* IN THE SOFTWARE.
*/
+#ifndef BRW_MULTISAMPLE_STATE_H
+#define BRW_MULTISAMPLE_STATE_H
+
#include <stdint.h>
+/**
+ * Note: There are no standard multisample positions defined in OpenGL
+ * specifications. Implementations have the freedom to pick the positions
+ * which give plausible results. But the Vulkan specification does define
+ * standard sample positions. So, we decided to pick the same pattern in
+ * OpenGL as in Vulkan to keep it uniform across drivers and also to avoid
+ * breaking applications which rely on this standard pattern.
+ */
+
+/**
+ * 1x MSAA has a single sample at the center: (0.5, 0.5) -> (0x8, 0x8).
+ *
+ * 2x MSAA sample positions are (0.25, 0.25) and (0.75, 0.75):
+ * 4 c
+ * 4 0
+ * c 1
+ */
+static const uint32_t
+brw_multisample_positions_1x_2x = 0x0088cc44;
+
/**
* Sample positions:
* 2 6 a e
* e 3
*/
static const uint32_t
-brw_multisample_positions_4x[] = { 0xae2ae662 };
+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.
+ * Sample positions:
*
- * Note: from the Ivy Bridge PRM, Vol2 Part1 p304 (3DSTATE_MULTISAMPLE:
+ * 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
*
* 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
+ * 1 7
+ * 3 3
+ * 5 0
+ * 7 5
+ * 9 2
+ * b 1
+ * d 4
+ * f 6
*/
static const uint32_t
-brw_multisample_positions_8x[] = { 0xdbb39d79, 0x3ff55117 };
+brw_multisample_positions_8x[] = { 0x53d97b95, 0xf1bf173d };
+
+/**
+ * Sample positions:
+ *
+ * 0 1 2 3 4 5 6 7 8 9 a b c d e f
+ * 0 15
+ * 1 9
+ * 2 10
+ * 3 7
+ * 4 13
+ * 5 1
+ * 6 4
+ * 7 3
+ * 8 12
+ * 9 0
+ * a 2
+ * b 6
+ * c 11
+ * d 5
+ * e 8
+ * f 14
+ */
+static const uint32_t
+brw_multisample_positions_16x[] = {
+ 0xc75a7599, 0xb3dbad36, 0x2c42816e, 0x10eff408
+};
+
+#endif /* BRW_MULTISAMPLE_STATE_H */