Camera¶

Target Type Camera¶

Camera Move Style > Camera Limits > Distance Limits

Set minimum and maximum distances from the camera to the pivot point. Allowable values: Min \(\le\) Max. Default values: Min = 1, Max = 10. Disabled by default.

Camera Move Style > Camera Limits > Horizontal Rotation Limits

Limit the horizontal (around the Z world axis in Blender) camera rotation around the corresponding point. Rotation is performed along the arc of a circle between Left Angle and Right Angle values. The rotation arc corresponds to movement from Left Angle to Right Angle anticlockwise. Default values: Left Angle = -45°, Right Angle = 45°. Disabled by default.

Camera Move Style > Camera Limits > Vertical Rotation Limits

Limit the horizontal (around the Z world axis in Blender) camera rotation around the corresponding point. Rotation is performed along the arc of a circle between Left Angle and Right Angle values. The rotation arc corresponds to movement from Left Angle to Right Angle anticlockwise. Default values: Left Angle = -45°, Right Angle = 45°. Disabled by default.

Camera Move Style > Camera Limits > Pivot Translation Limits

Limit the translation of the camera’s pivot point. Default values: MinZ = 0, MaxZ = 10. Not rendered in the viewport.

Camera Move Style > Camera Limits > Use Panning Mode

Allow camera panning.

Eye Type Camera¶

Blend4Web > Horizontal Rotation Limits

Limit the horizontal (around the Z world axis in Blender) camera rotation around the corresponding point. Rotation is performed along the arc of a circle between Left Angle and Right Angle values. The rotation arc corresponds to movement from Left Angle to Right Angle anticlockwise. Default values: Left Angle = -45°, Right Angle = 45°. Disabled by default.

Camera Move Style > Camera Limits > Vertical Rotation Limits

Limit the vertical (around the local X axis in Blender) camera rotation around the corresponding point. Rotation is performed along the arc of a circle between Down Angle and Up Angle values. The rotation arc corresponds to movement from Down Angle to Up Angle anticlockwise. Default values: Down Angle = -45°, Up Angle = 45°. Disabled by default.

Hover Type Camera¶

Camera Move Style > Camera Limits > Horizontal Translation Limits

Limit movement of the pivot point along the Blender’s world X axis. Allowable values: Min \(\le\) Max. Default values: MinX = -10, MaxX = 10. Disabled by default.

Camera Move Style > Camera Limits > Vertical Translation Limits

Limit movement of the pivot point along the Blender’s world X axis. Allowable values: Min \(\le\) Max. Default values: MinY = -10, MaxY = 10. Disabled by default.

Camera Move Style > Camera Limits > Use Zooming

Allows user to zoom the camera in and out from the pivot point. If this parameter is disabled, the camera will always remain at a fixed distance from the pivot point. Disable by default.

Camera Move Style > Camera Limits > Distance Limits

Set minimum and maximum distances from the camera to the point of intersection between the camera’s view direction and the horizontal reference plane (Blender’s world XOY plane by default). Allowable values: Min \(\le\) Max. Default values: Min = 1, Max = 10. Disabled by default.

Camera Move Style > Camera Limits > Vertical Rotation Limits

Limits the camera’s angle of elevation (an angle between the camera’s sight line and a horizontal plane. Possible value interval: 0° \(\le\) Down \(\le\) Up \(\le\) 90°. Default values: Down = 0°, Up = 90°.

Camera Move Style > Camera Limits > Zero Level

A distance between reference plane and the coordinates origin. Set to zero by default.

If the Blend4Web > Use Zooming setting is turned on, the limits for distance and inclination angle will be applied simultaneously, to define the camera movement path in the vertical plane.

Setting incorrect distance or elevation angle limits will disable this parameter.

Camera Move Style > Camera Limits > Use Horizontal Rotation

Allow camera rotation in Blender’s XOY plane around to the pivot point. Enabled by default.

Static Camera

This type of camera does not have limits, as it can’t be directly controlled by the user.

Peculiarities of Limiting Settings

• For EYE/TARGET cameras, interchanging Left/Right or Down/Up values results in movement along the opposite arc of a circle.

• When limiting the camera’s horizontal and vertical rotation, it is possible to choose between the following coordinate spaces:

Camera Space

All angles are measured relative to the initial camera position and orientation.

World Space

Horizontal angles are measured relative to the Y axis in world space; vertical angles are measured relative to the Blender’s XOY plane in world space.

Default value: Camera Space.

Horizontal limits by the example of the TARGET camera:

Vertical limits by the example of the TARGET camera:

Control Mode Setup¶

To change the control mode and to completely define a camera’s behavior, the following methods can be used: static_setup(), eye_setup(), target_setup() and hover_setup(). These methods receive an object that contains a set of optional parameters, which can be used to set the camera’s position, rotation, available limits and so on.

var camera = m_scenes.get_active_camera();
var POS = new Float32Array([1,1,1]);
var LOOK_AT = new Float32Array([0,0,0]);
var EYE_HORIZ_LIMITS = { left: Math.PI/4, right: -Math.PI/4 };
var EYE_VERT_LIMITS = { down: -Math.PI/4, up: Math.PI/4 };
var TARGET_DIST_LIMITS = { min: 1, max: 10 };
var HOVER_DIST_LIMITS = { min: 1, max: 10 };
var HOVER_ANGLE_LIMITS = { down: 0, up: -Math.PI/4 };
var HOVER_HORIZ_TRANS_LIMITS = { min: -5, max: 3 };
var HOVER_VERT_TRANS_LIMITS = { min: -1, max: 1 };

...

// setup STATIC camera by defining the new position and the new look-at point
m_cam.static_setup(camera, { pos: POS, look_at: LOOK_AT });

// setup STATIC camera by defining the new look-at point and keeping the existing position
m_cam.static_setup(camera, { look_at: LOOK_AT });

// setup STATIC camera by defining the new position and keeping the existing orientation
m_cam.static_setup(camera, { pos: POS });

// setup EYE camera with horizontal rotation limits
m_cam.eye_setup(camera, { pos: POS, look_at: LOOK_AT,
        horiz_rot_lim: EYE_HORIZ_LIMITS });

// setup EYE camera with vertical rotation limits
m_cam.eye_setup(camera, { pos: POS, look_at: LOOK_AT,
        vert_rot_lim: EYE_VERT_LIMITS });

// setup TARGET camera with distance limits and panning mode
m_cam.target_setup(camera, { pos: POS, pivot: LOOK_AT,
        dist_lim: TARGET_DIST_LIMITS, use_panning: true });

// setup HOVER camera on a fixed distance (without zooming) relatively to its pivot
m_cam.hover_setup(camera, { pos: POS, pivot: LOOK_AT });

// setup HOVER camera with zooming (distance + angle limits)
m_cam.hover_setup(camera, { pos: POS, pivot: LOOK_AT,
        dist_lim: HOVER_DIST_LIMITS, hover_angle_lim: HOVER_ANGLE_LIMITS });

// setup HOVER camera with translation limits
m_cam.hover_setup(camera, { pos: POS, pivot: LOOK_AT,
        horiz_trans_lim: HOVER_HORIZ_TRANS_LIMITS,
        vert_trans_lim: HOVER_VERT_TRANS_LIMITS });

// setup HOVER camera with horizontal rotation enabled
m_cam.hover_setup(camera, { pos: POS, pivot: LOOK_AT, enable_horiz_rot: true });

The main characteristic of the HOVER type camera is the fact that the distance and elevation angle limits define a certain path of movement toward the pivot point. The camera will always be located on this path, so its final position can be different from the one returned by the hover_setup() method (basically, it is projected onto the path). If you need to set the camera’s position on some path, you can use the hover_setup_rel() method to set the relative limits.

var camera = m_scenes.get_active_camera();
var POS = new Float32Array([1,1,1]);
var PIVOT = new Float32Array([0,0,0]);

...

