gallium: add support for programmable sample locations

Signed-off-by: Rhys Perry <[email protected]>
Reviewed-by: Brian Paul <[email protected]> (v2)
Reviewed-by: Marek Olšák <[email protected]> (v2)

2 files changed, 17 insertions, 0 deletions

diff --git a/src/gallium/docs/source/context.rst b/src/gallium/docs/source/context.rst
index e8e80dcbc39..20d0df79312 100644
--- a/src/gallium/docs/source/context.rst
+++ b/src/gallium/docs/source/context.rst
@@ -68,6 +68,9 @@ objects. They all follow simple, one-method binding calls, e.g.
   that this takes effect even if multisampling is not explicitly enabled if
   the frambuffer surface(s) are multisampled.  Also, this mask is AND-ed
   with the optional fragment shader sample mask output (when emitted).
+* ``set_sample_locations`` sets the sample locations used for rasterization.
+  ```get_sample_position``` still returns the default locations. When NULL,
+  the default locations are used.
 * ``set_min_samples`` sets the minimum number of samples that must be run.
 * ``set_clip_state``
 * ``set_polygon_stipple``
@@ -270,6 +273,17 @@ format.
 multi-byte element value starting at offset bytes from resource start, going
 for size bytes. It is guaranteed that size % clear_value_size == 0.
 
+Evaluating Depth Buffers
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+``evaluate_depth_buffer`` is a hint to decompress the current depth buffer
+assuming the current sample locations to avoid problems that could arise when
+using programmable sample locations.
+
+If a depth buffer is rendered with different sample location state than
+what is current at the time of reading the depth buffer, the values may differ
+because depth buffer compression can depend the sample locations.
+
 
 Uploading
 ^^^^^^^^^
diff --git a/src/gallium/docs/source/screen.rst b/src/gallium/docs/source/screen.rst
index 0f18b7a94b9..a41c421ec47 100644
--- a/src/gallium/docs/source/screen.rst
+++ b/src/gallium/docs/source/screen.rst
@@ -438,6 +438,9 @@ PIPE_CONSERVATIVE_RASTER_PRE_SNAP mode is supported for points and lines.
 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_capf: