gallium: clear interface changes

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.

1 files changed, 4 insertions, 2 deletions

diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
index b54a6ef824..420649c5a9 100644
--- a/src/gallium/include/pipe/p_defines.h
+++ b/src/gallium/include/pipe/p_defines.h
@@ -189,9 +189,10 @@ enum pipe_texture_target {
  */
 /** All color buffers currently bound */
 #define PIPE_CLEAR_COLOR        (1 << 0)
+#define PIPE_CLEAR_DEPTH        (1 << 1)
+#define PIPE_CLEAR_STENCIL      (1 << 2)
 /** Depth/stencil combined */
-#define PIPE_CLEAR_DEPTHSTENCIL (1 << 1)
-
+#define PIPE_CLEAR_DEPTHSTENCIL (PIPE_CLEAR_DEPTH | PIPE_CLEAR_STENCIL)
 
 /**
  * Transfer object usage flags
@@ -453,6 +454,7 @@ enum pipe_cap {
    PIPE_CAP_INDEP_BLEND_ENABLE,
    /** different blend funcs per rendertarget */
    PIPE_CAP_INDEP_BLEND_FUNC,
+   PIPE_CAP_DEPTHSTENCIL_CLEAR_SEPARATE,
    PIPE_CAP_TGSI_FS_COORD_ORIGIN_UPPER_LEFT,
    PIPE_CAP_TGSI_FS_COORD_ORIGIN_LOWER_LEFT,
    PIPE_CAP_TGSI_FS_COORD_PIXEL_CENTER_HALF_INTEGER,