nothing wrong with just rewriting the formula for projection matrix and it will work just fine 😊

shut geode Dec 7, 2022, 9:57 AM

#

But its more fun to implement urself (jk)

#Perspective projection