[Mesa-dev] [PATCH] gallium: document conservative rasterization flags

[Marek Olšák]

From: Marek Olšák <marek.olsak at amd.com>

---
 src/gallium/docs/source/screen.rst   |  5 +++++
 src/gallium/include/pipe/p_defines.h | 11 +++++++++++
 2 files changed, 16 insertions(+)

diff --git a/src/gallium/docs/source/screen.rst b/src/gallium/docs/source/screen.rst
index b7b5f3504b2..41008816ee2 100644
--- a/src/gallium/docs/source/screen.rst
+++ b/src/gallium/docs/source/screen.rst
@@ -449,24 +449,29 @@ The integer capabilities:
 * ``PIPE_CAP_FENCE_SIGNAL``: True if the driver supports signaling semaphores
   using fence_server_signal().
 * ``PIPE_CAP_CONSTBUF0_FLAGS``: The bits of pipe_resource::flags that must be
   set when binding that buffer as constant buffer 0. If the buffer doesn't have
   those bits set, pipe_context::set_constant_buffer(.., 0, ..) is ignored
   by the driver, and the driver can throw assertion failures.
 * ``PIPE_CAP_PACKED_UNIFORMS``: True if the driver supports packed uniforms
   as opposed to padding to vec4s.
 * ``PIPE_CAP_CONSERVATIVE_RASTER_POST_SNAP_TRIANGLES``: Whether the
   ``PIPE_CONSERVATIVE_RASTER_POST_SNAP`` mode is supported for triangles.
+  The post-snap mode means the conservative rasterization occurs after
+  the conversion from floating-point to fixed-point coordinates
+  on the subpixel grid.
 * ``PIPE_CAP_CONSERVATIVE_RASTER_POST_SNAP_POINTS_LINES``: Whether the
   ``PIPE_CONSERVATIVE_RASTER_POST_SNAP`` mode is supported for points and lines.
 * ``PIPE_CAP_CONSERVATIVE_RASTER_PRE_SNAP_TRIANGLES``: Whether the
   ``PIPE_CONSERVATIVE_RASTER_PRE_SNAP`` mode is supported for triangles.
+  The pre-snap mode means the conservative rasterization occurs before
+  the conversion from floating-point to fixed-point coordinates.
 * ``PIPE_CAP_CONSERVATIVE_RASTER_PRE_SNAP_POINTS_LINES``: Whether the
   ``PIPE_CONSERVATIVE_RASTER_PRE_SNAP`` mode is supported for points and lines.
 * ``PIPE_CAP_CONSERVATIVE_RASTER_POST_DEPTH_COVERAGE``: Whether
   ``PIPE_CAP_POST_DEPTH_COVERAGE`` works with conservative rasterization.
 * ``PIPE_CAP_MAX_CONSERVATIVE_RASTER_SUBPIXEL_PRECISION_BIAS``: The maximum
   subpixel precision bias in bits during conservative rasterization.
 * ``PIPE_CAP_PROGRAMMABLE_SAMPLE_LOCATIONS``: True is the driver supports
   programmable sample location through ```get_sample_pixel_grid``` and
   ```set_sample_locations```.
 * ``PIPE_CAP_MAX_GS_INVOCATIONS``: Maximum supported value of
diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
index 9909e7f3ac1..72dc448aecc 100644
--- a/src/gallium/include/pipe/p_defines.h
+++ b/src/gallium/include/pipe/p_defines.h
@@ -637,21 +637,32 @@ enum pipe_reset_status
    PIPE_UNKNOWN_CONTEXT_RESET,
 };
 
 
 /**
  * Conservative rasterization modes.
  */
 enum pipe_conservative_raster_mode
 {
    PIPE_CONSERVATIVE_RASTER_OFF,
+
+   /**
+    * The post-snap mode means the conservative rasterization occurs after
+    * the conversion from floating-point to fixed-point coordinates
+    * on the subpixel grid.
+    */
    PIPE_CONSERVATIVE_RASTER_POST_SNAP,
+
+   /**
+    * The pre-snap mode means the conservative rasterization occurs before
+    * the conversion from floating-point to fixed-point coordinates.
+    */
    PIPE_CONSERVATIVE_RASTER_PRE_SNAP,
 };
 
 
 /**
  * resource_get_handle flags.
  */
 /* Requires pipe_context::flush_resource before external use. */
 #define PIPE_HANDLE_USAGE_EXPLICIT_FLUSH     (1 << 0)
 /* Expected external use of the resource: */
-- 
2.17.1