i965: Move arrays brw_multisample_positions* to new header

Move the arrays to the new header brw_multisample_state.h, which will be
shared with Broadwell code.

Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Chad Versace <chad.versace@linux.intel.com>

1 files changed, 72 insertions, 0 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_multisample_state.h b/src/mesa/drivers/dri/i965/brw_multisample_state.h
new file mode 100644
index 0000000..79566f0
--- /dev/null
+++ b/src/mesa/drivers/dri/i965/brw_multisample_state.h
@@ -0,0 +1,72 @@
+/*
+ * Copyright © 2013 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include <stdint.h>
+
+/**
+ * Sample positions:
+ *   2 6 a e
+ * 2   0
+ * 6       1
+ * a 2
+ * e     3
+ */
+static const uint32_t
+brw_multisample_positions_4x[] = { 0xae2ae662 };
+
+/**
+ * Sample positions are based on a solution to the "8 queens" puzzle.
+ * Rationale: in a solution to the 8 queens puzzle, no two queens share
+ * a row, column, or diagonal.  This is a desirable property for samples
+ * in a multisampling pattern, because it ensures that the samples are
+ * relatively uniformly distributed through the pixel.
+ *
+ * There are several solutions to the 8 queens puzzle (see
+ * http://en.wikipedia.org/wiki/Eight_queens_puzzle).  This solution was
+ * chosen because it has a queen close to the center; this should
+ * improve the accuracy of centroid interpolation, since the hardware
+ * implements centroid interpolation by choosing the centermost sample
+ * that overlaps with the primitive being drawn.
+ *
+ * Note: from the Ivy Bridge PRM, Vol2 Part1 p304 (3DSTATE_MULTISAMPLE:
+ * Programming Notes):
+ *
+ *     "When programming the sample offsets (for NUMSAMPLES_4 or _8 and
+ *     MSRASTMODE_xxx_PATTERN), the order of the samples 0 to 3 (or 7
+ *     for 8X) must have monotonically increasing distance from the
+ *     pixel center. This is required to get the correct centroid
+ *     computation in the device."
+ *
+ * Sample positions:
+ *   1 3 5 7 9 b d f
+ * 1     5
+ * 3           2
+ * 5               6
+ * 7 4
+ * 9       0
+ * b             3
+ * d         1
+ * f   7
+ */
+static const uint32_t
+brw_multisample_positions_8x[] = { 0xdbb39d79, 0x3ff55117 };