Displace TOP

From TouchDesigner 099 Wiki

Summary

The Displace TOP will cause one image to be warped by another image. A pixel of the output image at (Uo,Vo) gets its RGBA value from a different pixel (Ui, Vi) of the Source Image by using the second input image (the Displace Image).

For each pixel in the output image, three factors affect which pixel to fetch from the source:

  • the red and blue channels of the Displace Image.
  • the Uo and Vo coordinate of the output pixel.
  • a constant Ua and Va anchor point (offset).

Displace Image - In using the Displace Image, for each pixel in the output, it gets the corresponding pixel from the input, and uses the red channel and blue channel as its U and V displacement. If the red and blue are .5, .5, then Uo = Ui and Vo = Vi. That is, there is no warp if the Displace Image is a 50% grey. Also the warp is reduced to 0 if the Displace Weight is 0. Where red < .5 in the Displace Image, it fetches a pixel from the left of Uo in the Source Image. If blue < .5, it fetches a pixel from below Vo in the Source Image. Thus the pixel is retrieved from Ui, Vi at Uo*Scale*(red-.5), Vo*Scale*(.5-blue) of the Source Image.

Uo and Vo offset - By default, the warping of each output pixel is relative to its Uo, Vo. But when the UV Weight parameter is 0, the displacement is relative to the center pixel of the Source Image.

Ua and Va anchor (offset) point - This zooms into a pixel of the input if you bring the two other weights down to 0.

For the Displace Image, you can change which of its RGBA channels cause the warp.

You can choose if there is wraparound in the image warping. If the computed Uo and Vo is less than 0 or greater than 1, it can wraparound, clamp or mirror.

The Displace Image can be any photograph followed by a Slope TOP, which will give luminance gradients in red and blue, with the neutral value at .5, exactly the form required by the Displace TOP.

One way to experiment is to make a Displace Image from Ramp TOPs. Alternately use a Constant TOP set to .5, .5, .5, 1, then subtract a photo using a Subtract TOP, and add another photo image using an Add TOP. Before subtracting and adding the images, you can lower their effect using Level TOPs and adjusting Brightness.

See also: Remap TOP

PythonIcon.png displaceTOP_Class

Parameters - Displace Page

Horizontal Source horzsource - Instead of using the Red channel to displace horizontally, you can choose a different channel.

Vertical Source vertsource - Instead of using the Blue channel to displace vertically, you can choose a different channel.

Source Midpoint midpoint1 midpoint2 - This value is the color values that will result in no displacement. Values below this will cause the displacment to come from the left/bottom of the pixel, while values above this will cause the displacement to come from the right/top of the pixel.

Displace Weight displaceweight1 displaceweight2 - This scales the offset caused by the Displace Image. It will cause the pixels fetched to be closer/farther along the sample vector created by the Horizontal and Vertical Source.

UV Weight uvweight - This reduces the influence of the pixel's position when brought toward 0. At its default of 1, it doesn't zoom into the Displace Image. When 0, it anchors the displacements relative to one pixel in the Source Image defined by the Offset and Offset Weight parameters.

Offset offset1 offset2 - The pixel (anchor point) in the Source Image that it converges to when UV Weight is reduced.

Offset Weight offsetweight - The effect of the offset anchor point, defaulting to 1-uvweight.

Extend extend - This parameter determines what happens at the edges of the tiles.

  • Hold - The pixel values at the edges of the tile continue to extend past that edge.
  • Zero - The image does not extend past the edges of the tile.
  • Repeat - The image is repeated at the edges of the tile.
  • Mirror - The image is mirrored at the edges of the tile.

Parameters - Common Page

Output Resolution - quickly change the resolution of the TOP's data.

  • Use Input - uses the input's resolution.
  • Eighth, Quarter, Half, 2X, 4X, 8X - multiply the input's resolution by that amount.
  • Fit Resolution - Resizes the input to the size specified in Resolution using the best possible match that does not crop any of the input. It will resize the image to be larger than the input resolution if a larger resolution is specified. It's a "fit inside", Aspect Ratio is maintained.
  • Limit Resolution - Limits the input to the size specified in Resolution using the best possible match that does not crop any of the input. It will NOT resize the image to be larger than the input resolution if a larger resolution is specified. It's a "fit inside", Aspect Ratio is maintained.
  • Custom Resolution - enables the Resolution parameter below, giving direct control over width and height.

Resolution - enabled only when the Resolution parameter is set to Custom Resolution. Some Generators like Constant and Ramp do not use inputs and only use this field to determine their size. The drop down menu on the right provides some commonly used resolutions.

Use Global Res Multiplier - Uses the Global Resolution Multiplier found in Edit>Preferences>TOPs. This multiplies all the TOPs resolutions by the set amount. This is handy when working on computers with different hardware specifications. If a project is designed on a desktop workstation with lots of graphics memory, a user on a laptop with only 64MB VRAM can set the Global Resolution Multiplier to a value of half or quarter so it runs at an acceptable speed. By checking this checkbox on, this TOP is affected by the global multiplier.

Output Aspect - sets the image aspect ratio allowing any textures to be viewed in any size. Watch for unexpected results when compositing TOPs with different aspect ratios. (You can define images with non-square pixels using xres, yres, aspectx, aspecty where xres/yres != aspectx/aspecty.)

  • Input - uses the input's aspect ratio.
  • Resolution - uses the aspect of the image's defined resolution (ie 512x256 would be 2:1), whereby each pixel is square.
  • Custom Aspect - lets you explicitly define a custom aspect ratio in the Aspect parameter below.

