CODEWITHSUNDEEP
opengl
Chandan
Chandan

Reputation: 1504

Perspective projection matrix -clip space co ordinates

I have have been reading The Matrix has You trying to understand the perpective matrix.

This tutorial uses frustum scale fator S to define the perspective matrix as below . 

Xclip = S * Xcamera
Yclip = S * Ycamera

But there are other tutorials like OpenGL Projection Matrix which define the 

xclip = 2 * n / (r-l)
yclip = 2 * n / (t-b)

Could some one please help me understand if they are same ?

Upvotes: 0

Views: 93

Answers (1)

Nico Schertler
Nico Schertler

Reputation: 32587

When you assign S=2n/(r-l) or S=2n/(t-b) respectively, you end up with the same equations (don't forget the multiplication with x_camera and y_camera in the second case). In the first equations, the scale factor is just precalculated from other constants. Note that the scale factor is usually different for x and y, because the view frustum's base is not a square.

Upvotes: 1

Related Questions