Online Graphics Transforms 2: GluLookAt
Why Stack Overflow recommends it
Stack Overflow users link it when someone asks how gluLookAt or the view matrix is derived, or needs to implement it without the GLU call.
Recommended by 2 people across 2 different months, 2013 to 2017.
What it is
A short lecture segment from Ravi Ramamoorthi's Foundations of Computer Graphics course that derives the gluLookAt matrix step by step. It builds a camera coordinate frame from the eye, center and up vectors, then combines the rotation and translation into the final form.
What people said
Recommends Sumanth · 2013-11 · Stack Overflow · on “Derivation of (glu)lookAt”
I am trying to learn (modern) OpenGL and I am thoroughly confused about the various transformations... The viewing matrix have me confused so I need some clarification. Here's what I have understood about the (conventional) pipeline. Vertices are specified in world space , which are scaled, translated, rotated etc. to the required positions using the modelling matrix (Here's where I start to get confused) We can (optionally) position a virtual camera in the required location using a "lookAt" function (gluLookAt). I followed the derivation of the matrix here: [this video] . I understood until the point, where the professor calculates the "look-at" vector. He says that the look-at vector = eye - ce
Recommends legends2k · 2014-03 · Stack Overflow · on “Calculating gluLookAt, glOrtho and glFrustum”
we are told we cannot use gluAtLook(), glOrtho(), glFrustrum but we must use glTranslate(), glScale() and glRotate gluLookAt sets up the world to view space transformation, glOrtho does view to orthographic projection space transformation and glFrustum does view to perspective projection space transformation. When you say your tutor hasn't allowed to use it, it clearly means that the intention is to understand how these functions work in the first place. There're many resources on the internet which teach you that. Here's one [this video] by a renowned UC Berkeley professor Dr. Ravi Ramamoorthi. SongHo has good articles [LINK] which will help you do the same thing. I can demonstrate a simple case
Cites Narek · 2017-09 · Stack Overflow · on “About LookAt() function”
that is true that it is first T and R transformation applied for LooAt. I have seen some discussion in this video too: [this video] But I have no idea whey we can't apply R and then T. Do you have an explanation?