X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fmesa%2Fdrivers%2Fdri%2Fi965%2Fbrw_util.h;h=68f4318d37174566f5f7ad5fcb8bbc9bfe1ab4c0;hb=b38fcd0aea8d17919ecd9cc7afc518cfb2c01c27;hp=71a5765825ddcdf6f35b74e32107cb4774b57814;hpb=a7bdd4cba8ddcab8dff59ecaaa7efbd436c6c307;p=mesa.git

diff --git a/src/mesa/drivers/dri/i965/brw_util.h b/src/mesa/drivers/dri/i965/brw_util.h
index 71a5765825d..68f4318d371 100644
--- a/src/mesa/drivers/dri/i965/brw_util.h
+++ b/src/mesa/drivers/dri/i965/brw_util.h
@@ -1,6 +1,6 @@
 /*
  Copyright (C) Intel Corp.  2006.  All Rights Reserved.
- Intel funded Tungsten Graphics (http://www.tungstengraphics.com) to
+ Intel funded Tungsten Graphics to
  develop this 3D driver.
 
  Permission is hereby granted, free of charge, to any person obtaining
@@ -26,7 +26,7 @@
  **********************************************************************/
  /*
   * Authors:
-  *   Keith Whitwell <keith@tungstengraphics.com>
+  *   Keith Whitwell <keithw@vmware.com>
   */
 
 
@@ -35,9 +35,47 @@
 
 #include "main/mtypes.h"
 #include "main/imports.h"
+#include "brw_context.h"
 
 extern GLuint brw_translate_blend_factor( GLenum factor );
 extern GLuint brw_translate_blend_equation( GLenum mode );
 extern GLenum brw_fix_xRGB_alpha(GLenum function);
 
+static inline uint32_t
+brw_get_line_width(struct brw_context *brw)
+{
+   /* From the OpenGL 4.4 spec:
+    *
+    * "The actual width of non-antialiased lines is determined by rounding
+    * the supplied width to the nearest integer, then clamping it to the
+    * implementation-dependent maximum non-antialiased line width."
+    */
+   float line_width =
+      CLAMP(!brw->ctx.Multisample._Enabled && !brw->ctx.Line.SmoothFlag
+            ? roundf(brw->ctx.Line.Width) : brw->ctx.Line.Width,
+            0.0f, brw->ctx.Const.MaxLineWidth);
+   uint32_t line_width_u3_7 = U_FIXED(line_width, 7);
+
+   /* Line width of 0 is not allowed when MSAA enabled */
+   if (brw->ctx.Multisample._Enabled) {
+      if (line_width_u3_7 == 0)
+         line_width_u3_7 = 1;
+   } else if (brw->ctx.Line.SmoothFlag && line_width < 1.5f) {
+      /* 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;
+   }
+
+   return line_width_u3_7;
+}
+
 #endif