# MatrixLens¶

class MatrixLens

Bases: Lens

A completely generic linear lens. This is provided for the benefit of low- level code that wants to specify a perspective or orthographic frustum via an explicit projection matrix, but not mess around with fov’s or focal lengths or any of that nonsense.

Inheritance diagram

MatrixLens(void)
void clear_left_eye_mat(void)

Removes the custom projection matrix set for the left eye, and uses the center matrix (set by set_user_mat()) instead.

void clear_right_eye_mat(void)

Removes the custom projection matrix set for the right eye, and uses the center matrix (set by set_user_mat()) instead.

static TypeHandle get_class_type(void)
LMatrix4 const &get_left_eye_mat(void) const

Returns the custom projection matrix for the left eye, if any, or the center matrix if there is no custom matrix set for the left eye.

LMatrix4 const &get_right_eye_mat(void) const

Returns the custom projection matrix for the right eye, if any, or the center matrix if there is no custom matrix set for the right eye.

LMatrix4 const &get_user_mat(void) const

Returns the explicit projection matrix as set by the user. This does not include transforms on the lens or film (e.g. a film offset or view hpr).

bool has_left_eye_mat(void) const

Returns true if the camera has a custom projection matrix set for the left eye, or false if the center matrix (set by set_user_mat()) will be used for the left eye.

bool has_right_eye_mat(void) const

Returns true if the camera has a custom projection matrix set for the right eye, or false if the center matrix (set by set_user_mat()) will be used for the right eye.

void set_left_eye_mat(LMatrix4 const &user_mat)

Sets a custom projection matrix for the left eye. This is only used if the lens is attached to a stereo camera, in which case the left eye matrix will be used to draw the scene in the left eye (but the center matrix–the user_mat–will still be used to cull the scene).

This matrix should not be too different from the center matrix (set by set_user_mat()) or culling errors may become obvious.

void set_right_eye_mat(LMatrix4 const &user_mat)

Sets a custom projection matrix for the right eye. This is only used if the lens is attached to a stereo camera, in which case the right eye matrix will be used to draw the scene in the right eye (but the center matrix–the user_mat–will still be used to cull the scene).

This matrix should not be too different from the center matrix (set by set_user_mat()) or culling errors may become obvious.

void set_user_mat(LMatrix4 const &user_mat)

Explicitly specifies the projection matrix. This matrix should convert X and Y to the range [-film_size/2, film_size/2], where (-fs/2,-fs/2) is the lower left corner of the screen and (fs/2, fs/2) is the upper right. Z should go to the range [-1, 1], where -1 is the far plane and 1 is the near plane. Note that this is a left-handed Y-up coordinate system.

The default film_size for a MatrixLens is 2, so the default range is [-1, 1] for both X and Y. This is consistent with the GL conventions for projection matrices.