https://bugzilla.gnome.org/show_bug.cgi?id=744763
Add a pivot vector for setting the origin of rotations and scales.
With the pivot point the rotation and scale operations can have
different origins. This adds the ability to rotate around different points.
Currently the default (0, 0) pivot point is possible,
a rotation around the center, and zooming into and out of the center.
With an pivot point this is optional.
I defined the following image coordinates for the pivot point:
(-1,1) ------------------------- (1,1)
| |
| |
| |
| (0,0) |
| |
| |
| |
(-1,-1) ------------------------- (1,-1)
Example:
Rotate the video at the bottom left corner
gst-launch-1.0 videotestsrc \
! gltransformation \
scale-x=0.5 \
scale-y=0.5 \
rotation-z=25.0 \
pivot-x=-1.0 \
pivot-y=-1.0 \
! glimagesink
The pivot-z option defines the pivot point in 3D space.
This only affects rotation, since we have no Z data to scale.
With this option a video can be rotated around a point in 3D space.
Example:
Rotate around point behind the video:
gst-launch-1.0 videotestsrc \
! gltransformation \
rotation-x=10.0 \
pivot-z=-4.0 \
! glimagesink
The graphene-1.0 part should not be in the source code. This directory
is part of the cflags include. This is similar to gstreamer-1.0/
directory. This break compilation if the include directory where
graphene is installed is not in your include path.
* aspect should not be 0 on init
* rename fovy to fov
* add mvp to properties as boxed graphene type
* fix transformation order. scale first
* clear color with 1.0 alpha
https://bugzilla.gnome.org/show_bug.cgi?id=734223
