Table 6.27 — DRM_Camera_Point
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Property |
Description |
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Class |
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Superclass |
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Subclass |
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Definition |
An instance of this DRM class specifies an eye point to view from, specifying a location, an orientation, and either an orthographic or perspective viewing volume. A viewing volume is defined, oriented along the axis defined to start at the camera <DRM 3D Location> and oriented as specified by the components of the <DRM Camera Point>. This orientation defines the coordinate space of the camera, where the camera is at (0,0,0) and is oriented to look down the +Y axis (assuming the XY plane defines the horizontal plane and the right-hand rule applies). The viewing volume of a given <DRM Camera Point> instance is defined based on two planes specified by two parallel rectangles in space, the near clipping plane and the far clipping plane. The near clipping plane is the plane perpendicular to the camera axis and located camera_near metres from the <DRM Location> of the <DRM Camera Point>. The far clipping plane is parallel to the near clipping plane, but is located camera_far metres from the <DRM Location> of the <DRM Camera Point>. If projection = ORTHOGRAPHIC, then the viewing volume is the parallelepiped volume between the two clipping planes, bounded by the rectangle specified by (left, bottom) as its lower left corner and (right, top) as its upper right corner. If the camera defines a perspective view point, then the viewing volume is a frustum that can be described by in one of two ways. The perspective viewing volume can be defined as the volume starting at the near clipping plane rectangle and expanding to the far clipping plane. Alternatively, the perspective viewing volume can be described by a field-of-view angle, an aspect ratio that is the width of the frustum divided by its height, and the distance to the near and far clipping planes. |
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Class diagram |
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Inherited field elements |
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Field elements |
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Associated to (one-way) |
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Associated by (one-way) (inherited) |
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Associated by (one-way) |
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Associated with (two-way) (inherited) |
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Associated with (two-way) |
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Composed of (two-way) (inherited) |
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Composed of (two-way) |
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Composed of (two-way metadata) (inherited) |
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Composed of (two-way metadata) |
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Component of (two-way) (inherited) |
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Component of (two-way) |
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Constraints |
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Clarifications |
1 This is required to be unique from all other <DRM Camera Point> instances' IDs. 2 This is the distance from camera position to near clipping plane, in metres. 3 This is the distance from camera position to far clipping plane, in metres. 4 If this value is TRUE, use the parameters from the left, right, bottom, and top fields. These fields are always used for orthographic viewing, but perspective viewing can either use these fields or the field-of-view and aspect ratio fields. 5 This is the X coordinate of the lower left corner of the rectangle in the near clipping plane. 6 This is the Y coordinate of the lower left corner of the rectangle in the near clipping plane. 7 This is the Y coordinate of the upper right corner of the rectangle in the far clipping plane. 8 This is the X coordinate of the upper right corner of the rectangle in the far clipping plane. 9 This is the angle, in degrees, of the horizontal field of view. This value is used for perspective viewing if the use_left_right_bottom_top flag is FALSE. This assumes a on-axis symmetric viewing volume. Off axis viewing volumes are not supported. 10 This is the width of the frustum divided by its height. This value is used for perspective viewing if the use_left_right_bottom_top flag is FALSE. |
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Example(s) |
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