# HG changeset patch
# User Rik <rik@octave.org>
# Date 1400448024 25200
# Node ID be8d7721ac16058852e5446f021f593672555cc0
# Parent  ff39ddf84a1972b0132198d5b58f02c69ca81695
Use OpenGL line smoothing when multisample is not available.

* gl-render.cc (opengl_renderer::init_gl_context): Check whether multisample is
enabled and use GL_LINE_SMOOTH if it is not.
* gl-render.cc (opengl_renderer::setup_opengl_transformation).  Remove call to
disable GL_LINE_SMOOTH.
* gl-render.cc (opengl_renderer::draw_axes_children): Remove call to enable
GL_LINE_SMOOTH.
* gl-render.cc (opengl_renderer::draw_axes): Disable GL_LINE_SMOOTH for axes
lines, but re-enable for axes children.

diff -r ff39ddf84a19 -r be8d7721ac16 libinterp/corefcn/gl-render.cc
--- a/libinterp/corefcn/gl-render.cc	Sat May 17 13:17:47 2014 -0700
+++ b/libinterp/corefcn/gl-render.cc	Sun May 18 14:20:24 2014 -0700
@@ -622,7 +622,17 @@
   if (enhanced)
     {
       glEnable (GL_BLEND);
-      glEnable (GL_LINE_SMOOTH);
+      glEnable (GL_MULTISAMPLE);
+      GLint iMultiSample, iNumSamples;
+      glGetIntegerv (GL_SAMPLE_BUFFERS, &iMultiSample);
+      glGetIntegerv (GL_SAMPLES, &iNumSamples);
+      if (iMultiSample != GL_TRUE || iNumSamples == 0)
+        {
+          // MultiSample not implemented.  Use old-style anti-aliasing
+          glDisable (GL_MULTISAMPLE);
+          glEnable (GL_LINE_SMOOTH);
+          glHint (GL_LINE_SMOOTH_HINT, GL_NICEST);
+        }
     }
   else
     {
@@ -817,8 +827,6 @@
 
   glClear (GL_DEPTH_BUFFER_BIT);
 
-  glDisable (GL_LINE_SMOOTH);
-
   // store axes transformation data
 
   xform = props.get_transform ();
@@ -1340,12 +1348,6 @@
 {
   // Children
 
-  GLboolean antialias;
-  glGetBooleanv (GL_LINE_SMOOTH, &antialias);
-
-  if (antialias == GL_TRUE)
-    glEnable (GL_LINE_SMOOTH);
-
   Matrix children = props.get_all_children ();
   std::list<graphics_object> obj_list;
   std::list<graphics_object>::iterator it;
@@ -1429,6 +1431,12 @@
 
   setup_opengl_transformation (props);
 
+  // Disable line smoothing for axes 
+  GLboolean antialias;
+  glGetBooleanv (GL_LINE_SMOOTH, &antialias);
+  if (antialias == GL_TRUE)
+    glDisable (GL_LINE_SMOOTH);
+
   // draw axes object
 
   draw_axes_planes (props);
@@ -1444,6 +1452,10 @@
 
   set_clipbox (x_min, x_max, y_min, y_max, z_min, z_max);
 
+  // Re-enable line smoothing for children
+  if (antialias == GL_TRUE)
+    glEnable (GL_LINE_SMOOTH);
+
   draw_axes_children (props);
 }