Projection TOP

From TouchDesigner 088 Wiki


The Projection TOP takes a Cube Map created with a Render TOP and converts that to a fisheye projection suitable for domes, and a “equirectangular" projection, where u-v is latitude-longitude, suitable for spheres. This produces superior-quality as it's based on the cube maps.

For every pixel of output, it takes one sample from the input cube map. Better anti-aliasing may be achieved by rendering double-resolution and scaling down to your desired resolution with the High Quality Resize option of the Resolution TOP.

PythonIcon.png projectionTOP_Class


Parameters - Project Page

Input input - At this time the only option is a Cube Map input. You can generate a Cube Map by rendering one using the Render TOP, or converting 2D images into one using the Cube Map TOP.

Output output - Select output format from the menu.

  • Equirectangular - A 2D Texture is usually 2:1 aspect ration. This format is typically used to map the texture onto a sphere with UVs set to to lat/long. This format is very popular for 360 video. A more details explanation is available here.
  • Fish-Eye - A projection where the image takes up a circle in the 2D texture(with the corners of the texture being black). The circle contains image data that is 'FOV Angle' degrees wide across the diameter of the circle.

FOV Angle fov - Only enabled in Fish-Eye output mode to specify the field of view of the Fish-Eye camera.

Parameters - Common Page

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

  • Input - uses the input's resolution.
  • Eighth, Quarter, Half, 2X, 4X, 8X - multiply the input's resolution by that amount.
  • Custom Resolution - enables the Custom Res parameter below, giving direct control over res in the X and Y axis.

Custom Res - 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 Resolution 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.

Aspect Ratio - sets the image aspect ratio, which is the visible width vs height, independent of the pixel resolution. If the pixels are not square, the aspect ratio is not the resolution's width/height. Watch for unexpected results when compositing TOPs with different aspect ratios.

  • 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 Ratio - lets you explicitly define a custom aspect ratio.

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 Worst - 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. 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 mipmapfiltering 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 nearest filtering will always be used, regardless of what is selected in the menu.

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.
  • 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 (R) - has 8-bits for the red channel, 8-bits total per pixel.
  • 16-bit fixed (R) - has 16-bits for the red channel, 16-bits total per pixel.
  • 16-bit float (R) - has 16-bits for the red channel, 16-bits per pixel.
  • 32-bit float (R) - has 32-bits for the red channel, 32-bits per pixel.
  • 8-bit fixed (RG) - has 8-bits for the red and green channels, 16-bits total per pixel.
  • 16-bit fixed (RG) - has 16-bits for the red and green channels, 32-bits total per pixel.
  • 16-bit float (RG) - has 16-bits for the red and green channels, 32-bits per pixel.
  • 32-bit float (RG) - has 32-bits for the red and green channels, 64-bits per pixel.
  • 8-bit fixed (A) - An Alpha only format that has 8-bits per channel, 8-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.