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authorMarius Predut <marius.predut@intel.com>2015-04-23 18:41:14 +0300
committerMatt Turner <mattst88@gmail.com>2015-05-05 11:44:37 -0700
commita9b04d8a0d96922a49ac7eb1b91b3a376a959f64 (patch)
tree5775bdaaf665c89f0db9ee95a9d9d626f56c03f7 /src/mesa
parent6da2d7188866ddc8e461004dfae4332071ec3015 (diff)
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i965/aa: fixing anti-aliasing bug for thinnest width lines - GEN6
On SNB and IVB hw, for 1 pixel line thickness or less, the general anti-aliasing algorithm give up - garbage line is generated. Setting a Line Width of 0.0 specifies the rasterization of the “thinnest” (one-pixel-wide), non-antialiased lines. Lines rendered with zero Line Width are rasterized using Grid Intersection Quantization rules as specified by bspec section 6.3.12.1 Zero-Width (Cosmetic) Line Rasterization. v2: Daniel Stone: Fix = used instead of == in an if-statement. v3: Ian Romanick: Use "._Enabled" flag insteed ".Enabled". Add code comments. re-word wrap the commit message. Add a complete bugzillia list. Improve the hardcoded values to produce better results. v4: Matt Turner: typo fixes and adjust <= 1.49 to become < 1.5 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=28832 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=9951 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=27007 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=60797 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=15006 Acked-by: Chris Forbes <chrisf@ijw.co.nz> Acked-by: Kenneth Graunke <kenneth@whitecape.org> Signed-off-by: Marius Predut <marius.predut@intel.com>
Diffstat (limited to 'src/mesa')
-rw-r--r--src/mesa/drivers/dri/i965/gen6_sf_state.c22
1 files changed, 19 insertions, 3 deletions
diff --git a/src/mesa/drivers/dri/i965/gen6_sf_state.c b/src/mesa/drivers/dri/i965/gen6_sf_state.c
index ea5c47a..e445ce2 100644
--- a/src/mesa/drivers/dri/i965/gen6_sf_state.c
+++ b/src/mesa/drivers/dri/i965/gen6_sf_state.c
@@ -367,9 +367,25 @@ upload_sf_state(struct brw_context *brw)
float line_width =
roundf(CLAMP(ctx->Line.Width, 0.0, ctx->Const.MaxLineWidth));
uint32_t line_width_u3_7 = U_FIXED(line_width, 7);
- /* TODO: line width of 0 is not allowed when MSAA enabled */
- if (line_width_u3_7 == 0)
- line_width_u3_7 = 1;
+
+ /* Line width of 0 is not allowed when MSAA enabled */
+ if (ctx->Multisample._Enabled) {
+ if (line_width_u3_7 == 0)
+ line_width_u3_7 = 1;
+ } else if (ctx->Line.SmoothFlag && ctx->Line.Width < 1.5) {
+ /* For 1 pixel line thickness or less, the general
+ * anti-aliasing algorithm gives up, and a garbage line is
+ * generated. Setting a Line Width of 0.0 specifies the
+ * rasterization of the "thinnest" (one-pixel-wide),
+ * non-antialiased lines.
+ *
+ * Lines rendered with zero Line Width are rasterized using
+ * Grid Intersection Quantization rules as specified by
+ * bspec section 6.3.12.1 Zero-Width (Cosmetic) Line
+ * Rasterization.
+ */
+ line_width_u3_7 = 0;
+ }
dw3 |= line_width_u3_7 << GEN6_SF_LINE_WIDTH_SHIFT;
}
if (ctx->Line.SmoothFlag) {