Runs a VEX script on the planes it generates.
This COP runs a VEX script on the planes it generates. The vex script should not read from R,G,B,A, C1,C2,C3 or C4. The vex script should write to C1, C2, C3 and C4 (components 1 to 4 of each vector).
Generator Usage
This operator is a generator, which allows it to create new sequences or planes. A generator can be used without any inputs, with one input or with two.
When a generator has no inputs, it generates a new sequence of frames. By default, most of the main generator parameters use the Composite Project settings:
Resolution
Pixel Aspect Ratio
Raster Depth
Sequence Range
Frame Rate
Each of these parameters may be overridden to enter specific values.
Tip
If you are working consistently in a certain bit depth, resolution or frame range, it is recommended that you alter the Composite Project settings rather than individually modify the generator nodes' settings. The Composite Project settings, when changed, will automatically update all COPs settings that are linked to it.
Note
Color and Alpha are always created, though if the generator does not include them in its Image Planes parameter, they will be empty.
Attaching a Node to the Merge Input
The Merge input is the main input on the top of the node. When connecting a node to this input, the generator creates a new plane and merges into that node’s sequence. The plane may exist in the input, in which case the generator can modify it using simple compositing operations or replace it entirely. This process is called 'Inline Generation'.
When using Inline Generation, the parameters on the Image and Sequence pages cannot be modified, as they are inherited from the input.
Note
If you disconnect the generator from its merge input, any overridden generator parameters (Resolution, Pixel Aspect Ratio, Sequence Range) will be modified to match the input’s settings, so that the generated output remains roughly the same.
Attaching a Node to the Mask Input
The Mask input is the side input. Connecting a node to this input will restrict the generated output to the area of the mask. This mask can be selected from the list of planes in the connected node, and inverted, brightened or dimmed, if desired.
If an input is connected to the Merge input, and the generator is modifying one of the input’s planes, the mask will blend the generated output with the input.
The parameters for selecting the mask can be found on the Mask page.
Parameters
VEX Generate
| VEX Function | The VEX script to run, with any parameter arguments you wish to override. |
| Reload VEX Functions | Reloads the VEX script. Useful if the script has been modified and re-compiled. |
Mask
The mask parameters control the mask applied when a node is connected to the mask input. The Effect Amount parameter is always available, whether a mask is connected or not.
| Effect Amount | If no mask is present, this multiplies the output by a constant amount (0 = black, 1 = all output). If a mask is present, this amount multiplies the mask. |
| Mask Plane | A mask can be a component of a plane or an entire plane. If a vector plane is supplied as a mask, its components are multiplied by the images' components. Scalar Mask ('A', 'C.r')
C.r = I.r * M
C.g = I.g * M
C.b = I.b * M
Vector Mask ('C')
C.r = I.r * M.r
C.g = I.g * M.g
C.b = I.b * M.b
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| Invert Mask | Inverts the mask so that all fully 'masked' portions become unmasked. This saves you from inserting an Invert COP after the node with the mask. |
Image
Parameters relating to the structure of the image generated, including Resolution, Pixel Aspect Ratio and Raster Depth.
| Override Size | If off, the resolution of the image is defined by the resolution in the Composite Project settings. If on, any resolution can be specified. | ||||||||||||||||||||||||||||
| Pixel Aspect Ratio | If off, the pixel aspect ratio of the image is defined by the pixel aspect ratio in the Composite Project settings. If on, any pixel aspect ratio can be specified. The pixel aspect ratio determines the shape of the pixel; it represents the width of the pixel compared to the height. A pixel with an aspect ratio of '2' is twice as wide as it is high (2:1). Pixel aspect ratios less than 1 are taller than they are wide. The image viewer attempts to show the image as it would appear by horizontally scaling the image by the pixel aspect ratio. This can result in slight artifacts for non-integer ratios (ie, 0.9:1, 1.442:1). Turn off 'Fast Pixel Aspect' in the Display Options to suppress these artifacts. Many effect filters that have parameters that represent width and height will have the width scaled appropriately (such as Blur, Defocus, Expand). | ||||||||||||||||||||||||||||
| Image Planes | Specifies the plane(s) to generate. Color and Alpha will always be present, but the generator does not always have to write to them. The list of planes is all the ones Halo recognizes as special. Other planes can be added with the 'Custom Planes' parameter.
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| Add Plane | When a generator is connected to an input, it generates a Mask plane by default. This parameter determines which planes are generated in this case. The list of planes to generate are the same as 'Image Planes'. In addition, if the plane already exists in the input sequence, one of the following operations will be performed to combine the new plane.
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| Custom Planes | This string parameter allows you to create your own plane formats. The syntax is:
planename(arraysize){comp1,comp2,comp3,comp4}:format(black,white)
All parts are optional except for planename. arraysize must
be 1 or greater (default 1). comp1-4 are arbitrary strings
representing the component names. 'format' is either i8,
i16, i32, f16 or f32. black and white are integers
representing the black & white points for integer formats.
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| Raster Depth | The byte format of the image. Higher bit depths provide better color resolution and range at the expense of memory.
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| Black/White Points | The integer formats (8, 16 and 32 bit) can specify the raw values that the black and white points occur at. The white point must always be higher than the black point. The minimum and maximum values for the black and white points for each format are:
Floating point formats always have their black point at 0 and their white point at 1. | ||||||||||||||||||||||||||||
| Interlacing | Controls the ability to generate images that are compatible with interlaced images. If you are manipulating the generated output with a filter that uses neighboring pixels (like Blur or Expand), it is recommended that you do not use Black Interlaced, as the filter will use the black scanlines as well. The second menu determines which scanlines are in which fields (odd,even)
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Sequence
This tab contains parameters which deal with the timing and frame range of the generated sequence.
| Override Global Range | If off, the global animation range is used as the frame range. If on, the frame range of the sequence can be specified in the following parameters. | ||||||||||
| Still Image | A still image is time-invariant. It exists at every frame. If off, the Start Frame and Length are used to determine the frame range. | ||||||||||
| Start Frame | The starting frame of the sequence. | ||||||||||
| Length | The length of the sequence (number of frames in the sequence). | ||||||||||
| Frame Rate | If on, the frame rate of the sequence can be overridden. | ||||||||||
| Pre Extend | For sequences with a frame range, this determines how to show frames before the start frame.
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| Pre Hold | The number of frames to hold the first frame for, if 'Hold N Frames' is selected. | ||||||||||
| Post Extend | For sequences with a frame range, this determines how to show frames after the last frame.
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| Post Hold | The number of frames to hold the last frame for, if 'Hold N Frames' is selected. |
Local variables
| L | Sequence length |
| S | Start of sequence |
| E | End of sequence |
| IL | Input sequence length |
| SR | Sequence frame rate |
| NP | Number of planes in sequence |
| W,H | Width and height of image |
| I | Image index (0 at start frame) |
| IT | Image time (0 at start frame) |
| AI | Current plane array index |
| PI | Current plane index |
| PC | Num of channels in current plane |
| CXRES | Composite Project X resolution |
| CYRES | Composite Project Y resolution |
| CPIXA | Composite Project pixel aspect ratio |
| CDEPTH | Composite Project raster depth |
| CBP | Composite Project black point |
| CWP | Composite Project white point |