View Full Version : Rotating glScissor for layer clipping

Kumar K
01-23-2011, 11:49 PM
Dear All,

I am looking forward for implementing layer Clipping for OpenGL ES 2.0 based UI system where in all childern are
clipped inside parent region. Imagine like a Message box as parent with buttons as childern in it. This UI Tree has more than 5 levels of depth ( parent->parent->....parent->leaf child).

The idea is to make sure child is clipped with in Parent bounds
even during rotation. Let me know the right appoarch
1) stencil buffers. ( need to know performance hit)
2) re-generate the verticies of childern (in this case rect may not stay rect).
3) glScissor ( is not helping us during rotation of parent or child)
4) Clipping planes ( not directly supported in OpenGL ES )


01-24-2011, 02:18 AM
"even during rotation" : what is your UI use case for this ?
Scissor is probably the fastest, but GL ES hardware is special, you have to benchmark each way to very the performance impact.

Kumar K
01-24-2011, 03:48 AM
"even during rotation" : what is your UI use case for this ?

Find the attached images explaining where childern goes out of parent, and needs clipping, Images are only in XY Plane they can be any any orientation( both parent and child).