About Projection Transform
Author
Hi,
I'm wondering sth. about the projection of 3d objects. After the projection transformation, are these vertices of 3D objects projected to the near plane or the far plane ?
The perspective transformation (including the nonlinear divide by w) maps the frustum volume into the box volume [-1,1]x[-1,1]x[0,1] (Direct3D style).
The far plane is part of the frustum description. Without it, your frustum would be unbounded. It is basically to clip geometry far away from the eye.
perspective transform maps the view frustum
into a rectangle with depth
each point on the rectangle maps
to everything in world space
that could be behind that pixel
ie: something small close up
or something big along way away
imagine each pixel is a window into the 3D world
like a real window one meter wide
it can show something close up to one meter wide
but a mountain range could be 10 thousand meter's wide
both visible in the same window
the Z coordinate of each pixel represents how far
from the camera that vertex is
hope that helps
into a rectangle with depth
each point on the rectangle maps
to everything in world space
that could be behind that pixel
ie: something small close up
or something big along way away
imagine each pixel is a window into the 3D world
like a real window one meter wide
it can show something close up to one meter wide
but a mountain range could be 10 thousand meter's wide
both visible in the same window
the Z coordinate of each pixel represents how far
from the camera that vertex is
hope that helps
Author
Quote:Original post by skytiger
perspective transform maps the view frustum
into a rectangle with depth
each point on the rectangle maps
to everything in world space
that could be behind that pixel
ie: something small close up
or something big along way away
imagine each pixel is a window into the 3D world
like a real window one meter wide
it can show something close up to one meter wide
but a mountain range could be 10 thousand meter's wide
both visible in the same window
the Z coordinate of each pixel represents how far
from the camera that vertex is
hope that helps
It helps, so this window is near-plane of the frustum, right?
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