jitter super keystone? slanted screen projection...

Bruce mowson's icon

Hi Folks,

I'm looking for a function similar to rota or gridshape, to shape a
simple color matte into an isosceles trapezoid. The image is
projected onto an angled screen, and the projector's keystone is not
radical enough.

all the best,

Bruce

Joshua Kit Clayton's icon

One way to accomplish this is with jit.gl.videoplane(rotate about the
x axis with the default perspective transform enabled), or more
flexibly using a texture mapped quadrilateral in jit.gl.sketch.
Either of these will use the GPU for faster mapping.

-Joshua

Eric L.'s icon

Joshua Kit Clayton wrote :
"...or more flexibly using a texture mapped quadrilateral in jit.gl.sketch. "
This appears to be false. The result is different because rotation on videoplane follows the perspective rules, but "using a texture mapped quadrilateral in jit.gl.sketch" creates distortion, as I mentionned here :
https://cycling74.com/forums/cornerpins-and-keystone
Cheers,
Eric