Aspect - Use when Output Aspect parameter is set to Custom Aspect.

Input Smoothness - This controls pixel filtering on the input image of the TOP.

  • Nearest Pixel - uses nearest pixel or accurate image representation. Images will look jaggy when viewing at any zoom level other than Native Resolution.
  • Interpolate Pixels - uses linear filtering between pixels. This is how you get TOP images in viewers to look good at various zoom levels, especially useful when using any Fill Viewer setting other than Native Resolution.
  • Mipmap Pixels - uses mipmap filtering when scaling images. This can be used to reduce artifacts and sparkling in moving/scaling images that have lots of detail.

Fill Viewer - determine how the TOP image is displayed in the viewer.

  • Input - uses the same Fill Viewer settings as it's input.
  • Fill - stretches the image to fit the edges of the viewer.
  • Fit Horizontal - stretches image to fit viewer horizontally.
  • Fit Vertical - stretches image to fit viewer vertically.
  • Fit Best - stretches or squashes image so no part of image is cropped.
  • Fit Outside - stretches or squashes image so image fills viewer while constraining it's proportions. This often leads to part of image getting cropped by viewer.
  • Native Resolution - displays the native resolution of the image in the viewer.

NOTE: To get an understanding of how TOPs works with images, you will want to set this to Native Resolution as you lay down TOPs when starting out. This will let you see what is actually happening without any automatic viewer resizing.

Viewer Smoothness - This controls pixel filtering in the viewers.

  • Nearest Pixel - uses nearest pixel or accurate image representation. Images will look jaggy when viewing at any zoom level other than Native Resolution.
  • Interpolate Pixels - uses linear filtering between pixels. Use this to get TOP images in viewers to look good at various zoom levels, especially useful when using any Fill Viewer setting other than Native Resolution.
  • Mipmap Pixels - uses mipmap filtering when scaling images. This can be used to reduce artifacts and sparkling in moving/scaling images that have lots of detail. When the input is 32-bit float format, only nearest filtering will be used (regardless of what is selected).

Passes - duplicates the operation of the TOP the specified number of times.

Channel Mask - Allows you to choose which channels (R, G, B, or A) the TOP will operate on. All channels are selected by default.

Pixel Format - format used to store data for each channel in the image (ie. R, G, B, and A). Refer to Pixel Formats for more information.

  • Input - uses the input's pixel format.
  • 8-bit fixed (RGBA) - uses 8-bit integer values for each channel.
  • sRGB 8-bit fixed (RGBA) - uses 8-bit integer values for each channel and stores color in sRGB colorspace.
  • 16-bit float (RGBA) - uses 16-bits per color channel, 64-bits per pixel.
  • 32-bit float (RGBA) - uses 32-bits per color channel, 128-bits per pixels.


  • 10-bit RGB, 2-bit Alpha, fixed (RGBA) - uses 10-bits per color channel and 2-bits for alpha, 32-bits total per pixel.
  • 16-bit fixed (RGBA) - uses 16-bits per color channel, 64-bits total per pixel.
  • 11-bit float (RGB), Positive Values Only - A RGB floating point format that has 11 bits for the Red and Green channels, and 10-bits for the Blue Channel, 32-bits total per pixel (therefore the same memory usage as 8-bit RGBA). The Alpha channel in this format will always be 1. Values can go above one, but can't be negative. ie. the range is [0, infinite).
  • 8-bit fixed (Mono) - Single channel, where RGB will all have the same value, and Alpha will be 1.0. 8-bits per pixel.
  • 16-bit fixed (Mono) - Single channel, where RGB will all have the same value, and Alpha will be 1.0. 16-bits per pixel.
  • 16-bit float (Mono) - Single channel, where RGB will all have the same value, and Alpha will be 1.0. 16-bits per pixel.
  • 32-bit float (Mono) - Single channel, where RGB will all have the same value, and Alpha will be 1.0. 32-bits per pixel.
  • 8-bit fixed (RG) - A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 8-bits per channel, 16-bits total per pixel.
  • 16-bit fixed (RG) - A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 16-bits per channel, 32-bits total per pixel.
  • 16-bit float (RG) - A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 16-bits per channel, 32-bits total per pixel.
  • 32-bit float (RG) - A 2 channel format, R and G have values, while B is 0 always and Alpha is 1.0. 32-bits per channel, 64-bits total per pixel.
  • 8-bit fixed (A) - An Alpha only format that has 8-bits per channel, 8-bits per pixel.
  • 16-bit fixed (A) - An Alpha only format that has 16-bits per channel, 16-bits per pixel.
  • 16-bit float (A) - An Alpha only format that has 16-bits per channel, 16-bits per pixel.
  • 32-bit float (A) - An Alpha only format that has 32-bits per channel, 32-bits per pixel.
  • 8-bit fixed (Mono+Alpha) - A 2 channel format, one value for RGB and one value for Alpha. 8-bits per channel, 16-bits per pixel.
  • 16-bit fixed (Mono+Alpha) - A 2 channel format, one value for RGB and one value for Alpha. 16-bits per channel, 32-bits per pixel.
  • 16-bit float (Mono+Alpha) - A 2 channel format, one value for RGB and one value for Alpha. 16-bits per channel, 32-bits per pixel.
  • 32-bit float (Mono+Alpha) - A 2 channel format, one value for RGB and one value for Alpha. 32-bits per channel, 64-bits per pixel.


Examples

This example shows a few basic uses of the Displace TOP.

Media:Displace_TOP_Basic.tox