Projection Mapping Node

Feature Requests
,
1

A simple keystone / projection mapping node. Options:

  • change between perspective and orthographic projection
  • soften / smooth / blur edges

In quartz composer I use a GLSL shader from Thomas Pachoud which works quite good.

makequadlayer.png

2

@iason: I’m having trouble understanding your suggestion about toggling between perspective and orthographic projection. How would orthographic projection be useful (or even technically possible) in the context of applying projection distortions to a quad? Could you provide an example?  

3

hi maybe im using the wrong terms, im not good with 3D stuff :D

here are two examples.

correct

correct
correct1280Ă—800 124 KB

false

correct
false1280Ă—800 130 KB

the “correct” one was done with the GLSL Shader mentioned in my first comment.

the “false” one was created using memos Shader: Projection mapping / quad warping with Quartz Composer & VDMX | memo.tv  

4

Thanks, @iason. To me, your “correct” image looks like perspective-correct mapping, and your “false” image looks like affine mapping.

I’m thinking that in Vuo’s mapping node, we’d just provide perspective-correct mapping.

Is there a reason you’d ever want to use projection that looks like your “false” image?

5

i think one of the advantages of affine mapping is, that it keeps lines in parallel.
that can be useful for certain projection mappings.

i havent used the affine mapping in a while, so im not sure about the visual differences.
but thats the reason why i wished for that feature in the first place. so i can just flip a switch and see the difference.

6

A great addition to this node would be a crop on the input texture. Top, bottom, left and right crop. Take a look at the mapping features of other apps to get a feel for the tools that are used for mapping. This is a great start, the next logical step would be a grid warp patch with bezier options.

7

In vvvv we have a source points input and an output points input, so you can warp from the corner points, but by setting the source points inside the image you can specify a point that isn’t the corner of the quad, but is the corner of part of an image/realworld geometry, i.e. for mapping things that aren’t rectangles, maybe a building with turrets or similar. We also can do a 4 point 3d homography by specifying these input points, mapped to the output points, and multiplying by a perspective transform, you can map a 3d object rather than just a plane, which requires the object to be exact, but can be fudged for real world applications.

8
  • “4 point 3d homography by specifying input points, mapped to the output points, multiplying by a perspective transform to map a 3d object”

maybe add this as separate feature request. really would like to try 3D mapping with VUO, never found the time to try it with vvvv. do you know some vvvv example projects for this type of mapping? (besides the vvvv 3d mapping tutorial)

  • " setting the source points inside"
  • “grid warp patch with bezier options”

this is another feature request as well i guess.
data inputs for grids and bezier curves are very large. take a look at the 1024 qc bezier wrap patch. it has 20+ inputs for all the points and curves.

still two very nice features to have in VUO.

9

Excellent work here everyone! Let’s begin by getting proposed Make Quad Layer node fully pledged. Then, once it’s implemented, we can create and refine feature requests for the complimentary functionality. I’m excited to see this happen.

10

http://vvvv.org/contribution/catmapper
is a 4 point 3d homography contribution I made.
For the homography node with custom corners, its only 4 2d vectors for the input corners, for bezier there are obviously tangents for each point too, but I’d see a bezier warp as something ontop of a corner pin, as the homography gets you nearly there, then the bezier warp tweaks that output, so I’d see it as occuring on the output of the homography maybe…

11

Is there any workaround until this node would be include in Vuo? I should use it for translating an QC composition in Vuo for a live show using _1024_Perspective Patch which do almost the same.

regards

12

@jeromebueche, I can think of 3 currently-available options:

  1. Play your Vuo composition in VDMX, which has built-in support for perspective warping
  2. Write GLSL code using Vuo’s Make Image with Shadertoy node to perspective-warp your image
  3. Output Syphon from your Vuo composition, and feed it to a perspective warping app that supports Syphon input (e.g., MadMapper)
13

Chosen to be implemented.

14

Released in Vuo 1.2.3.

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