Work around NVIDIA driver issue with glLineWidth(NaN)

gpu/command_buffer/build_gles2_cmd_buffer.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """code generator for GLES2 command buffers."""
 
 import itertools
 import os
 import os.path
@@ skipping 407 matching lines @@
   'LineWidth': {
     'type': 'Normal',
     'func': 'LineWidth',
     'enum': 'GL_LINE_WIDTH',
     'states': [
       {
         'name': 'line_width',
         'type': 'GLfloat',
         'default': '1.0f',
         'range_checks': [{'check': "<= 0.0f", 'test_value': "0.0f"}],
+        # This works around an NVIDIA driver bug, where an INVALID_VALUE error
+        # is generated if line width is set to NaN. The consequences of setting
+        # line width to NaN are undefined, so we just set it to an arbitrary
+        # valid value.
+        'convert_nan': '1.0f',
       }],
   },
   'DepthMask': {
     'type': 'Normal',
     'func': 'DepthMask',
     'enum': 'GL_DEPTH_WRITEMASK',
     'states': [
       {
         'name': 'depth_mask',
         'type': 'GLboolean',
@@ skipping 2905 matching lines @@
     file.Write("  if (%s) {\n" % " ||\n      ".join(code))
     for ndx,item in enumerate(states):
       file.Write("    state_.%s = %s;\n" % (item['name'], args[ndx].name))
     if 'state_flag' in state:
       file.Write("    %s = true;\n" % state['state_flag'])
     if not func.GetInfo("no_gl"):
       for ndx,item in enumerate(states):
         if item.get('cached', False):
           file.Write("    state_.%s = %s;\n" %
                      (CachedStateName(item), args[ndx].name))
+      if 'convert_nan' in item:
+        file.Write('    if (base::IsNaN(%s)) {' % args[ndx].name)
+        file.Write('      %s = %s;' % (args[ndx].name, item['convert_nan']))
+        file.Write('    }\n')
+
       file.Write("    %s(%s);\n" %
                  (func.GetGLFunctionName(), func.MakeOriginalArgString("")))
     file.Write("  }\n")
 
   def WriteServiceUnitTest(self, func, file):
     """Overrriden from TypeHandler."""
     TypeHandler.WriteServiceUnitTest(self, func, file)
     state_name = func.GetInfo('state')
     state = _STATES[state_name]
     states = state['states']
@@ skipping 4242 matching lines @@
           args = []
           for place, item in enumerate(state['states']):
             item_name = CachedStateName(item)
             args.append('%s' % item_name)
             if test_prev:
               if place > 0:
                 file.Write(' ||\n')
               file.Write("(%s != prev_state->%s)" %
                          (item_name, item_name))
           if test_prev:
-            file.Write("    )\n")
+            file.Write("    ) {\n")
+          for place, item in enumerate(state['states']):
+            if 'convert_nan' in item:
+              item_name = CachedStateName(item)
+              args[place] = 'sanitized_%s' % item_name
+              file.Write('  %s %s = %s;' %
+                  (item['type'], args[place], item_name))
+              file.Write('  if (base::IsNaN(%s))' % item_name)
+              file.Write('    %s = %s;' % (args[place], item['convert_nan']))
           file.Write("  gl%s(%s);\n" % (state['func'], ", ".join(args)))
+          if test_prev:
+            file.Write("    }\n")
 
     file.Write("  if (prev_state) {")
     WriteStates(True)
     file.Write("  } else {")
     WriteStates(False)
     file.Write("  }")
 
     file.Write("}\n")
 
     file.Write("""bool ContextState::GetEnabled(GLenum cap) const {
@@ skipping 719 matching lines @@
       "ppapi/shared_impl/ppb_opengles2_shared.cc"])
 
   if gen.errors > 0:
     print "%d errors" % gen.errors
     return 1
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))