The IOS penetration, video, projection, and thrust (turn)

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These parameters can also be based on the field of view (

FOV

–

Field of View

) parameters to obtain. Here are two

Visual field diagram of a plane:

which

Two

FoV

respectively, in

X-z

And

Y-z

Vision on the plane.

If only one view was given,

Also

Can be calculated by the aspect ratio of the projection plane:

Use a field of view to figure out

W

Or

H

, and then use the aspect ratio to figure out

H

Or

W

。

（

2

) Equation of the general condition

This set of equations is cumbersome but more general (and

Opengl

The derivation of the general matrix is consistent, which is also

D3dxmatrixperspectiveoffcenterlh

And

D3DXMatrixPerspectiveOffCenterRH

Two

Used by a method). We export it:

We continue to roll back the perspective projection matrix:

which

The last matrix is

D3d

The general perspective projection matrix.

All right

So far,

We have already exported the

D3d

Of two perspective projection matrices.

Next I'll take a guide to the last article

Out of

Opengl

The perspective projection matrix is written out, you can take it and just export the

D3d

The general

The perspective projection matrix makes a comparison.

If you look closely,

You can see that they are a transpose relationship on the layout of the element,

This is what it

The use of the left-hand coordinate system and the use of the difference between the determinant matrix.

And in some other elements of the

There are differences in the details,

This is due to

D3d

Of

CVV

Of

Z

caused by different ranges.

Visible in the principle phase

In the same situation,

Subtle environmental differences can cause very large changes,

And this is how the perspective projection matrix is stored

In many different versions of the reason. The perspective projection matrix of the general situation can also be defined using the visual field method,

Method is the same as the special case.

m3g

The Perspective projection matrix

m3g

is to

Opengl

In a package,

Its perspective projection transformation matrix is put into the class

Camera

In

Surface.

Because it encapsulates the

Opengl

，

Thus the environment and

Opengl

Same:

Right-hand coordinate system,

Column vector multiplication,

CVV

Range

[-1

，

1]

。 It's only and

Opengl

The difference is that it only uses the projection plane

The Center and

X-y

The center of the plane coincides

(In

X

And

Y

centered on the direction)

The situation

(That's what we

D3d

The first special case). We use

Opengl

Perspective projection Matrix final version to illustrate (again

Reminder, if the reader is confused, please refer to the first article):

Above is

Opengl

The final version of the perspective projection matrix is also a generic version, and we're going to turn it into a special

The uniqueness, the version, very simple, and above

D3d

In the special case, we

X

And

Y

To interpolate a value

The next step:

And

D3d

The first case, sell off both sides of the

1/2

Get:

Then we roll back the perspective projection matrix:

The right-most matrix is

m3g

The Perspective projection matrix.

Perspective projection can still be set through the field of view parameters.

This is the reader's own derivation, the method

D3d

The exact same