// setup HOVER camera with maintaining the given camera position and
// ability to zoom-in and zoom-out equally
m_cam.hover_setup_rel(camera, { pos: POS, pivot: PIVOT, dist_interval: 2,
        angle_interval: Math.PI/4 });

The current camera mode can be checked with the is_static_camera(), is_eye_camera(), is_target_camera(), is_hover_camera() or get_move_style() methods:

var camera = m_scenes.get_active_camera();

...

if (m_cam.is_static_camera(camera))
    console.log("STATIC camera!");

if (m_cam.get_move_style(camera) == m_cam.MS_EYE_CONTROLS)
    console.log("EYE camera!");

Translation and Rotation¶

To rotate a STATIC type camera, you need to use the static_get_rotation() and static_set_rotation() methods. In these methods, rotation is defined by a quaternion.

var camera = m_scenes.get_active_camera();

...

// rotation through a quaternion
var _quat_tmp = new Float32Array(4);
var old_quat = m_cam.static_get_rotation(camera, _quat_tmp);
var new_quat = m_quat.rotateX(old_quat, Math.PI/2, old_quat)
m_cam.static_set_rotation(camera, new_quat);

For the EYE, TARGET and HOVER type cameras, rotation is performed in spherical coordinates by using the eye_rotate(), target_rotate(), hover_rotate() and rotate_camera() methods:

var camera = m_scenes.get_active_camera();

...

// rotate by given delta angles
m_cam.eye_rotate(camera, Math.PI/6, Math.PI/2);

// set absolute rotation in world space
m_cam.eye_rotate(camera, Math.PI/6, Math.PI/2, true, true);

Current spherical coordinates of the camera can be obtained by using the get_camera_angles() method:

var camera = m_scenes.get_active_camera();
var _vec2_tmp = new Float32Array(2);

...

// get camera orientation in spherical coordinates
var angles = m_cam.get_camera_angles(camera, _vec2_tmp);
phi = angles[0];
theta = angles[1];

Access to the position of the camera can be obtained by using the get_translation() and set_translation() methods. For the TARGET and HOVER modes this means simultaneous translation of an entire model, including camera position and pivot point.

var camera = m_scenes.get_active_camera();
var _vec3_tmp = new Float32Array(3);

...

// get camera position
var pos = m_cam.get_translation(camera, _vec3_tmp);

// set new position
var new_pos = m_vec3.set(1, 0, 2, pos);
m_cam.set_translation(camera, new_pos);

Additional camera translation methods:

• target_set_trans_pivot(), target_set_pivot_translation(), hover_set_pivot_translation() - sets the position and the pivot point of the camera at the same time;
• target_get_distance(), target_set_distance() - translation based on the distance to the pivot point;
• static_set_look_at(), eye_set_look_at() - sets the camera’s position and point of sight simultaneously;

Limit Setup¶

Camera limits are available for the EYE, TARGET and HOVER type cameras. To set a specific limit, you need to use a specific method:

var camera = m_scenes.get_active_camera();
var _limits_tmp = {};
var EYE_HORIZ_LIMITS = { left: Math.PI/4, right: -Math.PI/4 };

...

// get limits
m_cam.eye_get_horizontal_limits(camera, _limits_tmp);

// set limits
m_cam.eye_set_horizontal_limits(camera, EYE_HORIZ_LIMITS);

Limit presence can be checked by using the has_distance_limits(), has_horizontal_rot_limits(), has_vertical_rot_limits(), has_horizontal_trans_limits() and has_vertical_trans_limits() methods.

Angular Coordinates Count¶

When working with the camera’s APIs (rotation, setting limits), all angles are defined as follows:

For the TARGET/HOVER camera:

For the EYE camera: