projecting on a globe / hemisphere
hey everybody!
for an installation i want to project with 3 projectors on the surface of a hemisphere (one half side of a globe). i tried out a small patch in vvvv using the "projektor node" (works like a virtual camera) but i would much more prefer to use max/jitter.
does anyone of you have experience projecting on a globe/sphere? how do you solve the problem with the distortion?
is there a similar object in jitter like the "projektor node" in vvvv? a virtual camera which which "films" a virtual globe from a certain point, the output to the video projector should be exactly the "real" texture of the globe?
or does anyone have a better idea to program all this? i haven't tried out yet if it works - just in virtual in vvvv.
uff, it's even difficult for me to explain my problem (in Englisher), so you'll find attached a jpg of the vvvv patch for better understanding... maybe someone of you can help me, would be great!
thanks so much!
hello,
you could use jit.gl.gridshape @shape sphere and texcoordmagic patch...(look for it n the forum you should find it easily) to place the image in the geometry.
Cheers
Hubert
Also look at the tex_map attribute when you're applying a texture to a sphere, there are 4 options and one should work, possibly in combination with some other parameters.
also texcoord magic only works on tex_map 1 and 3 I think
hi,
Also trying to map a hemisphere with a radial texture, I can't find the texcoord magic patch you are are talking about.
Could anyone advise me where to find it? or lead me to a text_map example?
thanks a lot
did you try searching the forum for "texcoord magic"? it comes up if you do.
yes , sorry, found it, I mistyped my search.
i think this is the texcoord magic patch...
marc, do you know how to handle the problem with image-distortion when projecting with multiple videoprojectors on a hemisphere? i have the problem that i can not project that way that all projectors output the texture for the whole surface of the hemisphere whithout DIFFERENT distortion on the borders/edges of the projector-images...
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hmmm, that's an interesting question, and does not seem related to texture mapping so much.
you're never going to get rid of distortion entirely because your projecting a rectangular image (your output window) onto a spherical surface. my first guess is that you don't need to to software based spherical mapping, because your are doing actual spherical mapping when you project. i would also guess that having corner-pin gl.mesh/gl.nurbs setups would allow you to achieve an acceptable mapping of each third/quadrant/whatever of the sphere.
however this is all conjecture, as i've never tried.
edit: actually, rereading, i'm still not quite sure i understand what you're asking, but am interested to hear what solutions you come up with.
there was a shader that someone made that did pretty good projection textures
cool, could you tell us how/where to get it..?