[Dri-devel] Stencil problems on i830M / i845?

[Ian R. <id...@us...>]

I was going to implement EXT_stencil_wrap in the i830 driver.  I added 
the extension string, added the right cases to i830StencilOp, and fired 
up (a modified version of) Mesa/tests/stencilwrap.  It turns out that 
the i830 fails ALL of the tests, even for GL_INCR and GL_DECR. 
Basically, it always returns the value that the stencil buffer was 
cleared to.  That is, it always gets 0 for the GL_INCR* tests and always 
gets 0xff for the GL_DECR* tests.

However, book/stencil, demos/reflect, and some stencil-shadow demos from 
SGI (http://www.sgi.com/software/opengl/examples/glut/advanced/) all 
work fine.

My guess is that the problem is just in the read-back path.  Has anyone 
seen anything like this before?  I know that Keith was doing some work 
in this area about a month ago.  Do you have any ideas?