Thanks again, Jonathan. That is very helpful.
However, I seem to be stuck at a very basic stage. How do I pass my own
function to the renderer. Using one of the lens functions you sent as an
example, I'm trying to get that returned
So, taking this as an example:
/*! Simple perspective projection lens function. */
static void myLensFunc(Scene* scene, CameraOp* cam, MatrixArray* transforms,
const VArray& in, Vector4& out,
void* data) {
out = transforms->matrix(LOCAL_TO_SCREEN).transform(in.PL <http://in.pl/>(),
1.0f);
}
I want lens_function() to return the above for any "mode". Which I'm naively
trying to do like this:
CameraOp::LensFunc* CamTest::lens_function(int mode) const {
return &myLensFunc;
}
<file:///home/ibusquets/Nuke6.3v1b20/Documentation/NDK/Plugins/classDD_1_1Image_1_1CameraOp.html#a0e50ad7bf1e85b4bc7efb5c37aece0b>
However, I'm not getting the result I want. Changing the "projection mode"
knob in my CamTest Op still behaves as usual, and seems to use the right
LensFunc for each projection mode, instead of myLensFunc.
Am I interpreting this wrong? How should I be returning a pointer to my
custom function in lens_function()?
Thanks,
Ivan
On Mon, Jun 27, 2011 at 1:20 PM, Jonathan Egstad <jegs...@earthlink.net>wrote:
> btw, don't worry about clipping the distorted vertices to the screen bbox,
> the renderer only worries about clipping to the near-Z plane. The only time
> you need to worry about the screen edges is if you're wrapping around like
> the spherical projection does.
>
>
>
> On Jun 27, 2011, at 11:15 AM, Ivan Busquets wrote:
>
> Wow, thanks for the info, Jonathan. I looked at CameraOp::LensNFunc, but
> didn't know what to make of it, or where to start, really. So that's exactly
> the kind of info I was hoping for.
>
> At DD there was a custom 'HypeCamera' that supported the 'Hype' distortion
>> file format so you could load a Hype file directly into the camera and it
>> applied the forward distortion via this method. There was also a
>> 'HypeDistort' geometry modifier that warped a card with the reverse
>> distortion so you could do a undistort/redistort in a single render/filter
>> pass.
>>
>
> And that's exactly the kind of application I wanted it for. :)
>
> Thanks,
> Ivan
>
>
> On Mon, Jun 27, 2011 at 11:03 AM, Jonathan Egstad
> <jegs...@earthlink.net>wrote:
>
>> So the current scanline renderer does handle general camera distortions -
>> with poly subdivision memory limitations.
>>
>> The CameraOp class supports several built-in linear projection and
>> non-linear distortions using its LensFunc/LensNFunc methods that are passed
>> back to the renderer via the CameraOp::lens_function()/lensNfunction()
>> virtual methods, then on to the Primitives in the Scene structure for use
>> during tessellation.
>>
>> You can implement your own LensFunc routines and return them via the
>> virtual method. The idea is that a primitive can subdivide itself using the
>> output of a LensFunc by passing in vertex info which gets modified. The
>> 'void *' parameter at the end is a way to get add'l info from the Primitive
>> into the lens function.
>>
>>
>> /*! Simple perspective projection lens function. */
>> static void perspLensFunc(Scene* scene, CameraOp* cam, MatrixArray*
>> transforms,
>> const VArray& in, Vector4& out,
>> void* data) {
>> out = transforms->matrix(LOCAL_TO_SCREEN).transform(in.PL(), 1.0f);
>> }
>>
>> /*! Simple UV projection lens function. */
>> static void perspLensFunc(Scene* scene, CameraOp* cam, MatrixArray*
>> transforms,
>> const VArray& in, Vector4& out,
>> void* data) {
>> out = transforms->matrix(CLIP_TO_SCREEN).transform(in.UV()*2.0f -
>> Vector4(1,1,1,1));
>> }
>>
>> The LensNFunc method does the same thing, but operates on arrays of vert
>> info.
>>
>> At DD there was a custom 'HypeCamera' that supported the 'Hype' distortion
>> file format so you could load a Hype file directly into the camera and it
>> applied the forward distortion via this method. There was also a
>> 'HypeDistort' geometry modifier that warped a card with the reverse
>> distortion so you could do a undistort/redistort in a single render/filter
>> pass.
>>
>>
>> Have fun,
>>
>> -jonathan
>>
>>
>> On Jun 26, 2011, at 2:12 PM, Ivan Busquets wrote:
>>
>> > Hi,
>> >
>> > I've been looking at the lens_distortion parameters in CameraOp, and was
>> wondering if there's any way to implement a different lens
>> distortion/correction model within a CameraOp, or if one would need to write
>> a specific renderer to handle that.
>> >
>> > Specifically, I'm looking for a way to handle off-center and asymmetric
>> distortions. Assuming I can get a function that maps destination to source
>> vectors(uvs), would this be possible within a CameraOp?
>> >
>> > Many thanks,
>> > Ivan
>> >
>> >
>> >
>> >
>> >
>> > _______________________________________________
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>>
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