CameraUtil module
Summary: Camera Utilities
Camera utilities.
Classes:
Framing information. |
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Given a camera object, compute parameters suitable for setting up RenderMan. |
- class pxr.CameraUtil.ConformWindowPolicy
Methods:
Attributes:
- static GetValueFromName()
- allValues = (CameraUtil.MatchVertically, CameraUtil.MatchHorizontally, CameraUtil.Fit, CameraUtil.Crop, CameraUtil.DontConform)
- class pxr.CameraUtil.Framing
Framing information. That is information determining how the filmback plane of a camera maps to the pixels of the rendered image (displayWindow together with pixelAspectRatio and window policy) and what pixels of the image will be filled by the renderer (dataWindow).
The concepts of displayWindow and dataWindow are similar to the ones in OpenEXR, including that the x- and y-axis of the coordinate system point left and down, respectively.
In fact, these windows mean the same here and in OpenEXR if the displayWindow has the same aspect ratio (when accounting for the pixelAspectRatio) as the filmback plane of the camera has (that is the ratio of the horizontalAperture to verticalAperture of, e.g., Usd’s Camera or GfCamera).
In particular, overscan can be achieved by making the dataWindow larger than the displayWindow.
If the aspect ratios differ, a window policy is applied to the displayWindow to determine how the pixels correspond to the filmback plane. One such window policy is to take the largest rect that fits (centered) into the displayWindow and has the camera’s aspect ratio. For example, if the displayWindow and dataWindow are the same and both have an aspect ratio smaller than the camera, the image is created by enlarging the camera frustum slightly in the bottom and top direction.
When using the AOVs, the render buffer size is determined independently from the framing info. However, the dataWindow is supposed to be contained in the render buffer rect (in particular, the dataWindow cannot contain pixels withs negative coordinates - this restriction does not apply if, e.g., hdPrman circumvents AOVs and writes directly to EXR). In other words, unlike in OpenEXR, the rect of pixels for which we allocate storage can differ from the rect the renderer fills with data (dataWindow).
For example, an application can set the render buffer size to match the widget size but use a dataWindow and displayWindow that only fills the render buffer horizontally to have slates at the top and bottom.
Methods:
ApplyToProjectionMatrix(projectionMatrix, ...)Given the projectionMatrix computed from a camera, applies the framing.
IsValid()Is display and data window non-empty.
Attributes:
- ApplyToProjectionMatrix(projectionMatrix, windowPolicy) Matrix4d
Given the projectionMatrix computed from a camera, applies the framing.
To obtain a correct result, a rasterizer needs to use the resulting projection matrix and set the viewport to the data window.
- Parameters
projectionMatrix (Matrix4d) –
windowPolicy (ConformWindowPolicy) –
- IsValid() bool
Is display and data window non-empty.
- property dataWindow
- property displayWindow
- property pixelAspectRatio
- class pxr.CameraUtil.ScreenWindowParameters
Given a camera object, compute parameters suitable for setting up RenderMan.
Attributes:
float
Vec4d
Matrix4d
- property fieldOfView
float
The field of view.
More precisely, the full angle perspective field of view (in degrees) between screen space coordinates (-1,0) and (1,0). Give these parameters to RiProjection as parameter after”perspective”.
- Type
type
- property screenWindow
Vec4d
The vector (left, right, bottom, top) defining the rectangle in the image plane.
Give these parameters to RiScreenWindow.
- Type
type
- property zFacingViewMatrix
Matrix4d
Returns the inverse of the transform for a camera that is y-Up and z-facing (vs the OpenGL camera that is (-z)-facing).
Write this transform with RiConcatTransform before RiWorldBegin.
- Type
type