clears were a bit limited in gallium:
- no scissoring (OGL only) nor explicit rectangle list (d3d9)
- no color/stencil masks (OGL only)
- no separate depth/stencil clears (d3d9/d3d10/OGL)
- cannot really clear single color buffer (only with resource_fill_region)
Additionally, d3d can clear surfaces not currently bound to the framebuffer.
It is, however, not easy to find some common ground what a clear should be able
to do, due to both API requirements and also hw differences (a case which might
be able to use a special clear path on one hw might need a "normal" quad render
on another).
Hence several clear methods are provided, and a driver should implement all of
them.
- clear: slightly modified to also be able to clear only depth or stencil in a
combined depth/stencil surface. This is however optional based on driver
capability though ideally it wouldn't be optional. AFAIK this is in fact
something used by applications quite a bit.
Otherwise, for now still doesn't allow clearing with scissors/mask (or single
color buffers)
- clearRT: clears a single (potentially unbound) color surface. This was formerly
roughly known as resource_fill_region. mesa st will not currently use this,
though potentially would be useful for GL ClearBuffer.
- clearDS: similar to above except for depth stencil surfaces.
Note that clearDS/clearRT currently handle can handle partial clear. This might
change however.
Flush means flush, i.e., all previous operations should be visible from
other contexts.
This does not imply unswizzling tiles, since unswizzling should be done on
a needed basis for any context.
This fixes a double-free() error when not using a shared memory XImage.
The XDestroyImage() function frees the ximage->data buffer if non-NULL.
If we free it ourselves, we also need to NULL-out the pointer.
Convert Z from a normalized value in the range [0, 1] to an
object-space Z coordinate in [-1, +1] so that drawing at the new Z
position with the default/identity ortho projection results in the
original Z value. Used by the meta-Clear, Draw/CopyPixels and Bitmap
functions where the Z value comes from the clear value or raster
position.
Fixes piglit tests fdo23670-depth_test, quad-invariance and
glsl-orangebook-ch06-bump as well as oglc zbfunc.c.
https://bugs.freedesktop.org/show_bug.cgi?id=23670
