[Mesa-dev] [PATCH] gallium: add API for setting window rectangles

[Ilia Mirkin]

Window rectangles apply to all framebuffer operations, either in
inclusive or exclusive mode. They may also be specified as part of a
blit operation.

In exclusive mode, any fragment inside any of the specified rectangles
will be discarded.

In inclusive mode, any fragment outside every rectangle will be
discarded.

The no-op state is to have 0 rectangles in exclusive mode.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

Wanted to get some early feedback on the interface, while I go around adding pipe caps and the state tracker code (which is easy but a little time-consuming).

This is for GL_EXT_window_rectangles.

 src/gallium/docs/source/context.rst  | 15 ++++++++++++---
 src/gallium/include/pipe/p_context.h |  5 +++++
 src/gallium/include/pipe/p_state.h   |  6 ++++++
 3 files changed, 23 insertions(+), 3 deletions(-)

diff --git a/src/gallium/docs/source/context.rst b/src/gallium/docs/source/context.rst
index 3a45f40..667d9a2 100644
--- a/src/gallium/docs/source/context.rst
+++ b/src/gallium/docs/source/context.rst
@@ -79,6 +79,15 @@ objects. They all follow simple, one-method binding calls, e.g.
   should be the same as the number of set viewports and can be up to
   PIPE_MAX_VIEWPORTS.
 * ``set_viewport_states``
+* ``set_window_rectangle_states`` sets the window rectangles to be
+  used for rendering, as defined by GL_EXT_window_rectangles. There
+  are two modes - include and exclude, which define whether the
+  supplied rectangles are to be used for including fragments or
+  excluding them. All of the rectangles are ORed together, so in
+  exclude mode, any fragment inside any rectangle would be culled,
+  while in include mode, any fragment outside all rectangles would be
+  culled. xmin/ymin are inclusive, while xmax/ymax are exclusive (same
+  as scissor states above).
 * ``set_tess_state`` configures the default tessellation parameters:
   * ``default_outer_level`` is the default value for the outer tessellation
     levels. This corresponds to GL's ``PATCH_DEFAULT_OUTER_LEVEL``.
@@ -492,9 +501,9 @@ This can be considered the equivalent of a CPU memcpy.
 
 ``blit`` blits a region of a resource to a region of another resource, including
 scaling, format conversion, and up-/downsampling, as well as a destination clip
-rectangle (scissors). It can also optionally honor the current render condition
-(but either way the blit itself never contributes anything to queries currently
-gathering data).
+rectangle (scissors) and window rectangles. It can also optionally honor the
+current render condition (but either way the blit itself never contributes
+anything to queries currently gathering data).
 As opposed to manually drawing a textured quad, this lets the pipe driver choose
 the optimal method for blitting (like using a special 2D engine), and usually
 offers, for example, accelerated stencil-only copies even where
diff --git a/src/gallium/include/pipe/p_context.h b/src/gallium/include/pipe/p_context.h
index 9d7a8eb..0ea18c7 100644
--- a/src/gallium/include/pipe/p_context.h
+++ b/src/gallium/include/pipe/p_context.h
@@ -274,6 +274,11 @@ struct pipe_context {
                                unsigned num_scissors,
                                const struct pipe_scissor_state * );
 
+   void (*set_window_rectangle_states)( struct pipe_context *,
+                                        boolean include,
+                                        unsigned num_rectangles,
+                                        const struct pipe_scissor_state * );
+
    void (*set_viewport_states)( struct pipe_context *,
                                 unsigned start_slot,
                                 unsigned num_viewports,
diff --git a/src/gallium/include/pipe/p_state.h b/src/gallium/include/pipe/p_state.h
index 396f563..9c69355 100644
--- a/src/gallium/include/pipe/p_state.h
+++ b/src/gallium/include/pipe/p_state.h
@@ -69,6 +69,7 @@ extern "C" {
 #define PIPE_MAX_VIEWPORTS        16
 #define PIPE_MAX_CLIP_OR_CULL_DISTANCE_COUNT 8
 #define PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT 2
+#define PIPE_MAX_WINDOW_RECTANGLES 8
 
 
 struct pipe_reference
@@ -710,6 +711,11 @@ struct pipe_blit_info
    boolean scissor_enable;
    struct pipe_scissor_state scissor;
 
+   /* Window rectangles can either be inclusive or exclusive. */
+   boolean window_rectangle_include;
+   unsigned num_window_rectangles;
+   struct pipe_scissor_state window_rectangles[PIPE_MAX_WINDOW_RECTANGLES];
+
    boolean render_condition_enable; /**< whether the blit should honor the
                                     current render condition */
    boolean alpha_blend; /* dst.rgb = src.rgb * src.a + dst.rgb * (1 - src.a) */
-- 
2.7.3